Abstract P121

Brentuximab vedotin as bridging and maintenance therapy in hematopoietic cell transplant in a national access program for relapsed or refractory classical Hodgkin lymphoma patients

Background: Hematopoietic cell transplantation (HCT) is standard treatment for people with relapsed or refractory classical Hodgkin lymphoma (R/RcHL), but controlling the disease before HCT is crucial for success. Brentuximab vedotin (BV), an anti-CD30 antibody-drug conjugate, has proven useful as maintenance after HCT. We examined BV as bridging and post-HCT maintenance therapy through Mexico’s Patient Access Program (PAP) in R/RcHL.

Methods: We retrospectively analyzed data from R/RcHL patients in the PAP from January 2017 to December 2021. Of 231 people identified, 193 (83.5%) were deemed eligible for HCT (autologous or allogeneic) by their physicians. We collected demographic data, disease status, prior therapy, BV use (doses, purpose, timing), transplant type, eligibility, completion, and outcomes (relapse, death, survival). Patients were grouped by BV use as bridging and/or maintenance therapy. Main outcomes included HCT completion rate, post-HCT relapse, relapse-free survival (RFS), and overall survival (OS).

Results: Among 193 eligible patients, 71 (36.8%) underwent HCT (59 autologous, 12 allogeneic [9 matched related, 3 haploidentical]). Two patients had an allo-HCT after relapsing from an auto-HCT. The rest (n=122) missed HCT due to limited access (62), progression (42), refusal (6), death (3), stem-cell mobilization failure (3), or other reasons. BV was used as bridging in 46/193 (23.8%); 28/46 (60.9%) later had HCT, vs. 43/147 (29.3%) without BV bridging (p<0.001). Of 71 who had HCT, 28 got BV as a bridge; 12/28 (42.9%) also received BV as post-HCT maintenance. Of those not given BV as a bridge, 17/43 (39.5%) still got BV as maintenance. In total, 29 people had post-HCT BV maintenance (median 12 doses). Post-HCT relapse happened in 19 (median time: 10.5 months); 24.1% (7/29) relapsed in the maintenance group vs. 28.6% (12/42) without it (p=0.6780). No significant RFS (p=0.4917) or OS (p=0.3529) differences were seen with BV maintenance. Of maintenance patients, 41.4% also had BV as bridging. The 36-month OS rate was higher in HCT vs. non-HCT patients (100% vs. 85.9%).

Conclusions: BV use as bridge to HCT may increase the likelihood of undergoing HCT. While post-HCT maintenance with BV did not significantly improve OS or RFS, several factors could explain this result, including prior BV exposure or insufficient power of the study