Regeneron Discloses Two Deaths from its Bispecific Antibody RGN1979

Regeneron logo on side of large building

Shares of Regeneron fell more than 6 percent Tuesday after the company disclosed two deaths related to its vaunted bispecific antibody program.

During a conference call with analysts and investors regarding quarterly earnings, Regeneron Chief Scientific Officer George Yancopoulos briefly mentioned the fatalities in the RGN1979 program. RGN1979 is a bispecific antibody against CD20 and CD3. In a small 30 patient trial combining RGN1979 with the company’s PD-1 antibody as a therapy for advanced lymphoma, Regeneron said it observed increased levels of toxicity in patients. Yancopoulos said researchers discovered enhanced cytokine release syndrome that may be associated with increased tumor response. That increased toxicity was the possible cause of the two deaths, he said.

“We plan to modify the dosing regimen with the goal of minimizing toxicity while potentially capturing the potentially increased activity. Over the coming months and years, we expect to advance a steady stream of bispecifics into clinical development,” Yancopoulos said, according to a transcript of the call.

During a question and answer session with analysts about company earnings, Goldman Sachs’ Terrence Flynn sought more information about the deaths. Flynn sought additional context, such as dosing information regarding RGN1979, what indications they were diagnosed with and if the company would disclose any prior treatment history.

Yancopoulos reiterated that the toxicity levels were seen in combination with PD-1.

“And as I noted that in some ways, it indicates that the theoretical concept of combining these two classes actually increases the immune activation is actually you know pertaining in the situation here. And what we believe is that we have ways of adjusting the dosing regimen, so that we can avoid the increase cytokine-release syndrome while capturing the potential increased activity of combining these two classes,” Yancopoulos said.

Additionally, Yancopoulos discussed RGN1979’s in stacking up against CAR-T therapies. Yancopoulos said the company will be reporting details of how RGN1979 benefits patients who failed CAR-T treatments next month. The company plans to present updated results of the Phase I study in relapsed or refractory B-cell non-Hodgkin lymphoma, including in patients who have failed previous CAR-T therapy during the June European Hematology Association meeting.

“We think that there is a lot of opportunity here for the CD20 bispecific, both in the relapsed refractory setting where we're setting it in. It's obviously going to be much more convenient and amendable therapy to more patients, who don't have to go through the whole process that's required for CAR-T therapies. The possibility that can actually also work in individuals who has failed CAR-T therapies is very exciting. Let alone the possibility that with its profile, and the way we give it that we can also be moving relatively rapidly into the frontline settings as well. So we think this is a very exciting opportunity that can really address a lot of the need in lymphoma from the latest stage patients who have failed every other kind of therapy eventually to a frontline therapy that could really impact the disease in the earliest of patients,” Yancopoulos said.

Regeneron has big plans for its bispecific antibody. The company anticipates the launch of a pivotal Phase II study in advanced follicular lymphoma this quarter, as well as a potentially pivotal Phase II study in diffuse large B-cell lymphoma (DLBCL) later this year.

Click to create a jobseeker profile

Back to news