Efficacy of Chemotherapy or Chemo-Anti-PD-1 Combination after Unsatisfactory Response of Anti-PD-1 Therapy for Relapsed and Refractory Hodgkin Lymphoma: A Retrospective Series from Lysa Centers

Introduction: Hodgkin lymphoma (HL) pts who relapse after high-dose therapy (HDT) and autologous stem cell transplantation (ASCT) and brentuximab vedotin (BV) therapy have a poor outcome. For these relapsed and refractory (R/R) HL pts, anti-PD-1 therapy gives a high rate of objective responses. However, the rate of complete response (CR) remains modest and in the updated results of anti-PD-1 therapy clinical trials, about 50% of pts are still without progressive disease after one year of treatment. As anti-PD-1 therapy modifies the anticancer immune response, we hypothesize that anti-PD-1 therapy may increase sensitivity to chemotherapy (CT) given after anti-PD-1 therapy (sequential strategy) or in combination with anti-PD-1 therapy after an unsatisfactory response to immunotherapy (concomitant strategy). We retrospectively analyzed these two clinical situations in 30 R/R HL pts from LYSA centers treated with anti-PD-1 therapy.

Methods: We included R/R HL pts from 14 LYSA centers who received anti-PD-1 therapy in the context of clinical trials (N=4) or an authorization for temporary use (ATU) from the French medical drug agency (N=26). Before the anti-PD-1 therapy, pts had received a median of six (range, 2-14) lines of therapy, 69% had HDT+ASCT, 14% had allograft and 93% had been treated with BV. We considered two groups of pts: i. 19 pts (63%) in whom the anti-PD-1 therapy was stopped at the introduction of CT (Group 1); ii. 11 pts (37%) with an unsatisfactory response to anti-PD-1 therapy in whom a combination of CT with immunotherapy was initiated to optimize the response (Group 2). The quality of the response after the introduction of CT was evaluated retrospectively by each treating physicians according to Cheson 2007 or 2014 criteria. We also determined whether new CT treatments after and in combination with anti-PD-1 therapy led to unexpected toxicities and whether new treatment schedules made pts eligible for allograft.

Results: At the start of anti-PD-1, the median age of pts was 37 years old (range, 20-75), 24% had Ann Arbor III/IV stages, 34% had B symptoms and 21% had a performance status (PS) of 2-3. Patients received a median of 10 infusions (range, 2-52) of anti-PD-1 therapy with nivolumab (N=26, 87%) or pembrolizumab (N=4, 13%). The best responses achieved during anti-PD-1 therapy were a complete response (CR) for 5 patients, a partial response (PR) for 17 pts, stable disease (SD) for 2 pts and progression for 6 pts. In group 1, 17 pts were in progression, one pt in PR, and another pt in SD at the end of anti-PD-1 therapy alone. In group 1, after anti-PD-1 therapy, the pts were treated with vinblastine (N=3), gemcitabine (N=2) or bendamustine alone (N=3) or in combination with BV (N=4), GVD (N=1), ICE (N=1), DHAP (N=1), escalated BEACOPP (N=1), vinorelbine (N=1), vepeside (N=1) and caelyx (N=1). In group 2, before the combination, the response status was progression for 7 pts and PR for 4 pts. In group 2, to optimize the response to anti-PD-1, pts received vinblastine (N=7), gemcitabine (N=2) and BV (N=2). In the 28 evaluable pts, 11/18 (61%) in group 1 and 9/10 (90%) in group 2 showed an improved response after chemotherapy alone or combination with anti-PD-1 therapy respectively. In group 1, there were 6 CR (32%), 5 PR (26%), 1 SD (5%) and 6 PD (32%) (Figure 1B). In group 2, there were 5 CR (45%), 5 PR (45%) and 1 SD (10%) (Figure 1A). Of note, among the ten pts treated with vinblastine, 4 were in CR, 3 in RP, 1 in SD and 2 in progression. No unexpected toxicity was observed during the CT. Four pts had an allograft after the sequential CT (N=3) and concomitant CT strategy (N=1). Three pts were in CR 274, 279 and 480 days after the allograft and the fourth has not yet been evaluated. Allografts are now scheduled for 6 pts. With a median follow-up of 9.1 months (95%CI, 6.1-14) following the initiation of chemotherapy (alone or combined) the median PFS and OS were 8.4 and 14.6 months, respectively.

Conclusions: Our retrospective study showed that pts with an unsatisfactory response or PD with anti-PD-1 therapy had a new objective response with CT alone (61%) or CT in combination with anti-PD-1 therapy (90%). This response could make some pts eligible for allograft. Prospective clinical trials are needed to confirm the synergistic effect of CT with anti-PD-1 therapy and to determine which CT provides the best results in combination with these checkpoint inhibitors.

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