What happened
Shares of Agenus (AGEN 13.88%) were soaring 27.7% higher as of 10:48 a.m. ET on Wednesday. The big gain came after the company announced results from a phase 1b study evaluating a combination of botensilimab and balstilimab in treating microsatellite-stable colorectal cancer (MSS CRC).
So what
Agenus presented data at the European Society for Medical Oncology (ESMO) World Congress on Gastrointestinal Cancer that it said demonstrated "unprecedented activity" for the botensilimab-balstilimab combo. The company reported an overall response rate of 24%, with a disease control rate of 73% in heavily pre-treated patients.
The durability of the combination cancer therapy was especially impressive. Agenus stated that 80% of objective responses were ongoing at the time of the data cut-off. Thirty percent of objective responses exceeded one year. As a result, a median duration of response hasn't yet been determined.
With these results, it's not surprising that the biotech stock took off today. Colorectal cancer is the No. 2 cause of cancer-related deaths in the world. Around 95% of cases are categorized as microsatellite stable (not predisposed to genetic mutations) and often don't respond to immunotherapy. The current standard of care for treatment-resistant MSS CRC patients typically has a response rate of only between 1% and 2%.
Agenus' data is encouraging. However, more studies will be needed to show that the combination of botensilimab and balstilimab is safe and effective.
Now what
The first of those additional studies should be on the way soon. Agenus said that it plans to begin a global phase 2 study evaluating the botensilimab-balstilimab combo.
