RAS buzz lifts Erasca

RAS has been one of the hottest topics in oncology in the opening weeks of 2026, following market rumours late last week around a potential acquisition of Revolution Medicines. While the speculation has yet to amount to anything, it has lifted sentiment across the sector, buoying companies developing drugs against this target.

One of the beneficiaries has evidently been Erasca. Shares closed up 20% on Tuesday after the company reported early clinical data on ERAS-0015, the pan-RAS programme it licensed from Joyo Pharmatech in 2024. Still, the market response, which has seen Erasca’s stock double over five days, seems overblown given the notable gaps in the information disclosed.

8mg dose

Erasca, which now carries a market capitalisation of $2.1bn, reported three ongoing responses at a low daily dose of 8mg, comprising two confirmed partial responses and one unconfirmed partial response. The responses were observed in the phase 1 Auroras-1 trial in patients with different tumour types and RAS mutations, the company noted.

However, Erasca did not disclose how many patients were treated at that dose level, and neither did it specify the tumour types involved, leaving key questions unanswered and underscoring the fact that ERAS-0015 still has significant ground to cover before its potential can be meaningfully assessed.

Even so, the low dose has drawn favourable comparisons with Revolution’s daraxonrasib, which first demonstrated clinical activity at substantially higher doses, starting at 80mg daily. The lower apparent active dose could ultimately work in Erasca’s favour if it translates into a better tolerability profile, an area where Revolution has faced some issues.

Daraxonrasib has been associated with particularly high rates of rash, prompting Revolution to reduce dosing in certain settings. In its pivotal lung cancer trial, Rasolve-301, the company has lowered the dose to 200mg to manage such concerns.

By contrast, Erasca has so far reported low-grade adverse events across all dose levels evaluated, though again it has provided no further detail to date. It must also be stressed that no two molecules have the same pharmacokinetic properties, so a particular dose of one won't necessarily be bioequivalent to the same dose of the other.

Looking ahead, Erasca expects to report monotherapy data in the first half of 2026, and plans to initiate expansion cohorts as well as looking at combinations in the second half of the year.

Meanwhile, Revolution is set to report pivotal data in 2026 from its Rasolute-302 study in second line pancreatic ductal adenocarcinoma. This trial is evaluating daraxonrasib in patients with or without RAS mutations.

Clinical-stage projects with pan-RAS activity

Source: OncologyPipeline.