A non-antibiotic-disrupted gut microbiome is associated with clinical responses to CD19-CAR-T cell cancer immunotherapy.

Increasing evidence suggests that the gut microbiome may modulate the efficacy of cancer immunotherapy. In a B cell lymphoma patient cohort from five centers in Germany and the United States (Germany, n = 66; United States, n = 106; total, n = 172), we demonstrate that wide-spectrum antibiotics treatment ('high-risk antibiotics') prior to CD19-targeted chimeric antigen receptor (CAR)-T cell therapy is associated with adverse outcomes, but this effect is likely to be confounded by an increased pretreatment tumor burden and systemic inflammation in patients pretreated with high-risk antibiotics. To resolve this confounding effect and gain insights into antibiotics-masked microbiome signals impacting CAR-T efficacy, we focused on the high-risk antibiotics non-exposed patient population. Indeed, in these patients, significant correlations were noted between pre-CAR-T infusion Bifidobacterium longum and microbiome-encoded peptidoglycan biosynthesis, and CAR-T treatment-associated 6-month survival or lymphoma progression. Furthermore, predictive pre-CAR-T treatment microbiome-based machine learning algorithms trained on the high-risk antibiotics non-exposed German cohort and validated by the respective US cohort robustly segregated long-term responders from non-responders. Bacteroides, Ruminococcus, Eubacterium and Akkermansia were most important in determining CAR-T responsiveness, with Akkermansia also being associated with pre-infusion peripheral T cell levels in these patients. Collectively, we identify conserved microbiome features across clinical and geographical variations, which may enable cross-cohort microbiome-based predictions of outcomes in CAR-T cell immunotherapy.

Apheresis for chimeric antigen receptor T-cell production in adult lymphoma patients.

BACKGROUND: To date, in-depth analysis of leukapheresis products as starting material for CAR T-cell manufacturing, specifically Tisagenlecleucel production, are scarce. In this study, we report on lymphapheresis data for production of Tisagenlecleucel for elderly and pretreated lymphoma patients. STUDY DESIGN AND METHODS: Spectra Optia from Terumo BCT, Lakewood, CO, was employed for apheresis using the cMNC program. Apheresis success was defined as meeting a target total nucleated cell (TNC) count of ≥2 × 109 , a CD3-positive lymphocyte count of ≥1 × 109 and an overall viability of ≥70% in the lymphapheresis product. RESULTS: Twenty-three patients (age 37-77 years) and 24 apheresis runs were evaluated. The median CD3-positive lymphocyte count in peripheral blood at the beginning of apheresis was 565 cells/µl (range: 70-1345 cells/µl). Circulating lymphoma cells were detected in one patient prior to apheresis. Target criteria were met in 21 of 23 patients. The median TNC count in the apheresate was 11.2 × 109 (range: 2.9 × 109 -47.4 × 109 ). The median CD3-positive lymphocyte count in the apheresate was 2.55 × 109 (range: 0.370 × 109 -6.915 × 109 ), which resulted in a median collection efficiency for CD3-positive lymphocytes of 63.7% (range: 9.56%-93.6%). No adverse events associated with the apheresis process were observed. CONCLUSIONS: Lymphapheresis with the Spectra Optia cMNC program provided a sufficient quantity of CD3-positive lymphocytes for CAR T-cell manufacturing for the majority of patients despite their heavy pretreatment and advanced age. Moreover, we are the first to advocate early pre-emptive lymphocyte collection in DLBCL-NOS patients intended to undergo treatment with Tisagenlecleucel.

Abatacept as salvage therapy in chronic graft-versus-host disease-a retrospective analysis.

The immunomodulatory fusion protein abatacept has recently been investigated for the treatment of steroid-refractory chronic graft-versus-host disease (cGvHD) in a phase 1 clinical trial. We analyzed the safety and efficacy of abatacept for cGvHD therapy in a retrospective study with 15 patients who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) and received abatacept for cGvHD with a median age of 49 years. Grading was performed as part of the clinical routine according to the National Institute of Health's (NIH) consensus criteria at initiation of abatacept and 1, 3, 6, 9 and 12 months thereafter. The median time of follow-up was 191 days (range 55-393 days). Best overall response rate (ORR) was 40%. In particular, patients with bronchiolitis obliterans syndrome showed significant clinical improvement and durable responses following abatacept treatment with a response rate of 89% based on improvement in lung severity score (n = 6) or stabilized lung function (n = 4) or both (n = 3). Infectious complications CTCAE °III or higher were observed in 3/15 patients. None of the patients relapsed from the underlying malignancy. Thus, abatacept appears to be a promising treatment option for cGvHD, in particular for patients with lung involvement. However, further evaluation within a phase 2 clinical trial is required.