Brentuximab Vedotin (SGN-35) in Patients with Relapsed or Refractory Systemic Anaplastic Large Cell Lymphoma: A Phase 2 Study Update

Systemic anaplastic large cell lymphoma (sALCL) is a T-cell non-Hodgkin lymphoma (NHL) characterized by the uniform expression of CD30. sALCL accounts for 2–5% of all cases of NHL; approximately 40–65% of patients experience recurrent disease after frontline treatment with few effective treatment options. Brentuximab vedotin (SGN-35) comprises an anti-CD30 antibody conjugated by a protease-cleavable linker to the potent antimicrotubule agent, monomethyl auristatin E (MMAE). A phase 2 study was conducted to determine the efficacy and safety of brentuximab vedotin in patients with relapsed or refractory sALCL (ClinicalTrials.gov #NCT00866047); updated results of this trial are presented.

Brentuximab vedotin 1.8 mg/kg was administered every 3 weeks as a 30-minute outpatient IV infusion for up to 16 cycles of treatment. Determination of efficacy was based on objective response assessments per independent review according to the Revised Response Criteria for Malignant Lymphoma (Cheson 2007). Patients were enrolled between June 2009 and May 2010 at 22 clinical sites in the US, Canada, and Europe.

58 patients with a median of 2 prior therapies (range 1–6) were treated; 57% were male and the median age was 52 years (range 14–76). Seventy-two percent of patients had ALK-negative disease, 62% had primary refractory disease (defined as no complete remission (CR) or relapse within 3 months of frontline therapy), and 26% had failed a prior autologous stem cell transplant (SCT). As previously reported, the objective response rate (ORR) was 86%, the CR rate was 57%, and 97% of patients had a reduction in tumor volume postbaseline. At the time of this updated analysis (data cut May 2011), all but 2 patients had discontinued treatment with brentuximab vedotin; the median number of treatment cycles was 7 (range 1–16). The median duration of objective response was 13.0 months (range 0.1–19.1+) and the median duration of response for patients achieving a CR was 17.1 months (range 0.7–19.1+). Median progression-free survival (PFS) was 14.6 months and median overall survival was not yet reached. Per investigator assessment, the median PFS with brentuximab vedotin was significantly longer than the median PFS achieved with the most recent prior therapy (20.0 months vs. 5.9 months; P value <0.001). All subgroups of patients analyzed in the study achieved a similar level of antitumor activity, regardless of baseline disease characteristics, tumor burden, or prior treatment history. Responses were particularly noteworthy in patients who had never responded to any previous therapy (n=13); in this subgroup of patients, 10 achieved an objective response (77%) and 4 a CR (31%). After discontinuing treatment in the study, 16 patients (28%) received a hematopoietic SCT (8 allogeneic, 8 autologous). The most common adverse events observed in the study were peripheral sensory neuropathy (41%), nausea (40%), fatigue (38%), pyrexia (34%), diarrhea (29%), rash (24%), constipation (22%), and neutropenia (21%). Most AEs in the study were Grade 1 or 2 in severity. Ten patients (17%) experienced Grade 3 events of peripheral neuropathy as defined in a Standardised MedDRA Query; no Grade 4 events were observed. In patients with neuropathy, 79% (26 of 33) have experienced resolution or some improvement and the median time to resolution or improvement was 13.3 weeks (range 0.3–48.7).

Durable complete remissions were achieved with brentuximab vedotin, and treatment was associated with manageable toxicity, in patients with relapsed or refractory sALCL. Approximately half of the responding patients (24 of 50) continued in remission at the time of this analysis; updated results of efficacy and long term safety will be presented at the meeting. Based on the results from this study, a trial evaluating the safety of brentuximab vedotin administered in sequence and in combination with multiagent chemotherapy was initiated and is currently ongoing in frontline sALCL.

Advani:Seattle Genetics, Inc.: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Off Label Use: Brentuximab vedotin (SGN-35) comprises an anti-CD30 antibody conjugated by a protease-cleavable linker to the potent antimicrotubule agent, monomethyl auristatin E (MMAE). It is an investigational agent that is being studied in CD30+ malignancies. Shustov:Millennium: Honoraria; Seattle Genetics, Inc.: Consultancy, Research Funding. Brice:Roche: Honoraria; Seattle Genetics, Inc.: Honoraria, Research Funding. Bartlett:Seattle Genetics, Inc.: Consultancy, Research Funding, Travel Expenses. Rosenblatt:Seattle Genetics, Inc.: Research Funding. Illidge:Seattle Genetics, Inc.: Consultancy, Research Funding; Millennium/Takeda: Consultancy, Honoraria. Matous:Cephalon: Speakers Bureau; Celgene: Speakers Bureau; Seattle Genetics, Inc.: Research Funding; Millennium: Speakers Bureau. Ramchandren:Seattle Genetics, Inc.: Research Funding. Fanale:Seattle Genetics, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Connors:Seattle Genetics, Inc.: Research Funding. Yang:Seattle Genetics, Inc.: Employment, Equity Ownership. Kennedy:Seattle Genetics, Inc.: Employment, Equity Ownership. Pro:Seattle Genetics, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding.