Now that the pioneer PD-1 checkpoints have hit the market and started earning their billions, researchers in oncology are focused on the next big thing in cancer R&D: using new combinations to reach tumors that remain stubbornly resistant to approved therapies.
To that end, you can count Apexigen as the early winner in the AACR meeting in Atlanta.
A group of investigators organized by The Parker Institute for Cancer Immunotherapy in partnership with the Cancer Research Institute conducted an early-stage clinical trial that combined a pair of chemotherapies with Apexigen’s CD40 drug APX005M, with or without Bristol-Myers Squibb’s Opdivo. In the first part of the Phase I trial for advanced pancreatic cancer, they wanted to see how CD40 — designed to spur an immune attack — worked with a PD-1, which is designed to take the brakes off an immune system attack.
This is the first trial where the institute held the IND as the principal sponsor, says Joyson Karakunnel, medical director for The Parker Institute and vice president-clinical development at Arcus Biosciences, who took some time on Sunday to explain the work. And they’re particularly happy that Parker was able to organize and execute an academic study like this in just 18 months, offering a new and more efficient approach to drug development that Sean Parker had hoped for when he founded the institute.
Of the 24 patients who were evaluable by AACR, 20 experienced a response with tumor shrinkage. And a few of those patients have responses that endured for more than 12 months. That’s particularly positive for pancreatic cancer, which has been resistant to PD-1 and where disease progression typically starts in about 5 months.
“To quote (first author) Mark O’Hara, you do not see those kind of waterfall plots, so it is extremely encouraging,” says Karakunnel.
Toxicity, however, is a key concern. Thirteen patients — 54% — discontinued the regimen due to an adverse event from the cocktail. Ten of the adverse events were serious. Investigators followed up with me to note that 9 of the 13 continued on at least one of the drugs and 4 stopped altogether.
So why use Apexigen’s drug? There are other CD40s out there.
Karakunnel explains that senior author Bob Vonderheide was familiar with the Apexigen program and thought it would be a good choice. Oddly, though, while the biotech had no trouble discussing its $73 million raise from a group of Chinese investors last summer and put out their own release Sunday, the company turned down an interview request.
The trial is now pushing ahead to the Phase II portion of the trial with the high, 0.3 mg dose of Apexigen’s drug. And the private, venture-backed Apexigen researchers plan to roll out more data on APX005M in combination therapy for patients with metastatic or unresectable melanoma who have progressed on anti-PD-1/PD-L1 therapy.
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