Concomitant Use of Antibiotics During Immune Checkpoint Inhibitor (CPI)-Based Salvage Therapy Does Not Impact Post-ASCT Outcomes in Patients with Relapsed/Refractory Hodgkin Lymphoma (RRHL)

Introduction Emerging evidence suggests that responses to CPI in Hodgkin lymphoma (HL) may be adversely affected by the reductions in microbiome diversity associated with concomitant antibiotic (abx) exposure. Given the increasingly key role that CPI-based regimens (CPI+) appear to have on improving post-ASCT outcomes, we evaluated the potential impact of abx exposure on CPI+ efficacy and post-ASCT outcomes in RRHL patients treated with CPI+ prior to ASCT.

Methods This retrospective study of RRHL patients at 11 US academic centers included patients ≥18 who received CPI+ between 1/2012-12/2022. Patient/disease characteristics, treatment histories, outcomes, and abx exposure (2 weeks prior to and 30 days after CPI+) were collected by participating sites and analyzed centrally. Primary and key secondary objectives were overall response rate (ORR) to CPI+ by Lugano criteria, and PFS/overall survival (OS) by abx exposure. PFS/OS were estimated by Kaplan-Meier and compared by log-rank tests. Univariate and multivariate regression models evaluated the impact of abx exposure on ORR/complete response rate (CR)/PFS/OS.

Results 237 patients with median follow-up of 3.20 and 2.73 years from CPI+ initiation and ASCT, respectively, were evaluated. At diagnosis: median age 30.6 (range 7.8 - 71.7) years, female (53.6%), nodular sclerosing (75.1%), and stages I-IIB/bulky and III/IV (73.4%). 1L regimens were ABVD/ABVD-like (75.5%), brentuximab vedotin (BV)+AVD (15.2%), and other (9.3%). 65.8% received 6 cycles of chemotherapy, and 10.5% received 1L radiation. End of 1L responses were CR (39.7%), partial response (PR; 13.1%), refractory disease (37.6%), and unknown (8.0%).

Median time to first relapse from diagnosis was 0.95 (range 0.15 - 22.2) years. All patients underwent ASCT after 1 (58.2%), 2 (22.8%), or 3+ (19.0%) lines of salvage. CPI+ was given as 1st (65.8%), 2nd (21.5%), or 3rd+ (12.5%) salvage therapy. CPI+ included BV-nivolumab (44.3%) + ipilimumab (7.2%), pembrolizumab, gemcitabine, vinorelbine, and liposomal doxorubicin (P-GVD; 24.5%), and CPI-monotherapy (20.2%). ORR to CPI+ was 88.0% (CR 68.4%) in all lines; as 1st salvage ORR was 91.7% (CR 76.3%). 75.1% of patients underwent ASCT in CR (PR 19.4%) increasing to 91.1% CR after ASCT. At 3-years, PFS was 88.0% (95% CI: 83.5% - 92.8%) and OS was 94.8% (95% CI: 91.3% - 98.3%) for the full cohort.

Overall, 46.8% patients were abx exposed during CPI+, 22.8% fluoroquinolone/beta-lactams (BL) prophylaxis (ppx) and 38.8% abx [BL 29.5%, carbapenems (CB) 12.2%, vancomycin (VM) 19.8%, anti-pseudomonas (PA) 24.9%, anti-MRSA (SA) 22.4%, anti-anaerobe (AN) 16.5%] for suspected/documented infection. Use of ppx, BL, CB, VM, PA, SA were significantly higher with CP1+ as 2nd+ vs 1st salvage. At 3-years, PFS (87.0% vs 88.4%, p=0.91) and OS (92.5% vs 95.8%, p=0.47) were similar for abx exposed vs naïve patients, respectively. On univariate analysis, line of salvage and CPI+ regimen (Cytotoxic vs Monotherapy) were associated with ORR/CR, while overall abx exposure was not associated with inferior ORR (OR 0.62; p=0.24), CR (OR 0.85, p=0.56), PFS (HR 0.95, p=0.91), or OS (HR 1.58, p=0.47). When adjusted for line of salvage and CPI+ regimen, exposure to BL, CB, VM, PS, SA, or AN, abx indication (ppx vs treatment), duration of abx exposure (<7 vs ≥7 days) by class were all not associated with ORR/CR or PFS/OS.

