Gut microbiome modulates response to anti-PD-1 immunotherapy in melanoma patients.

Preclinical mouse models suggest that the gut microbiome modulates tumor response to checkpoint blockade immunotherapy; however, this has not been well-characterized in human cancer patients. Here we examined the oral and gut microbiome of melanoma patients undergoing anti-programmed cell death 1 protein (PD-1) immunotherapy (n = 112). Significant differences were observed in the diversity and composition of the patient gut microbiome of responders versus nonresponders. Analysis of patient fecal microbiome samples (n = 43, 30 responders, 13 nonresponders) showed significantly higher alpha diversity (P < 0.01) and relative abundance of bacteria of the Ruminococcaceae family (P < 0.01) in responding patients. Metagenomic studies revealed functional differences in gut bacteria in responders, including enrichment of anabolic pathways. Immune profiling suggested enhanced systemic and antitumor immunity in responding patients with a favorable gut microbiome as well as in germ-free mice receiving fecal transplants from responding patients. Together, these data have important implications for the treatment of melanoma patients with immune checkpoint inhibitors.

Autologous stem cell transplantation is safe and feasible in elderly patients with multiple myeloma.

Several clinical trials have shown the superiority of autologous stem cell transplantation over conventional dose therapy for patients with multiple myeloma. This treatment, however, is limited to younger patients (<65 years) owing to concerns about toxicity and treatment-related mortality (TRM) in older patients. We treated 26 elderly myeloma patients (>70 years), who received a preparative regimen of melphalan 200 mg/m2 (19 patients), melphalan 180 mg/m2 (six patients) or melphalan 140 mg/m2 (one patient). Twenty-two of the 26 patients were alive after a median follow-up of 25 months (range=8-74). Responses (complete+partial response) were seen in 20 patients (77%), five (19%) of which were complete responses. Median PFS was 24 months, whereas median OS has not been reached. Cumulative incidence of 100-day TRM was 0%. Three-year PFS and OS were 39% (range=16-61) and 65% (range=35-83), respectively. A low serum albumin (<3.5 g/dl) was associated with a shorter PFS (P=0.02). Patients with relapsed disease at transplant, and an interval of >12 months between diagnosis and autotransplant, had a shorter OS (P=0.0004 and 0.04). HDT and autologous transplant is safe and feasible in elderly myeloma patients.

B-cell activating factor (BAFF) plasma level at the time of chronic GvHD diagnosis is a potential predictor of non-relapse mortality.

Biological markers for risk stratification of chronic GvHD (cGvHD) could improve the care of patients undergoing allogeneic hematopoietic stem cell transplantation. Increased plasma levels of B-cell activating factor (BAFF), chemokine (C-X-C motif) ligand 9 (CXCL9) and elafin have been associated with the diagnosis, but not with outcome in patients with cGvHD. We evaluated the association between levels of these soluble proteins, measured by ELISA at the time of cGvHD diagnosis and before the initiation of therapy, with non-relapse-mortality (NRM). Based on the log-transformed values, factor levels were divided into tertiles defined respectively as low, intermediate, and high levels. On univariable analysis, BAFF levels were significantly associated with NRM, whereas CXCL9 and elafin levels were not. Both low (⩽2.3 ng/mL, hazard ratio (HR)=5.8, P=0.03) and high (>5.7 ng/mL, HR=5.4, P=0.03) BAFF levels were associated with a significantly higher NRM compared with intermediate BAFF level. The significant effect of high or low BAFF levels persisted in multivariable analysis. A subset of cGvHD patients had persistently low BAFF levels. In conclusion, our data show that BAFF levels at the time of cGvHD diagnosis are associated with NRM, and also are potentially useful for risk stratification. These results warrant confirmation in larger studies.

Umbilical cord blood graft engineering: challenges and opportunities.

