Phathom Pharmaceuticals : Corporate Overview – April 2024

CORPORATE OVERVIEW

March 2024

Safe harbor statement

This presentation contains forward-looking statements. All statements other than statements of historical facts contained in this presentation, including statements regarding our future results of operations and financial position, anticipated milestones, anticipated cash runway, expectations of generating stability data necessary to support the proposed shelf life of vonoprazan, business strategy, prospective products, product approvals, research and development costs, timing and likelihood of success, plans and objectives of management for future operations, and future results of current and anticipated products, are forward-looking statements.

In some cases, you can identify forward-looking statements by terms such as "may," "will," "should," "expect," "plan," "anticipate," "could," "intend," "target," "project," "contemplates," "believes," "estimates," "predicts," "potential" or "continue" or the negative of these terms or other similar expressions. These statements involve known and unknown risks, uncertainties and other important factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements. These risks, uncertainties and other factors include, without limitation: our ability to launch and successfully commercialize approved products containing vonoprazan; our new drug application for non-erosive GERD may not be approved by the FDA; our Phase 3 trial for as need dosing of vonoprazan for non- erosive GERD may not successfully be completed; the inherent risks of clinical development of vonoprazan; our dependence on third parties in connection with product manufacturing, research and preclinical and clinical testing; regulatory developments in the United States and foreign countries; unexpected adverse side effects or inadequate efficacy of vonoprazan that may limit its development, regulatory approval and/or commercialization, or may result in recalls or product liability claims; our ability to obtain and maintain intellectual property protection for vonoprazan; our ability to comply with our license agreement with Takeda; our ability to achieve and maintain adequate levels of coverage and reimbursement for vonoprazan; the availability of additional funds under our revenue interest financing agreement and term loan agreement; the sufficiency of our capital to fund our operations; and other risks described in our filings with the Securities and Exchange Commission (SEC), including our Annual Report on Form 10-K and any subsequent filings with the SEC. You are cautioned to place undue reliance on these forward-looking statements, which speak only as of the date hereof, and we undertake no obligation to revise or update this presentation to reflect events or circumstances after the date hereof. All forward-looking statements are qualified in their entirety by this cautionary statement, which is made under the safe harbor provisions of the Private Securities Litigation Reform Act of 1995.

This presentation also contains estimates and other statistical data made by independent parties and by us relating to market size and other data about our industry. This data involves a number of assumptions and limitations, and you are cautioned not to give undue weight to such estimates. In addition, projections, assumptions, and estimates of our future performance and the future performance of the markets in which we operate are necessarily subject to a high degree of uncertainty and risk.

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VOQUEZNA®:

First innovative acid-suppressant from a new drug class in the US in over 30 years

Going beyond

to advance treatments for patients with acid related disorders

Belongs to a novel class of therapies called PCABs (Potassium Competitive Acid Blockers)

• First and only approved PCAB in the US
• US FDA approval for the treatment of Erosive GERD and H. pylori in adults
• VOQUEZNA launch underway

• Commercial product available as of 4Q 2023
• Potential to displace PPIs
• Large market opportunity

			Approved in numerous countries
		US / Europe /	in Asia & Latin America, including:
		Japan, China,
Locations	Formed In 2019	Canada rights
HQ: Florham Park, NJ	Listed on NASDAQ:	licensed from	Brazil, & Russia
Buffalo Grove, IL	PHAT	Takeda
FDA APPROVED PRODUCTS

~$850M

Annual net sales in Japan. Achieving market leadership of 60% revenue-based market share1

	1 US dollars based on conversion rate of 0.0090 dollars to one yen. Annual net sales figure reflects the twelve-months ended Dec. 31, 2021.
3	Revenue-based market share reflects the three-months ended June 30, 2023.

