Jamieson, Catriona

Abstract Abstract 459 Background: A Phase I study of TG101348, a potent, oral JAK2-selective inhibitor in patients with high- or intermediate-risk primary, post-polycythemia vera (PV) and post-essential thrombocythemia (ET) myelofibrosis (MF) recently completed enrollment. Data from the dose escalation cohort (n=28; 30–800 mg administered as a single daily dose) showed dose-linear plasma exposure, with mean elimination T1/2 at steady state ranging from 16 to 34 hours. The dose-limiting toxicity was reversible asymptomatic grade 3 or 4 amylasemia/lipasemia; the maximum tolerated dose was 680 mg. We now present updated results from an extension study in which subjects continued treatment beyond six 28-day cycles. Result: In the entire study, 59 subjects (median age 64 years) were treated. Forty four patients had PMF, 12 post-PV MF, and 3 post-ET MF; 86% were JAK2V617F-positive. Median palpable spleen size was 18 cm and 21 (36%) patients were transfusion-dependent at study enrollment. Forty three (73%) subjects continued treatment on the extension study; the median (range) cumulative exposure to TG101348 was 380 days (170-767); the number of cycles of treatment completed ranged from 7–29, and the proportion of subjects who completed 12, 18, and 24 cycles of treatment was 72%, 28%, and 14%, respectively. The median (range) treatment dose at data cutoff was 440 mg/day (120 to 680 mg/day; n = 35). Toxicity: TG101348 was well tolerated. Non-hematologic, at least possibly related adverse events included nausea (69%; Grade 3=3%), diarrhea (64%; Grade 3=10%), and vomiting (58%; Grade 3=3%), that were dose-dependent; the symptoms were self-limited or controlled with symptomatic treatment and/or dose reduction. Also observed were asymptomatic increases in serum lipase (27%), AST/ALT (27%/25%), creatinine (24%), and alkaline phosphatase (17%). Grade 3/4 hematological adverse events possibly related to TG101348 included treatment-emergent anemia (35% of patients who were not transfusion dependent at baseline), thrombocytopenia (24%), and neutropenia (10%). Spleen: During cycles 1–6, 42% of patients achieved Clinical Improvement (CI) per the International Working Group for Myeloproliferative Neoplasms Research and Treatment (IWG-MRT) criteria for spleen response. The CI rate for the 43 subjects who continued treatment beyond 6 cycles was 65%, and the median time (range) to CI was 140 days (77-802). After 12 cycles, 36 (95%) of the 38 evaluable patients had some degree of spleen size reduction; 32 (85%), 26 (68%), and 10 (26%) of subjects had a minimum 25%, 50%, and 100% decrease in palpable splenomegaly. JAK2V617F allele burden: Of the 48 JAK2V617F mutation-positive subjects, 23 (48%) had a baseline mutant allele burden of >20%. Of these, 20 subjects with a baseline median allele burden (range) of 62% (23% to 100%) completed at least 6 cycles of treatment. Sixteen subjects (80%) exhibited a median 62% (range 6% to 96%) decrease in JAK2V617F burden, including 9 (45%) with a ≥50% decrease; 4 subjects (20%) had increases (range 18% to 58%). Eighteen subjects (78%) completed 12 cycles of treatment; 13 (72%) had a median 50% decrease (range 29% to 82%), including 7 (39%) subjects with a ≥50% decrease; 5 subjects (28%) had no change or increases (range 0% to 22%) in JAK2V617F. Constitutional symptoms: For patients with data at baseline and cycle 6, early satiety, fatigue, night sweats, cough, and pruritus were reported by 56%, 47%, 24%, 22%, and 19% of subjects, respectively. Improvement (complete resolution) rates observed at cycle 6 were: 75% (40%), 65% (29%), 89% (89%), 88% (75%), and 100% (57%) for the aforementioned symptoms, respectively. Leukocytosis/Thrombocytosis: Leukocytosis was present at baseline in 33 subjects; following 6 and 12 cycles of therapy, 57% (n=28) and 56% (n=25) achieved normal WBC counts. Thrombocytosis was noted at baseline for 10 (17%) subjects; following 6 and 12 cycles of therapy, 90% (n=10) and 88% (n=8) achieved normal platelet counts. Conclusion: The current study provides proof-of-concept that selective JAK2 inhibition has anti-myeloproliferative/anti-clonal activity in myelofibrosis. The majority of subjects treated with TG101348 for more than 6 cycles experienced a rapid, significant, and durable decrease in splenomegaly, normalization of leukocyte/platelet counts, and improvement of disease-related symptoms, all within the context significantly decreased JAK2V617F burden. Disclosures: Off Label Use: There is no FDA approved drug for Myelofibrosis.All the drugs discussed will be off-label. Stone:Novartis: Consultancy. Silverman:TargeGen: Consultancy. Shorr:TargeGen: Employment, Equity Ownership.

