Kymera Therapeutics Announces First Quarter 2021 Financial Results and Provides a Business Update Phase 1 trial of first-in-class oral IRAK4 degrader KT-474 initiated in February; on track to present human proof-of-biolo

Kymera Therapeutics Announces First Quarter 2021 Financial Results and Provides a Business Update

Phase 1 trial of first-in-class oral IRAK4 degrader KT-474 initiated in February; on track to present human proof-of-biology data in 4Q 2021

Oncology degrader programs KT-413 and KT-333 expected to enter clinical development in 2H 2021

Watertown, Mass. (May 6, 2021) - Kymera Therapeutics, Inc. (NASDAQ: KYMR), a clinical-stage biopharmaceutical company advancing targeted protein degradation to deliver novel small molecule protein degrader medicines, today reported business highlights and financial results for the first quarter ended March 31, 2021.

"This month marks Kymera's five-year anniversary, going from idea generation to clinical entry, and now towards becoming a fully integrated, best-in-class degrader medicines company," said Nello Mainolfi, PhD, Co-Founder, President and CEO of Kymera Therapeutics. "This year, we have launched the first randomized, placebo-controlled Phase 1 trial with a heterobifunctional degrader in healthy volunteers and patients with immune-inflammatory diseases and are on our way to advancing our two lead degrader programs in oncology into the clinic, while expanding our pipeline of novel protein degraders and continuing to broaden our platform and organizational capabilities."

Program Updates and Milestones

Kymera is discovering and developing novel small molecule therapeutics designed to selectively degrade disease-causing proteins by harnessing the body's own natural protein degradation system, with an initial focus on immune-inflammatory diseases and oncology.

IRAK4 Degrader Program

IRAK4 is a key protein involved in inflammation mediated by the activation of toll-like receptors (TLRs) and IL-1 receptors (IL-1Rs). Aberrant activation of these pathways is the underlying cause of multiple immune-inflammatory conditions. KT-474, a potential first-in-class, orally bioavailable IRAK4 degrader, is being developed for the treatment of TLR/IL-1R-driven immune-inflammatory diseases with high unmet medical need, such as atopic dermatitis, hidradenitis suppurativa, rheumatoid arthritis, and potentially others. KT-474 is designed to block TLR/IL-1R-mediated inflammation more broadly compared to monoclonal antibodies targeting single cytokines, and to enable pathway inhibition that is superior to IRAK4 kinase inhibitors by abolishing both the kinase and scaffolding functions of IRAK4.

Expected Milestones:

IRAKIMiD Degrader Program

IRAKIMiDs are novel heterobifunctional degraders designed to degrade both IRAK4 and IMiD substrates, including Ikaros and Aiolos, with a single small molecule. IRAKIMiDs synergistically target both the MYD88-NFkB and IRF4-Type 1 interferon pathways to enhance and broaden anti-tumor activity in multiple contexts, such as MYD88-mutant diffuse large B-cell lymphoma (DLBCL). KT-413 is being developed initially for the treatment of relapsed/refractory MYD88-mutant DLBCL, with the potential to expand into other MYD88-mutant indications and IL-1R/NFkB-driven malignancies. In preclinical studies, KT-413 has demonstrated a potential first-in-class profile as a targeted therapy for MYD88-mutant DLBCL, including strong single-agent antitumor activity against MYD88-mutant lymphomas in vitro and in mouse xenograft models derived from lymphoma cell lines and patient tumors, which has led to rapid, complete, and sustained tumor regressions. Kymera plans to submit an Investigational New Drug Application (IND) to the FDA and, if cleared, initiate a Phase 1 clinical trial in relapsed/refractory B cell lymphomas, including MYD88-mutant DLBCL, in the second half of 2021.

Expected Milestones:

STAT3 Degrader Program

Kymera is developing selective STAT3 degraders for the treatment of hematological malignancies and solid tumors, as well as autoimmune diseases and fibrosis. STAT3 is a transcription factor activated through a variety of different cytokine and growth factor receptors via Janus kinases (JAKs), as well as through oncogenic fusion proteins and mutations in STAT3 itself. Long considered an undruggable target, STAT3 hyperactivation is prominent in numerous liquid and solid tumors, including clinically aggressive lymphomas. Kymera's potent and selective STAT3 degraders have demonstrated strong anti-tumor effects in mouse xenograft and syngeneic models of liquid and solid tumors.

Expected Milestones:

Platform and Discovery Programs

Kymera is also actively advancing a broad pipeline of preclinical programs across a wide variety of diseases, both internally and in collaboration with existing partners Vertex Pharmaceuticals and Sanofi. The internal programs continue to be focused on undrugged or inadequately drugged nodes within highly validated pathways in immune-inflammatory and oncology indications. Kymera is also developing a new generation of tissue-selective or -restrictive degrader medicines with the goal of drugging an entirely new set of protein targets.

