ALBERT

Description: Background A subset of patients with the Philadelphia-chromosome negative myeloproliferative neoplasms (MPNs) transform to AML, and the prognosis of post-MPN AML patients is very poor. As such, new genomic insights are needed to define the mechanisms that govern transformation from MPN to AML, and to identify new therapeutic targets for clinical intervention in this poor-risk myeloid neoplasm. Importantly, patients with JAK2V617F mutant chronic-phase disease transform to JAK2 wildtype AMLs in approximately half of cases, indicating that diverse genomic paths lead to transformation. Aims To characterize the genomic alterations, including point mutations, short indels, translocations, and copy number alterations, in 33 post-MPN AML samples. Methods Genomic DNA and total RNA was isolated from formalin fixed paraffin embedded (FFPE) tissue, blood and bone marrow aspirates. Adaptor ligated sequencing libraries were captured by solution hybridization using two custom baitsets targeting 374 cancer-related genes and 24 genes frequently rearranged for DNA-seq, and 272 genes frequently rearranged for RNA-seq. All captured libraries were sequenced to high depth (Illumina HiSeq), averaging 〉590X for DNA and 〉20,000,000 total pairs for RNA, to enable the sensitive and specific detection of genomic alterations. We achieved a mean coverage depth of 511x (range 405-645). Results The most common genomic alterations identified in post-MPN AML samples were mutations in JAK2 (51.5%), ASXL1 (48.5%), and IDH2 (30.3%). Mutually exclusive mutations in the genes of spliceosome components SRSF2, U2AF1, and SF3B1 were identified in 39% of patients in this cohort, suggesting that somatic mutations in splicing factors are a common genomic event in transformation from MPN to AML. These data were in contrast to de-novo AML, in which mutations in FLT3, NPM1, and DNMT3A are the most common disease alleles (NEJM 2013; 368: 2059), suggesting that the spectrum of genomic alteration in post-MPN AML differs from that in de novo AML. Within our cohort of post–MPN AML samples, 52% of the patients had JAK2V617F positive AML and 48% of our cohort presented with JAK2 wildtype AML. Notably, the two subsets of post-MPN AML had distinct mutational patterns. In the JAK2V617F mutant subgroup, we identified frequent mutations in ASXL1 (41.2%), TP53 (41.2%), and IDH2 (41.2%). In JAK2-wildtype AML subgroup we identified frequent ASXL1 mutations (56.3%) and NRAS point mutations (37.5%). NRAS mutations were exclusive of JAK2 mutations in the entire cohort, consistent with alternate disease alleles which activate signaling in JAK2V617F positive AML and in JAK2 wildtype AML. SETBP1 mutations were found in 19% of patients with JAK2 wildtype post-MPN AML but not in any patients with JAK2V617F-positive post-MPN AML. Several alterations not previously described in post-MPN AML, to the best of our knowledge, were identified in this cohort including MLL-PTD, which was observed in both JAK2V617F and wildtype JAK2 patients. Copy number analysis of our high-depth sequencing data allowed us to identify homozygous deletions of TET2 and ETV6 and MYC amplifications in post-MPN AML. Univariate analysis demonstrated TP53 mutations were associated with significantly impaired overall survival (p

Description: Key Points This analysis demonstrates the universality of the early response in CML, regardless of the treatment modality used. Factors correlating with poor cytogenetic responses at 3-mo assessment in a multivariate analysis across all 4 TKIs.

