Endpoints for clinical trials testing treatment of acute graft-versus-host disease: a joint statement

Ruxolitinib for the treatment of acute and chronic graft-versus-host disease in children: a systematic review and individual patient data meta-analysis

Steroid-refractory graft-versus-host disease (SR-GvHD) represents a major complication of pediatric allogenic hematopoietic stem cell transplantation. Ruxolitinib, a selective JAK 1-2 inhibitor, showed promising results in the treatment of SR-GvHD in adult trial, including patients >12 years old. This systematic review aims to evaluate ruxolitinib use for SR-GvHD in the pediatric population. Among the 12 studies included, ruxolitinib administration presented slight differences. Overall response rate (ORR) ranged from 45% to 100% in both acute and chronic GvHD. Complete response rates (CR) varied from 9% to 67% and from 0% to 28% in aGvHD and cGvHD, respectively. Individual-patient meta-analysis from 108 children under 12 years showed an ORR and CR for aGvHD of 74% and 56%, respectively, while in cGvHD ORR was 78% but with only 11% achieving CR. Treatment-related toxicities were observed in 20% of patients, including cytopenia, liver toxicity, and infections. Age, weight, graft source, previous lines of therapy, and dose did not significantly predict response, while a higher rate of toxicities was observed in aGvHD patients. In conclusion, ruxolitinib shows promising results in the treatment of SR-GvHD in children, including those under 12 years. Specific pediatric perspective trials are currently ongoing to definitely assess its efficacy and safety.

Mini-dose methotrexate combined with methylprednisolone for the initial treatment of acute GVHD: a multicentre, randomized trial

BACKGROUND

There is an urgent unmet need for effective initial treatment for acute graft-versus-host disease (aGVHD) adding to the standard first-line therapy with corticosteroids after allogeneic haematopoietic stem cell transplantation (allo-HSCT).

METHODS

We performed a multicentre, open-label, randomized, phase 3 study. Eligible patients (aged 15 years or older, had received allo-HSCT for a haematological malignancy, developed aGVHD, and received no previous therapies for aGVHD) were randomly assigned (1:1) to receive either 5 mg/m2 MTX on Days 1, 3, or 8 and then combined with corticosteroids or corticosteroids alone weekly.

RESULTS

The primary endpoint was the overall response rate (ORR) on Day 10. A total of 157 patients were randomly assigned to receive either MTX plus corticosteroids (n = 78; MTX group) or corticosteroids alone (n = 79; control group). The Day 10 ORR was 97% for the MTX group and 81% for the control group (p = .005). Among patients with mild aGVHD, the Day 10 ORR was 100% for the MTX group and 86% for the control group (p = .001). The 1-year estimated failure-free survival was 69% for the MTX group and 41% for the control group (p = .002). There were no differences in treatment-related adverse events between the two groups.

CONCLUSIONS

In conclusion, mini-dose MTX combined with corticosteroids can significantly improve the ORR in patients with aGVHD and is well tolerated, although it did not achieve the prespecified 20% improvement with the addition of MTX.

TRIAL REGISTRATION

The trial was registered with clinicaltrials.gov (NCT04960644).

Flares of acute graft-versus-host disease: a Mount Sinai Acute GVHD International Consortium analysis

ABSTRACT

The absence of a standardized definition for graft-versus-host disease (GVHD) flares and data on its clinical course are significant concerns. We retrospectively evaluated 968 patients across 23 Mount Sinai Acute GVHD International Consortium (MAGIC) transplant centers who achieved complete response (CR) or very good partial response (VGPR) within 4 weeks of treatment. The cumulative incidence of flares within 6 months was 22%, and flares were associated with a higher risk of nonrelapse mortality (NRM; adjusted hazard ratio [aHR], 4.84; 95% confidence interval [CI], 3.19-7.36; P < .001). Flares were more severe (grades 3/4, 41% vs 16%; P < .001) and had more frequent lower gastrointestinal (LGI) involvement (55% vs 32%; P < .001) than the initial GVHD. At CR/VGPR, elevated MAGIC biomarkers predicted the future occurrence of a flare, along with its severity and LGI involvement. In multivariate analyses, higher Ann Arbor (AA) biomarker scores at CR/VGPR were significant risk factors for flares (AA2 vs AA1: aHR, 1.81 [95% CI, 1.32-2.48; P = .001]; AA3 vs AA1: aHR, 3.14 [95% CI, 1.98-4.98; P < .001]), as were early response to initial treatment (aHR, 1.84; 95% CI, 1.21-2.80; P = .004) and HLA-mismatched unrelated donor (aHR, 1.74; 95% CI, 1.00-3.02; P = .049). MAGIC biomarkers also stratified the risk of NRM both at CR/VGPR and at the time of flare. We conclude that GVHD flares are common and carry a significant mortality risk. The occurrence of future flares can be predicted by serum biomarkers that may serve to guide adjustment and discontinuation of immunosuppression.

A Day 14 Endpoint for Acute GVHD Clinical Trials

The overall response rate (ORR) 28 days after treatment has been adopted as the primary endpoint for clinical trials of acute graft versus host disease (GVHD). However, physicians often need to modify immunosuppression earlier than day (D) 28, and non-relapse mortality (NRM) does not always correlate with ORR at D28. We studied 1144 patients that received systemic treatment for GVHD in the Mount Sinai Acute GVHD International Consortium (MAGIC) and divided them into a training set (n=764) and a validation set (n=380). We used a recursive partitioning algorithm to create a Mount Sinai model that classifies patients into favorable or unfavorable groups that predicted 12 month NRM according to overall GVHD grade at both onset and D14. In the Mount Sinai model grade II GVHD at D14 was unfavorable for grade III/IV GVHD at onset and predicted NRM as well as the D28 standard response model. The MAGIC algorithm probability (MAP) is a validated score that combines the serum concentrations of suppression of tumorigenicity 2 (ST2) and regenerating islet-derived 3-alpha (REG3α) to predict NRM. Inclusion of the D14 MAP biomarker score with the D14 Mount Sinai model created three distinct groups (good, intermediate, poor) with strikingly different NRM (8%, 35%, 76% respectively). This D14 MAGIC model displayed better AUC, sensitivity, positive and negative predictive value, and net benefit in decision curve analysis compared to the D28 standard response model. We conclude that this D14 MAGIC model could be useful in therapeutic decisions and may offer an improved endpoint for clinical trials of acute GVHD treatment.

Mesenchymal stromal cells plus basiliximab improve the response of steroid-refractory acute graft-versus-host disease as a second-line therapy: a multicentre, randomized, controlled trial

BACKGROUND

For patients with steroid-refractory acute graft-versus-host disease (SR-aGVHD), effective second-line regimens are urgently needed. Mesenchymal stromal cells (MSCs) have been used as salvage regimens for SR-aGVHD in the past. However, clinical trials and an overall understanding of the molecular mechanisms of MSCs combined with basiliximab for SR-aGVHD are limited, especially in haploidentical haemopoietic stem cell transplantation (HID HSCT).

METHODS

The primary endpoint of this multicentre, randomized, controlled trial was the 4-week complete response (CR) rate of SR-aGVHD. A total of 130 patients with SR-aGVHD were assigned in a 1:1 randomization schedule to the MSC group (receiving basiliximab plus MSCs) or control group (receiving basiliximab alone) (NCT04738981).

