MaaT013 as Salvage Therapy in Ruxolitinib Refractory GI-aGVHD Patients (ARES)

Standard first-line therapy for the treatment of acute GVHD involves corticosteroids, usually methyl-prednisolone at a dose of 2 mg/kg per day (Martin PJ R. J., 2012; Van Lint MT, 1998). Despite initial responses (around 60%), fewer than half of patients have durable complete responses, and those patients who do not respond or progress after an initial response have high mortality (Weisdorf D, 1990; Alousi AM, 2009; Bolanos-Meade J, 2014). Moreover, prolonged high-dose corticosteroids (CS) exposure is associated with deleterious complications and long-term morbidity (Mohty M, 2010).

For these reasons, there is great interest in identifying effective therapies for corticosteroid-resistant aGvHD and improve outcomes.

Recently, ruxolitinib (Jakafi®), which has an Orphan Drug status in the USA, was granted an approval on 24 May 2019 from the FDA based on study INCB 18424-271 (NCT02953678). This open-label, single-arm study enrolled 72 grade 2-4 SR-aGvHD patients who were treated with 5 mg (possibly increased to 10mg) ruxolitinib b.d. Of the 72 patients, 49 were included in the efficacy evaluation that led the FDA to grant market authorization. Of these 49 patients, Overall Response Rate (ORR - Complete + Very Good Partial + Partial Responses) after 28 days was 100%, 40.7% and 44.4% for patients with Grade 2, Grade 3, and Grade 4 aGVHD respectively. The overall survival (OS) estimate at 6 months was 51.0% for the entire cohort.

The more recent REACH2 phase 3 randomized trial (NCT02913261) investigating ruxolitinib versus best available therapy in patients with corticosteroid-refractory acute GVHD has further established the role of ruxolitinib in the treatment of corticosteroid-refractory acute GvHD. The ORR at day 28 was higher in the ruxolitinib than in the control group (62% versus 39%; odds ratio, 2.64; 95%CI, 1.65-4.22; P<0.001). Similarly, the durable overall response at day 56 was higher in the ruxolitinib than in the control group (40% versus 22%; odds ratio, 2.38; 95% CI, 1.43-3.94; P<0.001) (Zeiser R, 2020) In the REACH1 and REACH2 trials, 45% and 38% of patients, failed to respond to ruxolitinib at day 28, respectively. Moreover, in the REACH2 trial, the overall response at day 56 after initiation of therapy decreased from 62.3% at D28 after initiation of therapy to 39.4% at D56, suggesting a clear unmet medical need for those patients who failed to respond at D28, or worsened afterwards (Zeiser R. 2020). More importantly, results from the REACH1 trial showed only a 22% probability of survival at 2 months in ruxolitinib-non responder patients (Jagasia 2020).

MaaT013 is made of allogeneic, full-ecosystem pooled biotherapeutic intestinal microbiota manufactured by MaaT Pharma in Lyon, France, according to GMP requirements. The intestinal microbiota material in its natural environment is derived from healthy, strictly-vetted and selected donors, following the European consensus recommendations (Cammarota 2016) with the purpose of minimizing the risk associated with fecal material transplants (FMT) for clinical research. Thus, prior to donation, donors undergo a thorough medical evaluation and laboratory screening including SARS-CoV-2 detection, to avoid any known contamination risk. MaaT013 is administered as an enema.

MaaT013 showed interesting results in steroids and ruxolitinib-resistant aGVHD patients with gut involvement (55% ORR at D28) and 47% and 39% OS at 6 and 12 months respectively (Malard 2020), therefore warrant being tested as salvage therapy in steroid and JAK inhibitors-resistant GI-aGvHD patients. Given the absence of an approved 3rd line strategy or 2nd line strategy in ruxolitinib intolerant patients and the extremely poor prognosis of these patients, who are mostly left with no viable therapeutic option, a single-arm open-label design was proposed.