Description: Abstract 1753 Background: Ruxolitinib (INC424), a potent and selective oral JAK1 and JAK2 inhibitor, has demonstrated rapid and durable reductions in splenomegaly and improved disease-related symptoms, role functioning, and quality of life (QoL) in 2 phase 3 studies in patients with myelofibrosis (MF) (the COMFORT studies). These studies compared ruxolitinib with either placebo or best available therapy (BAT). This analysis compares the efficacy outcomes between the placebo arm from COMFORT-I and the BAT arm from COMFORT-II. Methods: COMFORT-I is a randomized (1:1), double-blind, multicenter study comparing ruxolitinib 15 or 20 mg twice daily (bid) with placebo, and COMFORT-II is a randomized (2:1), open-label, multicenter study comparing ruxolitinib 15 or 20 mg bid with BAT (investigator-selected therapy, including no treatment). Both studies met their primary end points with statistical significance (ruxolitinib vs control): the percentage of patients achieving ≥35% reduction in spleen volume at week 24 (COMFORT-I, P

Description: Abstract 313 Background: While advanced PV and ET patients at high thrombotic risk are managed primarily with HU, patients who are intolerant or refractory to HU have limited therapeutic options. Identification of a dominant gain-of-function mutation in the JAK2 kinase, V617F, in myeloproliferative neoplasms (MPNs), including PV and ET, provided a key rationale for the development of a molecularly targeted therapy for these diseases. Long term follow-up data from an ongoing trial of INCB018424, a selective JAK 1/ JAK 2 inhibitor, in PV and ET patients refractory or intolerant to HU are presented. Methods: Study 18424-256 is an uncontrolled open-label Phase 2 study being conducted at 6 sites in the United States and Italy. An initial 8-week run-in evaluation established 10-mg and 25-mg twice daily as starting doses for expansion cohorts in PV and ET, respectively; dose adjustments for safety and efficacy are allowed so that each subject is titrated to their most appropriate dose. For PV, response is defined based on Hct control in the absence of phlebotomy, improvement or elimination of palpable splenomegaly when present, and normalization of leukocytosis and thrombocytosis. For ET, response is defined based on improvement or normalization of WBC and platelet counts and, when present, elimination of palpable splenomegaly. PV results (n=34; median 108 months from diagnosis): After a median follow-up of 15 months (range 8–21), 97% of enrolled subjects achieved Hct control to 15×109/L was present in 47% of subjects and improved (≤ 15×109/L) or normalized (≤ upper limit of normal) in 88% and 63%, respectively. Thrombocytosis 〉 600×109/L was present in 38% of subjects and improved (≤ 600×109/L) or normalized (≤ upper limit of normal) in 92% and 69%, respectively. 59% of subjects achieved phlebotomy independence, resolution of splenomegaly and normalization of leukocytosis and thrombocytosis. 6 patients discontinued therapy (3 due to AEs, 2 withdrew consent, 1 for no response). Grade 3 AEs potentially related to study medication included thrombocytopenia (2 patients), neutropenia (1), renal tumor (1), asthenia (1), viral infection (1), and atrial flutter (1). No Grade 4 drug-related AEs have occurred. ET results (n=39; median 84 months from diagnosis): After a median follow-up of 15 months (range 4–21), 49% of enrolled subjects normalized platelet counts to ≤ upper limit of normal after a median of 0.5 months and for a median duration of 3.5 months. 82% maintained platelet counts 〈 600×109/L, for a median duration of 9.8 months. Of 14 patients with baseline platelet counts 〉 1000×109/L, 13 have experienced 〉 50% reduction. 88% maintained normal WBC (median duration 14.5 months). Palpable spleens resolved in 3 of 4 subjects; 1 reduced 〉50% from baseline. 49% of subjects achieved normalization of WBC and platelet counts in the presence of non-palpable splenomegaly. 9 patients discontinued therapy (4 due to AEs, 2 withdrew consent, 3 for no response). Grade 3 AEs potentially related to study medication included leukopenia (2 patients), GI disorder (1), and peripheral neuropathy (1). No Grade 4 drug-related AEs have occurred. Both patient groups demonstrated reductions in patient-reported symptom scores for pruritus, night sweats, and bone pain. Of 26 PV patients reporting pruritus at baseline (median score of 6 on a 10-point scale), 24 reported scores of 0 after a median duration of 1 month and for a median duration of 7 months. 42% of PV and 56% of ET patients had at least a 20% decrease in JAK2V617F allele burden; 6% of PV and 12% of ET had 〉50% decrease. Clinical responses were unrelated to the presence/absence of JAK2V617F mutation at entry or to the allele burden changes following treatment. Conclusions: Rapid and durable clinical benefits (normalization of hematological parameters, resolution of splenomegaly and alleviation of symptoms) have been demonstrated in advanced PV and ET patients with 〉1 year of follow-up. In this study, INCB018424 continues to be a well tolerated, effective therapy in patients with PV and ET refractory or intolerant to hydroxyurea. Disclosures: Verstovsek: Incyte Corporation: Research Funding. Levy:Incyte Corporation: Employment, Equity Ownership. Bradley:Incyte Corporation: Employment. Garrett:Incyte Corporation: Employment. Vaddi:Incyte corporation: Employment. Huber:Incyte Corporation: Employment, Equity Ownership. Schacter:Pfizer Corporation: Employment. Vannucchi:Novartis: Membership on an entity's Board of Directors or advisory committees.

