This section should be read in conjunction with our unaudited condensed
consolidated financial statements and related notes included in Part I, Item 1
of this Quarterly Report on Form 10-Q and the section contained in our Annual
Report on Form 10-K for the year ended December 31, 2020 under the caption
"Part II-Item 7 - Management's Discussion and Analysis of Financial Condition
and Results of Operations". This discussion contains certain forward-looking
statements, which are often identified by words such as "believe," "anticipate,"
"expect," "intend," "plan," "will," "may," "estimate," "could," "continue,"
"ongoing," "predict," "potential," "likely," "seek" and other similar
expressions, as well as variations or negatives of these words. These statements
relate to our future plans, objectives, expectations, intentions and financial
performance and the assumptions that underlie these statements. These
forward-looking statements include, but are not limited to:

• the expected or potential impact of the ongoing COVID-19 pandemic on our

business, including our commercial sales, ongoing and planned clinical

trials, manufacturing and operations;

• our belief that our proprietary technology platforms and collaborations


          can be used to develop potential therapeutic candidates to treat a broad
          range of diseases;

• our expectation that our partnerships with manufacturers will support

our clinical and commercial manufacturing capacity for our

micro-dystrophin Duchenne muscular dystrophy gene therapy programs and

Limb-girdle muscular dystrophy programs, while also acting as a

manufacturing platform for potential future gene therapy programs, and


          our belief that our current network of manufacturing partners are able
          to fulfil the requirements of our commercial plan;


      •   our plan to continue building out our network for commercial
          distribution in jurisdictions in which our products are approved;

• estimated timelines and milestones for 2021 and beyond, including

discussing with the U.S. Food and Drug Administration ("FDA") the path

for commencing Part B of Study 5051-201 in 2021, announcing additional


          results from Part 2 of Study SRP-9001-102 in the first quarter of 2022,
          initiating our pivotal trial (Study 301) for SRP-9001 in 2021,
          completing GMP runs for SRP-9003 in 2021, and meeting with the FDA in
          2021 to discuss our pivotal trial for SRP-9003;


      •   our plan to expand our pipeline through internal research and
          development and through strategic transactions;


• the timely completion and satisfactory outcome of our post-marketing

requirements and commitments, including verification of a clinical

benefit for our products in confirmatory trials;

• our plan to evaluate future engagement with the European Medicines


          Agency (the "EMA") on potential next steps for EMA approval of our
          products;

• our ability to further secure long-term supply of our commercial

products and our product candidates to satisfy our planned commercial,

early access programs ("EAP") and clinical needs;

• the possible impact of regulations and regulatory decisions by the FDA

and other regulatory agencies on our business, as well as the

development of our product candidates and our financial and contractual

obligations;




      •   the possible impact of any competing products on the commercial success
          of our products and our product candidates and our ability to compete
          against such products;

• our ability to enter into research, development or commercialization

alliances with universities, hospitals, independent research centers,

non-profit organizations, pharmaceutical and biotechnology companies and

other entities for specific molecular targets or selected disease

indications and our ability to selectively pursue opportunities to

access certain intellectual property rights that complement our internal

portfolio through license agreements or other arrangements;

• our expectations regarding the potential benefits of the partnership,


          licensing and/or collaboration arrangements and other strategic
          arrangements and transactions we have entered into or may enter into in
          the future; our plans and ability to file and progress to issue
          additional patent applications to enhance and protect our new and
          existing technologies and programs;

• our estimates regarding how long our currently available cash and cash

equivalents will be sufficient to finance our operations and business

plans and statements about our future capital needs;

• our estimates regarding future revenues, research and development


          expenses, other expenses, capital requirements and payments to third
          parties;


                                       19

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      •   our expectation regarding the impact of environmental laws and
          regulations on our business; and

• our beliefs and expectations regarding milestone, royalty or other

payments that could be due to third parties under existing agreements.




We undertake no obligation to update any of the forward-looking statements
contained in this Quarterly Report on Form 10-Q after the date of this report,
except as required by law or the rules and regulations of the U.S. Securities
and Exchange Commission (the "SEC"). We caution readers not to place undue
reliance on forward-looking statements. Our actual results could differ
materially from those discussed in this Quarterly Report on Form 10-Q. The
forward-looking statements contained in this Quarterly Report on Form 10-Q, and
other written and oral forward-looking statements made by us from time to time,
are subject to certain risks and uncertainties that could cause actual results
to differ materially from those anticipated in the forward-looking statements,
including the risks, uncertainties and assumptions identified under the heading
"Risk Factors" in this Quarterly Report on Form 10-Q.

Overview



We are a commercial-stage biopharmaceutical company focused on helping patients
through the discovery and development of unique RNA-targeted therapeutics, gene
therapy and other genetic therapeutic modalities for the treatment of rare
diseases. Applying our proprietary, highly-differentiated and innovative
technologies, and through collaborations with our strategic partners, we are
developing potential therapeutic candidates for a broad range of diseases and
disorders, including Duchenne muscular dystrophy ("DMD"), Limb-girdle muscular
dystrophies ("LGMDs"), and other neuromuscular and central nervous system
("CNS") related disorders.

We commercialize three products that were approved by the FDA: EXONDYS 51
(eteplirsen) Injection ("EXONDYS 51"), was granted accelerated approval by the
FDA on September 19, 2016. EXONDYS 51 is indicated for the treatment of DMD in
patients who have a confirmed mutation of the DMD gene that is amenable to exon
51 skipping. EXONDYS 51 uses our phosphorodiamidate morpholino oligomer ("PMO")
chemistry and exon-skipping technology to skip exon 51 of the dystrophin gene.
VYONDYS 53 (golodirsen) Injection ("VYONDYS 53"), was granted accelerated
approval by the FDA on December 12, 2019. VYONDYS 53 is indicated for the
treatment of DMD in patients who have a confirmed mutation of the DMD gene that
is amenable to exon 53 skipping. VYONDYS 53 uses our PMO chemistry and
exon-skipping technology to skip exon 53 of the dystrophin gene. AMONDYS 45
(casimersen) Injection ("AMONDYS 45"), was granted accelerated approval by the
FDA on February 25, 2021. AMONDYS 45 is indicated for the treatment of DMD in
patients who have a confirmed mutation of the DMD gene that is amenable to exon
45 skipping. AMONDYS 45 uses our PMO chemistry and exon-skipping technology to
skip exon 45 of the dystrophin gene.