We are entering a very exciting era in umbilical cord blood transplantation (UCBT), where many of the associated formidable challenges may become treatable by ex vivo graft manipulation and/or adoptive immunotherapy utilizing specific cellular products. We envisage the use of double UCBT rather than single UCBT for most patients; this allows for greater ability to treat larger patients as well as to manipulate the graft. Ex vivo expansion and/or fucosylation of one cord will achieve more rapid engraftment, minimize the period of neutropenia and also give certainty that the other cord will provide long-term engraftment/immune reconstitution. The non-expanded (and future dominant) cord could be chosen for characteristics such as better HLA matching to minimize GvHD, or larger cell counts to enable part of the unit to be utilized for the development of specific cellular therapies such as the production of virus-specific T-cells or chimeric-antigen receptor T-cells which are reviewed in this study.

Complement component C3 mediates Th1/Th17 polarization in human T-cell activation and cutaneous GVHD.

The complement system has been shown to regulate T-cell activation and alloimmune responses in GVHD. Mice deficient in the central component of complement system C3 have significantly lower GVHD-related mortality/morbidity, and C3 modulates Th1/Th17 polarization in mouse GVHD. To investigate whether anticomplement therapy has any impact on human T-cell activation, a drug candidate Compstatin was used to inhibit C3 activation in this study. We found the frequency of IFN-γ (Th1)-, IL-4 (Th2)-, IL-17 (Th17)-, IL-2- and TNF-α-producing cells were significantly reduced among activated CD4(+) cells in the presence of Compstatin. Compstatin treatment decreased the proliferation of both CD4(+) and CD8(+) T cells upon TCR stimulation. However, Compstatin does not affect the production of IL-2 and TNF-α in activated CD8(+) T cells, and the differentiation of CD8(+) T cells into distinct memory and effector subsets remained intact. Furthermore, we examined complement deposition in skin and lip biopsy samples of patients diagnosed with cutaneous GVHD. C3 deposition was detected in the squamous epithelium and dermis, blood vessels and damaged sweat glands, and was associated with gland damage and regeneration. We conclude that C3 mediates Th1/Th17 polarization in human T-cell activation and skin GVHD in patients.

Prognostic value of response after upfront therapy for acute GVHD.

One challenge in designing clinical trials for treatment of acute GVHD (aGVHD) is the lack of an established standardized end point to measure the success of therapies. To facilitate assessment of end points in clinical trials for treatment of aGVHD in the current allo-SCT era, a national workshop was recently organized. In this study, which was presented at the workshop, we evaluated the prognostic value of response to upfront therapy in a cohort of 83 patients who had been enrolled on two clinical trials testing novel therapies for aGVHD at our institution. Our results indicate that patients whose aGVHD has a CR or PR by day 28 after initiation of systemic therapy have a significantly lower 6-month cumulative incidence of non-relapse mortality (NRM) (16%) than patients whose aGVHD did not respond to therapy by day 28 (48%, P=0.005). Multivariate analysis based on the Cox proportional hazards regression analysis showed that the impact of response on NRM is independent of patient and aGVHD characteristics. Our data confirm the validity of using day-28 response as a primary end point in clinical trials for upfront therapy for aGVHD.

Long-term outcome of reduced-intensity allogeneic hematopoietic SCT in patients with AML in CR.

A total of 36 consecutive patients with AML in CR underwent reduced-intensity allogeneic hematopoietic SCT (RISCT) with fludarabine and melphalan conditioning. All patients were ineligible for myeloablative transplantation because of age or comorbidity. In total, 30 patients were in first CR and six patients were in second CR. Donors were siblings in 21 (58%) patients and were unrelated in 15 (42%) patients. Hematopoietic cell transplant specific comorbidity scores ≥3 were present in 26 (72%) patients. With a median follow-up of 52 months (range, 34-103 months), OS and PFS rates at 4 years were 71% (s.e., 8%) and 68% (s.e., 8%), respectively. At 4 years, the cumulative incidence of non-relapse mortality was 20% (s.e., 7%) and of relapse mortality was 8% (s.e., 5%). Neither OS nor PFS was affected by older age (>60 years), unrelated donor, melphalan dose, or comorbidity score. At last follow up, of the 24 surviving patients, 21 (88%) had performance status (ECOG) of 0 without any active chronic GVHD requiring steroids. Hence, RISCT with fludarabine and melphalan conditioning produces durable long-term remission in older patients with AML.