Miguel‐Angel Perales

BACKGROUND: The prognosis of patients with early relapsed or refractory large B-cell lymphoma after the receipt of first-line chemoimmunotherapy is poor. METHODS: In this international, phase 3 trial, we randomly assigned, in a 1:1 ratio, patients with large B-cell lymphoma that was refractory to or had relapsed no more than 12 months after first-line chemoimmunotherapy to receive axicabtagene ciloleucel (axi-cel, an autologous anti-CD19 chimeric antigen receptor T-cell therapy) or standard care (two or three cycles of investigator-selected, protocol-defined chemoimmunotherapy, followed by high-dose chemotherapy with autologous stem-cell transplantation in patients with a response to the chemoimmunotherapy). The primary end point was event-free survival according to blinded central review. Key secondary end points were response and overall survival. Safety was also assessed. RESULTS: A total of 180 patients were randomly assigned to receive axi-cel and 179 to receive standard care. The primary end-point analysis of event-free survival showed that axi-cel therapy was superior to standard care. At a median follow-up of 24.9 months, the median event-free survival was 8.3 months in the axi-cel group and 2.0 months in the standard-care group, and the 24-month event-free survival was 41% and 16%, respectively (hazard ratio for event or death, 0.40; 95% confidence interval, 0.31 to 0.51; P<0.001). A response occurred in 83% of the patients in the axi-cel group and in 50% of those in the standard-care group (with a complete response in 65% and 32%, respectively). In an interim analysis, the estimated overall survival at 2 years was 61% in the axi-cel group and 52% in the standard-care group. Adverse events of grade 3 or higher occurred in 91% of the patients who received axi-cel and in 83% of those who received standard care. Among patients who received axi-cel, grade 3 or higher cytokine release syndrome occurred in 6% and grade 3 or higher neurologic events in 21%. No deaths related to cytokine release syndrome or neurologic events occurred. CONCLUSIONS: Axi-cel therapy led to significant improvements, as compared with standard care, in event-free survival and response, with the expected level of high-grade toxic effects. (Funded by Kite; ZUMA-7 ClinicalTrials.gov number, NCT03391466.).

BACKGROUND: Bacteremia is a frequent complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT). It is unclear whether changes in the intestinal microbiota during allo-HSCT contribute to the development of bacteremia. We examined the microbiota of patients undergoing allo-HSCT, and correlated microbial shifts with the risk of bacteremia. METHODS: Fecal specimens were collected longitudinally from 94 patients undergoing allo-HSCT, from before transplant until 35 days after transplant. The intestinal microbiota was characterized by 454 pyrosequencing of the V1-V3 region of bacterial 16S ribosomal RNA genes. Microbial diversity was estimated by grouping sequences into operational taxonomic units and calculating the Shannon diversity index. Phylogenetic classification was obtained using the Ribosomal Database Project classifier. Associations of the microbiota with clinical predictors and outcomes were evaluated. RESULTS: During allo-HSCT, patients developed reduced diversity, with marked shifts in bacterial populations inhabiting the gut. Intestinal domination, defined as occupation of at least 30% of the microbiota by a single predominating bacterial taxon, occurred frequently. Commonly encountered dominating organisms included Enterococcus, Streptococcus, and various Proteobacteria. Enterococcal domination was increased 3-fold by metronidazole administration, whereas domination by Proteobacteria was reduced 10-fold by fluoroquinolone administration. As a predictor of outcomes, enterococcal domination increased the risk of Vancomycin-resistant Enterococcus bacteremia 9-fold, and proteobacterial domination increased the risk of gram-negative rod bacteremia 5-fold. CONCLUSIONS: During allo-HSCT, the diversity and stability of the intestinal flora are disrupted, resulting in domination by bacteria associated with subsequent bacteremia. Assessment of fecal microbiota identifies patients at highest risk for bloodstream infection during allo-HCST.

Highly diverse bacterial populations inhabit the gastrointestinal tract and modulate host inflammation and promote immune tolerance. In allogeneic hematopoietic stem cell transplantation (allo-HSCT), the gastrointestinal mucosa is damaged, and colonizing bacteria are impacted, leading to an impaired intestinal microbiota with reduced diversity. We examined the impact of intestinal diversity on subsequent mortality outcomes following transplantation. Fecal specimens were collected from 80 recipients of allo-HSCT at the time of stem cell engraftment. Bacterial 16S rRNA gene sequences were characterized, and microbial diversity was estimated using the inverse Simpson index. Subjects were classified into high, intermediate, and low diversity groups and assessed for differences in outcomes. Mortality outcomes were significantly worse in patients with lower intestinal diversity; overall survival at 3 years was 36%, 60%, and 67% for low, intermediate, and high diversity groups, respectively (P = .019, log-rank test). Low diversity showed a strong effect on mortality after multivariate adjustment for other clinical predictors (transplant related mortality: adjusted hazard ratio, 5.25; P = .014). In conclusion, the diversity of the intestinal microbiota at engraftment is an independent predictor of mortality in allo-HSCT recipients. These results indicate that the intestinal microbiota may be an important factor in the success or failure in allo-HSCT.

Immune checkpoint inhibitors (ICIs) are the standard of care for the treatment of several cancers. While these immunotherapies have improved patient outcomes in many clinical settings, they bring accompanying risks of toxicity, specifically immune-related adverse events (irAEs). There is a need for clear, effective guidelines for the management of irAEs during ICI treatment, motivating the Society for Immunotherapy of Cancer (SITC) to convene an expert panel to develop a clinical practice guideline. The panel discussed the recognition and management of single and combination ICI irAEs and ultimately developed evidence- and consensus-based recommendations to assist medical professionals in clinical decision-making and to improve outcomes for patients.

The relationship between intestinal microbiota composition and acute graft-versus-host disease (GVHD) after allogeneic blood/marrow transplantation (allo-BMT) is not well understood. Intestinal bacteria have long been thought to contribute to GVHD pathophysiology, but recent animal studies in nontransplant settings have found that anti-inflammatory effects are mediated by certain subpopulations of intestinal commensals. Hypothesizing that a more nuanced relationship may exist between the intestinal bacteria and GVHD, we evaluated the fecal bacterial composition of 64 patients 12 days after BMT. We found that increased bacterial diversity was associated with reduced GVHD-related mortality. Furthermore, harboring increased amounts of bacteria belonging to the genus Blautia was associated with reduced GVHD lethality in this cohort and was confirmed in another independent cohort of 51 patients from the same institution. Blautia abundance was also associated with improved overall survival. We evaluated the abundance of Blautia with respect to clinical factors and found that loss of Blautia was associated with treatment with antibiotics that inhibit anaerobic bacteria and receiving total parenteral nutrition for longer durations. We conclude that increased abundance of commensal bacteria belonging to the Blautia genus is associated with reduced lethal GVHD and improved overall survival.