JAK2/mTOR Inhibition Fails to Prevent Acute GVHD Despite Reduced Th1/Th17 cells: Final Phase II Trial Results.

Our phase I graft-versus-host disease (GVHD) prevention trial of JAK2 inhibitor, pacritinib, (recommended phase II dose: 100mg po BID day 0 to +70) plus sirolimus and tacrolimus (PAC/SIR/TAC) demonstrated the regimen was safe and free of pan-JAK myelosuppression after allogeneic hematopoietic cell transplantation (alloHCT). PAC inhibits IL-6 receptor activity and pathogenic Th1/Th17 differentiation in preclinical models and the phase I trial. Herein we report on our completed phase II trial of PAC/SIR/TAC after 8/8-HLA matched alloHCT. This single-arm phase II trial (NCT02891603) was powered to determine if PAC/SIR/TAC suppressed %pSTAT3+ CD4+ T cells at day +21 (primary endpoint: %pSTAT3+ CD4+ T cells ≤ 35%) and estimated grade II-IV acute GVHD by day +100. The impact of PAC/SIR/TAC on T cell subsets, CD28 (pS6 and pH3ser10), and IL-2 receptor (pSTAT5) signal transduction was also evaluated. Eligible patients (n=28) received alloHCT for hematologic malignancies or myeloproliferative neoplasms. Reduced or myeloablative intensity conditioning was permitted. PAC/SIR/TAC met the primary endpoint, reducing %pSTAT3+ CD4+ T cells to 9.62% at day +21. Th1/Th17 cells were decreased at day +21, increasing the ratio of Tregs to Th1 and Th17 cells with PAC/SIR/TAC at RP2D PAC compared to dose level 1 PAC. The cumulative incidence of grade II-IV acute GVHD by day +100 with PAC/SIR/TAC was similar to historic SIR/TAC values (46 v 43%). While PAC/SIR/TAC suppressed pSTAT3 and Th1/Th17 cells, the regimen did not improve acute GVHD prevention.

Allogeneic Hematopoietic Cell Transplant For Bone Marrow Failure or Myelodysplastic Syndrome in Dyskeratosis Congenita/Telomere Biology Disorders: Single-Center, Single-Arm, Open-Label Trial of Reduced-Intensity Conditioning Without Radiation.

BACKGROUND: Dyskeratosis congenita/telomere biology disorders (DC/TBD) often manifest as bone marrow failure (BMF) or myelodysplastic syndrome (MDS). Allogeneic hematopoietic cell transplant (alloHCT) rescues hematologic complications, but radiation and alkylator-based conditioning regimens cause diffuse whole-body toxicity and may expedite DC/TBD-specific non-hematopoietic complications. Optimization of conditioning intensity in DC/TBD to allow for donor hematopoietic cell engraftment with the least amount of toxicity remains a critical goal of the alloHCT field. OBJECTIVES/STUDY DESIGN: We report prospectively collected standard alloHCT outcomes from a single-center, single-arm, open-label clinical trial of bone marrow or peripheral blood stem cell alloHCT for DC/TBD-associated BMF or MDS. Conditioning was reduced intensity (RIC), including alemtuzumab 1 mg/kg, fludarabine 200 mg/m2, and cyclophosphamide 50 mg/kg. A previous single-arm, open-label phase II clinical trial for the same patient population conducted at the same center, differing only by inclusion of 200 cGy of total body irradiation (TBI), served as a control cohort. RESULTS: The non-TBI cohort included 10 patients (ages 1.7-65.9 years, median follow-up of 3.9 years) compared with the control TBI cohort, which included 12 patients (ages 2.2-52.2 years, median follow-up of 10.5 years). Baseline characteristics differed only in total CD34+ cells received, with a median of 5.6 (non-TBI) compared with 2.6 (TBI) x 106/kg (P = .02; no difference in total nucleated cells). The cumulative incidence of day +100 grade II-IV acute and 4-year chronic graft-versus-host disease (GvHD) were low at 0% and 10% (non-TBI) and 8% and 17% (TBI), respectively (acute, P = .36; chronic, P = .72). Primary graft failure was absent. Secondary non-neutropenic graft failure occurred in one (non-TBI cohort). The non-TBI cohort demonstrated delayed achievement of full donor chimerism but superior lymphocyte recovery. There was no difference in 4-year overall survival at 80% (non-TBI) and 75% (TBI; P = .78). MDS as an indication for alloHCT was uncommon but overall associated with poor outcomes. There were 3 MDS patients in the non-TBI cohort: 1 relapsed and died at day +387; 1 relapsed at day +500 and is alive 5.5 years later following salvage with a second alloHCT; 1 relapsed at day +1093 and is alive at day +100 after a second alloHCT. There was 1 MDS patient in the TBI cohort who achieved 100% donor myeloid engraftment without relapse but died at day +827 from a bacterial infection in the setting of immune-mediated cytopenia. CONCLUSION: Elimination of TBI from the RIC regimen for DC/TBD was not associated with significant changes in rates of graft failure, GvHD, and overall survival but was associated with delayed achievement of full donor chimerism and improved lymphocyte reconstitution. For DC/TBD-associated BMF, TBI appears to be dispensable. Optimal approaches to DC/TBD-associated MDS remain unclear. Larger cohorts are needed to better assess the unique contribution of TBI and donor CD34+ cell dose. Longer follow-up is required to assess differences in DC/TBD complications and late effects.