Conclusion In this large cohort abx exposure does not appear to adversely affect ORR/CR to CPI+ or PFS/OS following ASCT, when adjusted for line of CPI+ salvage and CPI+ regimen. Our findings may be related the high proportion of patients (79.8%) receiving CPI-combinations compared to CPI monotherapy (20.2%), whereas in previous series all patients received CPI without cytotoxic agents. This observation could be related to intrinsic antimicrobial activities of some cytotoxic agents (e.g. gemcitabine and doxorubicin) that may overshadow impact from concomitant abx exposure. Alternatively, the lack of effect could be related to the inherent fitness of patients with RRHL who undergo ASCT, compared to those treated with CPI+ following ASCT or those with solid tumors receiving where abx exposure may indicate an overall sicker/higher-risk population. Overall, our findings demonstrate that combination of CPI with BV or chemotherapy may overcome any adverse impact of abx on the efficacy of CPI+ prior to ASCT.

Varma:Affimed NV: Current equity holder in publicly-traded company. Baek:Postgraduate Healthcare Education, LLC / Bristol Myers Squibb: Other: Co-presented an educational activity (continuing education) that was sponsored by Postgraduate Healthcare Education, LLC and supported by an educational grant from Bristol Myers Squibb.. Svoboda:Seagen: Honoraria; Merck: Honoraria; Abbvie: Honoraria; Atara: Honoraria; Incyte: Research Funding; TG Therapeutics: Honoraria; BMS: Honoraria; GenMab: Honoraria; Adaptive: Honoraria, Research Funding. Shah:AbbVie, Seattle Genetics: Consultancy; Incyte, Epizyme, Seattle Genetics, Loxo Oncology, Acerta: Research Funding. Yamshon:Kite Pharma: Consultancy; Bristol Myers Squibb: Consultancy. Gopal:Merck: Consultancy, Honoraria, Research Funding; I-Mab bio: Research Funding; IgM Bio: Research Funding; Takeda: Research Funding; Gilead: Consultancy, Honoraria, Research Funding; Astra Zeneca: Research Funding; Agios: Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Research Funding; BMS: Research Funding; SeaGen: Research Funding; Teva: Research Funding; Genmab: Honoraria, Research Funding; Beigene: Consultancy, Honoraria, Research Funding; Incyte: Consultancy, Honoraria; Kite: Consultancy, Honoraria; Morphosys/Incyte: Consultancy, Honoraria; ADCT: Consultancy, Honoraria; Acrotech: Consultancy, Honoraria; Merck: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria; Servier: Consultancy, Honoraria; Cellectar: Consultancy, Honoraria; Compliment: Consultancy, Current holder of stock options in a privately-held company, Honoraria; Epizyme: Consultancy, Honoraria; Lilly: Consultancy, Honoraria; Caribou: Consultancy, Honoraria; Fresenius-Kabi: Consultancy, Honoraria; Scitek: Consultancy, Honoraria; Sana: Consultancy, Honoraria. Bartlett:BMS: Research Funding; Celegne: Research Funding; Autolus: Research Funding; ADC Therapeutics: Research Funding; Washington University School of Medicine: Current Employment; AbbVie: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Research Funding; Roche/Genentech: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics: Research Funding; Millennium: Research Funding; Janssen: Research Funding; Kite Pharm: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Research Funding; Forty Seven: Research Funding; Genmab: Membership on an entity's Board of Directors or advisory committees, Research Funding; Foresight Diagnostics: Membership on an entity's Board of Directors or advisory committees. Merryman:Genmab: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol Myers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; DG Medicine: Consultancy, Membership on an entity's Board of Directors or advisory committees; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech/Roche: Research Funding; Merck: Research Funding. Advani:Cyteir: Research Funding; Regeneron: Research Funding; Autolus: Honoraria, Other: DSMB/Advisory Boards; Gilead: Research Funding; Merck: Other: Steering committee, DSMB/Advisory Boards, Research Funding; Seattle Genetics: Research Funding; ADCT: Honoraria, Other: DSMB/Advisory Boards; BeiGene: Honoraria, Other: DSMB/Advisory Boards, Research Funding; Roche/Genentech: Honoraria, Other: Steering committee, DSMB/Advisory Boards, Research Funding. Ahmed:Nektar: Research Funding; Janssen: Research Funding; Bristol Myers Squibb: Research Funding; Kite, a Gilead Company: Consultancy, Research Funding; Myeloid Therapeutics: Consultancy; Merck: Research Funding; Xencor: Research Funding; ADC Therapeutics: Consultancy. Diefenbach:FATE Therapeutics: Consultancy, Research Funding; Morphosys: Consultancy, Research Funding; Millenium: Research Funding; Merck: Consultancy, Research Funding; Gilead: Current equity holder in publicly-traded company, Research Funding; Genmab: Consultancy, Research Funding; Genentech/Roche: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Incyte: Consultancy, Research Funding; MEI Pharma: Consultancy, Research Funding; I MAB: Consultancy, Current equity holder in private company; NYU Grossman School of Medicine/Perlmutter Cancer Center at NYU Langone Health: Current Employment; OverT Therapeutics: Current equity holder in private company; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding; Seattle Genetics: Consultancy, Research Funding.