AmMax Bio's attempt to muscle in on a market monopolized by Daiichi Sankyo has advanced, with the biotech posting midphase data on the effect of injecting an antibody into the joints of patients with rare tumors.
Daiichi’s development of Turalio showed reducing the activity of CSF-1, in its case by blocking CSF1R using an oral kinase inhibitor, can shrink the size of tenosynovial giant cell tumors (TGCTs). The approval of the drug gave U.S. doctors an alternative to surgery when treating patients who have benign tumors in their joints. However, European authorities rejected Turalio over doubts about the impact of the drug on quality of life and concerns about its effect on the liver.
AmMax may be able to deliver more compelling data by coming at the problem from a different angle. Rather than delivering a kinase inhibitor systemically, AmMax is administering an anti-CSF1R monoclonal antibody locally. Physicians inject the drug candidate directly into the joint space.
“We have sought to match our highly potent and selective monoclonal antibody with an optimal local delivery route for superior efficacy and safety, that delivers best-in-class clinical benefits for patients suffering from TGCT,” AmMax CEO Larry Hsu said in a statement.
AmMax now has early results from a test of its approach, although little information is available publicly at this stage. The company said all five patients who received three doses over six weeks “exhibited early evidence of clinical benefit, including tumor reduction based on RECIST criteria and improvements across clinically meaningful patient-reported functional outcomes including reduction of pain and stiffness, improvements in quality-of-life measures, and increased range-of-motion of the affected joint.” No serious adverse events occurred.
The open-label clinical trial is continuing to enroll patients and track existing participants out to 12 weeks. However, AmMax is now already starting to look beyond the study and prepare for a planned pivotal trial.