Abstract Background: NS-018 is an oral, selective, small molecule inhibitor of Janus kinase 2 (JAK2). OBJECTIVE: The purpose of this study is to determine the safety, tolerability and efficacy of orally administered NS-018 in patients with PMF, post-PV MF, or post-ET MF. METHODS: This multicenter, Phase 1/2, 3+3 dose-escalation study of NS-018 enrolled patients with IPSS intermediate-1, intermediate-2, or high risk PMF, post-PV MF, or post-ET MF. The study drug, NS-018, was given orally either daily (QD) or twice daily (BID) in 28-day cycles. In Phase 1, changes in spleen size were assessed by manual palpation, quality of life with the Myelofibrosis Symptom Assessment Form (MF-SAF), and responses were assessed according to the IWG-MRT/ELN consensus criteria. Bone marrow fibrosis (BMF) was evaluated by biopsy, according to WHO criteria. Changes in grade of BM fibrosis from baseline were categorized as improvement, stabilization, or worsening. The Phase 1 portion of the study has been completed and data are presented here. RESULTS: In this Phase 1 study, 48 patients were enrolled across 10 dosing cohorts (75-400 mg QD/100-400 mg BID). Characteristics: 37 PMF, 5 post-PV MF, 6 post-ET MF with a median age (range) 69.5 yrs (38-83); M/F:29/19; 35 JAK2V617F+, and 23 previously treated with a different JAK2 inhibitor. At 400 mg QD/BID, NS-018 dosing was associated with drug-related neurologic adverse events (AEs) including dizziness, peripheral neuropathy, headache, disturbance in attention, vertigo, dysesthesia, paresthesia, aphasia, and nervous system disorder (not otherwise specified). The 300 mg QD dose was better tolerated than 250 mg BID or 300 mg BID, with fewer neurologic AEs, and was selected as the recommended phase 2 dose (RP2D). For the 48 phase 1 patients, reductions in MF-SAF score were observed for all symptoms after 3 cycles, including for patients with prior JAK2 inhibitor treatment. In all dose cohorts, ≥ 50% patients achieved ≥ 50% score reduction from baseline in night sweats, pruritus and bone pain after 1 cycle. Moreover, ≥ 50% patients achieved ≥ 50% score reduction from baseline in abdominal pain and inactivity after 3 cycles. In patients who had received prior JAK2 inhibitor, ≥ 50% patients achieved ≥ 50% score reduction from baseline in filling up quickly, inactivity, night sweats and quality of life after 3 cycles. Among 36 patients with baseline splenomegaly ≥ 5 cm and treatment for ≥ 1 cycle, 20 (56%) showed ≥ 50% reduction in spleen size (confirmed for ≥ 8 weeks in 16 patients), including 9/19 (47%) patients with prior JAK2 treatment. According to IWG criteria, 14/36 (39%) patients showed splenic clinical improvement (CI) for ≥ 8 weeks, 4 had hemoglobin CI, and 1 had platelet CI. After 3 cycles of NS-018 treatment, 11/31 (37%) evaluable patients had a reduction in bone marrow fibrosis(BMF) by ≥ 1 grade. At any time during NS-018 treatment, 17/31 (55%) evaluable patients had a reduction in BMF by ≥ 1 grade. Overall, 23% (7/31) patients maintained improvement in BMF for ≥ 12 weeks. Reduction in BMF after 3 cycles was correlated with reduction in splenomegaly and hemoglobin responses. To date, 8 patients with prior JAK inhibitor treatment have been enrolled into the phase 2 portion of the trial. Updated Phase 2 data will presented at the meeting. CONCLUSIONS: The RP2D dose of NS-018 was 300 mg QD. This dose provided an acceptable safety and tolerability profile, and reduction in symptomatic splenomegaly. Phase 2 is ongoing and includes patients previously treated with other JAK2 inhibitors. Disclosures Talpaz: ARIAD: Research Funding; Bristol-Myers Squibb: Research Funding; Sanofi Aventis: Research Funding; Pfizer: Research Funding; Incyte: Research Funding. Ritchie:Incyte: Speakers Bureau; Celgene: Speakers Bureau. Odenike:Spectrum Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; Algeta Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi-Aventis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees; Suneisis Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; CTI/Baxter: Honoraria, Membership on an entity's Board of Directors or advisory committees; Geron: Research Funding. Jamieson:GlaxoSmithKline: Research Funding; Johnson & Johnson: Research Funding. Stein:Incyte Corporation: Consultancy, Membership on an entity's Board of Directors or advisory committees. Mesa:Novartis Pharmaceuticals Corporation: Consultancy; Pfizer: Research Funding; CTI Biopharma: Research Funding; NS Pharma: Research Funding; Gilead: Research Funding; Incyte Corporation: Research Funding; Promedior: Research Funding; Genentech: Research Funding.

