Consolidation with Nivolumab and Brentuximab Vedotin after Autologous Hematopoietic Cell Transplantation in Patients with High-Risk Hodgkin Lymphoma

Introduction: Standard of care for patients (pts) with relapsed or refractory (RR) Hodgkin lymphoma (HL) is salvage therapy (tx) followed by autologous hematopoietic cell transplantation (HCT). However, most pts with high-risk RR HL will relapse after HCT. The AETHERA study demonstrated that post-HCT consolidation with brentuximab vedotin (BV) in high-risk HL pts improved progression-free survival (PFS) compared to placebo, particularly in pts with 2+ risk factors (Moskowitz, 2018). Pts with prior BV exposure were excluded from AETHERA, and BV is increasingly used prior to HCT in HL. PD1 blockade is effective in pts with RR HL and PD1 monotherapy as post-HCT consolidation in HL resulted in promising 18 mo PFS (Armand, 2019). Combined BV and nivolumab (Nivo) is a safe and effective salvage tx in HL, therefore we conducted a multicenter phase 2 study to evaluate the safety and efficacy of BV-Nivo post-HCT consolidation in high risk RR HL.

Methods: After HCT, adult pts with high-risk HL defined as having ≥ 1 of the following modified AETHERA risk factors were eligible: primary refractory HL, relapse < 1 year of completing initial tx, extranodal disease (dz) at relapse, B symptoms (sx) at relapse, requiring > 1 salvage tx, not in CR at HCT. Prior BV or PD1 blockade were allowed if pts were not refractory. Pts underwent HCT according to institutional standards at the 5 centers. Starting between day 30-75 after HCT, pts received 1.8 mg/kg of BV and 3mg/kg nivo q21 days for a planned 8 cycles. If 1 drug was discontinued due to toxicity, the other could be continued. Investigators assessed response and progressive disease (PD) according to the 2014 Lugano classification. The primary endpoint was 18 mo PFS from study tx initiation. Secondary endpoints were overall survival (OS), safety, and the response rate in pts not in complete response (CR) at baseline.

Results: 59 pts were enrolled and treated with at least one dose of study tx. Baseline characteristics are listed in Table 1. 18 (31%) pts were primary refractory, 35 (59%) had early relapse, 23 (39%) had extranodal dz and 14 (24%) had B sx at relapse, 15 (25%) received > 1 salvage tx before HCT, and 48 (81%) were in CR at HCT. 21 (36%) had 1 modified AETHERA risk factor, 23 (40%) had 2 and 14 (24%) had 3+ risk factors. The median follow-up time from study tx initiation was 15.7 months (range, 2.8-35.5).

Patients initiated BV-nivo a median 54 days from HCT (range, 34-75) and received a median of 8 cycles (range, 1-8). 29 (49%) pts completed all 8 cycles of BV and nivo and 45 (76%) patients completed 8 cycles of one drug. 14 (24%) pts discontinued both BV and nivo early, including 6 for adverse events (AE), 6 pt withdrawals, 1 pt lost to follow-up, and 1 pt death from PJP pneumonia unrelated to study tx. BV was discontinued in 8 (14%) pts - due to grade (gr) 3 peripheral neuropathy (PN) in 2 pts, gr 2 PN in 2 pts, carpal tunnel syndrome in 1 pt, gastrointestinal AEs in 2 pts, and infusion related reaction in 1 pt. Nivo was discontinued in 7 (12%) pts - due to pneumonitis in 2 pts, and colitis, elevated bilirubin, abnormal transaminases, pneumonia with elevated creatinine, and hypotension with fever in 1 pt each. BV was dose reduced to 1.2mg/kg in 11 (19%) pts, 9 pts for PN, and 1 each for neutropenia and arthralgia. The most common AEs related to BV-Nivo consolidation were PN (51%, 3% gr 3), neutropenia (42%, 31% gr 3-4), fatigue (37%), diarrhea (29%, 3% gr 3), nausea (25%, 2% gr 3), arthralgia (24%), AST elevation (24%, 2% gr 3). The most frequent gr 3-4 AEs were neutropenia (31%), pneumonitis (7%), and ALT elevation (5%). Immune-related (ir) AEs requiring systemic corticosteroids occurred in 18 (31%) patients. Most common Gr 2 or higher irAEs included: pneumonitis (12%), AST or ALT elevation (8%), hypothyroidism (5%), and rash (3%).

6 pts were not in CR at baseline after HCT (all PR). 5 pts converted to CR with study tx and 1 pt remained in PR without PD. There were only 2 PFS events, 1 pt with relapse at 15 months and PJP-related death after prophylaxis was self-discontinued. The estimated 18 mo PFS and OS in all patients were 95% and 98%, respectively. The estimated 18 mo PFS in pts with 2+ and 3+ risk factors were 92% and 89%, respectively.

Conclusions: Post-HCT consolidation with BV-Nivo in pts with high-risk RR HL is a promising approach, with only 1 relapse observed in our cohort with short follow-up thus far. Post-HCT BV-Nivo was tolerable, though IrAEs were observed more frequently than in the pre-HCT setting and PN and neutropenia were common.

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