RESULTS

Most enrolled patients (96.2%) received HID HSCT. The 4-week CR rate of SR-aGVHD in the MSC group was obviously better than that in the control group (83.1% vs. 55.4%, P = 0.001). However, for the overall response rates at week 4, the two groups were comparable. More patients in the control group used ≥ 6 doses of basiliximab (4.6% vs. 20%, P = 0.008). We collected blood samples from 19 consecutive patients and evaluated MSC-derived immunosuppressive cytokines, including HO1, GAL1, GAL9, TNFIA6, PGE2, PDL1, TGF-β and HGF. Compared to the levels before MSC infusion, the HO1 (P = 0.0072) and TGF-β (P = 0.0243) levels increased significantly 1 day after MSC infusion. At 7 days after MSC infusion, the levels of HO1, GAL1, TNFIA6 and TGF-β tended to increase; however, the differences were not statistically significant. Although the 52-week cumulative incidence of cGVHD in the MSC group was comparable to that in the control group, fewer patients in the MSC group developed cGVHD involving ≥3 organs (14.3% vs. 43.6%, P = 0.006). MSCs were well tolerated, no infusion-related adverse events (AEs) occurred and other AEs were also comparable between the two groups. However, patients with malignant haematological diseases in the MSC group had a higher 52-week disease-free survival rate than those in the control group (84.8% vs. 65.9%, P = 0.031).

CONCLUSIONS

For SR-aGVHD after allo-HSCT, especially HID HSCT, the combination of MSCs and basiliximab as the second-line therapy led to significantly better 4-week CR rates than basiliximab alone. The addition of MSCs not only did not increase toxicity but also provided a survival benefit.

First-line steroid-free systemic treatment of acute and chronic graft-versus-host disease after novel prophylaxis regimens

In the early randomized trials the efficacy of calcineurin inhibitors (CNI) in the treatment of graft-versus-host disease (GVHD) was comparable to corticosteroids (CS), but these results became obsolete with the introduction of CNIs in prophylaxis. Recently several effective CNI-free GVHD prophylaxis regimens were introduced based on posttransplantation cyclophosphamide (PTCY) and αβ ex vivo T-cell depletion (αβ-TCD). Among patients treated under these protocols 34 patients with grade II-IV acute (aGVHD) and 40 with moderate and severe chronic (cGVHD) disease were treated with CNIs or other CS-free regimens as the first line. Overall response rate (ORR) was significantly higher in cGVHD than in aGVHD: 80% (95% CI 68-92) vs 47% (95% CI 30-64%), p = 0.0031. In aGVHD it was almost completely restricted to isolated stage III skin GVHD. In cGVHD patients with moderate disease ORR was higher than in severe: 96% (95% CI 88-100%) vs 56% (95%CI 32-81%), p = 0.0022. Two-year overall survival was 76% (95% CI 58-87%) in aGVHD and 95% (95% CI 81-99%) in cGVHD. Failure-free survival was 21% (95% CI 9-37%) in aGVHD and 81% (95% CI 64-91%) in cGVHD. Patients responding to steroid-free regimens had lower use of systemic antibiotics (p = 0.0095), antifungals (p = 0.0319) and antivirals (p < 0.0001).

Vedolizumab for acute gastrointestinal graft-versus-host disease: A systematic review and meta-analysis

OBJECTIVE

To determine the safety and efficacy of vedolizumab for the prophylaxis and treatment of gastrointestinal involvement of acute graft-versus-host disease (GVHD) (GI-aGVHD).

METHODS

Literature search within PubMed, EMBASE, Web of Science, and Cochrane Library for observational studies and clinical trials that evaluated the effect of vedolizumab on GI-aGVHD was done through 17 May 2022. A bivariate and random-effect meta-analysis derived the pooled observational percentages and pooled risk ratios (RRs) from baseline of primary endpoints including overall response, complete response, mortality, and adverse events.

RESULTS

There was a total of 122 participants in eight eligible studies, including one study on the prophylactic use of vedolizumab and seven studies on vedolizumab for the treatment of GI-aGVHD. Of seven studies that reported details on baseline grades of GI-aGVHD, a total of 47 patients (47.95%) were of stage 4, 31 patients (31.63%) were of stage 3, 10 patients (10.2%) were of stage 2, and 10 patients (10.2%) were of stage 1. The use of vedolizumab for the treatment of GI-aGVHD yielded a significantly improved objective response rate (ORR) at 14 days (pooled ORR = 60.53%, pooled RR = 14.14, 95% CI: 2.95-67.71), 28 days (pooled ORR = 50%, RR = 7.36, 95% CI = 2.14-25.37), and 12 months (pooled ORR = 76.92%, RR = 13.66, 95% CI = 3.5-53.35) from baseline. Likewise, the use of vedolizumab was followed by a significantly improved complete response (CR) at 12 months (pooled CR = 27.27%, RR = 5.50, 95% CI = 1.01-29.95), yet the CR at 14 days and 28 days did not reach statistical significance. Fifty-seven out of 87 (pooled overall survival, OS = 34.5%) and 46 out of 65 (pooled OS = 29.2%) patients expired at 6 and 12 months after the use of vedolizumab, respectively. Prophylactic use of vedolizumab was not associated with any specific type of reported adverse events, while patients with GI-aGVHD on vedolizumab presented with significantly increased risks of adverse events including infections (RR = 7.55) and impaired metabolism or nutritional complications (RR = 9.00). All analyses were of a low heterogeneity (all I-squares = 0%).

CONCLUSION

Vedolizumab was safe and effective for the prophylaxis and management of early grade GI-aGVHD. More clinical evidence is warranted to validate these findings.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=345584, identifier CRD42022345584.

Efficacy and safety of mesenchymal stem cells treatment for multidrug-resistant graft-versus-host disease after haploidentical allogeneic hematopoietic stem cell transplantation

PURPOSE

Graft-versus-host disease (GVHD) is an important complication after human leukocyte antigen (HLA) haploidentical donor (HID) hematopoietic stem cell transplantation (HSCT), which may lead to poor prognosis. Our study intends to identify the efficacy and safety of mesenchymal stem cells (MSCs) for multidrug-resistant (MDR)-GVHD after HID HSCT.

METHODS

MDR-GVHD was referring to GVHD remaining no response to at least two types of therapy, and hUCB-MSCs were given at the dose of (1.0-2.0) × 106/kg once a week.

RESULTS

A total of 21 patients were enrolled in this retrospective study (acute GVHD (aGVHD): n = 14, chronic GVHD (cGVHD): n = 7). The median dose of MSCs was 1.2 × 106 cells/kg (range, 0.8-1.8 × 106) cells/kg, and the median numbers of infusion were 2 (range, 1-7) and 3 (range, 2-12) for MDR-aGVHD and MDR-cGVHD patients, respectively. In MDR-aGVHD patients, the overall response rate (ORR) was 57.1%, including 50.0% complete response (CR) and 7.1% partial response (PR), and the median time to response was 49.5 days (range, 16-118) days. The 2-year probability of overall survival after MSCs was 64.3%. Five patients (35.7%) developed infections after MSCs, and no obvious hematologic toxicities were observed. Five MDR-aGVHD patients died after MSCs treatments because of GVHD progression (n = 1), severe infection (bacterial central nervous system infection: n = 1; fungal pneumonia: n = 2), and poor graft function (n = 1). In MDR-cGVHD patients, three patients (42.9%) achieved PR after MSCs and the median time to response was 56 days (22-84) days. The ORRs for moderate and severe cGVHD were 50.0% and 33.3%, respectively. Four MDR-cGVHD patients died after MSCs treatments because of GVHD progression (n = 2), severe fungal pneumonia (n = 1), and relapse (n = 1).

CONCLUSION

MSCs treatment may be safe and effective for MDR-GVHD after HID HSCT.

Off-the-shelf bone marrow-derived mesenchymal stem cell treatment for acute graft-versus-host disease: real-world evidence

Temcell is a cryopreserved, human bone marrow-derived mesenchymal stem cell (MSC) product approved for the treatment of patients of all ages with acute graft-versus-host disease (GVHD). Initial experience with Temcell in a real-world setting from a cellular therapy registry in Japan is presented. A total of 381 consecutive patients were enrolled since its approval in 2016. The median cell number infused was 2.00 × 106/kg. The most common number of infusions was 8 in 100 patients. Of the 306 evaluable patients, the overall response rate (ORR) on day 28 after the start of MSC therapy was 56%. Of the 151 evaluable patients who received it as second-line therapy following first-line steroid therapy for classic acute GVHD, the ORR was 61%. Liver involvement of GVHD and ≥14 days from first-line steroid therapy to second-line MSC therapy was associated with a lower ORR. Day 28 ORR, patient age, GVHD grade, GVHD organ involvement, and a number of GVHD therapies before MSC therapy were associated with nonrelapse mortality. Overall survival at 6 months in 381 patients was 40%. This study suggests that Temcell is one of the treatment options for steroid-refractory acute GVHD until a new treatment with survival benefit is developed.

