Seattle Genetics, Inc. (NASDAQ:SGEN), has announced that it has initiated a phase II clinical trial of SGN-35 for patients with relapsed or refractory systemic anaplastic large cell lymphoma (ALCL). SGN-35 is an antibody-drug conjugate (ADC) that utilizes Seattle Genetics’ proprietary technology to empower antibodies by linking them to potent cell-killing drugs.
“We have observed promising activity in ALCL patients in our phase I trials, notably six out of seven patients treated with SGN-35 have achieved a complete response,” said Clay B. Siegall, Ph.D., President and Chief Executive Officer of Seattle Genetics. “SGN-35 could become an important therapeutic option for patients who relapse or fail to respond to the standard front-line chemotherapy regimen, and we believe that systemic ALCL may offer an additional registration pathway for SGN-35.”
The single-arm phase II trial will assess efficacy and safety of single-agent SGN-35 in 55 patients with relapsed or refractory systemic ALCL. Patients will receive 1.8 milligrams per kilogram of SGN-35 every three weeks. The primary endpoint of the trial will be objective response rate determined by an independent review facility. Secondary endpoints include duration of response, progression-free survival, overall survival and tolerability. The company plans to enroll patients at more than 30 sites in the U.S., Canada and Europe.
Seattle Genetics is also conducting a pivotal trial of SGN-35 for Hodgkin lymphoma under a Special Protocol Assessment (SPA) with the U.S. Food and Drug Administration (FDA). Data from two phase I trials of SGN-35 were reported in June at the American Society of Clinical Oncology annual meeting and the 14th Congress of the European Hematology Association. In both phase I trials, relapsed or refractory Hodgkin lymphoma and systemic ALCL patients treated with single-agent SGN-35 achieved multiple objective responses at generally well-tolerated doses. The majority of adverse events were Grade 1 and 2, with the most common being fatigue, fever, peripheral neuropathy, diarrhea and nausea.
SGN-35 is an ADC comprising an anti-CD30 antibody attached by an enzyme cleavable linker to a potent, synthetic drug payload, monomethyl auristatin E (MMAE), using Seattle Genetics’ proprietary technology. The ADC is designed to be stable in the bloodstream, but to release MMAE upon internalization into CD30-expressing tumor cells, resulting in targeted cell-killing.