We are in the process of conducting various EXONDYS 51, VYONDYS 53 and AMONDYS
45 clinical trials, including studies that are required to comply with our
post-marketing FDA requirements/commitments to verify and describe the clinical
benefit of these products.

A summary description of our main product candidates, including those in collaboration with our strategic partners, is as follows:



      •   SRP-5051 uses our next-generation chemistry platform, PPMO, and our
          exon-skipping technology to skip exon 51 of the dystrophin gene.
          SRP-5051, a peptide conjugated PMO, is designed to bind to exon 51 of
          dystrophin pre-mRNA, resulting in exclusion of this exon during mRNA
          processing in patients with genetic mutations that are amenable to exon
          51 skipping. Exon skipping is intended to promote the production of an
          internally truncated but functional dystrophin protein. In the fourth
          quarter of 2017, we commenced a first-in-human, single ascending dose,
          study for the treatment of DMD in patients who are amenable to exon 51
          skipping. In 2019, we commenced Study 5051-201. In December 2020, we

announced an interim analysis on clinical results from the 10 mg/kg and

20 mg/kg dose cohorts of Part A of Study 5051-201. In May 2021, we

announced results from the 30 mg/kg cohort of Part A of Study 5051-201.


          We will discuss with the FDA the path for commencing Part B of Study
          5051-201 in 2021.


                                       20

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• SRP-9001 (DMD, micro-dystrophin gene therapy program), aims to express

micro-dystrophin - a smaller but functional version of dystrophin. A

unique, engineered micro-dystrophin is used because naturally-occurring


          dystrophin is too large to fit in an AAV vector. In the fourth quarter
          of 2017, an investigational new drug ("IND") application for the
          micro-dystrophin gene therapy program was cleared by the FDA, and a
          Phase 1/2a clinical trial in individuals with DMD was initiated. In

October 2018, Nationwide Children's Hospital ("Nationwide") presented

results from the Phase 1/2a clinical trial in four individuals with DMD

enrolled in the trial. In March 2019, we presented nine-month functional


          and creatine kinase ("CK") data from baseline from these four
          individuals, and twelve-month CK data from baseline from one of these
          individuals. In June 2020, we announced that functional, safety and
          tolerability data at twelve-months from baseline from these four

individuals had been published in JAMA Neurology. In September 2020, we

presented functional, safety and tolerability data at 24 months from

these four individuals. In the fourth quarter of 2018, we commenced a

randomized, double-blind, placebo-controlled trial of SRP-9001 with the

goal to establish the functional benefits of micro-dystrophin

expressions (Study 102). We have dosed all 41 participants in that trial


          and are dosing participants in the crossover phase of the study. In
          January 2021, we released top-line results for Part 1 of Study 102 (the
          48-week assessment of 41 participants) and interim expression results

from Part 2 of Study 102 (the crossover phase). We expect additional


          results from Part 2 of Study 102 in the first quarter of 2022. We have
          completed dosing in the first cohort in Study 103, an open-label study

evaluating the safety and expression of commercially representative

material for SRP-9001. In May 2021, we announced 12-week expression and


          safety results from the first 11 participants enrolled in Study 103. We
          plan to initiate our pivotal trial (Study 301) in 2021.


      •   SRP-9003 (LGMD, gene therapy program). We are developing gene therapy
          programs for various forms of LGMDs. The most advanced of our LGMD
          product candidates, SRP-9003, is designed to transfer a gene that codes

for and restores beta-sarcoglycan protein with the goal of restoring the


          dystrophin associated protein complex. It utilizes the AAVrh.74 vector
          system, the same vector used in the micro-dystrophin gene therapy
          program. A Phase 1/2a trial of SRP-9003 was commenced in the fourth

quarter of 2018. In February 2019, we announced positive two-month

biopsy data from the first three-patient low-dose cohort dosed in the

SRP-9003 trial, and in October 2019, we announced positive nine-month


          functional data from these three patients. We have recently dosed one
          additional cohort of three patients at a higher dose per the study

protocol. In June 2020, we announced safety and expression results from

three clinical trial participants in the high-dose cohort measured at 60

days, and one-year functional data from three clinical trial

participants in the low-dose cohort. In September 2020, we announced

six-month functional data from three clinical trial participants in the

high-dose cohort, and eighteen-month functional data from three clinical

trial participants in the low-dose cohort. In March 2021, we announced


          24-month functional and expression data from the three clinical trial
          participants in the low-dose cohort and twelve-month functional data

from the three clinical trial participants in the high-dose cohort. We


          expect to complete GMP runs for SRP-9003 in 2021. We also plan to meet
          with the FDA in 2021 to discuss our pivotal trial.


Our pipeline includes more than 40 programs in various stages of pre-clinical
and clinical development, reflecting our multifaceted approach and expertise in
precision genetic medicine to make a profound difference in the lives of
patients suffering from rare diseases.

Manufacturing, Supply and Distribution



We have developed proprietary state-of-the-art Chemistry, Manufacturing and
Controls ("CMC") and manufacturing capabilities that allow synthesis and
purification of our products and product candidates to support both clinical
development as well as commercialization. Our current main focus in
manufacturing is to continue scaling up production of our PMO-based therapies
and optimizing manufacturing for PPMO and gene therapy-based product candidates.
We have entered into certain manufacturing and supply arrangements with
third-party suppliers which will in part utilize these capabilities to support
production of certain of our product candidates and their components. In 2017,
we opened a facility in Andover, Massachusetts, which significantly enhanced our
research and development manufacturing capabilities. However, we currently do
not have internal large-scale Good Manufacturing Practices ("GMP") manufacturing
capabilities to produce our products and product candidates for commercial
and/or clinical use. For our current and future manufacturing needs, we have
entered into supply agreements with specialized contract manufacturing
organizations (each a "CMO") to produce custom raw materials, the active
pharmaceutical ingredients ("APIs"), drug product and finished goods for our
products and product candidates for both commercial and clinical use. All of our
CMO partners have extensive technical expertise, GMP experience and experience
manufacturing our specific technology.