Acute GVHD Diagnosis and Adjudication in a Multicenter Trial: A Report From the BMT CTN 1202 Biorepository Study

PURPOSE

Accurate and reproducible methods to diagnose, grade, and report acute graft-versus-host disease (GVHD) are critical for the evaluation of therapies and biomarkers.

PATIENTS AND METHODS

The Blood and Marrow Transplant Clinical Trials Network 1202 study is an observational study of 1,709 allogeneic hematopoietic cell transplantation recipients that implemented weekly data reporting and near real-time data adjudication by an end point review committee (ERC), assigning a confidence level (confirmed, probable, possible, or negative) to the diagnosis of acute GVHD at onset.

RESULTS

During the first 100 days, symptoms consistent with GVHD developed in 90% of cases but were often determined by centers to be due to causes other than GVHD. Indeed, GVHD was under consideration in only 23% of cases at symptom onset. Diagnostic biopsies were obtained in 40% of cases, but treatment often was incongruous with biopsy findings and 10.5% of biopsies were equivocal. Importantly, more than 40% of steroid courses were started for reasons other than GVHD. The ERC modified the determination of GVHD diagnosis and/or grade in 12.3% of onset cases. The cumulative incidence of acute GVHD as reported by the centers was 62%. When the ERC adjudicated GVHD onset to be present only if the confidence level was probable or confirmed, the incidence of GVHD declined to 49%.

CONCLUSION

This study demonstrates that the incidence of GVHD may be overestimated at symptom onset, establishes a contemporary benchmark for acute GVHD, and suggests a structured framework for reporting and adjudication of GVHD that could be used in prospective trials.

A phase 1 trial of itacitinib, a selective JAK1 inhibitor, in patients with acute graft-versus-host disease

Acute graft-versus-host disease (aGVHD) following allogeneic hematopoietic cell transplantation (HCT) is a primary cause of nonrelapse mortality and a major barrier to successful transplant outcomes. Itacitinib is a Janus kinase (JAK)1-selective inhibitor that has demonstrated efficacy in preclinical models of aGVHD. We report results from the first registered study of a JAK inhibitor in patients with aGVHD. This was an open-label phase 1 study enrolling patients aged ≥18 years with first HCT from any source who developed grade IIB to IVD aGVHD. Patients with steroid-naive or steroid-refractory aGVHD were randomized 1:1 to itacitinib 200 mg or 300 mg once daily plus corticosteroids. The primary endpoint was safety and tolerability; day 28 overall response rate (ORR) was the main secondary endpoint. Twenty-nine patients (200 mg, n = 14; 300 mg, n = 15) received ≥1 dose of itacitinib and were included in safety and efficacy assessments. One dose-limiting toxicity was reported (grade 3 thrombocytopenia attributed to GVHD progression in a patient receiving 300 mg itacitinib with preexisting thrombocytopenia). The most common nonhematologic treatment-emergent adverse event was diarrhea (48.3%, n = 14); anemia occurred in 11 patients (38%). ORR on day 28 for all patients in the 200-mg and 300-mg groups was 78.6% and 66.7%, respectively. Day 28 ORR was 75.0% for patients with treatment-naive aGVHD and 70.6% in those with steroid-refractory aGVHD. All patients receiving itacitinib decreased corticosteroid use over time. In summary, itacitinib was well tolerated and demonstrated encouraging efficacy in patients with steroid-naive or steroid-refractory aGVHD, warranting continued clinical investigations. This trial was registered at www.clinicaltrials.gov as #NCT02614612.

Refractory acute graft-versus-host disease: a new working definition beyond corticosteroid refractoriness

Graft-versus-host disease (GVHD) remains a major limitation of allogeneic hematopoietic stem cell transplantation. Only half of patients with severe acute GVHD respond to first-line treatment with corticosteroids and, for several decades, there was no optimal second-line treatment of patients with corticosteroid-refractory acute GVHD. Ruxolitinib was recently approved for the treatment of corticosteroid-refractory acute GVHD in adult and pediatric patients 12 years and older. Thus, it is important to define the patient population that would now be considered as refractory to ruxolitinib vs ruxolitinib dependent. Here, we propose to define ruxolitinib-refractory acute GVHD as disease that shows: (1) progression of GVHD compared with baseline after at least 5 to 10 days of treatment with ruxolitinib, based either on objective increase in stage/grade, or new organ involvement; (2) lack of improvement in GVHD (partial response or better) compared with baseline after ≥14 days of treatment with ruxolitinib; or (3) loss of response, defined as objective worsening of GVHD determined by increase in stage, grade, or new organ involvement at any time after initial improvement. GVHD manifestations that persist without improvement in patients who had a grade ≥3 treatment-emergent and ruxolitinib-attributed adverse event that did not resolve within 7 days of discontinuing ruxolitinib would serve as a clinical indication for additional treatment. In addition, absence of complete response or very good partial response at day 28 after ruxolitinib could be considered as an eligibility criterion.

Immunopathology and biology-based treatment of steroid-refractory graft-versus-host disease

Acute graft-versus-host disease (GVHD) is 1 of the major life-threating complications after allogeneic cell transplantation. Although steroids remain first-line treatment, roughly one-half of patients will develop steroid-refractory GVHD (SR-GVHD), which portends an extremely poor prognosis. Many agents that have shown encouraging response rates in early phase 1/2 trials for prevention and treatment have been unsuccessful in demonstrating a survival advantage when applied in the setting of SR-GVHD. The discovery of novel treatments has been further complicated by the absence of clinically informative animal models that address what may reflect a distinct pathophysiology. Nonetheless, the combined knowledge of established bone marrow transplantation models and recent human trials in SR-GVHD patients are beginning to illuminate novel mechanisms for inhibiting T-cell signaling and promoting tissue tolerance that provide an increased understanding of the underlying biology of SR-GVHD. Here, we discuss recent findings of newly appreciated cellular and molecular mechanisms and provide novel translational opportunities for advancing the effectiveness of treatment in SR-GVHD.

Ruxolitinib for the treatment of steroid-refractory acute GVHD (REACH1): a multicenter, open-label phase 2 trial

Patients who develop steroid-refractory acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic cell transplantation have poor prognosis, highlighting an unmet therapeutic need. In this open-label phase 2 study (ClinicalTrials.gov identifier: NCT02953678), patients aged at least 12 years with grades II to IV steroid-refractory aGVHD were eligible to receive ruxolitinib orally, starting at 5 mg twice daily plus corticosteroids, until treatment failure, unacceptable toxicity, or death. The primary end point was overall response rate (ORR) at day 28; the key secondary end point was duration of response (DOR) at 6 months. As of 2 July 2018, 71 patients received at least 1 dose of ruxolitinib. Forty-eight of those patients (67.6%) had grade III/IV aGVHD at enrollment. At day 28, 39 patients (54.9%; 95% confidence interval, 42.7%-66.8%) had an overall response, including 19 (26.8%) with complete responses. Best ORR at any time was 73.2% (complete response, 56.3%). Responses were observed across skin (61.1%), upper (45.5%) and lower (46.0%) gastrointestinal tract, and liver (26.7%). Median DOR was 345 days. Overall survival estimate at 6 months was 51.0%. At day 28, 24 (55.8%) of 43 patients receiving ruxolitinib and corticosteroids had a 50% or greater corticosteroid dose reduction from baseline. The most common treatment-emergent adverse events were anemia (64.8%), thrombocytopenia (62.0%), hypokalemia (49.3%), neutropenia (47.9%), and peripheral edema (45.1%). Ruxolitinib produced durable responses and encouraging survival compared with historical data in patients with steroid-refractory aGVHD who otherwise have dismal outcomes. The safety profile was consistent with expectations for ruxolitinib and this patient population.

