GILD
RCUS
Trial said “nope”
Arcus Biosciences hit pause in the most biotech way possible: it discontinued its Phase 3 STAR-121 study in metastatic non-small cell lung cancer after an interim look suggested the trial probably wasn’t going to meet its primary endpoint. In plain English, the data check looked at the road ahead and basically said, “you’re not getting there from here.”
The study was testing domvanalimab, Arcus’s anti-TIGIT antibody, paired with zimberelimab and chemotherapy against a pembrolizumab-based regimen. The decision came with Gilead Sciences, which co-ran the program, after an independent monitoring committee recommended stopping the trial for futility.
Why investors care
For biotech, a failed late-stage trial is never just a science headline — it can reset the valuation story overnight. Even though Arcus shares were up about 6.9% to $26.21 on Wednesday and hovered near a 52-week high, the bigger takeaway is that a key lung cancer shot on goal just got taken off the board.
A few other details matter too:
- The company said safety wasn’t the reason for the stop, and no new safety concerns were flagged.
- An exploratory arm, zimberelimab plus chemotherapy, showed overall survival results in line with the pembrolizumab regimen.
- Arcus also said its Phase 2 EDGE-Lung study will be discontinued.
The Gilead subplot
This isn’t just an Arcus story; Gilead is in the mix too. The two companies are also letting a 2020 collaboration option lapse, with Gilead declining to extend its rights after skipping a continuation payment.
That means Gilead keeps some time-limited options on select assets, but loses access to more early-stage programs once that window closes on July 14. Arcus, meanwhile, says it keeps full rights to casdatifan outside certain licensed territories.
Big picture: this is what biotech looks like when the science is the boss. One trial stop can knock down a storyline — or, apparently, give traders enough drama to bid the stock higher anyway.