Data were reported from the single-arm, single-agent study of dacetuzumab in 46 patients with diffuse large B-cell lymphoma (DLBCL). Patients were heavily pre-treated, with a median of four prior systemic therapies. The median age of enrolled patients was 72. Patients received six doses of dacetuzumab over five weeks, with an intra-patient dose escalation up to 8mg/kg.
According to the company, objective responses were observed in four out of 38 patients evaluable for response, including two complete remissions and two partial remissions, for an overall response rate of 10%. The duration of objective responses ranged from 78 days to greater than 271 days. Approximately 10 additional patients had stable disease and approximately one-third of all patients had reduction in tumor size. Dacetuzumab was generally well tolerated.
Data were also presented from preclinical studies of dacetuzumab plus Rituxan (rituximab) indicating enhanced activity of the combination regimen.
Seattle Genetics and Genentech are conducting a joint development plan that includes five Phase Ib-IIb clinical trials of dacetuzumab in combination with standard therapeutic regimens for the treatment of multiple myeloma and non-Hodgkin lymphoma.
Approximately two of these combination studies are in DLBCL, including a Phase Ib study of dacetuzumab in combination with Rituxan and Gemzar for patients with relapsed DLBCL and a Phase IIb study of dacetuzumab in combination with R-ICE (Rituxan, ifosfamide, carboplatin and etoposide) for second-line DLBCL. Data from these trials are expected in 2009 and 2010, respectively.
Thomas Reynolds, chief medical officer of Seattle Genetics, said: The data from this Phase II clinical trial are consistent with the activity and tolerability profile observed in our Phase I study and reinforce our enthusiasm about the potential of dacetuzumab for the treatment of DLBCL.