Infinity Pharmaceuticals : MEI Pharma and Infinity Pharmaceuticals Merger Announcement

MEI Pharma

MEI Pharma and Infinity Pharmaceuticals

Merger Announcement Webcast

February 23, 2023 at 8:00 a.m. Eastern

CORPORATE PARTICIPANTS

David Walsey - Senior Vice President of Corporate Affairs, MEI Adelene Perkins - Chair and Chief Executive Officer, Infinity Dan Gold - President and Chief Executive Officer, MEI

David Urso - Chief Operating Officer, General Counsel and Head of Corporate Development, MEI

Dr. Robert Ilaria - Chief Medical Officer, Infinity

1

PRESENTATION

Operator

Good day, and welcome to the MEI Pharma and Infinity Pharmaceuticals Merger Announcement Webcast. All participants will be in a listen only mode. And after today's prepared remarks, there will be an opportunity to ask questions. To ask a question, you may press star then one on a touchtone phone. And to withdraw your question, please press star then two. Please note, today's event is being recorded.

I would now like to turn the conference over to David Walsey, Senior Vice President of Corporate Affairs at MEI Pharma. Please go ahead, sir.

David Walsey

Good morning, and thank you for joining the MEI Pharma and Infinity Pharmaceuticals joint conference call today. My name is David Walsey, and I'm Senior Vice President of Corporate Affairs for MEI. With me today on the call from MEI are Dan Gold, President and CEO; David Urso, COO, General Counsel and Head of Corporate Development. From Infinity we're joined by Adelene Perkins, Chair and CEO; and Dr. Robert Ilaria, Chief Medical Officer. Additionally, Brian Drazba, MEI's CFO, is on the call to join in the Q&A as needed.

Before turning the call over to Adelene for opening remarks, I'd like to remind you that during today's call we'll be making some forward-looking statements. Such statements are based on current expectations and assumptions that are subject to risks and uncertainties and involve a number of risk factors that could cause actual results to differ materially from projected results. In particular, statements include but are not limited to, the sufficiency of our cash and cash equivalents to fund operations, the anticipated timing of release of data or clinical trials, our business and operations and our future financial performance and expense levels. Forward-looking statements may include words and phrases such as "we expect, we believe, we intend, we anticipate, we plan, may, likely, upcoming" and similar terms. For a discussion of material risks and other important factors that could affect our actual result, please refer to the accompanying slides as well as those risk factors contained under the heading Risk Factors in the latest 10-Q and 10-K reports followed by MEI and Infinity with the SEC. Actual results may differ materially from today's forward-looking statements, and MEI and Infinity don't assume any obligation or intent to update them except as required by law.

The statements in this discussion do not constitute an offer to sell or the solicitation of an offer to sell or the solicitation of an offer to buy any securities, nor shall there be any sale of securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. No public offer of security shall be made except by means of prospectus meeting the requirements of Section 10 of the Securities Act of 1933, as amended.

This discussion relates to proposed transaction between Infinity and MEI in connection with the proposed merger MEI and Infinity plan to file with the SEC [indiscernible] or otherwise provide to the respective stockholders or joint proxy statement prospectus regarding the proposed merger. Investors and MEI's and Infinity's expected stockholders are urged to read the joint proxy statement prospectus in its entirety when it becomes available and any other documents filed by each of MEI and Infinity with the SEC in connection with the proposed merger or incorporated by reference therein, because they will contain important information about the proposed merger and the parties to the proposed merger.

Investors and stockholders will be able to obtain a free copy of the joint proxy statement prospectus and other documents containing important information about MEI and Infinity once such documents are filed with the SEC from SEC's website at www.sec.gov, MEI and Infinity make available free of charge

MEI Pharma February 23, 2023 at 8:00 a.m. Eastern

2

at www.meipharma.com and www.infi.com respectively, copies of materials they file with or furnish to the SEC. MEI, Infinity and the respective directors, executive officers and certain employees and other persons may be deemed to be participants in the solicitation of proxies from the stockholders of MEI and Infinity in connection with the proposed merger. Security holders may obtain information regarding the names, affiliation and interest of MEI's directors and executive officers in MEI's report on Form 10-K for the fiscal year ended June 30, 2022, which was filed with the SEC on September 8, 2022, and its definitive proxy statement for the 2022 Annual Meeting of stockholders, which was filed with the SEC on October 27, 2022. Security holders may obtain information regarding the names, affiliation and interests of Infinity's directors and executive officers in Infinity's Annual Report on Form 10-K for the fiscal year ended December 31, 2021, which was filed with the SEC on March 29, 2022 and its definitive proxy statement for the 2022 Annual Meeting of stockholders, which was filed with the SEC on April 25, 2022. Additional information regarding the interest of such individuals and the proposed merger will be included in the joint proxy statement prospectus relating to the proposed merger when it is filed with the SEC. These documents, when available, may be obtained free of charge from the SEC's website at www.sec.gov, MEI's investor website, which is www.meipharma.com/investors and Infinity investor website at https://investors.infi.com/.

