Chronic Graft versus Host Disease (cGvHD) is still the leading cause of late mortality in transplanted patients. Among the new drugs potentially useful in patients with steroid-refractory cGVHD (SR-cGVHD), the Tyrosine Kinase Inhibitor (TKI) Imatinib emerged as promising agent; however in our previous experiences, patient's frailty and their reduced haematological tolerance heavily limited the daily dose of Imatinib (median dose administered was 200 mg/day). Thus we planned to evaluate in the same setting a the safety and activity of a second generation TKI, such as Nilotinib (NIL), characterized by a better haematological tolerance and that could allow to treat SR-cGVHD patients with a higher relative dosage than Imatinib, thus achieving a better efficacy. Basing on this rational we designed a phase I-II study, aimed to individuate the maximum tolerated dose ( MTD) and the activity of NIL in patients with SR-cGVHD (ClinicalTrials.gov ID: NCT01810718). Primary endpoint of the phase I study was to define the dose limiting toxicity (DLT) of NIL, defined as the occurrence of any grade≥3 toxicity during at least one month of treatment. According to the Fibonacci standard 3+3 design, we started from an initial dose of 200 mg/day of NIL, up to a maximum of 600 mg/day. The drug has been supplied free of charge by Novartis Italia, Milan. In the phase II the MTD will be used to define the efficacy of NIL in SR-cGVHD patients, with similar characteristics of the previously Imatinib-treated population. Moreover all the patients enrolled in the phase I were allowed to continue NIL at the same dose, up to a cGVHD progression, if an objective improvement (OI) was documented after 3 months of treatment. We report here the preliminary results of a pre-planned interim analysis, during the phase I study, in 12 patients with SR-cGVHD who received NIL at low dose. The main characteristics of the enrolled patients are reported in table 1. Six patients received NIL 200mg/day and 6 NIL 300 mg/day. Two patients stopped NIL within 30 days: one due to cGVHD progression, the other had asymptomatic hypertransaminasemia (>5xULN) which normalized 1 month after stopping NIL; these patients received an alternative treatment. In 3 cases severe adverse events (SAE) have been reported: 1 patient had extramedullary relapse of Acute Leukemia 8 months after start of NIL, while 2 patients have been hospitalized; one due to a transient cGVHD flare, without drug interruption, the second for a late cGVHD progression; he eventually died. The most frequent extrahematological toxicities (grade 1-2 according to CTCAE) were headache, nausea, pruritus, cramps, asthenia, constipation, while the main hematological abnormalities were represented by anemia grade 1 (5/12patients), neutropenia gr.1 (1/12 patients) and lymphocyte count increase gr.2 (1/12 patients). (tab.2) With a median F-U of 10 months (range 4-20), 10 patients are alive, while two died for cGVHD progression (7 and 9 months after the enrollment). After 3 months of treatment with NIL 6 patients (50%) achieved an OI and 4 (33%) a stable disease; all the 10 patients continued Nilotinib at the same dose until ≥6 months of treatment: after 6 months we observed 5 OI, 1 stable disease and 2 mixed responses (2 lung responses with skin failure), while in 2 the response evaluation is still ongoing. These preliminary data suggest that, like Imatinib, NIL at low doses is safe and effective in SR-cGVHD patients; up to day the MTD has not been still achieved, therefore only after the end of the phase I study we will be able to fully define the NIL activity. This study is supported by GITMO (Gruppo Italiano Trapianto di Midollo Osseo).
Disclosures:
Off Label Use: Bendamustine.
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