Treatment-Responsive Acute Graft-versus-Host Disease after Post-Transplantation Cyclophosphamide-Based Prophylaxis: Incidence and Clinical Outcomes.

Post-transplantation cyclophosphamide (PTCy) following hematopoietic cell transplantation (HCT) has emerged as standard of care for graft-versus-host disease (GVHD) prevention in adult patients without increasing malignant relapse. We previously defined acute GVHD (aGVHD) treatment response categories as corticosteroid-sensitive (SS), -dependent (SD), or -resistant (SR) based on response to first-line corticosteroids and reported their clinical outcomes following non-PTCy-based prophylaxis. More than one-third of patients developed aGVHD necessitating systemic therapy. Cases were predominantly SR, with a 14% overall incidence of SR aGVHD. The incidence and clinical outcomes of these 3 distinct aGVHD treatment response groups following PTCy-based prophylaxis have not been well described. The objective of this retrospective single-institution cohort study was to assess the incidence and clinical outcomes of SS, SD, and SR aGVHD following HCT with PTCy-based prophylaxis using a prophylactic regimen of PTCy, tacrolimus, and mycophenolate mofetil (MMF). We included 196 consecutive adult and pediatric patients undergoing allogeneic HCT for malignant and non-malignant disorders at the University of Minnesota between 2017 and 2021. Patients received PTCy on days +3 and +4 plus tacrolimus and MMF prophylaxis. Bone marrow and peripheral blood stem cell graft sources and related and unrelated donors were included. Recipients received myeloablative or reduced-intensity conditioning regimens. Of the 196 allografts, 54 (28%) developed aGVHD before day +180, with a median time to onset of 50 days (interquartile range, 34 to 71 days). Of those, 32 patients (16% overall) developed maximum grade II-III aGVHD necessitating systemic corticosteroids, with the following response: 13 SS (41%), 10 SD (31%), and 9 SR (28%). The overall incidence of SR aGVHD was 4.6%. Only 12 patients (6%) developed maximum grade III aGVHD, and none had grade IV aGVHD. The 2-year overall survival analyzed from 80 days after initiation of systemic treatment was similar in the SS and SD groups (77 and 75%, respectively), comparable to those without aGVHD (81%), and was lowest in the SR group (20%), with GVHD the primary cause of death. Nonrelapse mortality was highest in the SR group. MN high-risk and higher GVHD grade at onset were risk factors for developing SR aGVHD. Overall, we report a low incidence (16%) of aGVHD requiring systemic corticosteroids with PTCy-based prophylaxis. aGVHD cases were predominantly SS aGVHD, with lower incidences of SD and SR aGVHD. Our findings suggest that PTCy-based prophylaxis reduces the rate of treatment-resistant aGVHD. Patients with SR aGVHD had the worst clinical outcomes and poorest survival. Those with SS and SD aGVHD had similar clinical outcomes, both better than seen with SR aGVHD.

Multi-omics Analysis of a Fecal Microbiota Transplantation Trial Identifies Novel Aspects of Acute GVHD Pathogenesis.

Acute GVHD (aGVHD) is a major complication of allogeneic hematopoietic cell transplantation (alloHCT) associated with gut microbiota disruptions. However, whether therapeutic microbiota modulation prevents aGVHD is unknown. We conducted a randomized, placebo-controlled trial of third-party fecal microbiota transplantation (FMT) administered at the peak of microbiota injury in 100 patients with acute myeloid leukemia receiving induction chemotherapy and alloHCT recipients. Despite improvements in microbiome diversity, expansion of commensals, and shrinkage of potential pathogens, aGVHD occurred more frequently after FMT than placebo. Although this unexpected finding could be explained by clinical differences between the two arms, we asked whether a microbiota explanation might be also present. To this end, we performed multi-omics analysis of preintervention and postintervention gut microbiome and serum metabolome. We found that postintervention expansion of Faecalibacterium, a commensal genus with gut-protective and anti-inflammatory properties under homeostatic conditions, predicted a higher risk for aGVHD. Faecalibacterium expansion occurred predominantly after FMT and was due to engraftment of unique donor taxa, suggesting that donor Faecalibacterium-derived antigens might have stimulated allogeneic immune cells. Faecalibacterium and ursodeoxycholic acid (an anti-inflammatory secondary bile acid) were negatively correlated, offering an alternative mechanistic explanation. In conclusion, we demonstrate context dependence of microbiota effects where a normally beneficial bacteria may become detrimental in disease. While FMT is a broad, community-level intervention, it may need precision engineering in ecologically complex settings where multiple perturbations (e.g., antibiotics, intestinal damage, alloimmunity) are concurrently in effect. SIGNIFICANCE: Post-FMT expansion of Faecalibacterium, associated with donor microbiota engraftment, predicted a higher risk for aGVHD in alloHCT recipients. Although Faecalibacterium is a commensal genus with gut-protective and anti-inflammatory properties under homeostatic conditions, our findings suggest that it may become pathogenic in the setting of FMT after alloHCT. Our results support a future trial with precision engineering of the FMT product used as GVHD prophylaxis after alloHCT.

Treatment-Sensitive and Treatment-Dependent Chronic Graft-versus-Host Disease Yield Superior Failure-Free and Overall Survival Compared to Treatment-Resistant Chronic Graft-versus-Host Disease.

Response to treatment of chronic graft-versus-host disease (cGVHD) may help predict prognosis and outcomes. We hypothesized that the response of cGVHD to treatment and the ability to taper immunosuppression define distinct treatment response categories that differ in terms of risk factors and prognosis. Our aim was to determine specific clinical characteristics and outcomes associated with 3 distinct cGVHD treatment response groups based on the response to and duration of immunosuppressive therapy (IST) as treatment-sensitive (TS), treatment-resistant (TR), and treatment-dependent (TD) cGVHD. This retrospective single-institution cohort study included 1142 consecutive adult and pediatric recipients of allogeneic hematopoietic cell transplantation (HCT) performed for malignant and nonmalignant disorders at the University of Minnesota between 2008 and 2016. All donor, graft, conditioning regimen, and GVHD prophylaxis strategies were included, but only patients who commenced systemic treatment within 30 days of cGVHD diagnosis were included. A total of 185 patients who developed cGVHD necessitating IST within 30 days of cGVHD diagnosis were included in this analysis. At 1 year after cGVHD onset, 13% of the patients were TS, 27% were TD, and 60% were TR (including 14% deceased), whereas at 2 years after cGVHD onset, 29% were TS, 5% were TD, and 66% were TR (including 22% deceased). In a landmark analysis starting at 1 year after cGVHD onset, 5-year failure-free survival (FFS) and overall survival (OS) were lowest in the TR group (FFS, 38%; OS, 70%), with comparable outcomes in the TD (74% and 82%, respectively) and TS (79% for both) groups. Compared to no cGVHD, TR cGVHD was associated with worse OS at 5 years after cGVHD (hazard ratio, 2.09 versus no cGVHD; 95% confidence interval, 1.3 to 3.3; P < .01). Our findings suggest that refining cGVHD classification into 3 treatment response states defines important predictors of early and late clinical outcomes and identifies patients needing more effective treatment.

Long- and short-term effects of fecal microbiota transplantation on antibiotic resistance genes: results from a randomized placebo-controlled trial.

In small series, third-party fecal microbiota transplantation (FMT) has been successful in decolonizing the gut from clinically relevant antibiotic resistance genes (ARGs). Less is known about the short- and long-term effects of FMT on larger panels of ARGs. We analyzed 226 pre- and post-treatment stool samples from a randomized placebo-controlled trial of FMT in 100 patients undergoing allogeneic hematopoietic cell transplantation or receiving anti-leukemia induction chemotherapy for 47 ARGs. These patients have heavy antibiotic exposure and a high incidence of colonization with multidrug-resistant organisms. Samples from each patient spanned a period of up to 9 months, allowing us to describe both short- and long-term effects of FMT on ARGs, while the randomized design allowed us to distinguish between spontaneous changes vs. FMT effect. We find an overall bimodal pattern. In the first phase (days to weeks after FMT), low-level transfer of ARGs largely associated with commensal healthy donor microbiota occurs. This phase is followed by long-term resistance to new ARGs as stable communities with colonization resistance are formed after FMT. The clinical implications of these findings are likely context-dependent and require further research. In the setting of cancer and intensive therapy, long-term ARG decolonization could translate into fewer downstream infections.