Arcus Preps for Phase III with "Encouraging" Response Rates for NSCLC Immunotherapy

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The first interim analysis of a three-arm Phase II ARC-7 trial shows Arcus Biosciences anti-TIGIT immunotherapy combination features “encouraging clinical activity” as an initial therapy for patients with metastatic non-small cell lung cancer (NSCLC). On the day this news broke, shares in the company were up by nearly 2% post-market.

Both arms consisting of domvanalimab-based combination regimens showed promising overall response rates as the first-line therapy. Additionally, the group that received zimberelimab alone demonstrated activity similar to that previously reported with other marketed anti-PD-1 antibodies in this setting.

Arcus reported no unexpected safety signals at time of data cutoff, stating, “The current safety profile for each arm of the study appears to be consistent with known immune checkpoint inhibitors in this setting.” 

Gilead Sciences previously partnered with Arcus under an exclusivity agreement to co-develop and co-commercialize domvanalimab, an anti-TIGIT candidate and Fc-silent investigational monoclonal antibody. 

As Arcus continues to keep a lid on all there is to potentially say about the TIGIT immunotherapy, Gilead has decided to make a decision of opting into Arcus’ anti-TIGIT program later in the year. The two companies also are in the preparation phases for additional late-stage trials of domvanalimab-based combinations and plan to explore development plans for domvanalimab and etrumadenant combination strategies.

Given the most recent promising study results, the company said all three arms of its ARC-7 trial as well as the ongoing Phase III ARC-10 registrational trial will continue to enroll participants as planned. 

“This analysis of the dataset for the ongoing ARC-7 study revealed encouraging clinical activity for the anti-TIGIT domvanalimab-based combinations, and that the anti-PD-1 zimberelimab monotherapy arm showed activity similar to that of marketed anti-PD-1 antibodies studied in this setting,” Arcus’ chief medical officer Bill Grossman, M.D., Ph.D., said in a statement. 

Dr. Grossman added that the next steps will be to finish enrollment in the company’s “open domvanalimab studies, execute on our broader plans for Phase 3 studies for domvanalimab across multiple cancer types, and further explore combinations with domvanalimab and etrumadenant.”

Arcus most recently reported other positive findings for etrumadenant-based combinations in metastatic castrate-resistant prostate cancer (mCRPC) at the 2021 ASCO Annual Meeting. Etrumadenant (AB928) is the company’s dual A2a/A2b adenosine receptor antagonist, inhibiting the adenosine-driven impairment of tumor-infiltrating lymphocytes mediated by A2aR and myeloid cells mediated by A2bR.

Data from the Phase Ib cohort of the ARC-6 randomized Phase Ib/II platform study showed a combination of etrumadenant and docetaxel induced favorable responses in patients with taxane-naïve patients with mCRPC. In addition, the investigators reported the safety profiles of the drugs were consistent with those reported previously. 

Based on the Phase Ib findings, Dr. Grossman stated the company has started enrolling patients into the randomized Phase II portion of the ARC-6 trial. This portion of the study will compare the etrumadenant-based combination regimen to standard of care.

 

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