LEIPZIG, GERMANY—Combination therapies including the investigational drug MOR202 have produced “encouraging and long-lasting responses” in a phase 1/2 trial of patients with relapsed/refractory multiple myeloma (MM), according to researchers.
MOR202 is an antibody targeting CD38. In this trial, researchers are testing the drug in combination with dexamethasone (Dex), lenalidomide (Len) and Dex, or pomalidomide (Pom) and Dex.
Results thus far suggest the combinations are well-tolerated and can produce durable responses in heavily pretreated patients with relapsed/refractory MM.
The results were presented in a poster at the 2016 annual meeting of the German, Austrian and Swiss Societies for Hematology and Medical Oncology (abstract P235).
The study, which is ongoing, is sponsored by MorphoSys AG. The poster is available for download from the company’s website.
Treatment
This 3+3 dose-escalation study started with MOR202 monotherapy given at 0.01 mg/kg every 2 weeks, and the dose was escalated up to 16 mg/kg every 2 weeks and 8 mg/kg every week.
Once the dose-escalation phase was complete, researchers began testing MOR202 in combination with Dex, Pom and Dex, or Len and Dex.
Patients
As of September 05, 2016, 73 patients had been treated with MOR202, but the researchers only reported data on the 38 patients who received MOR202 as part of combination therapy.
Eighteen patients had received MOR202 plus Dex, 7 had received MOR202 plus Pom and Dex, and 13 had received MOR202 plus Len and Dex. The patients’ median age was 67, 64, and 64, respectively.
The median number of prior therapies was 3, 4, and 2, respectively. And the percentage of patients who were refractory to their last therapy was 78%, 100%, and 56%, respectively.
Safety
The researchers said the maximum-tolerated dose of MOR202, alone or in combination, has not yet been reached. However, the data suggest MOR202 can be safely administered as a 2-hour intravenous infusion at doses up to 16 mg/kg.
All 38 patients who received MOR202 in combination were evaluable for safety—18 in the Dex arm, 7 in the Pom/Dex arm, and 13 in the Len/Dex arm.
The most frequent grade 3 or higher adverse events were hematologic in nature. These included (in the Dex, Pom/Dex, and Len/Dex arms, respectively) leukopenia (11%, 57%, 31%), lymphopenia (39%, 29%, 54%), neutropenia (22%, 71%, 39%), thrombocytopenia (17%, 43%, 8%), and anemia (11%, 14%, 15%).
Infusion-related reactions occurred in 3 (8%) patients and were mainly limited to the first infusion. One patient developed a transient anti-MOR202 antibody response.
One patient discontinued treatment due to an adverse event that may have been caused by MOR202. However, researchers also said the event (decrease in platelet count) may have been caused by Dex.
There were no treatment-related deaths.
Efficacy
Efficacy data were available for 31 of the 38 patients. Fifteen patients responded, and 12 of these responses are ongoing for up to 56 weeks.
In all, there were 10 partial responses (PRs), 3 very good partial responses (VGPRs), and 2 complete responses (CRs).
There were 5 responses in the Dex arm—3 PRs and 2 VGPRs. There were 3 responses in the Pom/Dex arm—2 CRs and 1 PR. And there were 7 responses in the Len/Dex arm—6 PRs (3 unconfirmed) and 1 VGPR.
“We are very pleased that these results are consistent with earlier data from the ongoing trial and show further improved responses with more patients being evaluable for efficacy and safety assessment,” said Arndt Schottelius, MD, PhD, chief development officer of MorphoSys AG.
“In addition to the very short infusion time, we are particularly interested in the efficacy results in patients treated with MOR202 plus pomalidomide, who had a median of 4 prior therapies. The dose-escalation study is ongoing as planned, currently focusing on the highest dose cohorts of 16 mg/kg MOR202 in combination with pomalidomide and lenalidomide.”