For our commercial DMD program, we have worked with our existing CMOs to
increase product capacity from mid-scale to large-scale. While there are a
limited number of companies that can produce raw materials and APIs in the
quantities and with the quality and purity that we require for our commercial
products, based on our diligence to date, we believe our current network of CMOs
are able to fulfill these requirements, and are capable of expanding capacity as
needed. Additionally, we have, and will

                                       21

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continue to evaluate further relationships with additional suppliers to increase
overall capacity as well as further reduce risks associated with reliance on a
limited number of suppliers for manufacturing.

Our commercial products are distributed in the U.S. through a limited network of
home infusion specialty pharmacy providers that deliver the medication to
patients and a specialty distributor that distributes our products to hospitals
and hospital outpatient clinics. With respect to the pre-commercial distribution
of our products to patients outside of the U.S., we have contracted with third
party distributors and service providers to distribute our products in certain
countries through our EAPs. We plan to continue building out our network for
commercial distribution in jurisdictions in which our products are approved.

Our gene therapy manufacturing capabilities have been greatly enhanced through
partnerships with Thermo Fisher Scientific Inc. ("Thermo"), Catalent, Inc.
("Catalent") and Aldevron LLC ("Aldevron"). We have adopted a hybrid development
and manufacturing strategy in which we are building internal manufacturing
expertise relative to all aspects of AAV-based manufacturing, including gene
therapy and gene editing supply, while closely partnering with first-in-class
manufacturing partners to expedite development and commercialization of our gene
therapy programs. We expect that our partnerships with Thermo and Catalent will
support our clinical and commercial manufacturing capacity for our
micro-dystrophin DMD gene therapy programs and LGMD programs, while also acting
as a manufacturing platform for potential future gene therapy programs. The
collaboration integrates process development, clinical production and testing,
and commercial manufacturing. Aldevron is expected to provide GMP-grade plasmid
for our SRP-9001 micro-dystrophin DMD gene therapy program and LGMD programs, as
well as plasmid source material for future gene therapy programs, such as
Charcot-Marie-Tooth ("CMT") and other neuromuscular and CNS related disorders.

Manufacturers and suppliers of our commercial products and product candidates
are subject to the FDA's current GMP ("cGMP") requirements and other rules and
regulations prescribed by foreign regulatory authorities. We depend on our
third-party partners for continued compliance with cGMP requirements and
applicable foreign standards.

Cash, Cash Equivalents and Investments



As of June 30, 2021, we had approximately $1,736.6 million of cash, cash
equivalents and investments, consisting of $1,697.3 million of cash and cash
equivalents, $30.0 million of short-term investments, and $9.3 million of
long-term restricted cash and investments. We believe that our balance of cash,
cash equivalents and investments is sufficient to fund our current operational
plan for at least the next twelve months.

The likelihood of our long-term success must be considered in light of the
expenses, difficulties and delays frequently encountered in the development and
commercialization of new pharmaceutical products, competitive factors in the
marketplace, the risks associated with government sponsored programs and the
complex regulatory environment in which we operate.

COVID-19 Pandemic



The COVID-19 pandemic has presented a substantial public health and economic
challenge around the world. Our business operations and financial condition and
results have been impacted to varying degrees, and we expect the impact will
continue in future quarters.

We are continuing to assess the potential impact of the COVID-19 pandemic on our
business, operations and financial condition and results. Despite careful
tracking and planning, however, we are unable to accurately predict the extent
of the impact of the pandemic on our business, results of operations and
financial condition due to the uncertainty of future developments. The full
extent to which the COVID-19 pandemic will directly or indirectly impact our
business, results of operations and financial condition will depend on future
developments that are highly uncertain and cannot be accurately predicted,
including new information that may emerge concerning COVID-19, the actions taken
to contain it or treat its impact and the economic impact on local, regional,
national and international markets. For additional information on the various
risks posed by the COVID-19 pandemic, refer to the Risk Factors of this
Quarterly Report on Form 10-Q.

                                       22

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Critical Accounting Policies and Estimates



The discussion and analysis of our financial condition and results of operations
is based upon our unaudited condensed consolidated financial statements included
elsewhere in this report. The preparation of our unaudited condensed
consolidated financial statements in accordance with accounting principles
generally accepted in the U.S. requires us to make estimates and judgments that
affect the reported amounts of assets, liabilities, revenues and expenses and
related disclosure of contingent assets and liabilities for the periods
presented. Some of these judgments can be subjective and complex and,
consequently, actual results may differ from these estimates. We believe that
the estimates and judgments upon which we rely are reasonable based upon
historical experience and information available to us at the time that we make
these estimates and judgments. To the extent there are material differences
between these estimates and actual results, our unaudited condensed consolidated
financial statements will be affected. Although we believe that our judgments
and estimates are appropriate, actual results may differ from these estimates.

We believe the following accounting policies to be the most critical to the judgments and estimates used in the preparation of our unaudited condensed consolidated financial statements:



  • revenue recognition;


  • inventory; and


  • income tax.




Aside from the removal of valuation of product options as a critical accounting
policy as of January 1, 2021, there have been no changes to our critical
accounting policies and significant estimates as detailed in our Annual Report
on Form 10-K for the year ended December 31, 2020.

