Fresh off a major clinical win, Revolution Medicines alleges that Erasca’s pancreatic cancer drug infringes on key patent protections and that the rival has “improperly compared” the companies’ assets publicly.
After securing a prime post in the pancreatic cancer space with impressive data earlier this month, Revolution Medicines is now hustling to maintain its lead. Last week, the California biotech demanded that Erasca, a key competitor, stop working on its pancreatic cancer drug candidate in the U.S.
Erasca revealed the communication in an SEC filing on Monday, noting that Revolution claimed that Erasca’s asset, dubbed ERAS-0015, was “substantially equivalent” to certain formulations used in Revolution’s candidate daraxonrasib. Moving ERAS-0015 forward, according to Revolution, would infringe on patent protections.
Revolution also claimed in its letter that Erasca “improperly compared preclinical data of ERAS-0015 and [daraxonrasib] in public disclosures,” according to the securities document. Revolution has thus “demanded” that Erasca “immediately cease all making, using, offering for sale, selling, and importation of ERAS-0015” in the U.S.
Erasca should also “cease making any deceptive and untrue comparative statements” regarding ERAS-0015 and daraxonrasib.
For its part, Erasca insisted that “the assertions in [Revolution’s] letters are without merit.” Erasca plans to fight these claims “vigorously,” though the biotech did not specify how it plans to do so.
BioSpace has reached out to both Revolution and Erasca for comment.
There may be some merit to Revolution’s claims. Erasca on Monday also released Phase 1 dose escalation data for ERAS-0015, touting a 62% unconfirmed overall response rate (ORR) when used in patients with pancreatic ductal adenocarcinoma (PDAC) who had undergone at least two lines of therapy. Crucially, Erasca in its news release claimed that this ORR “exceeded comparator by 24 percentage points.” The “comparator” that the biotech was referring to is Revolution’s daraxonrasib, pointing to a 2025 article in the Journal of Thoracic Oncology by Punekar et al.
Erasca did not provide the title of the specific journal article used as reference. A BioSpace search through the journal’s database did yield a paper that seems to fit Erasca’s descriptions, showing a 38% confirmed ORR for daraxonrasib—exactly 24 percentage points behind Erasca’s readout on Monday. This journal article, however, was in non-small cell lung cancer. BioSpace has asked Erasca about this discrepancy.
Revolution earlier this month posted Phase 3 data for daraxonrasib in PDAC, touting overall survival of 13.2 months—nearly double the 6.7-month survival of those on chemotherapy. The late-stage victory gave a 40% boost to Revolution’s shares.
Investors also seem encouraged by the company’s action on Erasca, with Revolution trading 8% higher after Monday’s closing bell, reaching $141.94.
Erasca, on the other hand, closed Monday’s trading session down to almost 11% to $19.15, and the company further crashed more than 42% before the opening bell on Tuesday, hitting $11.09. In addition to the legal drama with Revolution, however, Erasca’s data drop also included the disclosure of a patient death, which likely contributed to the stock drop.
Specifically, a 66-year-old trial participant who had received ERAS-0015 suffered severe lung inflammation and was initially treated aggressively before choosing to withdraw supportive care. Erasca CEO Jonathan Lim suggested on an analyst call Monday that the outcome may have been different had the patient chosen to continue supportive care, Reuters reported.
Analysts were not overly concerned by the death, with H.C. Wainwright calling it “likely an isolated case in a complex patient” and J.P. Morgan analyst Anupam Rama similarly saying it was “more of a one-off case versus a clear drug-related concern,” as per Reuters.
Nevertheless, Wainwright added, “it introduces tension with the otherwise benign safety narrative and raises questions around attribution and reporting consistency.”
Editor’s note (April 28): This story has been updated to include the news of the patient death in Erasca’s clinical trial.