Description: Background: Polycythemia vera (PV) is characterized by erythrocytosis, thrombocytosis, and/or leukocytosis and a broad range of disease-related symptoms. In high-risk patients, the most common first-line treatment is hydroxyurea (HU). The open-label RESPONSE trial demonstrated that ruxolitinib (RUX), a JAK1/JAK2 inhibitor, provided superior efficacy compared with best available therapy in patients with PV who were resistant to or intolerant of HU according to modified European LeukemiaNet (ELN) criteria. This study (RELIEF) was conducted in patients receiving a stable dose of HU and who were generally well controlled but reporting disease-associated symptoms, comparing the change in PV-related symptom burden in patients continuing their HU therapy with those switching to RUX treatment. Methods: RELIEF was a randomized, multicenter, double-blind, double-dummy, phase 3b study of patients with PV aged ≥18 years on a stable dose of HU monotherapy and reporting PV-related symptoms. Patients were required to be receiving HU for ≥12 weeks prior to enrollment and on the same dose level for the last 4 weeks, and have a score ≥8 on the Myeloproliferative Neoplasm Symptom Assessment Form (MPN-SAF) cytokine total symptom score (TSS-C). The TSS-C comprised symptoms of itching, tiredness, muscle ache, night sweats, and sweats while awake; each symptom was rated on a scale of 0=absent to 10=worst imaginable, with a maximum TSS-C score of 50. Patients also had to meet one of the following: ≤1 phlebotomy in the previous 6 months or no palpable splenomegaly. Those eligible were randomized 1:1 to receive RUX 10 mg BID and HU-placebo, or HU at the same dose/schedule and RUX-placebo. Dose adjustments were permitted for safety and efficacy. After Week 16, patients could receive open-label RUX until Week 48. The primary endpoint was the proportion of patients with a ≥50% reduction in TSS-C at Week 16; secondary endpoints included proportion of patients with a ≥50% reduction in individual TSS-C symptoms and safety. Results: Overall, 54 and 56 patients were randomized to RUX and HU, respectively; 87.0% and 89.3% remained on treatment through Week 16. At baseline, the median age (range) was 64 (36-87) in the RUX group and 66 (19-85) in the HU group; 44% and 61% were men. The majority of patients in the RUX and HU groups did not have baseline platelet counts or WBC above ELN thresholds: platelets 〉400 and ≤600 x 109/L (RUX 31.5%, HU 28.6%), 〉600 x 109/L (3.7%, 8.9%); WBC 〉10 and ≤15 x 109/L (16.7%, 16.1%), 〉15 x 109/L (11.1%, 14.3%). In the RUX and HU groups, the mean TSS-C at screening (22.4, 23.1) was higher than that at baseline (16.7, 18.0); the ratio of screening to baseline TSS-C was 1.7 and 1.6. The proportion of patients achieving a ≥50% reduction from baseline in TSS-C at Week 16 (primary endpoint) was 43.4% in the RUX group and 29.6% in the HU group (P=0.139; OR, 1.82; 95% CI, 0.82-4.04). The proportions of patients in the RUX vs HU groups achieving a ≥50% reduction in scores for itching and tiredness at Week 16 were 40.0% vs 26.4% and 54.2% vs 32.0%, respectively. Median percentage changes in individual TSS-C symptoms are shown in Table 1. Additional analyses found no correlation between individual changes in HU dose from baseline to Weeks 13-16 and percentage change in TSS-C in the HU arm (r2=0.030). Even patients maintaining the same HU dose from prior to study entry through Week 16 reported symptom improvement: 12/35 (34.3%) with no dose change, 4/12 (33.3%) with a dose increase, and 0/9 (0%) with a dose decrease had a ≥50% reduction in TSS-C. The most common nonhematologic adverse events in the RUX arm on randomized treatment were fatigue (20.4% RUX vs 10.7% HU), headache (16.7% vs 5.4%), and dizziness (13.0% vs 8.9%). The most common adverse events on HU were diarrhea (9.3% RUX vs 19.6% HU) and constipation (7.4% vs 12.5%); most events were grade 1 or 2. Grade 3 or 4 anemia or thrombocytopenia (lab values) were not reported in the RUX group; two patients in the RUX group had grade 3 or 4 neutropenia. Conclusion: In generally well controlled PV patients receiving a stable dose of HU, there was a positive trend in symptom improvement for patients switched to RUX therapy versus those continuing on HU therapy, although this was not statistically significant. The 34% response rate among patients who continued to receive a stable HU dose suggests a placebo effect that led to an underpowered study. Further analyses are required to better interpret these findings. Disclosures Off Label Use: Ruxolitinib is a JAK1/JAK2 inhibitor approved for the treatment of patients with intermediate or high-risk myelofibrosis, including primary myelofibrosis, post polycythemia vera myelofibrosis, and post-essential thrombocythemia myelofibrosis. Vannucchi:Novartis Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Yacoub:Alexion Pharmaceutical: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees; Sanofi Aventis: Membership on an entity's Board of Directors or advisory committees. Koschmieder:Novartis Pharmaceuticals: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Byrne:Novartis Pharmaceuticals: Honoraria. Verstovsek:Incyte Corporation: Research Funding. Hunter:Incyte Corporation: Employment, Equity Ownership. Jones:Incyte Corporation: Employment, Equity Ownership. He:Incyte Corporation: Employment, Equity Ownership. Morozov:Novartis Pharmaceuticals: Employment, Equity Ownership.

