Agenus has scrapped a phase 3 study of its combo therapy in colorectal cancer after just three months in order to go all-in on colon cancer.
The biotech launched the late-stage Battman study in April to evaluate a combination of its CTLA-4 inhibitor botensilimab and an anti-PD-1 antibody balstilimab in unresectable microsatellite stable (MSS) metastatic colorectal cancer (mCRC). The aim was to enroll 830 patients across Canada, France, Australia and New Zealand.
At the time, Agenus pointed out that this patient population had been “long considered resistant to immunotherapy.” The company hoped to “quickly” complete enrollment due to the “unprecedented investigator and patient enthusiasm worldwide.”
But Agenus has abandoned the study three months later. Scrapping Battman allows the company to focus on Robbin, a planned phase 3 study assessing the same BOT+BAL combo in patients with MSS colon cancer. With around 38,000 addressable patients in the U.S. and no new curative-intent therapies for over two decades, Agenus said it hopes BOT+BAL could unlock a $7 billion sales opportunity in the U.S. alone.
The company said it has aligned with the FDA on the design of Robbin, and aims to enroll 850 patients. The trial will be bankrolled by a private placement, also announced this morning, that could ultimately bring in $340 million to the company. The financing was led by Commodore Capital, along with RA Capital Management, TCGX, Invus and Ligand Pharmaceuticals.
As for Battman, Agenus said it will “honor its obligations to patients currently receiving treatment” and “work closely with … participating investigators to manage this transition responsibly.”
“We have seen neoadjuvant and perioperative immunotherapy improve outcomes in immunologically 'hot' or 'warm' tumors such as melanoma and lung cancer, but MSS colon cancer—a ‘cold’ tumor—has resisted standard checkpoint inhibitors,” Agenus’ Chief Medical Officer Steven O'Day, M.D., said in Monday morning’s release.
“With the Robbin trial, we are bringing this regimen to patients with high-risk stage II and stage III MSS colon cancer, where treating an intact tumor gives BOT+BAL its greatest opportunity to generate a durable immune response and improve long-term outcomes,” O'Day added.
The BOT+BAL combo ran into trouble earlier this year when a regimen of BOT+BAL with MiNK’s invariant natural killer T cell candidate agenT-797 missed the primary endpoint of a phase 2 study in gastroesophageal cancer. Still, the biotechs insisted at the time that the data support further assessment of the combination.