ALBERT

Description: Background In myeloproliferative neoplasms (MPN), Interferon-α (IFN-α) has been shown effective in inducing hematologic and molecular responses and in reducing vascular events. In clinical practice its use is mainly limited by intolerance due to side effects. Aim We sought to evaluate the tolerability of IFN-α therapy, the thromboembolic incidence and the causes of termination of therapy in a cohort of MPN, treated outside of clinical trials. Methods One hundred patients (M/F 41/59, median age 48 years, range 15-73) with a diagnosis of polycythemia vera (PV, n=47), essential thrombocythemia (ET, n=43) and myelofibrosis (MF, n=10) according to the WHO 2008 criteria, on current or previous treatment with IFN-α (IFN-α-2b, Peg-IFN-α-2b, Peg-IFN-α-2a) were included. The patients, diagnosed 1987-2012, were recruited from 9 centers in Sweden and Norway, and retrospectively analyzed. Hematologic response in PV and ET was assessed according to ELN criteria from 2009. Response to treatment in MF was defined as platelets ² 400x109 /L, white blood counts ² 10x109/L and transfusion independency. Results IFN-α treatment characteristics are displayed in Table 1. The median treatment duration for IFN-α was 34 months. Treatment prior to IFN-α had been received by 44 pts including hydroxyurea (n=34), anagrelide (n=19), busulphan (n=2), radioactive phosphorus (n=1), 10 pts having received more than one cytoreductive agent. Complete hematologic response (CR) was observed in 58 pts (PV=28/47, ET=30/43) and partial hematologic response (PR) in 15 pts (PV=2, ET=13). In MF, hematologic response was noted in 8 out of 10 patients. IFN-α related adverse events (AE) were recorded in 76 pts (76/100, 76%) with similar rates between genders (M 30/41, 73%, F 45/59, 76%). AE were generally of low grade. Twenty pts experienced multiple (³ 3) side effects (M/F 6/14), females reporting a total of 96 AE compared to 53 in males. Hematologic toxicity was low with 4 pts presenting with anemia, 4 with leukopenia and 3 with thrombocytopenia. Most common non-hematologic toxicities were fatigue in 30 pts (M/F 11/19), myalgia in 28 (M/F 11/17) and depression in 21 (M/F 4/17), followed by liver function test elevation (n=9), headache (n=9), alopecia (n=8) and skin reaction (n=7). In two pts with autoimmune co-morbidities (rheumatoid arthritis, psoriasis), flare-up of symptoms related to autoimmune activity were seen, leading to discontinuation of therapy. Only one vascular event occurred in a 64 year old woman with PV, in CR since 92 months, who developed a myocardial infarction after 94 months of IFN-α-2b treatment. A total of 43 pts (M 16/41, 39%, F 27/59, 46%) discontinued therapy, of whom 34 (M 13/41, 32%, F 21/59, 36%) due to side effects. The most common cause of discontinuation of therapy due to side effects was depression (15/21), followed by fatigue (12/30) and myalgia (9/28). Nineteen (19/34, 58%) of the pts who discontinued therapy due to side effects were in CR. Discontinuation due to other reasons than side effects were lack of efficacy/progression of disease (n=5), co-morbidities (n=2), CR including molecular response (n=2) and pregnancy (n=1). Out of the 53 pts with ET and MF, 25 were JAK2V617F mutated and 14 had a CALR-mutation. No significant differences between these two groups were seen regarding side effects or discontinuation rate. Out of the 57 pts remaining on IFN-α, 19 still received IFN-α-2b (19/35, 54%), 7 PegIFN-α-2b (7/12, 58%) and 31 PegIFN-α-2a (31/53, 58%). Conclusion In this retrospective cohort study, the treatment discontinuation rate due to side effects was higher than in previous reports. This may be explained by the relatively long median duration of treatment in this cohort, reflecting a poor tolerance of low-grade toxicity over time. Depression was frequent and the most common reported side effect when therapy was discontinued. Gender difference, with females reporting a higher incidence of depression and a larger total burden of AE, was noted. The frequency of thromboembolic events was very low in this IFN-α treated cohort. Table 1. IFN-α treatment characteristics. Type of Interferon Patiens (n) Dose per week–median (range) Treatment time-median IFN α-2b 35 9 MIE (1,2-20) 58 PegIFN α-2b 12 40 μg (30-80) 46 PegIFN α-2a 53 90 μg (30-135) 15 Disclosures No relevant conflicts of interest to declare.

Description: Although imatinib, a BCR-ABL tyrosine kinase inhibitor, is used to treat acute Philadelphia chromosome–positive (Ph+) leukemia, it does not prevent central nervous system (CNS) relapses resulting from poor drug penetration through the blood-brain barrier. Imatinib and dasa-tinib (a dual-specific SRC/BCR-ABL kinase inhibitor) were compared in a preclinical mouse model of intracranial Ph+ leukemia. Clinical dasatinib treatment in patients with CNS Ph+ leukemia was assessed. In preclinical studies, dasatinib increased survival, whereas imatinib failed to inhibit intracranial tumor growth. Stabilization and regression of CNS disease were achieved with continued dasa-tinib administration. The drug also demonstrated substantial activity in 11 adult and pediatric patients with CNS Ph+ leukemia. Eleven evaluable patients had clinically significant, long-lasting responses, which were complete in 7 patients. In 3 additional patients, isolated CNS relapse occurred during dasatinib therapy; and in 2 of them, it was caused by expansion of a BCR-ABL–mutated dasatinib-resistant clone, implying selection pressure exerted by the compound in the CNS. Dasatinib has promising therapeutic potential in managing intracranial leukemic disease and substantial clinical activity in patients who experience CNS relapse while on imatinib therapy. This study is registered at ClinicalTrials.gov as CA180006 (#NCT00108719) and CA180015 (#NCT00110097).