SEC Form 8-K filed by Erasca Inc.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): April 27, 2026

Erasca, Inc.

(Exact name of Registrant as Specified in Its Charter)

Registrant’s Telephone Number, Including Area Code: (858) 465-6511

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company ☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

On April 27, 2026, Erasca, Inc. (the “Company”) announced positive preliminary Phase 1 dose escalation data for its potentially best-in-class, pan-RAS molecular glue ERAS-0015 in patients with RAS-mutant solid tumors.

Study Design

The preliminary data include data from both the Company’s ongoing AURORAS-1 Phase 1 dose escalation trial in the United States and the ongoing JYP0015M101 Phase 1 dose escalation trial in China sponsored by Joyo Pharmatech Co., Ltd. (“Joyo”). The trials include patients with RAS-mutant solid tumors, including colorectal cancer (CRC), non-small-cell lung cancer (NSCLC) and pancreatic adenocarcinoma (PDAC). The estimated incidence of the number of patients in the United States with KRAS-mutant tumors in CRC, NSCLC and PDAC are approximately 74,000, 55,000 and 50,000 patients, respectively. The trial designs are depicted below:

ATD= Accelerated Titration Design; BOIN= Bayesian Optimal Interval; DCR=disease control rate; DLT=dose limiting toxicity; DOR=duration of response; NSCLC=non-small-cell lung cancer; ORR=objective response rate; OS=overall survival; PDAC=pancreatic adenocarcinoma; PK=pharmacokinetics; PFS=progression free survival; QD=once daily; RASi=RAS inhibitor; SOC=standard of care; TTR=time to response.

Highlights of Phase 1 Preliminary Results

Additional AURORAS-1 Safety Data

The following table summarizes all treatment-related adverse events occurring in 10% or more of patients in the AURORAS-1 trial as of the April 4, 2026 data cutoff date:

Baseline Characteristics

The following tables summarize the baseline characteristics for the JYP0015M101 and AURORAS-1 trials in patients with PDAC and NSCLC:

NA = not available.

Key Upcoming and Completed Milestones

The Company initiated ERAS-0015 monotherapy expansion and combination dose escalation cohorts in the U.S. in the second quarter of 2026 and the first quarter of 2026, respectively, ahead of previous Company guidance.

Upcoming anticipated milestones include:

Forward-Looking Statements

The Company cautions you that statements contained in this report regarding matters that are not historical facts are forward-looking statements. The forward-looking statements are based on the Company’s current beliefs and expectations and include, but are not limited to: the Company’s expectations regarding the potential therapeutic benefits of its product candidates, including ERAS-0015 and ERAS-4001, and the planned advancement of its development pipeline, including the anticipated timing of data readouts for the AURORAS-1 and BOREALIS-1 trials, characterizations of the clinical profile of the Company’s product candidates and any comparisons against other products or product candidates in development, the potential for ERAS-0015 to be best-in-class or serve as backbone therapy for future combination therapies, and the potential for ERAS-4001 to be first-in-class or best-in-class. Actual results may differ from those set forth in this report due to the risks and uncertainties inherent in the Company’s business, including, without limitation: the timing of its clinical data readouts, including for the AURORAS-1 and BOREALIS-1 trials may be delayed; the Company’s product candidates, including ERAS-0015 and ERAS-4001, may not demonstrate therapeutic benefits that it expects; this report includes clinical data generated by the Company’s third-party licensor, and such data are presented as received and have not been independently verified by the Company; topline and preliminary results of a clinical trial are not necessarily indicative of final results and one or more of the 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; the Company’s observations, including those regarding the first dosage level at which a clinical response is detected and the efficacy and safety of ERAS-0015 compared to other products and product candidates, are based on data generated within separate, individual clinical trials with different designs, patient characteristics and other factors and are not based on any head-to-head clinical studies, and caution should be exercised in drawing any conclusions from a comparison of the data across studies as cross-study comparisons are inherently limited and such data may not be directly comparable; differences exist between trial designs, patient characteristics and other factors for the AURORAS-1 and JYP0015M101 clinical trials, and caution should be exercised in drawing any conclusions from such data across separate studies as such pooling and comparative data is inherently limited and such data may not be directly comparable; any forward-looking statements regarding dose-response relationships reflect current expectations and/or assumptions that are subject to risks and uncertainties that could cause actual results to differ materially; the Company’s approach to the discovery and development of product candidates based on its singular focus on shutting down the RAS/MAPK pathway, a novel and unproven approach; results from preclinical studies not necessarily being predictive of future results; the Company’s assumptions around which

programs may have a higher probability of success may not be accurate, and the Company may expend its 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; the Company’s dependence on third parties in connection with manufacturing, research, and preclinical and clinical testing; unexpected adverse side effects or inadequate efficacy of the Company’s 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; the inability to realize any benefits from the Company’s current licenses, acquisitions, or collaborations, and any future licenses, acquisitions, or collaborations, and its ability to fulfill its obligations under such arrangements; regulatory developments in the United States and foreign countries; the Company’s ability to obtain and maintain intellectual property protection for its product candidates and maintain its rights under intellectual property licenses, including the Company’s ability to successfully defend against allegations raised by, or any future litigation initiated by, Revolution Medicines (RevMed) that ERAS-0015 infringes patents held by RevMed or was derived from RevMed trade secrets; the sufficiency of its cash, cash equivalents, and marketable securities to fund operations; the Company may use its capital resources sooner than it expects; and other risks described in the Company’s prior filings with the Securities and Exchange Commission (SEC), including under the heading “Risk Factors” in the Company’s annual report on Form 10-K for the year ended December 31, 2025, 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 the Company undertakes 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.

Cross-Study Comparisons

The data presented for the CN and US trials in this report are based on separate studies and include pooled and cross-study comparative data. The clinical data presented in this report comparing ERAS-0015 and other products and product candidates (including RMC-6236) are based on cross-study comparisons and are not based on any head-to-head clinical trials. Differences exist between trial designs, patient characteristics and other factors, and caution should be exercised in drawing any conclusions from a comparison of the data across studies as cross-study comparisons are inherently limited and such data may not be directly comparable.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.