The MAGIC algorithm probability is a validated response biomarker of treatment of acute graft-versus-host disease

The Mount Sinai Acute GVHD International Consortium (MAGIC) algorithm probability (MAP), derived from 2 serum biomarkers, measures damage to crypts in the gastrointestinal tract during graft-versus-host disease (GVHD). We hypothesized that changes in MAP after treatment could validate it as a response biomarker. We prospectively collected serum samples and clinical stages of acute GVHD from 615 patients receiving hematopoietic cell transplantation in 20 centers at initiation of first-line systemic treatment and 4 weeks later. We computed MAPs and clinical responses and compared their abilities to predict 6-month nonrelapse mortality (NRM) in the validation cohort (n = 367). After 4 weeks of treatment, MAPs predicted NRM better than the change in clinical symptoms in all patients and identified 2 groups with significantly different NRM in both clinical responders (40% vs 12%, P < .0001) and nonresponders (65% vs 25%, P < .0001). MAPs successfully reclassified patients for NRM risk within every clinical grade of acute GVHD after 4 weeks of treatment. At the beginning of treatment, patients with a low MAP that rose above the threshold of 0.290 after 4 weeks of treatment had a significant increase in NRM, whereas patients with a high MAP at onset that fell below that threshold after treatment had a striking decrease in NRM that translated into clear differences in overall survival. We conclude that a MAP measured before and after treatment of acute GVHD is a response biomarker that predicts long-term outcomes more accurately than change in clinical symptoms. MAPs have the potential to guide therapy for acute GVHD and may function as a useful end point in clinical trials.

[Fecal microbiota transplantation for graft-versus-host disease in children and adults: methods, clinical effects, safety]

AIM

Was to evaluate clinical efficacy, adverse events and changes in the gut microbiome after fecal microbiota transplantation (FMT) in patients with gastrointestinal (GI) form of graft-versus-host disease (GVHD).

MATERIALS AND METHODS

The prospective single-center study in R.M. Gorbacheva institute included 27 patients with GI GVHD after allogeneic stem cell transplantation. 19 patients received FMT, 8 patients received placebo. Clinical scales for GI autoimmune diseases were used to evaluate response. Microbiome alterations were assessed with multiplex PCR.

RESULTS

After FMT higher overall bacterial mass (р=0.00088), higher bacterial numbers ofBifidobacteriumspp. (р=0.021),Escherichia coli(р=0.049) andBacteroides fragilisgr. (р=0.000043) compared to placebo group. Also higher bacterial mass was observed in patients with clinical response (р=0.0057). The bacterial mass after procedure in non-responders was compared to the placebo group (р=0.31). Partial response of GVHD was achieved faster in the FMT group compared to placebo (median 4 days vs 48 days,p=0.014). Complete response was observed in 8 (42%), 14 (74%) and 16 (84%) at 30, 60 and 90 days respectively, while in the placebo group only 0%, 1 (13%) and 4 (50%) achieved complete response at the same time points. The incidence and severity of adverse events was comparable between FMT and the placebo group.

CONCLUSION

FMT in patients with refractory GI GVHD was associated with favorable clinical outcomes and recovery in certain marker bacterial populations. Multiplex PCR can be used to assess an engraftment of a donor microbiota. FMT in GI GVHD was not associated with life-threatening adverse events, but further studies are required to validate clinical efficacy.

Human-Derived α1-Antitrypsin is Still Efficacious in Heavily Pretreated Patients with Steroid-Resistant Gastrointestinal Graft-versus-Host Disease

Almost one-half of patients developing graft-versus-host disease (GVHD) will not respond to standard first-line steroid treatment. Alpha-1 antitrypsin (AAT) is able to induce tolerance in preclinical models of GVHD. AAT alters the cytokine milieu, promotes a tolerogenic shift of dendritic cells, and skews effector T cells toward regulatory T cells. Gastrointestinal steroid-refractory (SR)-GVHD is a protein-losing enteropathy that might represent the optimal setting in which to use AAT. Here we analyze the outcomes of 16 patients treated with human-derived AAT in advanced-stage gut SR-GVHD, with two-thirds of the patients having failed at least 1 treatment for SR-GVHD. The overall response rate (ORR) was 44%, with a complete response (CR) rate of 27%. Gastrointestinal response was observed in 61% of patients. The median time to best response was 21 days (range, 6 to 26 days). At day 56 after AAT treatment, all CRs were maintained, and the ORR was 39%. The 1-year overall survival was 48% (95% confidence interval, 26% to 74%). Ancillary studies showed that AAT serum levels were in the normal range at the beginning of treatment, whereas fecal loss was elevated. AAT levels consistently rose after exogenous administration, but no correlation was found between serum levels and response. REG3α and IL-33 levels were associated with response while, in contrast to previous reports, regulatory T cells decreased during AAT treatment. This retrospective analysis supports a previous report of AAT as a promising agent in the management of gut SR-GVHD and should prompt its evaluation at an earlier stage.

Extracorporeal photopheresis as first-line strategy in the treatment of acute graft-versus-host disease after hematopoietic stem cell transplantation: A single-center experience

BACKGROUND AIMS

Corticosteroids are the standard first-line treatment for acute graft-versus-host disease (aGVHD), but they are associated with many complications, and less than half of patients have a sustained response.

METHODS

To improve outcomes, we performed a retrospective study to analyze the efficacy of the addition of extracorporeal photopheresis (ECP) to low-dose corticosteroids in 37 adult patients (median age, 57 years) with skin-predominant aGVHD (grade I, n = 17; grade II, n = 18; and grade III, n = 2). All patients received ECP in combination with 1 mg/kg prednisone (n = 26) or topical steroids (n = 11).

RESULTS

Overall response rate was 81% after a median of three ECP procedures (range, 2-8), including 22 complete responses (CR, 59%) and eight very good partial responses (VGPR, 22%). The 11 patients treated with topical corticosteroids achieved CR. Furthermore, 16 (62%) patients reached prednisone withdrawal at a median of 100 days (range, 42-174 days) after its initiation. Eighteen patients developed chronic GVHD (cGVHD); 11 of them (who were in CR of aGVHD) had a new-onset cGVHD, and seven experienced progressive cGVHD (five non-responding and two VGPR patients). A second-line immunosuppressive treatment was initiated in only five (14%) non-responding patients. With a median follow-up of 31 months (range, 6-57 months) 2-year overall survival and non-relapse mortality were 74% and 11%, respectively.

CONCLUSIONS

Overall, the combination of low-dose corticosteroids and ECP appear to be safe and effective for first-line treatment of skin predominant aGVHD.

Long-term outcomes of ruxolitinib therapy in steroid-refractory graft-versus-host disease in children and adults

Acute and chronic steroid-refractory graft-versus-host disease (srGVHD) is a life-threatening complication of allogeneic stem cell transplantation. There are a number of reports on case series describing efficacy of ruxolitinib in both acute and chronic srGVHD. We conducted a prospective study (NCT02997280) in 75 patients with srGVHD (32 acute, 43 chronic, 41 adults, and 34 children). Patients with chronic GVHD had severe disease in 83% of cases, and acute GVHD patients had grade III-IV disease in 66% of cases. The overall response rate (ORR) was 75% (95% CI 57-89%) in acute GVHD and 81% (95% CI 67-92%) in chronic. Overall survival was 59% (95% CI 49-74%) in acute group and 85% (95% CI 70-93%). The major risk factors for lower survival were grade III-IV gastrointestinal involvement (29% vs 93%, p = 0.0001) in acute form and high disease risk score in chronic (65% vs 90%, p = 0.038). Toxicity was predominantly hematologic with 79% and 44% of grade III-IV neutropenia in acute and chronic groups, respectively. There was no difference between adults and children in terms of ORR (p = 0.31, p = 0.35), survival (p = 0.44, p = 0.12) and toxicity (p > 0.93). The study demonstrated that ruxolitinib is an effective option in acute and chronic srGVHD and can be used both in adults and children.