With that, I'll hand the call over to Adelene to start the discussion.

Adelene Perkins

Thank you, David. The transaction announced earlier today is very attractive for both MEI and Infinity. We have the opportunity to build a great oncology focused company by bringing the best of MEI and Infinity together. MEI brings two attractive, early stage therapeutic development candidates, an experienced team and a strong balance sheet to the combined company. We expect both voruciclib and ME-344 to generate data by the end of 2023, with the potential to demonstrate proof of concept in patients with acute myeloid leukemia for voruciclib and colorectal cancer for ME-344.

MEI was seeking a later stage development candidate, which Infinity brings with eganelisib, a potential first-in-class, PI3 kinase, gamma specific inhibitor designed to reprogram macrophages and reduce immune suppression in the tumor microenvironment as well as an experienced drug development team. The lead and most advanced program for the combined company will be eganelisib. With data supporting multiple paths forward for eganelisib, we prioritized head and neck cancer based on our ability to leverage encouraging progression-free survival data we generated in this patient population in our clinical study called MARIO-1. Unfortunately, people with head and neck cancer have relatively short progression-free survival and overall survival when treated with checkpoint inhibitor monotherapy. Because of that, we prioritize the planned initiation of a randomized controlled Phase 2 clinical study, combining eganelisib with pembrolizumab, or Keytruda, in people with head and neck cancer, as this combination regimen has the potential to demonstrate progression-free survival, and overall survival benefits for patients in a reasonably short period of time. Pending review by the FDA, we plan to start the study in the third quarter of 2023 and expect to have initial safety and progression-free survival data in the second half of 2024.

By merging our companies, we expand and diversify our pipeline with early and late stage therapeutic candidates, leverage our public company infrastructure, build a phenomenal team, and importantly, expect to have cash to fund operations through mid-2025, during which time we expect to generate data on all three programs. Positive data in any of our three programs would support their further development and potential to improve outcomes for patients in their respective settings. In addition, we complement each other really well, not only in the combining of our pipelines, teams and resources, but in our shared commitment to fighting cancer with great science, great people, and a culture that helps them thrive. Leveraging our combined capabilities and resources, we have a truly unique opportunity to build a company with the potential to deliver meaningfully better treatments for patients. And in so doing

MEI Pharma February 23, 2023 at 8:00 a.m. Eastern

3

create meaningful value for shareholders.

I'll now hand the call over to Dan Gold, David Urso and Rob Ilaria, who will share their perspectives on our merger and the potential of our key programs before opening the call up to Q&A. Dan?

Dan Gold

Good morning, everyone, and thank you for joining us today on what is a significant new chapter for MEI and Infinity. I echo Adelene's excitement and vision for the potential that this transaction brings in creating a combined entity which we believe best captures the opportunities that both companies have to offer. Over the course of my career, I've always been attracted to drug candidates backed by strong science with the opportunity to improve patient outcomes in cancer. At MEI, a large part of our development efforts over the years have been directed towards understanding and tackling both direct and indirect resistance mechanisms that cancers use to their advantage. This is evident in MEI's voruciclib and 344 programs. And this is also true for the eganelisib program, which is based on solid science and backed by a promising and extensive set of preclinical and clinical data, making it a logical addition to our drug development efforts.

As a Boston trained immunologist with an emphasis on T cells, I've watched with great excitement the major developments in recent years to harness T cells in the fight against cancer, with agents such as a checkpoint inhibitor. Our next challenge is to broaden the utility of these approaches so that more patients can benefit from these checkpoint inhibitor effects. While attempts by others to identify new stimulatory or regulatory receptors is of great interest, I believe these efforts will be incremental until we tackle a central problem in many solid tumor settings, namely making the tumor microenvironment more hospitable rather than suppressive to effector T cells. Eganelisib has shown evidence of its ability to reprogram the suppressive macrophage tumor microenvironment to a more activating one. In addition, eganelisib has been the subject of several studies in multiple indications when combined with a PD-1 pathway inhibitor, which collectively are indicative of clinical activity. We join Infinity in believing that eganelisib holds significant promise, warranting continued investment.