                                       23

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Results of Operations for the Three and Six Months Ended June 30, 2021 and 2020

The following tables set forth selected unaudited condensed consolidated statements of operations data for each of the periods indicated:





                                            For the Three Months Ended
                                                     June 30,
                                         2021                      2020             Change         Change
                                     (in thousands, except per share amounts)         $               %
Revenues:
Products, net                        $     141,839           $        111,344     $   30,495              27 %
Collaboration                               22,250                     26,019         (3,769 )           (14 )%
Total revenues                             164,089                    137,363         26,726              19 %
Cost and expenses:
Cost of sales (excluding
amortization of in-licensed
rights)                                     19,515                     13,341          6,174              46 %
Research and development                   239,622                    188,522         51,100              27 %
Selling, general and
administrative                              72,347                     73,688         (1,341 )            (2 )%
Amortization of in-licensed rights             179                        165             14               8 %
Total cost and expenses                    331,663                    275,716         55,947              20 %
Operating loss                            (167,574 )                 (138,353 )      (29,221 )            21 %
Other income (loss):
Gain from sale of Priority Review
Voucher                                    102,000                          -        102,000             NM*
Other expense, net                         (16,185 )                  (12,447 )       (3,738 )            30 %
Total other income (loss)                   85,815                    (12,447 )       98,262             NM*

Loss before income tax (benefit)
expense                                    (81,759 )                 (150,800 )       69,041             (46 )%
Income tax (benefit) expense                  (354 )                       20           (374 )           NM*
Net loss                             $     (81,405 )         $       (150,820 )   $   69,415             (46 )%

Net loss per share - basic and
diluted                                      (1.02 )                    (1.93 )   $     0.91             (47 )%


                                             For the Six Months Ended
                                                     June 30,
                                         2021                      2020             Change         Change
                                     (in thousands, except per share amounts)         $               %
Revenues:
Products, net                        $     266,765           $        211,792     $   54,973              26 %
Collaboration                               44,255                     39,245          5,010              13 %
Total revenues                             311,020                    251,037         59,983              24 %
Costs and expenses:
Cost of sales (excluding
amortization of in-licensed
rights)                                     41,861                     25,963         15,898              61 %
Research and development                   434,771                    324,666        110,105              34 %
Selling, general and
administrative                             143,478                    156,456        (12,978 )            (8 )%
Settlement and license charges              10,000                          -         10,000             NM*
Amortization of in-licensed rights             349                        331             18               5 %
Total cost and expenses                    630,459                    507,416        123,043              24 %
Operating loss                            (319,439 )                 (256,379 )      (63,060 )            25 %
Other income (loss):
Gain from sale of Priority Review
Voucher                                    102,000                    108,069         (6,069 )            (6 )%
Other expense, net                         (31,713 )                  (19,867 )      (11,846 )            60 %
Total other income (loss)                   70,287                     88,202        (17,915 )           (20 )%

Loss before income tax (benefit)
expense                                   (249,152 )                 (168,177 )      (80,975 )            48 %
Income tax (benefit) expense                  (497 )                      135           (632 )           NM*
Net loss                             $    (248,655 )         $       (168,312 )   $  (80,343 )            48 %

Net loss per share - basic and
diluted                              $       (3.12 )         $          (2.18 )   $    (0.94 )            43 %




* NM = Not Meaningful


                                       24

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Revenues



Revenues from product sales are recorded at the net sales price (transaction
price), which includes estimates of variable consideration for which reserves
are established and which result from Medicaid rebates, governmental chargebacks
including Public Health Services chargebacks, prompt pay discounts, co-pay
assistance and distribution fees. These reserves are based on the amounts earned
or to be claimed on the related sales and are classified as reductions of
accounts receivable (if no payments are required of us) or a current liability
(if a payment is required of us). Our estimates take into consideration current
contractual and statutory requirements. The amount of variable consideration
included in the transaction price may be constrained and is included in the net
sales price only to the extent that it is probable that a significant reversal
in the amount of the cumulative revenue recognized will not occur in a future
period. Actual amounts of consideration ultimately received or paid may differ
from our estimates. If actual results in the future vary from our estimates, we
will adjust these estimates, which would affect net product revenue and net loss
in the period such variances become known.

Net product revenues for our products for the three and six months ended June
30, 2021 increased by $30.5 million and $55.0 million, respectively, compared
with the three and six months ended June 30, 2020. These increases primarily
reflect increasing demand for our products in the U.S. and the commercial launch
of AMONDYS 45.

Collaboration revenue relates primarily to our collaboration arrangement with F.
Hoffman-La Roche Ltd. For the three and six months ended June 30, 2021, we
recognized $22.3 million and $44.3 million of collaboration revenue,
respectively. For the three and six months ended June 30, 2020, we recognized
$26.0 million and $39.2 million of collaboration revenue, respectively. For more
information, please read Note 3, Collaboration and License Agreements within our
Annual Report on Form 10-K for the year ended December 31, 2020.

Cost of Sales (excluding amortization of in-licensed rights)



Our cost of sales (excluding amortization of in-licensed rights) primarily
consists of royalty payments to BioMarin Pharmaceuticals, Inc. ("BioMarin") and
the University of Western Australia ("UWA"), inventory costs that relate to
sales of our products and the related overhead costs. Prior to receiving
regulatory approval for EXONDYS 51, VYONDYS 53, and AMONDYS 45 by the FDA in
September 2016, December 2019, and February 2021, respectively, we expensed such
manufacturing and material costs as research and development expenses. For
AMONDYS 45 sold in the three and six months ended June 30, 2021, and VYONDYS 53
sold in the three and six months ended June 30, 2020, the majority of related
manufacturing costs incurred had previously been expensed as research and
development expenses, as such costs were incurred prior to the FDA approval of
the products. For VYONDYS 53 sold in the three and six months ended June 30,
2021, and EXONDYS 51 sold in the three and six months ended June 30, 2021 and
2020, only part of the related manufacturing costs incurred had previously been
expensed as research and development expenses. If product related costs had not
previously been expensed as research and development expenses prior to receiving
FDA approval, the incremental inventory costs related to our products sold would
have been approximately $14.2 million and $11.4 million for the six months ended
June 30, 2021 and 2020, respectively.