A Phase 3, Single-Arm, Prospective Study of Remestemcel-L, Ex Vivo Culture-Expanded Adult Human Mesenchymal Stromal Cells for the Treatment of Pediatric Patients Who Failed to Respond to Steroid Treatment for Acute Graft-versus-Host Disease

Steroid-refractory acute graft-versus-host disease (SR-aGVHD) following hematopoietic cell transplantation (HSCT) is associated with poor clinical outcomes. Currently, there are no safe and effective therapies approved for use in the pediatric population under the age of 12 years. Accordingly, there is an urgent need for new treatments that are safe, well tolerated, and effective in managing this debilitating and potentially fatal complication of HSCT. In early phase clinical trials, mesenchymal stromal cells (MSCs) have demonstrated efficacy in the treatment of acute GVHD (aGVHD) in pediatric patients. We now report the results of a phase 3, prospective, single-arm, multicenter study (NCT02336230) in 54 children with primary SR-aGVHD who were naive to other immunosuppressant therapies for aGVHD treated with MSC product (remestemcel-L) dosed at 2 × 10⁶ cells/kg twice weekly for 4 weeks. Remestemcel-L therapy significantly improved day 28 overall response rate (OR) compared with the prespecified control OR value of 45% (70.4% versus 45%, P = .0003). The statistically significant OR (70.4%) was sustained through day 100, including an increase in complete response from 29.6% at day 28 to 44.4% at day 100. Overall survival was 74.1% at day 100 and 68.5% at day 180. Overall response in all participants at day 28 was highly predictive of improved survival through 180 days, and survival was significantly greater in day 28 responders compared with nonresponders through day 100 (86.8% versus 47.1% for responders and nonresponders, respectively, P = .0001) and through day 180 (78.9% versus 43.8%, P = .003). Remestemcel-L was well tolerated with no identified infusion-related toxicities or other safety concerns. This study provides robust, prospective evidence of the safety, tolerability, and efficacy of remestemcel-L as first-line therapy after initial steroid failure in pediatric SR-aGVHD.

Retrospective Multicenter Study of Extracorporeal Photopheresis in Steroid-Refractory Acute and Chronic Graft-versus-Host Disease

Extracorporeal photopheresis (ECP) is an established treatment strategy in steroid-refractory graft-versus-host disease (GVHD). This study's main objective was to analyze the clinical response and impact of ECP therapy in steroid dose reduction. A retrospective observational series of 113 patients from 7 transplantation centers was analyzed. Sixty-five patients (58%) had acute GVHD (aGVHD), and 48 (42%) had chronic GVHD (cGVHD). All ECP procedures were performed with the off-line system. The median number of procedures until achievement of initial response was 3 for both patients with aGVHD and those with cGVHD. ECP was the second-line therapy in 48% of the aGVHD cases and in 50% of the cGVHD cases. 71% of the cases of aGVHD were grade III-IV, and 69% of the cases of cGVHD were severe. The overall response rate on day 28 was 53% (complete response [CR] rate, 45%) in the patients with aGVHD and 67% (CR, 23%) in those with cGVHD. Skin was the most frequently involved organ, with a response rate of 58% (CR, 49%) in the patients with aGVHD and 69% (CR 29%) in those with cGVHD. At the end of ECP treatment, 60% of patients treated for aGVHD who responded were able to stop steroid therapy, with a median dose reduction of 100%. Significant differences in overall survival were observed for patients responding to ECP with aGVHD (hazard ratio [HR], 4.3; P < .001) and with cGVHD (HR, 4.8; P = .003). Our data indicate that ECP is a valid therapeutic alternative in patients with steroid-refractory aGVHD and cGVHD, permitting significant steroid dosage reductions.

Biomarkers in acute graft-versus-host disease: new insights

Hematopoietic cell transplantation (HCT) is a potentially curative therapy for hematologic malignancies that relies on the graft-versus-leukemia (GVL) effect to eradicate malignant cells. GVL is tightly linked to graft-versus-host disease (GVHD) however, in which donor T cells damage healthy host tissues. Acute GVHD occurs in nearly 50% of patients receiving HCT, and damages the skin, liver, and gastrointestinal (GI) tract. The organ stages are totaled in an overall grade (I-IV), and severe (grade III/IV) GVHD has a high mortality rate (50-70%). In the past decade, serum biomarkers have emerged as an additional potential measurement of acute GVHD severity. The discovery and validation of GVHD biomarkers is a principal objective of the Mount Sinai Acute GVHD International Consortium (MAGIC), a group of 25 HCT centers conducting GVHD research. MAGIC has validated an algorithm that combines two GI biomarkers (ST2 and REG3α) into a single value that estimates the probability of 6 month nonrelapse mortality (NRM) for individual patients, known as the MAGIC algorithm probability (MAP). The MAP reflects GI crypt damage and serves as a 'liquid biopsy' of the lower GI tract; it also predicts response to treatment and maximum GVHD severity and is now commercially available and widely used among scores of centers in clinical practice. The MAP is the focus of this review, with consideration of the categorization of types of biomarkers as defined by the United States National Institutes of Health (NIH) and Food and Drug Administration (FDA).

FDA Approval Summary: Ruxolitinib for Treatment of Steroid-Refractory Acute Graft-Versus-Host Disease

On May 24, 2019, the Food and Drug Administration approved ruxolitinib for steroid-refractory acute graft-versus-host disease (SR-aGVHD) in adult and pediatric patients 12 years and older. Approval was based on Study INCB 18424-271 (REACH-1; NCT02953678), an open-label, single-arm, multicenter trial that included 49 patients with grades 2-4 SR-aGVHD occurring after allogeneic hematopoietic stem cell transplantation. Ruxolitinib was administered at 5 mg twice daily, with dose increases to 10 mg twice daily permitted after 3 days in the absence of toxicity. The Day-28 overall response rate was 57.1% (95% confidence interval [CI]: 42.2-71.2). The median duration of response was 0.5 months (95% CI: 0.3-2.7), and the median time from Day-28 response to either death or need for new therapy for acute GVHD was 5.7 months (95% CI: 2.2 to not estimable). Common adverse reactions included anemia, thrombocytopenia, neutropenia, infections, edema, bleeding, and elevated transaminases. Ruxolitinib is the first drug approved for treatment of SR-aGVHD. IMPLICATIONS FOR PRACTICE: Ruxolitinib is the first Food and Drug Administration-approved treatment for steroid-refractory acute graft-versus-host disease in adult and pediatric patients 12 years and older. Its approval provides a treatment option for the 60% of those patients who do not respond to steroid therapy.

Feasibility of extracorporeal photopheresis in pediatric patients with graft-versus-host disease after hematopoietic stem cell transplantation

Graft-versus-host disease (GVHD) is a main cause of morbidity and mortality following hematopoietic stem cell transplantation. The cumulative incidence of acute and chronic GVHD (aGVHD, cGVHD) reaches 30%-50% and 20% in pediatric populations, respectively. Prednisolone and/or calcineurin inhibitors (CNI) are first-line treatments, but no superior second-line treatment has yet been established. Several treatments have been suggested, among others extracorporeal photopheresis (ECP). Technical advances have made treatment of pediatric patients possible; however, only few reports on the feasibility of ECP in children have been published. We retrospectively studied the feasibility, safety, and efficacy of ECP in 15 children with steroid-dependent/refractory acute or chronic GVHD, who initiated ECP treatment between April 2014 and January 2018. Only few and mild side effects directly related to the ECP procedure were registered, even in patients with low body weight. The most frequent cause of shortened or canceled ECP treatment was difficulties with vascular accesses, which were more rarely seen using central venous catheters with larger lumens and made of stiffer material. Nine patients had grade II-III aGVHD. Six of these experienced a response to ECP at day 28, while eight of nine had responded at the last ECP treatment. Six patients had cGVHD when ECP was initiated, and of these, four had a partial response at last ECP treatment. We found ECP to be a feasible and safe treatment, and particularly, children with aGVHD appeared to respond well to ECP.