Description: Background: MPN-AML, MPN-AP, and DIPSS-plus high risk PMF are associated with a poor response to therapy and shortened survival. Several studies have shown clinical activity of hypomethylating agents (DNA methyltransferase inhibitors) in these situations. We reviewed our database to evaluate the clinical outcome of patients (pts) with MPN-AML, MPN-AP and DIPSS-plus high risk PMF who received decitabine (DAC; a hypomethylating agent) in the course of their treatment at our institution. Methods: Retrospective chart review identified 21 pts with MPN-AML, 13 with MPN-AP and 11 with DIPSS-plus high risk PMF treated with DAC in our center over last 7 years. MPN- AP was defined by 10%-19% blasts in the peripheral blood or bone marrow (BM). DIPSS-plus is a prognostic model for PMF and can be applied at any point during the disease course (Gagnat et al. J Clin Oncol 2011; 29:392-7). Responses in MPN-AML were defined according to published recommendations (Mascarenhas et al. Leuk Res 2012; 36:1500-4). Responses in MPN-AP and DIPSS-plus high risk PMF were defined according to the revised IWG-MRT and ELN consensus report (Tefferi et al. Blood 2013; 122: 1395-8). Results: MPN-AML pts characteristics: median age 64 yrs (range, 45-82); initial MPN: ET 4 (19%), PV 5 (24%), PMF 10 (48%), and MPN unclassified 2 (10%) pts. The median number (no.) of prior therapies for MPN was 1 (range, 0-4). The median time for transformation from MPN to MPN-AML was 93 mo (range, 1.4-292). Thirteen (39%) pts had unfavorable cytogenetics. DAC was given as first-line therapy in 12 (57%) pts, as second-line therapy in 8 (38%), and as third-line in 1 (5%). The median no. of DAC cycles given was 2 (range, 1-15). MPN-AP pts characteristics: median age 63 yrs (range, 50-81); initial MPN: ET 2 pts (15%), PV 5 (39%), and PMF 6 (46%). The median no. of prior therapies for MPN was 2 (range, 0-5). The median time from diagnosis of MPN to DAC was 65 (0-389) mo. The median no. of DAC cycles given was 2 (range 1-37). PMF with DIPSS-plus high risk pts characteristics: median age 67 yrs (range, 55-77). Seven (64%) pts had a JAK2 mutation. The median hemoglobin (Hb) was 9.2 g/dl (range, 7.7-11.7), median WBC was 41.5 K/uL (range, 2-140), median platelet (plt) count was 69 K/uL (range, 9-860) and bone marrow blast percentage (BM BL %) was 2% (range, 0-9). The median number of DIPSS-plus risk factors was 6 (range, 4-8), and median no. of prior therapies was 1 (range, 0-4). The median time to DAC from diagnosis of PMF was 19 (3-195) mo. The median no. of DAC cycles given was 3 (range 1-8). Six (29%) MPN-AML pts responded to DAC: 3 CR, 2 CRi and 1 PR. Two pts who achieved CR, received DAC as second line after falling induction chemotherapy for AML. The median time to response was 2.6 mo (range, 1-13.5). Among non-responders; 10(48%) pts died due to disease progression, 3 (14%) pts died due to sepsis, one is alive with stable disease (SD) on therapy, and one pt died 2 months after bone marrow transplant (BMT). The median response duration (defined as time to next therapy/death/last follow up) was 7 mo (range, 2-24). One patient responding to DAC had BMT after 2 months of maintaining the response. The median OS from the time of post MPN-AML acquisition was 6.9 mo. The OS was 10.5 mo in responders vs 4 mo in non-responders (p= 0.024) (Fig. 1A). Among MPN-AP, 1 pt had clinical improvement (CI) in Hb and plt, and 7 had SD (with improvements in blood count), for overall benefit in 8 (61%) pts. The median benefit duration was 6.5 mo. (1.8-14). Four (31%) pts with SD after improvement in leukocytosis and BM BL % had BMT. The median OS from the time of MPN-AP acquisition was 9.7 mo. The OS in responders was 11.8 mo. vs 4 mo. in non-responders (p=0.28) (Fig.1B). Among non-responders 3 (23%) pts transformed to AML, one pt received next line of therapy and had BMT, one pt died due to disease progression. Nine (82%) pts with DIPSS-plus high risk PMF benefited from DAC: 1 had CI in plt, 1 had CI in spleen, and 7 had SD (with improvements in blood count). Median response duration was 9 mo (1-23). Three (27%) pts had BMT after improvement in leukocytosis and BM BL %. Both pts who did not respond, progressed to AML and died due to infectious complication. The median OS was 36.6 mo: OS in responders was 190 mo vs 4.7 mo in non-responders (p=0.027) (Fig. 1C). Conclusion: DAC is a viable therapeutic option for pts with MPN-AML, MP-AP and high-risk PMF. Prospective clinical studies combining DAC with other clinically active agents are needed to improve overall outcome. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.