The following tables summarize the components of our cost of sales for each of
the periods indicated:



                                              For the Three Months Ended
                                                       June 30,
                                               2021                2020           Change         Change
                                                    (in thousands)                   $             %
Inventory costs related to products sold   $      10,309       $       6,288     $   4,021             64 %
Royalty payments                                   9,206               7,053         2,153             31 %
Total cost of sales                        $      19,515       $      13,341     $   6,174             46 %



The cost of sales for the three months ended June 30, 2021 increased by $6.2 million, or 46%, compared with the same period in 2020. The changes were primarily driven by the following:

$4.0 million increase in inventory costs related to products sold
          primarily as a result of increasing demand for our products; and


      •   $2.2 million increase in royalty payments to BioMarin and UWA also
          reflects increasing demand for our products.




                                              For the Six Months Ended
                                                      June 30,
                                               2021               2020          Change         Change
                                                   (in thousands)                  $             %

Inventory costs related to products sold $ 24,638 $ 12,509

   $  12,129             97 %
Royalty payments                                 17,223             13,454         3,769             28 %
Total cost of sales                        $     41,861       $     25,963     $  15,898             61 %




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The cost of sales for the six months ended June 30, 2021 increased by $15.9 million, or 61%, compared with the same period in 2020. The changes were primarily driven by the following:

$12.1 million increase in inventory costs related to products sold
          primarily as a result of increasing demand for our products as well as
          write-offs of certain batches of our products not meeting our quality
          specifications for the six months ended June 30, 2021, with no similar
          activity for the six months ended June 30, 2020; and

$3.8 million increase in royalty payments to BioMarin and UWA reflects

increasing demand for our products.

Research and Development Expenses



Research and development expenses consist of costs associated with research
activities as well as costs associated with our product development efforts,
conducting pre-clinical trials, clinical trials and manufacturing activities.
Direct research and development expenses associated with our programs include
clinical trial site costs, clinical manufacturing costs, costs incurred for
consultants, up-front fees and milestones paid to third parties in connection
with technologies that have not reached technological feasibility and do not
have an alternative future use, and other external services, such as data
management and statistical analysis support, and materials and supplies used in
support of clinical programs. Indirect costs of our clinical programs include
salaries, stock-based compensation and allocation of our facility- and
technology-related costs.

Research and development expenses represent a substantial percentage of our
total operating expenses. We do not maintain or evaluate and, therefore, do not
allocate internal research and development costs on a project-by-project
basis. As a result, a significant portion of our research and development
expenses are not tracked on a project-by-project basis, as the costs may benefit
multiple projects.

The following tables summarize our research and development expenses by project for each of the periods indicated:





                                               For the Three Months Ended
                                                        June 30,
                                                  2021               2020         Change         Change
                                                     (in thousands)                  $             %
Micro-dystrophin                             $       94,236       $   60,279     $  33,957             56 %
Other gene therapies                                 35,995           29,937         6,058             20 %
Up-front and milestone expenses                      31,677           12,750        18,927            148 %
PPMO platform                                        11,407            7,499         3,908             52 %
Eteplirsen (exon 51)                                 10,568            6,325         4,243             67 %
Casimersen (exon 45)                                  6,300           23,991       (17,691 )          (74 )%
Golodirsen (exon 53)                                  5,785            5,219           566             11 %
Collaboration cost-sharing                              578            1,667        (1,089 )          (65 )%
Other projects                                        4,141            1,822         2,319            127 %
Internal research and development expenses           56,960           47,785         9,175             19 %
Roche collaboration reimbursement                   (18,025 )         (8,752 )      (9,273 )          106 %
Total research and development expenses      $      239,622       $  188,522     $  51,100             27 %






                                               For the Six Months Ended
                                                       June 30,
                                                 2021              2020         Change         Change
                                                    (in thousands)                 $             %
Micro-dystrophin                             $     153,609       $ 104,348     $  49,261             47 %
Other gene therapies                                69,950          45,133        24,817             55 %
Up-front, milestone, and other expenses             35,677          21,283        14,394             68 %
PPMO platform                                       20,497          11,027         9,470             86 %
Casimersen (exon 45)                                19,801          33,806       (14,005 )          (41 )%
Golodirsen (exon 53)                                19,279          21,072        (1,793 )           (9 )%
Eteplirsen (exon 51)                                17,078          12,135         4,943             41 %
Collaboration cost-sharing                           6,778           4,309         2,469             57 %
Other projects                                       8,778           2,791         5,987            215 %

Internal research and development expenses 114,477 93,958

       20,519             22 %
Roche collaboration reimbursement                  (31,153 )       (25,196 )      (5,957 )           24 %

Total research and development expenses $ 434,771 $ 324,666

   $ 110,105             34 %






                                       26

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The following tables summarize our research and development expenses by category for each of the periods indicated:





                                              For the Three Months Ended
                                                       June 30,
                                                 2021               2020         Change         Change
                                                    (in thousands)                  $             %
Manufacturing expenses                      $      119,769       $  103,132     $  16,637             16 %
Up-front and milestone expenses                     31,677           12,750        18,927            148 %
Compensation and other personnel expenses           28,697           26,606         2,091              8 %
Clinical trial expenses                             25,978           16,194         9,784             60 %
Facility- and technology-related expenses           16,914           12,883         4,031             31 %
Stock-based compensation                            12,860           11,140         1,720             15 %
Pre-clinical expenses                                5,746            2,586         3,160            122 %
Professional services                                3,168            4,014          (846 )          (21 )%
Collaboration cost-sharing                             578            1,667        (1,089 )          (65 )%
Research and other                                  12,260            6,302         5,958             95 %
Roche collaboration reimbursement                  (18,025 )         (8,752 )      (9,273 )          106 %
Total research and development expenses     $      239,622       $  188,522     $  51,100             27 %





Research and development expenses for the three months ended June 30, 2021 increased by $51.1 million, or 27%, compared with the three months ended June 30, 2020. The increase was primarily driven by the following:

$16.6 million increase in manufacturing expenses primarily due to a
          continuing ramp-up of our gene therapy programs;

$18.9 million increase in up-front and milestone expenses primarily due

to a $28.7 million increase of an accrued sublicense fee to Nationwide


          and a $3.0 million expense incurred as a result of a milestone
          achievement in a research and license agreement during the three months
          ended June 30, 2021, offset by $12.0 million of up-front payments as a

result of the execution of certain research and license agreements

during the same period of 2020;

