Nivolumab Before CAR-T: What the Data Shows

1. Nivolumab as Bridging Therapy (Before Infusion, After Leukapheresis)

• Retrospective series of 9 patients with R/R PMBCL who received brentuximab vedotin (1.8 mg/kg) + nivolumab (240 mg) every 3 weeks as bridging (median 2 cycles) before CAR-T.
• Median age 37 (range 21-75); 67% stage IV; prior R-CHOP then R-DHAP.
• The authors conclude BV-nivolumab is "a valuable therapeutic strategy" in this setting where conventional bridging fails, though formal response and PFS data were not extracted in the abstract.
• Notably, the CARTHYM study (French DESCAR-T registry, n=62 axi-cel in PMBCL) included 20 patients who received checkpoint inhibitors as bridging - 9 of whom got BV-nivolumab. No significant difference in response rates or PFS was observed between CPI-bridged patients and those who did not receive CPI bridging. Prior CPI exposure was not associated with increased grade 3-4 immune-mediated toxicities.

2. Nivolumab/PD-1 Blockade Before Leukapheresis (To Improve CAR-T Product Quality)

• Retrospective analysis of 31 R/R B-cell lymphoma patients treated with liso-cel. 4 PMBCL patients had received pembrolizumab prior to CAR-T, all achieving remission before infusion.
• 3 of 4 patients maintained durable CR (≥30 months).
• Toxicities were comparable to non-PD-1-exposed patients. One pembrolizumab-treated patient had fatal neurotoxicity (a notable safety signal).
• Key mechanistic finding: "Favorable hematologic recovery and preserved T-cell counts at leukapheresis suggest that preceding PD-1 blockade did not compromise CAR-T manufacturing and may have enhanced T-cell fitness."
• Authors note this is the first real-world data with liso-cel in this sequence (prior studies used axi-cel).

3. Biological Rationale and Mechanistic Context

• T-cell exhaustion is a recognized cause of CAR-T failure - exhausted T cells in heavily pretreated patients lead to poor expansion, persistence, and function of the final product.
• PD-1 blockade can theoretically "reinvigorate" exhausted T cells prior to harvest, improving the starting material.
• PMBCL is particularly sensitive because of 9p24.1 copy-number gains that constitutively upregulate PD-L1, making these tumors uniquely responsive to anti-PD-1 therapy.
• Preclinical data supported the concept that nivolumab's PD-1 blockade could improve CAR-T effector function - but in the post-CAR-T setting (PMID 40233298 context), circulating CAR-T cells were detectable in only 30% of patients at nivolumab initiation, and their frequency did not increase after treatment, suggesting endogenous T-cell reinvigoration (not CAR-T reinvigoration) may drive responses.

4. Nivolumab After CAR-T Failure (For Context)

• A major retrospective study of 96 patients from 15 US academic centers who relapsed after CAR-T (53% DLBCL, treated with axi-cel in 53%) and received ICI (pembrolizumab 49%, nivolumab 43%) as rescue: ORR 19%, CR 10%, median PFS 54 days, median OS 159 days. PMBCL patients had better responses. (Frontiers in Pediatrics, 2023)
• A commentary in Br J Haematol 2023 on the Gazeau et al. series of 11 patients treated with nivolumab after failure to achieve CR 30 days post-axi-cel for DLBCL: 10/12 patients experienced a second expansion of circulating CAR-T cells after anti-PD-1, particularly in those with PD-L1+ tumors.

Summary Table

Bottom Line

• Prior nivolumab/PD-1 blockade does not appear to impair CAR-T manufacturing or significantly worsen toxicity.
• In PMBCL, sequential PD-1 blockade → CAR-T can yield durable remissions, likely because it both debulks PD-L1-driven disease and may improve T-cell fitness.
• The CARTHYM data provide some reassurance that CPI bridging does not negatively impact axi-cel outcomes.
• Fatal neurotoxicity in the liso-cel/pembro case (PMID 41483380) is a real safety signal that prospective trials need to address.