Roche has offloaded its anti-CSF1R monoclonal antibody emactuzumab to Celleron Therapeutics. The licensing deal comes almost two years after Roche dropped the tumor microenvironment modulator after putting it through a clutch of early-phase studies in solid tumor patients.
Emactuzumab, also known as RG7155 and RO5509554, entered the clinic back in 2011. Roche went on to study the molecule in combination with other assets including checkpoint inhibitor Tecentriq in solid tumor patients. In 2018, Roche was gearing up to start another combination trial in lymphoma patients when it withdrew the study prior to the enrollment of the first subject.
Roche called the action a “business decision,” emphasizing that there were “no safety or efficacy concerns.” Even so, the decision marked the end of Roche’s interest in developing the asset.
Now, Celleron has struck a deal to rehabilitate the candidate. Celleron is set to land the global rights to the drug and take it forward as a treatment for diffuse tenosynovial giant cell tumours (TGCT), a rare disease that can damage joints and surrounding tissues.
TGCT is driven by cells that overproduce the CSF1 protein. The protein attracts macrophages, leading to the inflammatory changes that characterize the disease. The potential for emactuzumab to inhibit the CSF1 receptor activation that drives TGCT led Roche to include patients with the rare disease in its first clinical trial of the molecule.
Eighty-six percent of TGCT patients treated with emactuzumab responded to the drug, with 68% of people experiencing a partial response within six weeks of starting treatment. Respondents included people who had previously tried Novartis’ Gleevec or Tasigna without lasting success. There were two complete responses in the 28-subject study.
The authors of the paper said “even a short course of emactuzumab could offer durable benefit for patients for whom surgery is either not feasible or would result in major functional impairment.” Yet, subsequent trials failed to persuade Roche to continue developing the asset.
That decision has created an opportunity for Celleron, a British biotech that already has two drugs in phase 2. Celleron is evaluating dual mechanism HDAC inhibitor CXD101 as a monotherapy and in combination with checkpoint inhibitors, and assessing topoisomerase inhibitor CXD201 in colorectal cancer patients.