Safety and Effectiveness of Vedolizumab in Patients with Steroid-Refractory Gastrointestinal Acute Graft-versus-Host Disease: A Retrospective Record Review

Allogeneic hematopoietic cell transplantation (allo-HCT) can be curative in patients with hematologic malignancies but carries a significant risk of graft-versus-host disease (GVHD). There are no standard treatments for steroid-refractory (SR) gastrointestinal (GI) acute GVHD (aGVHD). This multicenter, international, retrospective medical record review aimed to evaluate the off-label use of vedolizumab, a gut-selective immunomodulator, for treating SR GI aGVHD. Data were collected from patients' medical records; criteria for extraction included no more than 1 allo-HCT and at least 1 dose of vedolizumab as treatment for SR GI aGVHD (ie, stage 1 to 4 GI aGVHD following ≥1 previous treatment regimen(s) containing ≥1 mg/kg methylprednisolone or equivalent). Descriptive analyses of response rate, overall survival (OS), and serious adverse effects (SAEs) were performed. Twenty-nine patients were identified from 7 sites who had received 1 to 10 doses of vedolizumab 300 mg i.v. (median 3 doses) as treatment for SR GI aGVHD. The overall response rate at 6 to 10 weeks after vedolizumab initiation was 64%, and OS at 6 months was 54%. There were 29 SAEs, including 12 infections; 3 SAEs were considered possibly related to vedolizumab, 2 of which were infections. Thirteen SAEs were fatal, 1 of which was possibly vedolizumab-related. There were 8 nonserious infections and 1 serious infection with confirmed GI origin in 8 patients; there was no apparent pattern in the timing of these infections relative to the initiation of vedolizumab treatment. Further data on the efficacy and safety of vedolizumab in this setting from prospective trials are needed.

Clinical Outcomes and Healthcare Resource Utilization for Gastrointestinal Acute Graft-versus-Host Disease after Allogeneic Transplantation for Hematologic Malignancy: A Retrospective US Administrative Claims Database Analysis

Graft-versus-host disease (GVHD) is the leading cause of nonrelapse mortality among patients who receive allogeneic hematopoietic cell transplantation (allo-HCT). In its acute form (aGVHD), GVHD involves the skin, liver, and gastrointestinal (GI) tract, with GI involvement most strongly associated with poor prognosis. This retrospective cohort study used US healthcare claims data for 2008 to 2015 to identify patients who developed GI aGVHD after allo-HCT performed as curative treatment for hematologic malignancy and compared them with patients who did not develop aGVHD in terms of outcomes related to survival, infections, healthcare resource utilization (HRU), and costs. Whereas the patients without aGVHD saw a 66% improvement in 1-year survival between 2009 and 2015, this effect was not observed in patients with GI aGVHD. Compared with patients without evidence of aGVHD, patients with GI aGVHD were 3.9-fold more likely to develop an infection in the year after allo-HCT. Similarly, patients who developed GI aGVHD were 4.3-fold more likely to have an inpatient admission after allo-HCT discharge, and such an admission cost on average 47% more than an admission for patients without aGVHD. Our findings confirm that GI involvement in aGVHD is associated with higher mortality, risk of infection, HRU, and cost compared with absence of aGVHD.

Second-line treatment for acute graft-versus-host disease with mesenchymal stromal cells: A decision model

OBJECTIVE

No standard second-line treatment exists for acute graft-versus-host disease steroid-refractory (SR-aGvHD), and long-term outcomes remain poor. Mesenchymal stromal cells (MSCs) have been evaluated as treatment, but no disease model (DM) exists that integrates and extrapolates currently available evidence. The aim of this study was to develop such a DM to describe the natural history of SR-aGvHD and to predict long-term outcomes.

METHOD

The DM was developed in collaboration with experts in haematology-oncology. Subsequently, a model simulation was run. Input parameters for transition and survival estimates were informed by published data of clinical trials on MSC treatment for SR-aGvHD. Parametric distributions were used to estimate long-term survival rates after MSCs.

RESULTS

The newly developed DM is a cohort model that consists of eight health states. For the model simulation, we obtained data on 327 patients from 14 published phase II trials. Due to limited evidence, DM structure was simplified and several assumptions had to be made. Median overall survival was 3.2 years for complete response and 0.5 years for no complete response.

CONCLUSION

The DM provides a comprehensive overview on the second-line treatment pathway for aGvHD and enables long-term predictions that can be used to perform a cost-effectiveness analysis comparing any treatment for SR-aGvHD.

Phase I trial of histone deacetylase inhibitor panobinostat in addition to glucocorticoids for primary therapy of acute graft-versus-host disease

Glucocorticoids for primary therapy of acute GVHD have limited responses. A phase I/II trial tested 4 weeks of deacetylase inhibitor panobinostat started within 48 h of glucocorticoids (1 mg/kg/day prednisone or equivalent) as primary treatment for patients with either classic acute GVHD (n = 16) or acute GVHD overlapping with chronic (n = 6). Four patients received 2.5 mg/m² IV three times a week (TIW). Subsequent to discontinuation of IV panobinostat, patients received oral doses (PO). Two patients treated with 10 mg TIW (PO level 1) had progressive GVHD, after which patients were treated with 5 mg TIW (PO level -1; n = 16); 31/41 adverse events were possibly related, including thrombocytopenia (n = 13), leukopenia (n = 7), hypercholesterolemia (n = 3), hypertriglyceridemia (n = 5), anemia (n = 1), fatigue (n = 1), and hepatobiliary disorder (n = 1). GVHD responses were complete (n = 12) or partial (n = 3), with 1 progression at PO level -1. T-regulatory cells increased at day 8, CD4/CD8 and monocytes exhibited enhanced H3 acetylation, and CD4 or CD8 numbers remained unchanged with a decreased interleukin 12p40 plasma level. Panobinostat in combination with prednisone is safe and warrants further testing in GVHD.

Infusion of bone marrow derived multipotent mesenchymal stromal cells for the treatment of steroid-refractory acute graft-versus-host disease: a multicenter prospective study

The prognosis of steroid-refractory acute graft-versus-host disease (aGVHD) remains poor and better treatments are urgently needed. Multipotent mesenchymal stromal cell (MSC)-based therapy emerged as a promising approach but response rates were highly variable across studies. We conducted a multicenter prospective study assessing the efficacy of 1-2 infusion(s) of cryopreserved, third-party donor bone marrow-derived MSCs for treating grade II-IV steroid-refractory or -dependent aGVHD in a series of 33 patients. MSCs were produced centrally and distributed to 8 hospitals throughout Belgium to be infused in 2 consecutive cohorts of patients receiving 1-2 or 3-4 × 106 MSCs/kg per dose, respectively. All patients received MSCs as the first rescue therapy after corticosteroids, with the exception for one patient who received prior treatment with mycophenolate mofetil (that was still ongoing by the time of MSC therapy). In these conditions, MSC therapy resulted in at least a partial response in 13 patients (40.6%) at day 30 and in 15 patients (46%) within 90 days after first MSC infusion. The corresponding complete response rates were 21.6% (7 patients) and 30% (10 patients), respectively. Only 5 patients achieved a sustained complete response, lasting for at least 1 month. The 1-year overall survival was 18.2% (95% CI: 8.82-37.5%). Higher response and survival rates were observed among patients receiving 3-4 × 106 MSCs/kg for first infusion, as compared with patients receiving 1-2 × 106 MSCs/ kg. Response and survival with MSC therapy for SR/SD-aGVHD remains to be optimized.

