Brentuximab Vedotin (SGN-35) in Patients with Relapsed/Refractory CD30-Positive Hematologic Malignancies without Prior High-Dose Chemotherapy and Stem Cell Transplantation.

Based on the impressive results of two pivotal phase II trials, the CD30 targeting antibody-drug conjugate brentuximab vedotin (SGN-35) was approved for the treatment of relapsed Hodgkin lymphoma (HL) and anaplastic large cell lymphoma (ALCL) by the Food and Drug Administration (FDA) in 2011. Recently, we reported the experience of the German Hodgkin Study Group (GHSG) with brentuximab vedotin as single agent in 45 patients suffering from refractory or relapsed CD30-positive HL. In this cohort with a median age of 35 years and a median number of four prior chemotherapy regimens, overall survival (OS) and progression-free survival (PFS) at 12 months were 83% (95%-CI: 72%-95%) and 43% (95%-CI: 28%-58%), respectively. Interestingly, 10 of 17 patients considered very high-risk (59%) who had primary refractory disease or early relapse and refractory disease prior to brentuximab vedotin treatment, achieved an objective response, which was comparable to the overall response rate of 60% for the whole cohort (Rothe et. al., Blood, July 2012). Since very limited data is available on relapsed or refractory HL patients who received brentuximab vedotin without prior high-dose chemotherapy (HDCT) and autologous stem cell transplantation (ASCT), we have expanded our analysis.

Since March 2010, the GHSG and associated centres have treated patients with refractory or relapsed HL or relapsed ALCL with brentuximab vedotin. In addition to six patients included in our previous analysis, we identified 10 further patients who had not undergone prior HDCT and SCT and were treated with brentuximab vedotin. All patients had histologically confirmed CD30-positive lymphoma and were treated within a named patient program (NPP). All participants gave written informed consent in accordance with the Declaration of Helsinki. Patients received a 30-minute infusion of brentuximab vedotin dosed at 1.8mg/kg body weight every three weeks. Response was defined according to the revised response criteria for malignant lymphoma. Overall survival (OS) was defined as the time from the initiation of therapy to death from any cause. Progression-free survival (PFS) was measured from initiation of therapy to progression, relapse, or death from any cause.

In total, 16 patients with HL (n=14) or ALCL (n=2) with a median age of 48.5 years and a median number of three prior chemotherapy regimens were analyzed. Reasons for ineligibility for HDCT and autologous SCT prior to treatment with brentuximab vedotin were refractory disease (n=11), comorbidity (n=4) and unknown reasons (n=1). Treatment with brentuximab vedotin resulted in an objective response in 11 patients (69%), including five complete remissions. Noteworthy, six of the 11 patients with chemotherapy refractory disease and all four patients with significant comorbidity achieved an response. Six patients received a consolidating HDCT followed by autologous (n=4) or allogeneic (n=2) SCT after brentuximab vedotin treatment. OS and PFS at 12 months were 68% (95%-CI: 40%-95%) and 22% (95%-CI: 0%-48%), respectively.

This retrospective analysis supports the previously reported excellent therapeutic efficacy of brentuximab vedotin in patients with heavily pre-treated CD30-positive malignancies. Moreover, we present the first data indicating therapeutic efficacy of brentuximab vedotin as reinduction therapy in chemotherapy-refractory HL and ALCL patients before HDCT and ASCT.

Engert:Millenium The Takeda Oncology Company: Honoraria.