The issued patent provides intellectual property protection for ERAS-4001 and related compositions until at least 2043

Expands Erasca's diversified IP portfolio for RAS-driven cancers

Initial Phase 1 monotherapy data expected for ERAS-0015 in 1H and for ERAS-4001 in 2H 2026

SAN DIEGO, Feb. 24, 2026 (GLOBE NEWSWIRE) -- Erasca, Inc. (NASDAQ:ERAS), a clinical-stage precision oncology company singularly focused on discovering, developing, and commercializing therapies for patients with RAS/MAPK pathway-driven cancers, today announced that the U.S. Patent and Trademark Office has issued Patent No. 12,552,813, titled "Heterocyclic Substituted Pyrimidopyran Compound And Use Thereof." The patent claims protect the composition of matter for Erasca's potentially first-in-class pan-KRAS inhibitor ERAS-4001 and related compositions until June 2043, which may be subject to patent term adjustments or extensions affording even later protection.

"This newly issued U.S. patent strengthens our ERAS-4001 program, builds on the momentum of our RAS franchise which includes our potential first-in-class pan-KRAS inhibitor ERAS-4001 and our potential best-in-class pan-RAS molecular glue ERAS-0015, and advances our diversified intellectual property (IP) strategy in RAS-driven cancers," said Jonathan E. Lim, M.D., Erasca's chairman, CEO, and co-founder. "With patent protection extending through at least 2043, the ERAS-4001 program is supported by a robust, long-term IP foundation, with additional patents pending. As both RAS-targeting molecules continue to advance rapidly in the clinic, we look forward to reporting Phase 1 data for ERAS-0015 in the first half of the year and for ERAS-4001 in the second half of the year."

About ERAS-4001

ERAS-4001 is an oral, highly potent, and selective pan-KRAS inhibitor with a potential first-in-class and best-in-class profile. Erasca is evaluating ERAS-4001 in the BOREALIS-1 Phase 1 trial in patients with KRAS-mutant solid tumors. ERAS-4001 demonstrated favorable preclinical in vitro potency against KRAS G12X mutations as well as KRAS wildtype amplifications, which may limit treatment resistance mediated through KRAS wildtype activation. No activity was observed for ERAS-4001 against HRAS or NRAS wildtype proteins in preclinical studies, which may enable a better therapeutic window compared to pan-RAS inhibitors. ERAS-4001 showed potent activity against both GTP-bound (active state) and GDP-bound (inactive state) KRAS with single digit nanomolar IC50s. In vivo, ERAS-4001 induced tumor regression in multiple KRAS-mutant models. In preclinical studies, ERAS-4001 showed encouraging absorption, distribution, metabolism, and excretion (ADME) and pharmacokinetic (PK) properties.

About ERAS-0015

ERAS-0015 is an oral, highly potent pan-RAS molecular glue designed to inhibit RAS signaling with a potential best-in-class profile. Erasca is evaluating ERAS-0015 in the AURORAS-1 Phase 1 trial in patients with RAS-mutant solid tumors. Early dose escalation data in AURORAS-1 demonstrated favorable safety and tolerability, well-behaved, linear PK, and confirmed and unconfirmed responses in multiple patients across multiple tumor types with different RAS mutations, including confirmed and unconfirmed partial responses at doses as low as 8 mg once daily (QD). In preclinical studies versus RMC-6236, ERAS-0015 demonstrated approximately 8-21 times higher binding affinity to cyclophilin A (CypA) , approximately 5 times greater potency in RAS inhibition, and greater in vivo antitumor activity evidenced by achieving comparable or greater tumor growth inhibition or regression at doses that are as low as approximately one-tenth to one-fifth of the dose of RMC-6236. ERAS-0015 is also designed to prevent resistance against mutant-selective inhibitors through inhibition of RAS wildtype variants. In addition, ERAS-0015 has demonstrated favorable ADME and PK properties in multiple animal species.