$2.1 million increase in compensation and other personnel expenses


          primarily due to a net increase in headcount;


      •   $9.8 million increase in clinical trial expenses primarily due to

increased patient enrollment for our ESSENCE and MOMENTUM programs as

well as certain start-up activities for our SRP-9001 micro-dystrophin

program;

$4.0 million increase in facility- and technology-related expenses due

to our continuing expansion efforts;

$1.7 million increase in stock-based compensation expense primarily


          driven by increases in headcount and changes in stock price;


      •   $3.2 million increase in pre-clinical expenses primarily due to an
          increase of toxicology studies in our PPMO platforms;

$1.0 million decrease in collaboration cost sharing with Genethon on its


          micro-dystrophin drug candidate;


      •   $6.0 million increase in research and other primarily driven by an
          increase in sponsored research with academic institutions during the
          three months ended June 30, 2021; and


      •   $9.3 million increase in the offset to expense associated with a

collaboration reimbursement from Roche primarily due to continuing


          development of our SRP-9001 micro-dystrophin gene therapy.


                                       27

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                                              For the Six Months Ended
                                                      June 30,
                                                2021              2020         Change         Change
                                                   (in thousands)                 $             %
Manufacturing expenses                      $     209,090       $ 165,396     $  43,694             26 %

Compensation and other personnel expenses 58,893 52,725

       6,168             12 %
Clinical trial expenses                            54,569          34,750        19,819             57 %
Up-front, milestone, and other expenses            35,677          21,283        14,394             68 %

Facility- and technology-related expenses 34,100 26,134


      7,966             30 %
Stock-based compensation                           23,986          20,389         3,597             18 %
Pre-clinical expenses                              10,982           3,228         7,754            240 %
Collaboration cost-sharing                          6,778           4,309         2,469             57 %
Professional services                               5,816           8,514        (2,698 )          (32 )%
Research and other                                 26,033          13,134        12,899             98 %
Roche collaboration reimbursement                 (31,153 )       (25,196 )      (5,957 )           24 %

Total research and development expenses $ 434,771 $ 324,666

  $ 110,105             34 %



Research and development expenses for the six months ended June 30, 2021 increased by $110.1 million, or 34%, compared with the six months ended June 30, 2020. The increase was primarily driven by the following:

$43.7 million increase in manufacturing expenses primarily due to a

continuing ramp-up of our gene therapy programs;

$6.2 million increase in compensation and other personnel expenses


          primarily due to a net increase in headcount;


      •   $19.8 million increase in clinical trial expenses primarily due to

increased patient enrollment for our ESSENCE and MOMENTUM programs as

well as certain start-up activities for our SRP-9001 micro-dystrophin

program;

$14.4 million increase in up-front, milestone and other expenses

primarily due to a $28.7 million increase of an accrued sublicense fee

to Nationwide and $7.0 million of expense incurred as a result of

milestone achievements in certain research and license agreements during

the six months ended June 30, 2021, offset by $9.3 million of expense

related to sublicense payments accrued to Nationwide and $12.0 million

of up-front payments as a result of the execution of certain research

and license agreements during the same period of 2020;

$8.0 million increase in facility- and technology-related expenses due

to our continuing expansion efforts;

$3.6 million increase in stock-based compensation expense primarily


          driven by increases in headcount and changes in stock price;


      •   $7.8 million increase in pre-clinical expenses primarily due to an
          increase of toxicology studies in our PPMO platforms;

$2.5 million increase in collaboration cost sharing with Genethon on its

micro-dystrophin drug candidate;

$2.7 million decrease in professional service expenses primarily due to


          a decrease in reliance on third-party research and development
          contractors;


      •   $12.9 million increase in research and other primarily driven by an
          increase in sponsored research with academic institutions during the six
          months ended June 30, 2021; and

$6.0 million increase in the offset to expense associated with a

collaboration reimbursement from Roche primarily due to continuing

development of our SRP-9001 micro-dystrophin gene therapy.

Selling, General and Administrative Expenses



Selling, general and administrative expenses consist of salaries, benefits,
stock-based compensation and related costs for personnel in our executive,
finance, legal, information technology, business development, human resources,
commercial and other general and administrative functions. Other general and
administrative expenses include an allocation of our facility- and
technology-related costs and professional fees for legal, consulting and
accounting services.

                                       28

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The following tables summarize selling, general and administrative expenses by category for each of the periods indicated:





                                              For the Three Months Ended
                                                       June 30,
                                               2021                2020           Change         Change
                                                    (in thousands)                   $             %
Compensation and other personnel
expenses                                   $      26,225       $      26,924     $    (699 )           (3 )%
Professional services                             20,039              20,662          (623 )           (3 )%
Stock-based compensation                          16,109              16,476          (367 )           (2 )%
Facility- and technology-related
expenses                                           7,527               7,186           341              5 %
Other                                              2,436               2,599          (163 )           (6 )%
Roche collaboration reimbursement                     11                (159 )         170           (107 )%
Total selling, general and
administrative expenses                    $      72,347       $      73,688     $  (1,341 )           (2 )%




Selling, general and administrative expenses for the three months ended June 30,
2021 decreased by $1.3 million, or 2%, compared with the three months ended June
30, 2020. This was primarily driven by the following:

$0.7 million decrease in compensation and other personnel expenses

primarily due to a change in headcount period over period; and

$0.6 million decrease in professional service expenses primarily due to


          a decrease in reliance on third-party selling, general and
          administrative contractors.




