Why Is Cancer Drug Developer Erasca Stock Plunging On Tuesday?

Erasca Inc. (NASDAQ:ERAS) said it intends to vigorously contest allegations made by Revolution Medicines, Inc. (NASDAQ:RVMD).

Legal Dispute Centers On Patent And Trade Secret Claims

On April 24, the company received a letter from RevMed alleging that ERAS-0015 is substantially equivalent to compositions covered under its U.S. Patent No. 12,409,225.

RevMed also claimed infringement under the doctrine of equivalents.

The letter further alleged that a third party misappropriated trade secrets tied to ERAS-0015 and that Erasca could be liable as a licensee.

It also challenged the company's public comparisons between ERAS-0015 and RevMed's RMC-6236.

RevMed demanded that Erasca halt development and commercialization activities related to ERAS-0015 in the U.S., except where protected under regulatory safe harbor provisions, and cease what it described as misleading comparative statements.

In an SEC filing on Monday, Erasca said it believes the claims lack merit and plans to defend its position.

Early Clinical Data Show Strong Tumor Activity

Separately, on Monday, Erasca reported preliminary Phase 1 dose-escalation data for ERAS-0015 in patients with RAS-mutant solid tumors, including colorectal cancer, non-small-cell lung cancer, and pancreatic adenocarcinoma.

All evaluable patients (14 of 14) showed at least a 75% reduction in KRAS G12X variant allele fraction, with five patients achieving a complete (100%) reduction.

The therapy also demonstrated encouraging response rates in non-small cell lung cancer and pancreatic cancer across ongoing trials.

Erasca Safety Profile And Development Plans

ERAS-0015 was generally well tolerated, with mostly low-grade adverse events and no dose-limiting toxicities observed. The company reported minimal treatment interruptions and no discontinuations linked to adverse events.

Based on early findings, Erasca selected 24 mg and 32 mg once-daily doses as recommended levels for monotherapy expansion.

The drug also showed potential for combination use, including with anti-EGFR therapy, panitumumab.

Erasca Pipeline Milestones Ahead

Erasca has already initiated monotherapy expansion and combination dose-escalation cohorts in 2026, ahead of prior timelines.

Looking ahead, additional data from the AURORAS-1 trial are expected in the first half of 2027, while preliminary data from another program, ERAS-4001, are anticipated in the second half of 2026.

ERAS Stock Price Activity: Erasca shares were down 41.98% at $11.10, and RVMD stock is up 8.61% at $143 during premarket trading on Tuesday, according to Benzinga Pro data.

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