Brentuximab Vedotin As Single Agent in the Treatment of Relapsed/Refractory CD30 Positive Peripheral T-Cell Lymphoma Patients: A Phase 2 Study of the Fondazione Italiana Linfomi

Options are limited for patients with relapsed or refractory (R/R) peripheral T-cell lymphoma (PTCL) for whom the median overall survival (OS) and progression free survival (PFS) are less than 6 months. Patients who are candidates for allogeneic stem cell transplantation can be cured should they achieve adequate response to salvage therapy prior to transplant. Patients who relapse after transplant or who are not transplant candidates are often treated with sequential single-agent therapies with non-curative intent. Only four agents are FDA-approved for the treatment of R/R PTCL including pralatrexate, romidepsin and belinostat. The objective response rate to each of these agents is only 25–30% and duration of response (DOR) is limited. For a specific subtype of PTCL, namely systemic anaplastic large-cell lymphoma, single-agent brentuximab vedotin (BV) treatment resulted in an 86% overall response rate (ORR) and a 57% complete response (CR) rate in R/R disease. A phase 2 study evaluated the efficacy and safety of BV in angioimmunoblastic T-cell lymphoma (AITL) and PTCL not otherwise specified reporting an ORR of 41% (Horwitz et al, Blood. 2014).

We conducted a phase 2 study to determine the antitumor efficacy of single-agent BV (1.8 mg/kg administered intravenously every 3 weeks for a maximum of 16 cycles) as measured by the ORR in R/R CD30+ PTCL patients (PTCL not otherwise specified, AITL and transformed mycosis fungoides). Secondary objectives were to assess duration of tumor control, including duration of response and progression-free survival, overall survival and the safety and tolerability of BV in this setting. ClinicalTrials.gov Identifier: NCT02497131.

From September 2015 and September 2019, 25 patients were enrolled and 23 (population for the final analysis) received at least one BV infusion (median 5, range 2-16). There were 10 females, 18 patients were in stage IV and 16 subjects were refractory to the last therapy. Median number of therapies received prior to BV was 2 (range 1-6). Final ORR was 30.4%, with 4 CR. CR patients were 3 PTCL not otherwise specified and 1 AITL with response duration of 2.8, 3.3, 4.5 and 10.7 months, respectively. Best response was achieved at the III cycle. PFS was 4.3% at 12 months (median reached at 4.4 months), OS at 12 months was 49.8% (median reached at 11.4 months) and median DOR was 3.4 months. No correlation between CD30 expression per central review and response was observed.

Twenty-one hematological toxicities occurred, 14 of them were grade ≥3 (10 thrombocytopenia and 4 neutropenia, all resolved or improved during BV therapy). Among extra-hematological toxicities (n=26, 3.5% grade ≥3), 7 were serious adverse events. To note, 6 of them (23.1%) were lung infection/pneumonia. Only one peripheral neuropathy (grade 1) occurred.

In terms of response, the ORR and PFS in this trial are comparable to those in similar populations studied with both other recently approved agents, such as pralatrexate and romidepsin, and with the other phase 2 study on BV. The ORR of 30% and the OS of in the present study places BV among the active agents for PTCL. Safety concerns emerged about infections, claiming for a strict monitoring for these toxicities.