Evaluation of infliximab as second-line treatment of acute graft versus host disease -validating response on day 7 and 28 as predictors of survival

Several immunosuppressive drugs have been proposed for second-line treatment of steroid-refractory acute graft versus host disease (aGvHD) after allogeneic hematopoietic stem cell transplantation. However, the studies on these drugs are small, retrospective, uncontrolled and use different endpoints. Therefore, it remains unknown which treatment is superior. We retrospectively evaluated 68 consecutive patients treated with infliximab for aGvHD. We adhered to recently proposed guidelines for aGvHD trials and thus evaluated response on day 7 and 28. Furthermore, we assessed the composite endpoint 6 months freedom from treatment failure (6MFTF). The majority of patients had grade III-IV aGvHD. We found that 41 patients (60%) responded on day 7 and 31 patients (46%) on day 28. Twenty-four patients (35%) achieved 6MFTF. The main reasons for failure within 6 months were death (n = 31) or additional immunosuppression (n = 16). By six and 24 months, 44 and 34% of the patients were alive respectively. Patients with response to infliximab on day 7 and 28 had significantly higher overall survival (OS) probability than non-responders. We show that response on day 7 and 28 identifies high and low risk groups. Patients who fail to respond should be identified early and offered alternative therapy.

Phase 1 multicenter trial of brentuximab vedotin for steroid-refractory acute graft-versus-host disease

BV has activity for SR-aGVHD. The MTD of BV was 0.8 mg/kg every 2 weeks for 4 doses.

Ex Vivo CD34+-Selected T Cell-Depleted Peripheral Blood Stem Cell Grafts for Allogeneic Hematopoietic Stem Cell Transplantation in Acute Leukemia and Myelodysplastic Syndrome Is Associated with Low Incidence of Acute and Chronic Graft-versus-Host Disease and High Treatment Response

Ex vivo CD34⁺-selected T cell depletion (TCD) has been developed as a strategy to reduce the incidence of graft-versus-host disease (GVHD) after allogeneic (allo) hematopoietic stem cell transplantation (HSCT). Clinical characteristics, treatment responses, and outcomes of patients developing acute (aGVHD) and chronic GVHD (cGVHD) after TCD allo-HSCT have not been well established. We evaluated 241 consecutive patients (median age, 57 years) with acute leukemia (n = 191, 79%) or myelodysplastic syndrome (MDS) (n = 50, 21%) undergoing CD34⁺-selected TCD allo-HSCT without post-HCST immunosuppression in a single institution. Cumulative incidences of grades II-IV and III-IV aGVHD at 180 days were 16% (95% confidence interval [CI], 12 to 21) and 5% (95% CI, 3 to 9), respectively. The skin was the most frequent organ involved, followed by the gastrointestinal tract. Patients were treated with topical corticosteroids, poorly absorbed corticosteroids (budesonide), and/or systemic corticosteroids. The overall day 28 treatment response was high at 82%. The cumulative incidence of any cGVHD at 3 years was 5% (95% CI, 3 to 9), with a median time of onset of 256 days (range, 95 to 1645). The 3-year transplant-related mortality, relapse, overall survival, and disease-free survival were 24% (95% CI, 18 to 30), 22% (95% CI, 17 to 27), 57% (95% CI, 50 to 64), and 54% (95% CI, 47 to 61), respectively. The 1-year and 3-year probabilities of cGVHD-free/relapse-free survival were 65% (95% CI, 59 to 71) and 52% (95% CI, 45 to 59), respectively. Our findings support the use of ex vivo CD34⁺-selected TCD allograft as a calcineurin inhibitor-free intervention for the prevention of GVHD in patients with acute leukemia and MDS.

Therapeutic targets and emerging treatment options in gastrointestinal acute graft-versus-host disease

Introduction

Graft-versus-host disease (GVHD) continues to be the major lethal complication of allogeneic hematopoietic stem cell transplantation (HCT) but the standard of care, high dose steroids, has not changed in 40 years. Approximately 50% of GVHD patients will develop steroid refractory disease, typically involving the gastrointestinal (GI) tract, which has a very poor prognosis. Newly developed GVHD biomarker-based risk scores provide the first opportunity to treat patients at the onset of symptoms according to risk of steroid failure. Furthermore, improvements in our understanding of the pathobiology of GVHD, its different signaling pathways, involved cytokines, and the role of post-translational and epigenetic modifications, has identified new therapeutic targets for clinical trials.

Areas covered

This manuscript summarizes the pathophysiology, diagnosis, staging, current and new targeted therapies for GVHD, with an emphasis on GI GVHD. A literature search on PubMed was undertaken and the most relevant references included.

Expert Opinion

The standard treatment for GVHD, high dose steroids, offers less than optimal outcomes as well as significant toxicities. Better treatments, especially for GI GVHD, are needed to reduce non-relapse mortality after allogeneic HCT. The identification of high risk patients through a biomarker-defined scoring system offers a personalized approach to a disease that still requires significant research attention.

Fecal calprotectin and α1-antitrypsin dynamics in gastrointestinal GvHD

In a previous study, the fecal biomarkers calprotectin and α1-antitrypsin (α1-AT) at symptom onset were reported to be significantly associated with the response to steroids in gastrointestinal GvHD (GI-GvHD). The purpose of this trial was to evaluate the dynamics of the fecal biomarkers calprotectin and α1-AT throughout the course of GvHD. Patients who were refractory to steroids had initially higher biomarker levels and in the course of GvHD demonstrated a continuous increase in fecal biomarkers. In contrast, the dynamics of calprotectin and α1-AT demonstrated low and decreasing levels in cortico-sensitive GvHD. In steroid-refractory patients who received a second line of treatment, the biomarker levels at the beginning of second-line treatment did not predict the subsequent response. Nevertheless, calprotectin levels progressively decreased in subsequent responders, whereas non-responders demonstrated continuously high levels of calprotectin. α1-AT values correlated to a lesser extent with the response to second-line treatment and remained elevated in both non-responders and responders. In conclusion, calprotectin monitoring can be of use in the management of immunosuppressive treatment in GI-GvHD.

Six-month freedom from treatment failure is an important end point for acute GVHD clinical trials

We studied the ASBMT 6 month (m) freedom from treatment failure (FFTF) as a predictor of survival for patients with acute graft-versus-host disease (aGVHD) requiring treatment. Adult patients undergoing allogeneic hematopoietic cell transplant (HCT) from February 2007 to March 2009 who were enrolled in a prospective biomarker clinical trial and developed aGVHD requiring systemic corticosteroids by day +100 were included (N=44). Six month FFTF was defined per ASBMT guidelines [absence of death, malignancy relapse/progression, or systemic immunosuppression change within 6 months of starting steroids and before chronic GVHD development]. aGVHD was treated with systemic corticosteroids in 44 patients. Day 28 response after steroid initiation (CR+VGPR+PR) occurred in 38 (87%) patients, but only 28 (64%) HCT recipients met the 6 m FFTF endpoint. Day 28 response predicted 6 m FFTF. Achieving 6 m FFTF was associated with improved 2 year (y) overall survival (OS) [81% vs. 48%, P= 0.03)] and decreased 2 y non-relapse mortality [8% vs. 49% (P= 0.01)]. In multivariate analysis, 6 m FFTF continued to predict improved OS (HR, 0.27; P=0.03). The 6 m FFTF endpoint measures fixed outcomes, predicts long-term therapeutic success, and could be less prone to measurement error than aGVHD clinical response at day 28.

