Results from a Phase 1/2 Study of Brentuximab Vedotin in Combination with Nivolumab in Patients with Relapsed or Refractory Hodgkin Lymphoma

Introduction

Brentuximab vedotin (BV) is an ADC directed against CD30, a receptor expressed by malignant Reed-Sternberg (RS) cells present in the inflammatory/immune cell microenvironment of classical Hodgkin lymphomas (cHL). Through induction of immunogenic cell death, BV may prime an antitumor immune response via microtubule disruption of CD30-expressing RS cells (Gardai 2015). Tumor cells expressing PD-1 ligands use the PD-1 pathway to evade an immune response. Nivolumab (Nivo) blocks the PD-1 receptor, inhibits binding of PD-1 ligands, and restores an effective antitumor immune response. Targeted killing of CD30-expressing RS cells, concurrent with restoration of the immune response, may lead to higher complete response (CR) rates in patients (pts) with relapsed or refractory cHL (R/R HL), as well as improved durability of responses post autologous stem cell transplant (ASCT). Here we present updated results from the phase 1/2 study of BV + Nivo in pts with R/R HL.

Methods

BV + Nivo was evaluated in cHL that had relapsed or was refractory to frontline (FL) chemotherapy in adult pts (NCT02572167). Pts were excluded if they had received prior salvage therapy, BV or immuno-oncology therapy, or allogeneic SCT or ASCT. Pts were treated in 21-day cycles for up to 4 cycles. In Parts 1 and 2 of the trial, BV (1.8 mg/kg) was given on Cycle 1 Day 1 and Nivo (3 mg/kg) on Cycle 1 Day 8. For Cycles 2-4, BV and Nivo were given on Day 1. After the Cycle 4 response assessment, pts were eligible to undergo ASCT. The investigators assessed response per the Lugano Classification (Cheson 2014).

Results

62 pts with R/R HL were enrolled in Parts 1 and 2; 61 pts received BV + Nivo, of whom 58 completed treatment (tx). 4 pts discontinued the study due to pt decision (2), AE (1), and investigator decision (1). Median age was 36 years, 52% were female, and 90% had received FL ABVD. 45% of pts had primary refractory disease and 31% experienced relapse within 1 year of FL therapy. Infusion-related reactions (IRRs) occurred in 41% of pts. Tx emergent AEs occurred in 98% of pts prior to ASCT (33% G3, 5% G4). Excluding IRRs, potential immune-related AEs (IrAEs) occurred in 84% of pts (10% G3, 3% G4) with 5 pts (8%) treated with systemic steroids for G4 pneumonitis, G4 pneumonitis and colitis, G2 pneumonitis, G3 diarrhea and G2 colitis, and G3 AST elevation.

Among the 60 efficacy-evaluable pts, the CR rate was 62%, (48% of CR pts had Deauville ≤ 2) with an objective response rate of 85%; 5 pts (8%) had stable disease and 4 pts (7%) progressed on tx. At the time of this analysis, 39 pts had initiated ASCT with a median 5.1x10⁶ CD34+ cells/kg (range; 3-60) collected. Median times to neutrophil and platelet engraftment were 12 and 15 days, respectively. Pts were followed for a median of 3 months from ASCT (N=39, range; 0-12) and 5.7 months from first dose (N=61, range; 1-17).

BV and Nivo effects on the immune system were evaluated by peripheral blood immunophenotyping, serum cytokine/chemokine analyses, T-cell receptor sequencing, and intracellular cytokine staining. The first dose of BV resulted in elevation of pro-inflammatory cytokines and chemokines and concurrent reduction in serum TARC levels, with these results maintained post Nivo. We observed a reduction in Tregs and other T cell subsets after the first dose of BV with an elevation of T cell subsets post BV + Nivo. While TCR clonality in the periphery did not change over the course of the trial, T cell clonal expansion was observed post BV + Nivo, concurrent with T cell elevation measured by flow cytometry. Ex vivo peptide stimulation of PBMCs isolated from blood revealed the enhanced ability of T cell subsets to respond to MHC I and MHC II antigens following BV + Nivo compared to baseline: e.g., effector memory CD8+ T cells from some pts displayed increased intracellular IL-2, and TNFa after stimulation with MHCI and MHCII peptide pools compared to baseline, potentially indicating elevated activation status of the immune system following combination tx.

Conclusion

R/R HL remains an unmet clinical need despite recent medical advances. These data suggest the combination BV + Nivo is a well tolerated and an active salvage therapy with a high rate of CR (62%) that has no adverse impact on stem cell collection. The safety and activity of this novel combination support further exploration in an ongoing pivotal phase 3 trial in pts with R/R HL who have either already received or are considered ineligible for ASCT (NCT03138499).