Expected Milestones:

First Quarter 2021 Financial Results

Collaboration Revenues: Collaboration revenues were $18.7 million for the first quarter of 2021, compared to $3.4 million for the same period of 2020. Collaboration revenues include revenue from our Sanofi and Vertex collaborations.

Research and Development Expenses: Research and development expenses were $26.0 million for the first quarter of 2021, compared to $12.1 million for the same period of 2020. This increase was primarily due to expenses related to IND-enabling studies and clinical activities for our IRAK4 and IRAKIMiD programs, lead optimization activities for our STAT3 program, investments in our platform and exploratory programs, the Vertex collaboration, as well as an increase in occupancy and related costs due to continued growth in the research and development organization.

General and Administrative Expenses: General and administrative expenses were $5.9 million for the first quarter of 2021, compared to $2.6 million for the same period of 2020. This increase was primarily due to increases in legal and professional service fees in support of the Company's growth and an increase in personnel, facility, occupancy, and other expenses from an increase in headcount to support growth as a public company.

Net Loss: Net loss was $13.1 million for the first quarter of 2021, compared to a net loss of $10.9 million for the same period of 2020.

Cash and Cash Equivalents: As of March 31, 2021, Kymera had approximately $435.2 million in cash, cash equivalents, and investments. Kymera expects that its cash, cash equivalents, and investments as of December 31, 2020, excluding any future potential milestones from collaborations, will enable the Company to fund its operational plans into 2025 while the Company continues to identify opportunities to accelerate growth and expand its pipeline, technologies, and clinical indications.

About Kymera Therapeutics

Kymera Therapeutics (Nasdaq: KMYR) is a clinical-stage biopharmaceutical company founded with the mission to discover, develop, and commercialize transformative therapies while leading the evolution of targeted protein degradation, a transformative new approach to address previously intractable disease targets. Kymera's Pegasus platform enables the discovery of novel small molecule degraders designed to harness the body's natural protein recycling machinery to degrade disease-causing proteins, with a focus on undrugged nodes in validated pathways currently inaccessible with conventional therapeutics. Kymera's initial programs are IRAK4, IRAKIMiD, and STAT3, which each address high impact targets within the IL-1R/TLR or JAK/STAT pathways, providing the opportunity to treat a broad range of immune-inflammatory diseases, hematologic malignancies, and solid tumors. Kymera's goal is to be a fully integrated biopharmaceutical company at the forefront of this new class of protein degrader medicines, with a pipeline of novel degrader medicines targeting disease-causing proteins that were previously intractable.

Cautionary Note Regarding Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including, without limitation, implied and express statements regarding its: strategy, business plans and objectives for the IRAK4, IRAKIMiD and STAT3 degrader programs; and plans and timelines for the clinical development of Kymera Therapeutics' product candidates, including the therapeutic potential and clinical benefits thereof. The words "may," "might," "will," "could," "would," "should," "expect," "plan," "anticipate," "intend," "believe," "expect," "estimate," "seek," "predict," "future," "project," "potential," "continue," "target" and similar words or expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. Any forward-looking statements in this press release are based on management's current expectations and beliefs and are subject to a number of risks, uncertainties and important factors that may cause actual events or results to differ materially from those expressed or implied by any forward-looking statements contained in this press release, including, without limitation, risks associated with: the impact of COVID-19 on countries or regions in which we have operations or do business, as well as on the timing and anticipated results of our current preclinical studies and future clinical trials, strategy and future operations; the delay of any current preclinical studies or future clinical trials or the development of Kymera Therapeutics' drug candidates; the risk that the results of current preclinical studies may not be predictive of future results in connection with future clinical trials; Kymera Therapeutics' ability to successfully demonstrate the safety and efficacy of its drug candidates; the timing and outcome of the Company's planned interactions with regulatory authorities, including the resolution of the current partial clinical hold for KT-474; and obtaining, maintaining and protecting its intellectual property. These and other risks and uncertainties are described in greater detail in the section entitled "Risk Factors" in the Annual Report on Form 10-Q for the period ended March 31, 2021, expected to be filed on or about May 6, 2021, as well as discussions of potential risks,

uncertainties, and other important factors in Kymera Therapeutics' subsequent filings with the Securities and Exchange Commission. In addition, any forward-looking statements represent Kymera Therapeutics' views only as of today and should not be relied upon as representing its views as of any subsequent date. Kymera Therapeutics explicitly disclaims any obligation to update any forward-looking statements. No representations or warranties (expressed or implied) are made about the accuracy of any such forward-looking statements.

VP, Investor Relations and Communications

Verge Scientific Communications for Kymera Therapeutics

KYMERA THERAPEUTICS, INC.

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CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS

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