ASH: Roche uncorks eyepopping responses in bispecific test, hoping to add a jewel to its future portfolio
In a heated race with some of pharma’s biggest players, Roche’s Genentech is looking to drive a lead bispecific antibody program through the clinic against stubborn blood cancers. As the field watches closely, Roche is now trotting out data it thinks could earn its drug a first shot at the market.
Roche’s mosunetuzumab, a bispecific targeting the CD20 protein on the surface of tumors and the CD3 protein on T cells, posted a 60% complete response rate, according to data from nearly 100 patients with third-line-or-later follicular lymphoma in an open-label, single-arm Phase I/II study dubbed GO29781 presented Saturday at #ASH21.
Mosun, as it’s called for short, posted an overall response rate of 80% in those patients, with a median progression-free survival of 17.9 months. Among responders, mosun posted a duration of response of 22.8 months.
The data are good enough that Roche expects to file these results with the FDA immediately. They drugmaker says this drug’s 60% CR rate compares extremely favorably with a 14% CR rate with “historical control” in these heavily pretreated patients.
With its blockbuster cancer trio of Avastin, Herceptin and Rituxan now facing biosimilar pressure in the US and abroad, Roche has looked to aggressively expand its pipeline of next-gen cancer agents to help pick up the expected slack in coming years. Mosun, alongside fellow bispecific glofitimab, are in early-stage human testing, but these data do add even more promise to this emerging drug class.
Before a recent spate of approvals, bispecifics were limited by an onerous safety profile, but early mosun data appears to tamp those fears down somewhat. while 44% of patients experienced cytokine release syndrome, a dangerous overreaction from the immune system, there was just one Grade 3 CRS event reported and one Grade 4 case. No patient deaths were tied to CRS.
There were two deaths reported in the study, neither of which were connected to mosun, investigators said.
Roche isn’t the only drugmaker developing a bispecific against CD20, a common and highly validated target best known as the protein that Rituxan attacks. Back in October, J&J signed away $125 million in cash and equity for access to Xencor’s plamotamab, a CD20xCD3 bispecific in Phase I testing against B cell malignancies.
Meanwhile, AbbVie and Regeneron are also working in this space. Regeneron’s odronextamab (REGN1979) recently restarted its own Phase II studies in follicular lymphoma and diffuse large B cell lymphoma after the FDA slammed a partial clinical hold on the program due to a high prevalence of Grade 3 or higher CRS cases. AbbVie and partner Genmab are currently running a Phase III study for their candidate epcoritimab in r/r DLBCL.