                                             For the Six Months Ended
                                                     June 30,
                                               2021              2020         Change         Change
                                                  (in thousands)                 $             %
Compensation and other personnel
expenses                                   $      54,354       $  53,716     $     638              1 %
Professional services                             35,557          51,786       (16,229 )          (31 )%
Stock-based compensation                          33,491          31,251         2,240              7 %
Facility- and technology-related
expenses                                          14,877          14,236           641              5 %
Other                                              5,422           5,626          (204 )           (4 )%
Roche collaboration reimbursement                   (223 )          (159 )         (64 )           40 %
Total selling, general and
administrative expenses                    $     143,478       $ 156,456     $ (12,978 )           (8 )%




Selling, general and administrative expenses for the six months ended June 30,
2021 decreased by $13.0 million, or 8%, compared with the six months ended June
30, 2020. This was primarily driven by the following:

$16.2 million decrease in professional service expenses primarily due to


          a decrease in reliance on third-party selling, general and
          administrative contractors, as well as a transaction fee for the Roche
          transaction incurred during the six months ended June 30, 2020, with no
          similar activity incurred during the six months ended June 30, 2021; and


      •   $2.2 million increase in stock-based compensation primarily due to
          changes in stock price.

Settlement and License Charges



In February 2021, we recognized a $10.0 million settlement charge related to
contingent settlement payments to BioMarin as a result of the approval of
AMONDYS 45 in the United States. This was a result of a settlement and license
agreement with BioMarin executed in July 2017. There was no such expense
recognized during the same period of 2020.

Amortization of In-licensed Rights



Amortization of in-licensed rights relates to the agreements we entered into
with BioMarin and UWA in July 2017 and April 2011, respectively. We recorded an
in-licensed right asset of approximately $6.6 million in 2017 as a result of the
settlement and license agreements with BioMarin. Additionally, following the
first sale of EXONDYS 51 in September 2016, VYONDYS 53 in December 2019 and
AMONDYS 45 in February 2021, we recorded an in-licensed right asset of $1.0
million, $0.5 million and $0.5 million, respectively, related to the license
agreement with UWA. Each in-licensed right is being amortized on a straight-line
basis over the life of the patent from the first commercial sale of each
product. For both the three months ended June 30, 2021 and 2020, we recorded
amortization of in-licensed rights of approximately $0.2 million. For both the
six months ended June 30, 2021 and 2020, we recorded amortization of in-licensed
rights of approximately $0.3 million.

                                       29

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Other expense, net



Other expense, net, primarily consists of interest income on our cash, cash
equivalents and investments, interest expense on our debt facilities,
amortization of investment discount, and unrealized gain or loss from our
investment in Lysogene. Our cash equivalents and investments consist of money
market funds, government and government agency debt securities, and certificates
of deposit. Interest expense includes interest accrued on our convertible notes
and term loan.

For the three and six months ended June 30, 2021, other expense, net, increased
by approximately $3.7 million and $11.8 million compared with the three and six
months ended June 30, 2020. The increase primarily reflected an increase in
interest expense incurred on our term loan debt facilities due to an increase in
the outstanding balance partially offset by a reduction of interest expense
incurred on our convertible debt related to the adoption of ASU 2020-06, as well
as a decrease in interest income and the amortization of investment discounts
due to the investment mix of the Company's investment portfolio. As a result of
the adoption of ASU 2020-06, interest expense was reduced by $5.5 million and
$11.0 million for the three and six months ended June 30, 2021, respectively.

Gain from sale of Priority Review Voucher



In February 2021, we entered into an agreement to sell the rare pediatric
disease Priority Review Voucher ("PRV") we received from the FDA in connection
with the approval of AMONDYS 45. Following the termination of the applicable
waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976,
as amended, in April 2021, we completed our sale of the PRV and received
proceeds of $102.0 million, with no commission costs, which was recorded as a
gain from sale of the PRV as it did not have a carrying value at the time of the
sale.

In February 2020, we entered into an agreement to sell the rare pediatric
disease PRV we received from the FDA in connection with the approval of VYONDYS
53. Following the early termination of the applicable waiting period under the
Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, in March 2020,
we completed our sale of the PRV and received proceeds of $108.1 million, net of
commission, which was recorded as a gain from sale of the PRV as it did not have
a carrying value at the time of the sale.

Income tax (benefit) expense



Income tax benefit for the three and six months ended June 30, 2021 was
approximately $0.4 million and $0.5 million, respectively. Income tax expense
for the three and six months ended June 30, 2020 was less than $0.1 million and
approximately $0.1 million, respectively. Income tax (benefit) expense for all
periods presented relates to state taxes.



Liquidity and Capital Resources



The following table summarizes our financial condition for each of the periods
indicated:



                                                  As of            As of
                                                June 30,        December 31,
                                                  2021              2020            Change         Change
                                                       (in thousands)                 $              %
Financial assets:
Cash and cash equivalents                      $ 1,697,275     $    1,502,648     $  194,627             13 %
Short-term investments                              30,000            435,923       (405,923 )          (93 )%
Restricted cash and investments                      9,315              9,315              -             (- )%
Total cash, cash equivalents and investments   $ 1,736,590     $    1,947,886     $ (211,296 )          (11 )%

Borrowings:
Term loan                                      $   530,376     $      527,731     $    2,645              1 %
Convertible debt                                   562,609            464,762         97,847             21 %
Total borrowings                               $ 1,092,985     $      992,493     $  100,492             10 %

Working capital
Current assets                                 $ 2,265,217     $    2,485,196     $ (219,979 )           (9 )%
Current liabilities                                425,022            416,026          8,996              2 %
Total working capital                          $ 1,840,195     $    2,069,170     $ (228,975 )          (11 )%






                                       30

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For the periods ended June 30, 2021 and December 31, 2020, our principal sources
of liquidity were primarily derived from our collaboration arrangement with
Roche, net proceeds from sale of the PRV, product sales of our products and net
proceeds for debt financing. Our principal uses of cash are research and
development expenses, selling, general and administrative expenses, investments,
capital expenditures, business development transactions and other working
capital requirements. The changes in our total borrowings reflect the adoption
of ASU 2020-06 as of January 1, 2021, which resulted in the convertible debt
being accounted for as a single liability measured at its amortized cost. For
more information on the adoption and impact of ASU 2020-06, please read Note 11,
Indebtedness. The changes in our working capital primarily reflect use of cash
in operating activities.

