Erasca Inc. (NASDAQ: ERAS) announced a clinical trial collaboration and supply agreement with Merck to evaluate the combination of ERAS-0015 and KEYTRUDA for treating patients with RAS-mutant solid tumors.

The agreement supports the AURORAS-1 clinical proof-of-concept study, which will test Erasca's pan-RAS molecular glue ERAS-0015 in combination with Merck's anti-PD-1 therapy pembrolizumab. Erasca will sponsor the study while Merck provides pembrolizumab at no cost.

ERAS-0015 is an investigational oral drug designed to inhibit RAS signaling across multiple RAS mutations. Early dose escalation data from the ongoing AURORAS-1 Phase 1 trial showed partial responses in multiple patients across different tumor types with various RAS mutations, including responses at doses as low as 8 mg once daily.

Approximately 2.7 million patients worldwide are diagnosed annually with RAS-mutant tumors. RAS mutations activate the RAS/MAPK pathway and create an immunosuppressive environment that can limit treatment effectiveness.

"RAS mutations activate the RAS/MAPK pathway and promote an immunosuppressive environment," said Jonathan E. Lim, Erasca's chairman, CEO, and co-founder. "Non-clinical data suggest that targeting the pathway with ERAS-0015 may complement PD-1 blockade by reducing immunosuppression and driving more robust and durable tumor responses."

The combination study aims to explore whether pan-RAS inhibition with ERAS-0015 alongside pembrolizumab can improve therapeutic benefits and limit treatment resistance development. ERAS-0015 is also designed to prevent resistance against mutant-selective inhibitors through inhibition of RAS wildtype variants.

The information is based on a company press release statement.