In total, 21 patients were treated: 16 patients had follicular lymphoma, four patients had marginal zone lymphoma, and one patient had small lymphocytic lymphoma. The median prior therapies received was two (range: 1-18) and five patients were treated who were refractory to prior anti-CD20 MAb therapy.
ALT-803 was well tolerated with no dose limiting toxicities or grade 4 or 5 adverse events. No patients discontinued ALT-803 and the recommended phase 2 dose was 20 mcg/kg subcutaneously. Grade 3 adverse events, regardless of attribution to ALT-803, included transient hypertension (14%), anemia (5%), nausea (5%), chills (5%), fever (5%), neutropenia (5%), and hyperglycemia (5%).
“Patients who received [subcutaneous] ALT-803 developed a unique injection site rash reaction that peaked 7-10 days later but resolved typically within 14 days. It was self-limited and resolved on its own,” Dr. Fehniger said.
At the time of the presentation, the best overall response rate was achieved in 11 of 21 patients (52%), with 9 complete responders (43%), and 2 partial responders (10%).