Commercial success of acid suppression treatments

ANTACIDS

H2 ANTAGONISTS

PPIs

PCAB

Introduced in Japan

2015

Marketed

OTC

Japan

Revenue-

Based Market

Share1

25 YEARS

No Innovation

~$3.5b	~$12.5B
peak US sales	peak US sales

70%

60%

50% Generics

40%

30%

20%

10%

0%

2015

2016

2017

2018

2019

2020

2021

2022

2023

(vonoprazan)

>$850M annual

net sales in Japan1

Vonoprazan has been highly successful in Japan

Driven predominantly by volumetric gains from generic competitors

Branded premium price

Majority of vonoprazan sales are in

GERD

1	US dollars based on conversion rate of 0.0090 dollars to one yen. Annual net sales figure reflects the twelve-months ended Dec. 31, 2021. Revenue-based market share reflects the three-months ended June 30, 2023.
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Vonoprazan demonstrated improved acid control versus PREVACID (lansoprazole) in a Phase 1 study

RAPID, POTENT, DURABLE ACID SUPPRESSION*

	Day 1	TIME ABOVE
7.0		pH 4.0 (%)
6.0		Vonoprazan
		20 mg
5.0		62%	88%
4.0		PREVACID
pH		(lansoprazole) 30 mg
3.0		23%	42%
2.0		Baseline
1.0		4%	4%
0.0

0	6	12	18	24	0
				Interval end time from dosing (hr)

Day 7

6		12		18		24

Mean gastric pH profiles for vonoprazan were higher than PREVACID (lansoprazole) on both Days 1 and 7

5	* VONO-103: Mean 0-24 hour gastric pH profiles; study evaluating the PK, PD, safety and tolerability of vonoprazan in comparison to PREVACID (lansoprazole) in 41 healthy adult subjects (out of 44 total subjects enrolled)

Mechanistic differences between PPIs and PCABs

PPI:VOQUEZNA:

COVALENTLY BINDING PRODRUG

COMPETITIVE ENZYME INHIBITOR

Secretory

canaliculus

Secretory

canaliculus

Quiescent phase	Active phase after meal
Tubulovesicle	Proton pump (H+, K+ -ATPase)

Quiescent phase	Active phase after meal
	Tubulovesicle	Proton pump (H+, K+ -ATPase)

• Short plasma half-life
• Acid needed for activation but unstable in presence of acid
• Meal required to stimulate pumps

Slow onset of action

Limited potency

Limited duration of activity

• Long plasma half-life
• Stable in acid
• High accumulation in canaliculus
• Very slow dissociation rate

Rapid onset of action

Potent acid control

Durable 24-hr activity

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Three approved products across two indications, with more anticipated

NOW APPROVED & COMMERCIALLY AVAILABLE

Non-Erosive GERD

EoE

Target indications	Phase 11	Phase 21	Phase 3	Milestones
						PDUFA target action date:
Daily dosing treatment of heartburn						July 19, 2024
associated with Non-Erosive GERD						Targeting US
						Launch in 3Q 2024
As Needed treatment of heartburn						Positive Phase 2 results
					Phase 3 trial initiation
associated with Non-Erosive GERD
						anticipated in 2024

Treatment of eosinophilic esophagitis			Phase 2 trial initiation
(EoE) for adult & pediatric use			anticipated in 2024

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1 Phase 1 and 2 studies supporting applications for Erosive GERD and H. pylori were conducted by Takeda; Phathom has development & commercialization rights to vonoprazan in the US, Europe, & Canada

VOQUEZNA vision builds on each targeted indication with the potential to transform the landscape of acid-related disorders

Targeting US Daily	Phase 3 As Needed
dosing launch	trial initiation
in 3Q 20241	anticipated in 2024

Goal:

Displace PPIs

GERD	Non-Erosive GERD	Non-Erosive GERD
(or non-erosive reflux	(or non-erosive reflux
	disease / NERD)	disease / NERD)
	Daily dosing	As Needed (or on-demand)dosing
	Symptom control	Symptom relief

Erosive GERD

(or erosive esophagitis / EE)

Improved healing and maintenance

1. pylori
   (or HP)

Increased eradication

Launch Sequence:

Combined First Launch

Second Launch

Third Launch

~45M

people

~20M

people

~2M

people

Growth opportunity

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1 Pending FDA approval.

VOQUEZNA is now the FIRST AND ONLY FDA APPROVED PCAB in the US

Commercial product NOW AVAILABLE

VOQUEZNA is indicated for the

healing and maintenance of healing of all grades of erosive esophagitis and relief of heartburn in adults.

VOQUEZNA is a novel, first-in-class,potassium-competitive acid blocker (PCAB) and the first innovative

acid suppressant from a new drug class approved in the US in over 30 years.

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Erosive GERD label includes multiple superiority claims

Healing

Maintenance of Healing

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