Our future expenditures and capital requirements may be substantial and will depend on many factors, including but not limited to the following:

• our ability to continue to generate revenues from sales of EXONDYS 51,


          VYONDYS 53, AMONDYS 45 and potential future products;


  • the timing and costs associated with our expansion efforts;


  • the timing and costs of building out our manufacturing capabilities;


      •   the timing of advanced payments related to our future inventory
          commitments and manufacturing obligations;


      •   the timing and costs associated with our clinical trials and
          pre-clinical trials;

• the attainment of milestones and our obligations to make milestone


          payments to Myonexus' selling shareholders StrideBio, BioMarin,
          Lysogene, Lacerta, Nationwide, UWA and other institutions;


  • repayment of outstanding debt; and

• the costs of filing, prosecuting, defending and enforcing patent claims

and our other intellectual property rights.




Our cash requirements are expected to continue to increase as we advance our
research, development and commercialization programs and we expect to seek
additional financings primarily from, but not limited to, the sale and issuance
of equity, debt financing, the licensing or sale of our technologies or
additional government contracts. We cannot provide assurances that financing
will be available when and as needed or that, if available, the financings will
be on favorable or acceptable terms. If we are unable to obtain additional
financing when and if we require, this would have a material adverse effect on
our business and results of operations. To the extent we issue additional equity
securities, our existing stockholders could experience substantial dilution.

Cash Flows



                                            For the Six Months Ended
                                                    June 30,
                                               2021             2020          Change         Change
                                                 (in thousands)                 $              %
Cash (used in) provided by
Operating activities                      $     (289,517 )    $ 520,187     $ (809,704 )         (156 )%
Investing activities                             477,725        (51,905 )      529,630            NM*
Financing activities                               6,419        336,597    

(330,178 ) (98 )% Increase in cash and cash equivalents $ 194,627 $ 804,879 $ (610,252 ) (76 )%






* NM = Not Meaningful




Operating Activities

Cash used in operating activities was $289.5 million for the six months ended
June 30, 2021. Cash provided by operating activities for the six months ended
June 30, 2020 was $520.2 million. The unfavorable change was primarily driven by
the following items:

$74.3 million increase in net loss, excluding the gain from the sale of

the PRV, primarily driven by an increase in research and development

expense, offset by increases in net product revenues and collaboration


          revenue and a decrease in selling, general and administrative expense;
          and


                                       31

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$838.7 million decrease in the change in deferred revenue primarily as a

result of the collaboration arrangement with Roche being executed during

the six months ended June 30, 2020, with no similar activity during the

six months ended June 30, 2021.

The decreases were partially offset by:

$8.7 million net increase in non-cash adjustments; and

$94.6 million net increase in use of operating assets and liabilities,

excluding deferred revenue.

Investing Activities



Cash provided by investing activities was $477.7 million for the six months
ended June 30, 2021. Cash used in investing activities was $51.9 million for the
six months ended June 30, 2020. The favorable change was primarily driven by the
following:

$726.7 million decrease in purchase of available-for-sale securities

during the six months ended June 30, 2021; and

$1.2 million decrease in purchase of property and equipment during the

six months ended June 30, 2021.

The changes were partially offset by:

$191.0 million decrease in proceeds from the sale or maturity of

available-for-sale securities during the six months ended June 30, 2021;

and

$6.1 million decrease in net proceeds from the sale of the PRV during

the six months ended June 30, 2021.

Financing Activities



Cash provided by financing activities decreased by $330.2 million for the six
months ended June 30, 2021 compared with the six months ended June 30, 2020,
primarily driven by the following:

$312.1 million decrease in net proceeds from the issuance of common

stock to Roche;

$16.6 million decrease in proceeds from the exercise of options and the

purchase of stock under our Employee Stock Purchase Program; and

$1.5 million increase in taxes paid related to net share settlement of

equity awards.

Off-Balance Sheet Arrangements



During the periods presented, we did not have any relationships with
unconsolidated entities or financial partnerships, such as entities often
referred to as structured finance or special purpose entities, which would have
been established for the purpose of facilitating off-balance sheet arrangements
or for another contractually narrow or limited purpose.

Contractual Payment Obligations



In our continuing operations, we have entered into long-term contractual
arrangements from time to time for our facilities, the provision of goods and
services, and acquisition of technology access rights, among others. The
following table presents contractual obligations arising from these arrangements
as of June 30, 2021:



                                                                 Payment Due by Period
                                                      Less Than                                         More than
                                         Total          1 Year        1 - 3 Years      3 - 5 Years       5 Years
                                                                     (in thousands)
Debt obligations (1)                  $ 1,292,817     $   55,949     $     350,636     $    886,232     $        -
Lease obligations (2)                      52,892         13,445            24,077           15,370              -
Manufacturing obligations (3)           1,429,765        695,688           360,673          193,723        179,681
Total contractual obligations and
contingencies                         $ 2,775,474     $  765,082     $     735,386     $  1,095,325     $  179,681




(1) Interest is included.

(2) Lease obligations only include real estate leases. The leases embedded in

certain supply agreements are included in the manufacturing obligations.




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(3) Manufacturing obligations include agreements to purchase goods and services

that are enforceable and legally binding or subject to cancellation fees and

that specify all significant terms. Manufacturing obligations relate

primarily to our commercialization of EXONDYS 51, VYONDYS 53 and AMONDYS 45,

and clinical programs for DMD as well as our gene therapy programs.

Milestone Obligations



For product candidates that are currently in various research and development
stages, we may be obligated to make up to $3.9 billion of future development,
regulatory, commercial and up-front royalty and sales milestone payments
associated with our license and collaboration agreements. Payments under these
agreements generally become due and payable upon achievement of certain
development, regulatory or commercial milestones. Because the achievement of
these milestones is not probable, and payment is not required as of June 30,
2021, such contingencies have not been recorded in our unaudited condensed
consolidated financial statements. Amounts related to contingent milestone
payments are not yet considered contractual obligations as they are contingent
on the successful achievement of certain development, regulatory approval and
sales milestones.

Recent Accounting Pronouncements

For additional information, please read Note 2, Summary of Significant Accounting Policies and Recent Accounting Pronouncements of the unaudited condensed consolidated financial statements contained in Part I, Item 1 of this Quarterly Report on Form 10-Q.

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