Quince Therapeutics : Investor Presentation – November 2023

Leveraging a patient's own biology to deliver rare disease therapeutics

Investor Presentation

November 2023

Forward-looking statements

Statements in this presentation contain "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995 as contained in Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, which are subject to the "safe harbor" created by those sections. All statements, other than statements of historical facts, may be forward-looking statements. Forward-looking statements contained in this presentation may be identified by the use of words such as "believe," "may," "should," "expect," "anticipate," "plan," "believe," "estimated," "potential," "intend," "will," "can," "seek," or other similar words. Examples of forward-looking statements include, among others, statements relating to the expected benefits of the current and future clinical development and potential expansion of EryDel assets, related platform, and related timing and costs; the strategic development path for EryDex; planned regulatory agency submissions and clinical trials and timeline, prospects, and milestone expectations; the timing and success of the clinical trials and related data, including plans and the ability to initiate, fund, conduct and/or complete current and additional studies; the potential therapeutic benefits, safety, and efficacy of EryDex; statements about its ability to obtain, and the timing relating to, further development of EryDex; therapeutic and commercial potential; the integration of EryDel's business, operations, and employees into Quince; Quince's future development plans and related timing; its cash position and projected cash runway; the company's focus, objectives, plans, and strategies; the company's market opportunities; and the ability to execute on any strategic transactions. Forward-looking statements are based on Quince's current expectations and are subject to inherent uncertainties, risks, and assumptions that are difficult to predict and could cause actual results to differ materially from what the company expects. Further, certain forward-looking statements are based on assumptions as to future events that may not prove to be accurate. Factors that could cause actual results to differ include, but are not limited to, the risks and uncertainties described in the section titled "Risk Factors" in the company's Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission (SEC) on August 3, 2023, and other reports as filed with the SEC. Forward-looking statements contained in this presentation are made as of this date, and Quince undertakes no duty to update such information except as required under applicable law.

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Unlocking the power of a patient's own biology

to deliver innovative and life-changing therapeutics to those living with rare diseases

Our Difference

Highly differentiated and proprietary drug delivery technology platform designed to optimize biodistribution and pharmacokinetics of therapeutic by using patient's own red blood cells to deliver sustained therapy

Our Focus

Advancing Phase 3 lead asset EryDex for potential treatment of Ataxia-Telangiectasia(A-T) with no currently approved treatments and $1+ billion estimated peak sales opportunity globally

Our Potential

Well-capitalized into 2026 with ability to fully fund EryDex through Phase 3 trial to NDA submission, assuming positive study results

Note: $1+ billion estimated global peak sales opportunity is based on company's internal projections

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Highly differentiated and proprietary AIDE technology platform

A

I

D

E

Autologous

Intracellular

Drug

Encapsulation

Designed to optimize biodistribution and pharmacokinetics of therapeutic by using patient's own red blood cells to deliver sustained therapy

Unique drug/device combination fully automated process completed in two-hour treatment administered at point-of-care

Flexible technology designed to deliver wide range of therapeutics from small to large molecules, as well as biologics - with minimal CMC costs

Strong patent protections with IP exclusivity until at least 2034 globally and 2035 in the U.S.

20+ years of research & development and $100 million invested in

AIDE technology creates high barriers to entry

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AIDE technology hypothesis for Phase 3 lead asset EryDex

Therapeutic encapsulated in patient's own red blood cells through AIDE process

Designed to mitigate chronic toxicity and allow long-term use of dexamethasone sodium phosphate (DSP; a pro-drug) for potential A-T therapy

+

AIDE process results in encapsulated pro-drug and then re-infused into patient

Designed to fundamentally alter therapeutic's

biodistribution and pharmacokinetics to allow for sustained therapy with demonstrated efficacy and safety profile

Studies show demonstrated efficacy signals and ability to treat A-T patients with steroids for years without significant safety issues

Evidence of clinical response signals across multiple diseases for potential expansion to additional disease indications

