Merck & Co (MSD) and Erasca have entered a clinical trial collaboration and supply agreement to assess ERAS-0015 in combination with Keytruda (pembrolizumab) in patients with rat sarcoma virus (RAS)-mutant solid tumours.
The AURORAS-I proof-of-concept study, sponsored by Erasca, will be supported by MSD providing pembrolizumab at no cost.
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Erasca seeks to determine if pan-RAS inhibition using ERAS-0015, together with pembrolizumab, can increase therapeutic gains and reduce the development of resistance.
ERAS-0015 is an investigational oral pan-RAS molecular glue designed to inhibit RAS signalling and potentially offer a best-in-class profile.
In the ongoing AURORAS-I Phase I trial, Erasca is evaluating ERAS-0015 in patients with RAS-mutant solid tumours.
Early dose escalation results have shown favourable safety, tolerability, linear pharmacokinetics, and partial responses at doses as low as 8mg once daily.
ERAS-0015 also aims to counter resistance against mutant-selective inhibitors by inhibiting RAS wildtype variants and has shown positive absorption, distribution, metabolism, and excretion, as well as pharmacokinetic properties in multiple studies.
Erasca chairman, CEO and co-founder Jonathan Lim said: “We are excited to work with MSD to advance this promising investigational combination in RAS-driven cancers. RAS mutations activate the RAS/MAPK pathway and promote an immunosuppressive environment.
“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 tumour responses.”
In March 2026, MSD announced findings from the pivotal Phase III LITESPARK-022 trial, assessing the combination of Keytruda and Welireg (belzutifan) as adjuvant therapy for patients with clear cell renal cell carcinoma (RCC) after nephrectomy.
In early 2024, Erasca entered two clinical trial collaboration and supply agreements with Novartis to support the development of mitogen-activated protein kinase kinase (MEK) inhibitor trametinib in combination with naporafenib for cancer.
