Early toxicity and clinical outcomes after chimeric antigen receptor T-cell (CAR-T) therapy for lymphoma

Background Chimeric antigen receptor T-cell (CAR-T) infusion is associated with early toxicity. Yet, whether early toxicity development holds ramifications for long-term outcomes is unknown. Methods From a large cohort of consecutive adult patients treated with CAR-T therapies for relapsed or refractory lymphomas from 2016 to 2019, we assessed progression-free survival (PFS), by toxicity development (cytokine release syndrome (CRS), neurotoxicity, or cardiotoxicity]. We also assessed the relationship of toxicity development to objective disease response, and overall survival (OS). Multivariable regression was utilized to evaluate relationships between standard clinical and laboratory measures and disease outcomes. Differences in outcomes, by toxicity status, were also assessed via 30-day landmark analysis. Furthermore, we assessed the effects of early anti-CRS toxicity therapy use (at ≤grade 2 toxicity) on maximum toxicity grade observed, and long-term disease outcomes (PFS and OS). Results Overall, from 102 CAR-T-treated patients, 90 were identified as treated with single-agent therapy, of which 88.9% developed toxicity (80 CRS, 41 neurotoxicity, and 17 cardiotoxicity), including 28.9% with high-grade (≥3) events. The most common manifestations were hypotension at 96.6% and fever at 94.8%. Among patients with cardiac events, there was a non-significant trend toward a higher prevalence of concurrent or preceding high-grade (≥3) CRS. 50.0% required tocilizumab or corticosteroids. The median time to toxicity was 3 days; high grade CRS development was associated with cardiac and neurotoxicity. In multivariable regression, accounting for disease severity and traditional predictors of disease response, moderate (maximum grade 2) CRS development was associated with higher complete response at 1 year (HR: 2.34; p=0.07), and longer PFS (HR: 0.41; p=0.02, in landmark analysis), and OS (HR: 0.43; p=0.03). Among those with CRS, relative blood pressure (HR: 2.25; p=0.004), respectively, also associated with improved PFS. There was no difference in disease outcomes, or maximum toxicity grade (CRS, neurotoxicity, or cardiotoxicity) observed, based on the presence or absence of the use of early CRS-directed therapies. Conclusions Among adult lymphoma patients, moderate toxicity manifest as grade 2 CRS after CAR-T infusion may associate with favorable clinical outcomes. Further studies are needed to confirm these findings.