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No currently approved treatments for A-T patients

A-T is an inherited rare neurodegenerative and immunodeficiency disorder caused by mutations in ATM gene

Approximately 10,000 A-T patients in U.S., U.K., and EU4 countries

Neurological symptoms worsen until patients are wheelchair dependent, usually by age 12- with teenage years typically marked by pulmonary impairment and malignancies

Median lifespan of approximately 25-30 years

Currently no approved treatments for A-T and no known effective approaches to delay progression of disease

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EryDex efficacy and safety profile demonstrated in	EryDex
prior ATTeST clinical trial
ATTeST Trial

EryDex consistent and			ATTeST ICARS Values in ITT Population
							FDA Endpoint
statistically significant effect
		ICARS		mICARS		RmICARS
in 6 to 9 year-old subgroup
	0
across multiple endpoints	Placebovs.
-3
demonstrated EryDex
		-1
12-month safety analysis		-2
well-tolerated with no	Improvement							P=0.009
-7	P=0.020
from ATTeST to next
major adverse events		-4						Phase 3 NEAT
		-5			P=0.002	Primary Endpoint
Apply key learnings		-6
confirmatory NEAT study					All Ages (n=58)		6-9 Years (n=33)

Note: Values reflect Least Square Means (LSM) difference from placebo and the P value presented • ICARS = International Cooperative Ataxia Rating Scale • mICARS = Modified International Cooperative Ataxia Rating	7
Scale • RmICARS = Rescored Modified International Cooperative Ataxia Rating Scale

Pivotal Phase 3 NEAT study design

Pivotal study to be conducted under Special Protocol Assessment (SPA) agreed with FDA

Allows for NDA submission, assuming positive results, following a single global Phase 3 NEAT study

Double-blind, randomized, placebo-controlled study with 6-month treatment period

Plan to enroll first patient in global Phase 3 NEAT clinical trial of EryDex in second quarter 2024

Plan to enroll approximately of 86 A-T patients ranging in age from 6 to 9 years-old

Addition of approximately 20 patients aged 10 or over to be included

Eligible patients will be offered the opportunity to participate in open label extension (OLE) following trial completion

Primary endpoint - RmICARS (FDA)

Plan to collect mICARS (EMA) data as supporting data

Screening

~ 86 Patients

	Baseline visit	Six month treatment period	Study completion visit	Safety follow up visit
			EryDex		Safety follow up
			Placebo		Safety follow up

Note: RmICARS = Rescored Modified International Cooperative Ataxia Rating Scale • mICARS = Modified International Cooperative Ataxia Rating Scale

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Attractive commercial opportunity for EryDex lead indication

$1+ billion

estimated global

peak sales opportunity for A-T indication alone

EryDex for A-T

Approximately 10,000 A-T patients suffering from A-T in U.S., U.K., and EU4 countries with no currently approved A-T therapies

First-to-market potential with no known late-stagecompetition andgranted orphan drug designation for the treatment of A-T from FDA and EMA

Attractive rare disease pricing comparables with recently approved treatment for ataxia indication

Highly scalable manufacturing infrastructure in place with low cost of goods - less than 1% of comparable rare disease pricing

Strong patent & EU/US orphan drug designation protections with IP exclusivity until at least 2034 globally and 2035 in the U.S.

Note: $1+ billion estimated global peak sales opportunity is based on company's internal projections

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Expansion potential of EryDex and AIDE technology into additional rare disease indications

EryDex

A Autologous

I Intracellular

D Drug

E Encapsulation

EryDex for indications beyond A-T

Plans to investigate additional indications for EryDex where chronic steroid treatment is - or has the potential to be - a standard of care

Evaluating clinical trial opportunities for potential additional rare disease indications

Rare and debilitating disease expansion potential

Flexible technology designed to deliver range of therapeutics - from small to large molecules, as well as biologics

Evaluation of additional potential applications of the AIDE technology platform for rare and debilitating disease indications already underway

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