About Erasca

At Erasca, our name is our mission: To erase cancer. We are a clinical-stage precision oncology company singularly focused on discovering, developing, and commercializing therapies for patients with RAS/MAPK pathway-driven cancers. Our company was co-founded by leading pioneers in precision oncology and RAS targeting to create novel therapies and combination regimens designed to comprehensively shut down the RAS/MAPK pathway for the treatment of patients with cancer. We believe our team's capabilities and experience, further guided by our scientific advisory board which includes the world's leading experts in the RAS/MAPK pathway, uniquely position us to achieve our bold mission of erasing cancer.

Cautionary Note Regarding Forward-Looking Statements

Erasca cautions you that statements contained in this press release regarding matters that are not historical facts are forward-looking statements. The forward-looking statements are based on our current beliefs and expectations and include, but are not limited to: statements relating to our intellectual property portfolio, including the future granting of patents and the anticipated periods of time until such patents expire, and the related implications for us; our expectations regarding the potential therapeutic benefits of our product candidates, including ERAS-0015 and ERAS-4001; and the planned advancement of our development pipeline, including the anticipated timing of data readouts for the AURORAS-1 (ERAS-0015) and BOREALIS-1 (ERAS-4001) trials. Actual results may differ from those set forth in this press release due to the risks and uncertainties inherent in our business, including, without limitation: preliminary results of a clinical trial are not necessarily indicative of final results and one or more clinical outcomes may materially change as patient enrollment continues, following more comprehensive reviews of the data and as more patient data becomes available, including the risk that an unconfirmed partial response to treatment may not ultimately result in a confirmed partial response to treatment after follow-up evaluations; any forward-looking statements regarding dose-response relationships reflect current expectations and/or assumptions, and are subject to risks and uncertainties that could cause actual results to differ materially; preclinical comparisons between different compounds may not be predictive of clinical outcomes or relative performance in humans; our approach to the discovery and development of product candidates based on our singular focus on shutting down the RAS/MAPK pathway, a novel and unproven approach; our assumptions about the development potential of ERAS-0015 and ERAS-4001 are based in large part on the preclinical data generated by the licensors and we may observe materially and adversely different results as we conduct our planned studies and trials; results from preclinical studies or early clinical trials not necessarily being predictive of future results; our assumptions around which programs may have a higher probability of success may not be accurate, and we may expend our limited resources to pursue a particular product candidate and/or indication and fail to capitalize on product candidates or indications with greater development or commercial potential; potential delays in the commencement, enrollment, data readout, and completion of clinical trials and preclinical studies; our dependence on third parties in connection with manufacturing, research, and preclinical and clinical testing; unexpected adverse side effects or inadequate efficacy of our product candidates that may limit their development, regulatory approval, and/or commercialization, or may result in recalls or product liability claims; unfavorable results from preclinical studies or clinical trials; we may be unable to secure partnerships or other strategic collaborations for naporafenib on acceptable terms or at all; the inability to realize any benefits from our current licenses, acquisitions, and collaborations, and any future licenses, acquisitions, or collaborations, and our ability to fulfill our obligations under such arrangements; regulatory developments in the United States and foreign countries; our ability to obtain and maintain intellectual property protection for our product candidates and maintain our rights under intellectual property licenses; the sufficiency of our cash, cash equivalents, and marketable securities to fund operations; we may use our capital resources sooner than we expect; and other risks described in our prior filings with the Securities and Exchange Commission (SEC), including under the heading "Risk Factors" in our annual report on Form 10-K for the year ended December 31, 2024, and any subsequent filings with the SEC. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof, and we undertake no obligation to update such statements to reflect events that occur or circumstances that exist 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.

Contact:

Joyce Allaire

LifeSci Advisors, LLC

jallaire@lifesciadvisors.com

Source: Erasca, Inc.

Erasca Announces Issuance of a U.S. Patent Covering Pan-KRAS Inhibitor ERAS-4001