A Phase 2 Study Of Brentuximab Vedotin In Patients With Relapsed Or Refractory CD30-Positive Non-Hodgkin Lymphomas: Interim Results In Patients With DLBCL and Other B-Cell Lymphomas

Brentuximab vedotin (ADCETRIS^®) is an anti-CD30 monoclonal antibody conjugated by a protease-cleavable linker to a microtubule-disrupting agent, monomethyl auristatin E. Variable CD30 expression has been demonstrated in several B-cell non-Hodgkin lymphoma (NHL) subtypes such as diffuse large B-cell lymphoma (DLBCL) and primary mediastinal B-cell lymphoma (PMBL).

A phase 2, open-label, single-arm study is ongoing to evaluate the antitumor activity of brentuximab vedotin in relapsed or refractory CD30-positive NHL, including B-cell neoplasms (Clinical Trials.gov NCT01421667). CD30 expression is determined by immunohistochemistry per local laboratory; any level of CD30-positive expression is permitted for enrollment. Brentuximab vedotin, 1.8 mg/kg, is administered every 3 weeks by IV infusion. Patients who achieve at least stable disease are eligible to receive continued treatment until disease progression or unacceptable toxicity. The primary efficacy endpoint is objective response rate (ORR) as assessed by the Revised Response Criteria for Malignant Lymphoma (Cheson 2007). Correlation between antitumor activity and quantitative CD30 expression is also being explored. This subset analysis presents interim data for patients with relapsed/refractory Bcell neoplasms.

Sixty-two B-cell lymphoma patients with variable CD30 expression by central review (range 0–100%) have been enrolled to date. Diagnoses include DLBCL (n=44) and other B-cell neoplasms (n=18) [grey zone lymphoma (n=6), PMBL (n=6), follicular lymphoma (n=3), and post-transplant lymphoproliferative disorder (n=3)]. The median age of all patients was 55 years (range, 16–85 years), and the majority had an ECOG performance status of 0/1 (92%). Patients had received a median of 2 prior therapies (range, 1 to 19); 11 (18%) had received prior stem cell transplant. Forty patients (65%) had primary refractory disease, and 47 patients (76%) were refractory to their most recent prior therapy. Fourteen patients (23%) had never responded to any prior therapy. At the time of this analysis, patients had received a median of 3 cycles of treatment (range, 1–17 cycles), with a median duration of treatment of 10.5 weeks (range, 2.4 to 57.1 weeks). Twelve (19%) patients remain on treatment.

Of the 43 efficacy evaluable DLBCL patients, 40% achieved an objective response [7 complete remission (CR), 10 partial remission (PR)]; the median duration of objective response was 36 weeks (range, 0.1+ to 62.3+ weeks). Of the 18 efficacy evaluable patients with other Bcell neoplasms, 22% achieved an objective response: PMBL (1 CR), PTLD (1 CR), and grey zone lymphoma (2 PRs). The median duration of objective response was 21.7 weeks (range, 6.1 to 37.1 weeks). CD30 expression levels for patients with a CR or PR were variable and ranged from <1% to 90%. There was no statistical correlation between CD30 expression and response rate.

Treatment-emergent adverse events (AEs) occurring in >20% of patients included fatigue (40%), nausea and neutropenia (37% each), pyrexia (32%), diarrhea (31%), peripheral sensory neuropathy (26%), vomiting (23%), and anemia and constipation (21% each). Peripheral neuropathy events have been primarily Grade 1 or 2. Neutropenia (29%) was the only Grade 3/4 related AE observed in >10% of patients. AEs led to treatment discontinuation in 6 patients; the most common reason was peripheral sensory neuropathy (2 patients).

In this interim analysis of 62 patients with highly refractory B-cell lymphomas, compelling antitumor activity has been observed with brentuximab vedotin. Forty percent of DLBCL patients achieved an objective response, with median remission duration of >8 months and a notable proportion of complete remissions. No correlation between CD30 expression and response rate has been observed to date. Safety data are consistent with the profile of brentuximab vedotin. This study continues to enroll patients and updated results will be presented at the meeting.

Bartlett:Seattle Genetics, Inc.: Advisory/scientific board membership and travel expenses Other, Research Funding. Off Label Use: Brentuximab vedotin is indicated for treatment of patients with Hodgkin lymphoma after failure of autologous stem cell transplant or after failure of at least two prior multi-agent chemotherapy regimens in patients who are not ASCT candidates and for the treatment of patients with systemic anaplastic large cell lymphoma after failure of at least one prior multi-agent chemotherapy regimen. Sharman:Seattle Genetics, Inc.: Research Funding, Travel expenses Other; Genentech: Research Funding; Gilead: Research Funding. Oki:Seattle Genetics, Inc.: Research Funding. Advani:Millennium: Advisory/scientific board membership, Advisory/scientific board membership Other, Research Funding; Seattle Genetics, Inc.: Advisory/scientific board membership Other, Research Funding; Genentech: Membership on an entity’s Board of Directors or advisory committees, Research Funding; Pharmacyclics, Inc.: Research Funding; Janssen R&D: Research Funding; Allos Therapeutics: Research Funding; Celgene: Membership on an entity’s Board of Directors or advisory committees; Abbott: Research Funding. Bello:Seattle Genetics, Inc.: Research Funding, Speakers Bureau; Celgene: Membership on an entity’s Board of Directors or advisory committees; Spectrum pharmaceuticals: Speakers Bureau. Winter:Seattle Genetics, Inc.: Research Funding. Yang:Seattle Genetics, Inc.: Employment, Equity Ownership. Kennedy:Seattle Genetics, Inc.: Employment, Equity Ownership. Jacobsen:Seattle Genetics, Inc.: Advisory/scientific board membership Other, Research Funding.