Abstract Introduction Polycythemia vera (PV) is characterized by excessive production of erythroid cells and in most cases a point mutation (V617F) in the Jak2 cytokine signaling kinase. We investigated whether a selective JAK2 inhibitor decreased Jak2 V617F induced erythroid differentiation. Methods Wild-type and mutant Jak2 V617F genes were excised from the retroviral Jak2-mus-MSCV-neo vector (Levine et al), cloned into the lentiviral vector pLV CMV IRES2 GFP and their presence verified by DNA sequencing. Lentiviral vectors bearing the wild-type and mutant Jak2 genes or vector alone were used to transduce human peripheral blood CD34+ cells, which were then divided for plating into megacult medium for megakaryocytic colony growth and methylcellulose culture for enumeration of all other progenitor cell types. Normal cord blood HSC (CD34+/CD38−/CD90+) were clone sorted with the FACS Aria and transduced with no vector, backbone vector, wild-type JAK2 or mutant JAK2 vector in methocult media (Stem Cell Technologies Inc, GF+ H4435) +/− 300 nM of a selective JAK2 inhibitor, TG101348. Colonies were scored at day 14. RNA was isolated from the colonies (Qiagen RNeasy kit) and RT-PCR was performed with wild-type and mutant JAK2 allele specific primers. Results Transduction of cord blood HSC with the mutant Jak2 vector resulted in skewed erythroid colony formation compared to wild-type Jak2, vector alone and untransduced HSC (Figure 1; n=3). RT-PCR with murine Jak2 specific primers resulted in ~900 bp fragments corresponding to murine Jak2 from colonies transduced with the wild-type and mutant Jak2 and confirmed by sequencing, but not those from colonies transduced with the vector alone or the untransduced cells. Like the results in cord blood cells, adult peripheral blood CD34+ cells transduced with the mutant Jak2 developed a skewed developmental pattern, with far greater erythroid colony formation compared to wild-type Jak2 or vector alone. In megacult assays, CD34+ cells transduced with the mutant Jak2 had similar megakaryocytic potential as wild-type Jak2 or vector alone. Addition of TG101348 (300 nM), inhibited mutant kinase-induced erythroid colony formation (Figure 1) in 3 experiments while 100– 300 nM was inhibitory to PV (n=2 patients) HSC and progenitors. Current experiments focus on inhibition of Jak2 in a bioluminescent highly immunocompromised mouse model of Jak2V617F-induced myeloproliferation (Figure 2). Conclusion JAK2 V617F skews differentiation of HSC toward the erythroid lineage and may be inhibited with a selective JAK2 inhibitor - TG101348. Figure 1. In vitro JAK2 Inhibition. Figure 1. In vitro JAK2 Inhibition. Figure 2. Bioluminescent JAK2 V617F-induced Myeloproliferation Model. Figure 2. Bioluminescent JAK2 V617F-induced Myeloproliferation Model.

Abstract Abstract 2837 Introduction: Treatment with the JAK2 selective inhibitor SAR302503 reduced spleen size, disease-related symptoms, and the JAK2 V617F allele burden, with an acceptable safety profile in patients with primary MF, post-PV MF, or post-ET MF in a Phase I/II study (J Clin Oncol 2011;29:789, ASH 2011; Abs 3838). The objective of this Phase II study is to assess the efficacy, safety, pharmacokinetics (PK), and pharmacodynamics (PD) of 3 doses of SAR302503. Methods: Patients with intermediate-2 or high-risk primary MF, post-PV MF, or post-ET MF were randomized to 1 of 3 dose groups of SAR302503 (300, 400, or 500 mg per day). Eligibility criteria included age ≥18 years, ECOG PS 0–2, and an enlarged spleen (length ≥5 cm). SAR302503 was taken orally, once a day, in consecutive 28-day cycles until disease progression or unacceptable toxicity. The primary endpoint is the absolute change in spleen volume at the end of cycle 3 assessed by MRI with independent central review. Secondary endpoints include spleen response (≥35% reduction in spleen volume vs baseline), safety, symptom response (MPN-SAF), PK, and PD (changes in leukocyte pSTAT3). Results: From August–December 2011, at total of 31 patients were enrolled (n=10 in the 300 and 400 mg groups; n=11 to 500 mg). Risk status (intermediate-2 vs high) was balanced in the 400 mg and 500 mg groups (∼50%), whereas the 300 mg group had more high-risk patients (70%). The majority of patients (88% to 91%) had the JAK2 V617F mutation and most (∼80%) were blood transfusion independent. Mean (median) percentage