A Phase 2 Study of Brentuximab Vedotin in Patients with Relapsed or Refractory CD30-Positive Non-Hodgkin Lymphomas: Interim Results.

Brentuximab vedotin (ADCETRIS^®) is a CD30-directed antibody-drug conjugate approved for the treatment of relapsed Hodgkin lymphoma and systemic anaplastic large cell lymphoma (ALCL). Several non-Hodgkin lymphoma (NHL) subtypes such as diffuse large B-cell lymphoma (DLBCL) and peripheral T-cell lymphomas (PTCL) have variable quantitative and qualitative expression of CD30. As a result of the high objective response rate (86%) and durable complete remissions (CR) observed in a pivotal phase 2 study in ALCL, a study was initiated to investigate the efficacy and safety of brentuximab vedotin in other NHLs that express the CD30 antigen.

A phase 2, open-label, single-arm, multicenter study is currently ongoing to evaluate the antitumor activity of brentuximab vedotin in approximately 75 patients with relapsed or refractory CD30-positive NHL (ClinicalTrials.gov NCT01421667). 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). Efficacy variables will be analyzed by total patients, WHO NHL classification, DLBCL (excluding peripheral mediastinal large B-cell lymphoma [PMBL] due to differing treatment paradigms and outcomes for this DLBCL subtype), and by each individual disease. The correlation between antitumor activity and quantitative CD30 expression is also being explored.

Fifty-three patients with various CD30-positive NHLs have been enrolled to date (35 with B-cell neoplasms and 18 with mature T-/NK-cell neoplasms). Twenty-nine (55%) patients had refractory disease, 19 (36%) had relapsed since their most recent prior therapy, and 5 (9%) had primary refractory disease (did not achieve a CR with frontline therapy or relapsed within 3 months of completing frontline therapy). Diagnoses include DLBCL (assorted disease subtypes, n=22), angioimmunoblastic T-cell lymphoma (AITL, n=9), PTCL-NOS (n=8), grey zone lymphoma (n=5), PMBL (n=4), follicular lymphoma (n=3), post-transplant lymphoproliferative disorder (n=1), and cutaneous T-cell lymphoma (n=1). The median age is 64 years (range 16–83) and 30 patients (57%) are male. Patients have received a median of 3 prior systemic therapies and 6 patients have received prior stem cell transplants.

Of the 36 patients who have had a response assessment to date, 12 (33%) have achieved an objective response (5 CR, 7 partial remissions [PR]). The ORR for B-cell NHLs is 36% (9/25), and 27% (3/11) for mature T-/NK-cell NHLs. Thus far, responses are particularly noteworthy in DLBCL (excluding PMBL) where 7 of 15 patients (47%) have responded (3 CR, 4 PR), in AITL where 3 of 5 patients (60%) have responded (2 CR, 1 PR), and in grey zone lymphoma where 2 of 5 patients (40%) have achieved a PR. Median duration of response has not been reached. Of the 12 responding patients, 7 remain on treatment, 3 discontinued due to a patient decision (non-adverse event), and 2 due to adverse events of neutropenia (related) and pneumocystis jiroveci pneumonia (unrelated). CD30 expression levels for patients with a CR or PR were widely variable and ranged from <1% to 90%.

Treatment-emergent adverse events (TEAEs) occurring in ≥10% of patients include fatigue (26%), diarrhea (16%), nausea (16%), pyrexia (16%), neutropenia (14%), dyspnea (12%), and abdominal pain (10%), and TEAEs considered related to study drug include fatigue (16%) and neutropenia (14%). Most AEs have been Grade 1 or 2. Grade 3 dyspnea, hyponatremia, and decreased white blood cell count have occurred in 2 patients each, while Grade 3 neutropenia has occurred in 3 patients. Two patients have experienced Grade 4 neutropenia. Peripheral neuropathy events have been Grade 1 or 2.

In this interim analysis of 53 patients (36 with response evaluations), compelling antitumor activity has been demonstrated in both B-cell and mature T-/NK-cell NHLs, in particular DLBCL, AITL, and grey zone lymphoma. Due to the range of CD30 expression in patients achieving an objective response, more data are needed to determine if there is a correlation between CD30 expression and antitumor activity. Preliminary safety data are consistent with the safety profile of brentuximab vedotin.

Jacobsen:Seattle Genetics, Inc.: 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. These indications are based on response rate. There are no data available demonstrating improvement in patient reported outcomes or survival with brentuximab vedotin. Advani:Seattle Genetics, Inc.: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; Genentech: Research Funding; Pharmacyclics: Research Funding; Abbott: Research Funding. Oki:Seattle Genetics, Inc.: Research Funding. Sharman:Seattle Genetics, Inc.: Research Funding. Horwitz:Seattle Genetics, Inc.: Consultancy, Research Funding; Novartis: Consultancy; Millennium: Consultancy; Celgene: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy; Allos Therapeutics: Consultancy, Research Funding; Merck: Honoraria; Genzyme: Research Funding; Infinity Pharmaceuticals: Research Funding. Forero-Torres:Seattle Geentics, Inc.: Research Funding, Speakers Bureau. O'Connor:Seattle Genetics, Inc.: Consultancy, Research Funding; Millennium: Consultancy, Research Funding. Shustov:Seattle Genetics, Inc.: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Siddiqi:Seattle Genetics, Inc.: Consultancy, Research Funding. Grove:Seattle Genetics, Inc.: Employment, Equity Ownership. Bartlett:Seattle Genetics, Inc.: Consultancy, Research Funding, Travel expenses Other.