Leading the combined company will be David Urso. David is currently MEI's Chief Operating Officer and General Counsel. In the coming months, David will transition into the CEO role at MEI and will be prepared to hit the ground running when the merger closes. David joined MEI in 2014, and during this time has exhibited tremendous leadership across the organization. Importantly, he has been my partner in developing and overseeing corporate strategy, while leading our business development efforts. With a science background and over 25 years of experience in the life science industry, serving in many different capacities, I can think of no one better to lead this next chapter for our combined company.

And with that, I'll hand it over to David.

David Urso

Thanks, Dan and Adelene. I appreciate those kind words. I'm excited for the opportunity to lead the combined organization and pursue the potential of all three of our clinical programs, which each have the potential to be transformative for the company and advance the standard of care in the indications we're evaluating. A key point to be underscored is that the pipeline is supported by starting capital of the merged company projected to be about $100 million at closing, which is expected to fund operations through mid-2025. We expect that this funding would enable us to move each of these programs forward in clinical development and to clinical data over the next 12 to 14 months. Also of importance, and particularly attractive from my perspective, is that each of these three clinical stage programs have promising differentiated mechanisms of action targeting indications of high unmet need, and each has existing data showing potential disease activity and mechanistic proof of concept for the combinations being evaluated.

MEI Pharma February 23, 2023 at 8:00 a.m. Eastern

4

The complementary core competencies across the combined team will be critical to the potential success of these programs. This includes significant industry expertise between me, Rob and Stefan, who will serve as CMO and CSO of the combined company respectively, as well as Dan and Adelene's experience, as they will both be joining the board along with the remainder of our new board and the full management team.

Rob joined Infinity as CMO in September of 2021, from BMS and Celgene, where he focused on immune-oncology drug development, including leadership roles on CTLA-4 and PD-1 inhibitor programs. Prior to that he was at Eli Lilly for over 12 years. His experience in drug development, coupled with his familiarity with immune-oncology will continue to be invaluable as we shape the clinical programs and is already evident in the approach we're taking with the planned eganelisib Phase 2 study.

Stefan will serve as Chief Science Officer. Prior to re-joining Infinity in August of 2021, Stefan was at Epson Bioscience as VP, Global Head of Oncology and External Innovation. During his earlier work at Infinity, he held increasing roles and responsibility, ultimately leading the company's early discovery and pipeline expansion efforts to internal R&D and business development. Beyond Dan and Adelene, you can see the composition of the remainder of the board with Norman Selby as chair.

I'm very much looking forward to working with our new team. Already, I've had an opportunity to observe how well the team works together through our joint discussions about the future direction and development plans for the pipeline.

As we've noted, the combined company will have three clinical stage oncology drug candidates in development. We will go into more detail shortly on each program. But as shown on this next slide, each program addresses a clear medical need and represents significant market opportunities. Briefly, eganelisib is expected to be evaluated in combination with Keytruda in controlled Phase 2 clinical study for the potential treatment of head and neck squamous cell cancer carcinoma, starting in the third quarter. Initial safety and PFS data from the planned Phase 2 study is expected in the second half of 2024.

Voruciclib is currently being evaluated in Phase 1b study exploring dose and schedule in patients with AML and B cell malignancies as a single agent, and in combination with venetoclax. The ongoing Phase 1b trial is expected to report top line combination data around year-end.

ME-344 is expected to be evaluated in a Phase 1b trial in combination with Avastin in patients with relapsed colorectal cancer, which is expected to start in the first half of this year. Data from the Phase 1b study to support opening enrollment and an expansion cohort are also expected around the end of this year.

So by the end of next year, our plan calls for eganelisib to have initial safety and PFS data from a Phase 2 trial and for voruciclib and ME-344 to read out data from their respective Phase 1 clinical studies. Pending these studies providing meaningful support for their potential in combination with existing therapies Keytruda, Venclexta and Avastin we have the opportunity to create, with existing capital and resources, a very compelling developmental oncology story in just the next couple of years.

Now, the summary of the proposed transaction. This is an all stock transaction, pursuant to which Infinity stockholders will receive shares of MEI common stock. Infinity will become a wholly-owned subsidiary of MEI Pharma, with outstanding equity ownership post-closing of about 58% being held by MEI stockholders and about 42% being held by Infinity stockholders. The combined company will

MEI Pharma February 23, 2023 at 8:00 a.m. Eastern