Data presented at December's American Society of Hematology virtual meeting showed along with tolerable safety for patients with relapsed/refractory multiple myeloma.
In this exclusive 51˶ video, study co-author , director of the Judy and Bernard Briskin Center for Multiple Myeloma Research at City of Hope in Duarte, California, discusses the findings.
Following is a transcript of her remarks:
This is a first-in-human study, looking at a new novel target in myeloma, GPRC5. And this was a phase I dose escalation study in a traditional model. We enrolled a total of 157 patients. Patients were treated with initially IV dosing and ultimately moved to subcutaneous dosing. These are very refractory patients with advanced disease and median of six prior lines of therapy in the entire cohort, with a third of the patients being penta-drug refractory. Also note, 17% of the patients that had prior anti-BCMA therapy.
We were encouraged at the responses as well as the toxicity profile that we've seen. First, in terms of toxicity, we did see cytokine release syndrome, though it was only 3% of patients who had grade 3 or greater CRS -- 54% total had CRS. Because where the GPRC receptor is expressed, we did see other toxicities that were specific to this compound, specifically dysgeusia in 38% of patients, and nail disorders, because it is expressed in 18% of patients.
There was some hematologic toxicity, not unexpected, in a group of heavily pretreated patients, with 48% of patients having anemia and neutropenia of any grade. Response rates were promising, with an overall response rate of 69%. And also that patients had durability of these responses. We have eight responders with a duration of over 12 months. So again, very encouraging in terms of the durability of those responses. And also that we saw deepening of the responses over time. We saw induction of cytokines consistent with dose responses in patients at all dose levels.
So in short, talquetamab for GPRC5 has an acceptable safety profile. CRS was seen, but generally manageable with the subcutaneous dosing, and the step-up dosing overall response rate of 69%.