Response endpoints and failure-free survival after initial treatment for acute graft-versus-host disease

We evaluated short-term response endpoints for acute graft-versus-host disease treatment trials. We postulated that response endpoints should correlate with reduced symptom burden and decreased subsequent treatment failure, defined as non-relapse mortality, recurrent malignancy, or additional systemic treatment. The cohort included 303 consecutive patients who received initial systemic steroid treatment for acute graft-versus-host disease. Response was evaluated at day 28 after initial treatment, which in all cases preceded the onset of chronic graft-versus-host disease. At day 28, 36% of patients had a complete response, 26% had a very good partial response, 10% had another degree of partial response (other partial response) and 28% had no response. As expected, the symptom burden was lower in patients with very good partial response compared to those with other partial response. The frequencies of subsequent treatment failure were similar in patients with complete and very good partial responses, but lower than in patients with other partial response or no response at day 28. The frequency of second-line treatment was lower in patients with very good partial response than in those with other partial response. Risk factors associated with a lower probability of complete or very good partial response at day 28 were unrelated or human leukocyte antigen-mismatched related donor grafts and liver or gastrointestinal involvement at onset of initial treatment. Taken together, these results suggest that endpoints in acute graft-versus-host disease treatment trials should distinguish between very good partial response and other partial response. Our results support the use of complete or very good partial response at day 28 as an appropriate short-term primary endpoint.

Rituximab prophylaxis prevents corticosteroid-requiring chronic GVHD after allogeneic peripheral blood stem cell transplantation: results of a phase 2 trial

B cells are implicated in the pathophysiology of chronic graft-vs-host disease (GVHD), and phase 2 trials suggest that B cell depletion can treat established chronic GVHD. We hypothesized that posttransplantation B cell depletion could prevent the occurrence of chronic GVHD. We performed a 65-patient phase 2 trial of rituximab (375 mg/m(2) IV), administered at 3, 6, 9, and 12 months after transplantation. Rituximab administration was safe without severe infusional adverse events. The cumulative incidences of chronic GVHD and systemic corticosteroid-requiring chronic GVHD at 2 years from transplantation were 48% and 31%, respectively, both lower than the corresponding rates in a concurrent control cohort (60%, P = .1, and 48.5%, P = .015). There was no difference in relapse incidence, but treatment-related mortality at 4 years from transplantation was significantly lower in treated subjects when compared with controls (5% vs 19%, P = .02), and overall survival was superior at 4 years (71% vs 56%, P = .05). At 2 years from transplantation, the B-cell activating factor/B-cell ratio was significantly higher in subjects who developed chronic GVHD in comparison with those without chronic GVHD (P = .039). Rituximab can prevent systemic corticosteroid-requiring chronic GVHD after peripheral blood stem cell transplantation and should be tested in a prospective randomized trial.

Mesenchymal stem cells as cellular immunotherapeutics in allogeneic hematopoietic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative treatment option in hematopoietic disorders, immunodeficiencies and leukemia. To date graft-versus-host disease (GvHD) represents a life-threatening complication even if associated with beneficial antileukemic reactivity. GvHD is the clinical manifestation of donor cells reacting against host tissue. Because of their ability to facilitate endogenous repair and to attenuate inflammation, MSC have evolved as a highly attractive cellular therapeutic in allo-HSCT. Here we report on the clinical experience in the use of MSC to enhance engraftment and prevent and treat acute and chronic GvHD. In early clinical trials, MSC have shown considerable benefit in the setting of manifest GvHD. These encouraging results warrant further exploration.

Secondary treatment of acute graft-versus-host disease: a critical review

Management of steroid-resistant or steroid-refractory acute graft-versus-host disease (aGVHD) poses one of the most vexing and difficult problems faced by transplantation physicians. In the current study, we used 10 criteria to evaluate 67 reports describing secondary treatment of patients with aGVHD. The goal of this exercise was not only to provide a critical summary of the literature but also to offer suggestions that could improve future studies. Areas especially in need of improvement include the use of a consistent treatment regimen, the assessment of response at a consistent prespecified time point, consideration of concomitant treatment in assessing response, documentation that selection bias was minimized, and the use of methods that test a formal statistical hypothesis based on a contemporaneous or historical benchmark. Our results suggest that previous published reports collectively offer little guidance in discerning the most effective treatments for patients with steroid-resistant or steroid-refractory aGVHD. Adherence to the proposed criteria in future reports would enable meaningful comparisons across studies and thereby accelerate progress in evaluating new treatments for patients with aGVHD.

Association between calcineurin inhibitor blood concentrations and outcomes after allogeneic hematopoietic cell transplantation

To determine whether calcineurin inhibitor (CNI) blood concentrations within the first month after allogeneic hematopoietic cell transplantation (HCT) correlated with the incidence of graft-versus-host disease (GVHD) and other outcomes, we retrospectively analyzed data from 1181 patients with hematologic malignancies who had HCT from HLA-matched related (n = 634) or unrelated (n = 547) donors at a single institution between 2001 and 2009. After myeloablative HCT (n = 774), higher CNI concentrations were not associated with lower risks of acute or chronic GVHD (aGVHD, cGVHD). After nonmyeloablative HCT (n = 407), higher cyclosporine concentrations were associated with decreased risks of grade 2-4 and 3-4 aGVHD (hazard ratio [HR] per 100 ng/mL change in cyclosporine concentrations, 0.7; 95% confidence interval [CI], 0.6-0.82; and HR, 0.66, 95% CI, 0.49-0.9, respectively), nonrelapse mortality (HR, 0.6, 95% CI, 0.41-0.88), and overall mortality (HR, 0.83, 95% CI, 0.71-0.99). Cyclosporine concentrations were not associated with risks of cGVHD and recurrent malignancy after nonmyeloablative HCT. Among patients given tacrolimus after nonmyeloablative HCT, a similar trend of CNI-associated GVHD-protection was observed. Higher CNI concentrations were not associated with apparent renal toxicity. We conclude that higher cyclosporine concentrations relatively early after nonmyeloablative HCT confer protection against aGVHD that translates into reduced risks of nonrelapse and overall mortality.

Treatment of graft-versus-host disease with monoclonal antibodies and related fusion proteins

Allogeneic hematopoietic stem cell transplantation has evolved from an experimental treatment approach to a widely used, curative therapy to treat malignant and nonmalignant diseases of the hematopoietic system. Despite advances in donor selection, conditioning regimens and supportive care, acute and chronic graft-versus-host disease (GvHD) remain a major cause of morbidity and mortality. Steroids are the standard first-line treatment and are able to control GvHD in approximately 50% of patients. Those who fail on steroids have a poor long-term prognosis. Therefore, a large number of drugs and procedures have been evaluated as second-line therapy. Monoclonal antibodies have increasingly been used to treat malignancy and autoimmune disease during the last 20 years. Their unique ability to target specific antigens theoretically enables them to directly interfere with cellular mechanisms that are involved in GvHD pathology. For this reason, monoclonal antibodies have been studied extensively as a second-line treatment for acute and chronic GvHD. The purpose of this article is to collect published data on clinical trials from the current literature and to give an overview on efficacy and toxicity of monoclonal antibody treatment for GvHD.

Mesenchymal stem cells expanded in vitro with human serum for the treatment of acute and chronic graft-versus-host disease: results of a phase I/II clinical trial

This trial evaluated the feasibility and efficacy of the infusion of mesenchymal stem cells expanded using human serum for the treatment of refractory acute or chronic graft-versus-host disease. Twenty-eight expansions were started. In 22, a minimum of more than 1 x 10⁶ mesenchymal stem cells/kg were obtained after a median of 26 days; this threshold was not obtained in the remaining cases. Ten patients received cells for the treatment of refractory or relapsed acute graft-versus-host disease and 8 for chronic disease. One patient treated for acute graft-versus-host disease obtained a complete response, 6 had a partial response and 3 did not respond. One of the chronic patients achieved complete remision, 3 a partial response, and 4 did not respond. The current study supports the use of this approach in less heavily treated patients for both acute and chronic graft-versus-host disease. The trial has been registered at ClinicalTrials.gov: identifier NCT00447460.