reductions in spleen volume vs baseline at the end of cycle 3 were 30% (26%) in the 300 mg group, 33% (31%) with 400 mg, and 42% (38%) with 500 mg. A spleen response at the end of cycle 3 was seen in 30% of patients (3/10) in the 300 mg group, 50% (5/10) in the 400 mg group, and 64% (7/11) in the 500 mg group. Patients with constitutional symptoms at baseline in all groups reported a symptom response at the end of cycle 3, with at least a 2-point improvement in or resolution of night sweats in 93% (14/15) of patients, itching in 71% (10/14), early satiety in 56% (10/18), abdominal pain in 56% (10/18), and abdominal discomfort in 50% (10/20). Safety was evaluated in all patients. The most common grade 3–4 hematological adverse event (laboratory) was anemia, with rates across the 300, 400, and 500 mg doses of 33%, 30%, and 55%, respectively. Rates of grade 3–4 thrombocytopenia were 20%, 0, and 9%. There was no grade 3–4 neutropenia. Most common grade 3–4 nonhematological events were diarrhea (10%, 20%, 0), nausea (10%, 10%, 0), and vomiting (10%, 10%, 0). Adverse events in the 300 mg group led to discontinuation in 2 patients: 1 patient had grade 3 anemia, and 1 patient with pre-existing intermittent mild transaminase elevations and polyarthritis had hepatic failure, but completely recovered after discontinuation. No other grade 3–4 increases of AST, ALT, or bilirubin were observed. No deaths were due to an adverse event. Following repeated once-daily oral doses, SAR302503 exposure increased in a dose-dependent manner, with a median time to maximum plasma concentration of 2 to 3 hours. Steady state was achieved by cycle 1 day 15 (C1D15), with a 2.95- to 3.88-fold accumulation of drug. Time-dependent pSTAT3 inhibition was observed at all doses, with the highest mean percentage decreases from baseline (range) occurring at C1D15 (44% to 52%) and C2D1 (40% to 51%). The relationship between PK and PD pSTAT3 suppression can be described by an Emax model. There was also a correlation between percentage of pSTAT3 inhibition and spleen response rate at C1D15 and C2D1 and evidence of a steady state exposure-response relationship for spleen volume reduction at the end of cycle 3. Conclusions: In this Phase II trial, treatment with SAR302503 was associated with clinically meaningful reductions in splenomegaly and improvements in constitutional symptoms. SAR302503 was generally well tolerated in this trial and adverse events were consistent with the known safety profile. Time-dependent decreases in pSTAT3 and exposure-response correlations can be demonstrated across the three doses tested. Sponsored by Sanofi (NCT01420770) Disclosures: Talpaz: Novartis: Research Funding, Speakers Bureau; BMS: Research Funding; ARIAD: Research Funding; Deciphera: Research Funding. Gabrail:Sanofi: Research Funding. Lebedinsky:Sanofi: Employment, Equity Ownership. Gao:Sanofi: Employment, Equity Ownership. Liu:Sanofi: Employment, Equity Ownership. Pardanani:YM BioSciences: Clinical trial support, Clinical trial support Other; BMS: Clinical trial support, Clinical trial support Other; Sanofi: Clinical trial support Other.

Abstract Background: PAC is an oral kinase inhibitor with specificity for JAK2, FLT3, IRAK1, and CSF1R that has demonstrated significant and sustained spleen volume reduction (SVR) and symptom control vs BAT (excluding JAK2 inhibitors) in MF pts regardless of platelet count (PERSIST-1). The PERSIST-2 study was a randomized, controlled, open-label, phase 3 trial of PAC 200 mg BID and PAC 400 mg QD vs BAT (including JAK1/JAK2 inhibitor ruxolitinib [RUX]) in pts with 10 or 20 MF whose platelet counts were ≤100,000/µL, a recognized adverse prognostic variable. Prior JAK2 inhibitor use was allowed. Methods: Pts were randomized 1:1:1 to PAC BID, PAC QD, or BAT. The co-primary efficacy endpoints were the percentages of pts achieving ≥35% SVR (MRI or CT) and ≥50% reduction in total symptom score (TSS; MPN-SAF TSS 2.0), both from baseline to Week 24. The primary objective was to compare the efficacy of pooled PAC (BID+QD) to BAT and the secondary objectives were to compare PAC BID and PAC QD individually to BAT. PK samples were collected and analyzed for PAC. Safety analyses were based on all pts exposed to study treatment of any duration (safety population); efficacy analyses were based on ITT pts with a randomization date allowing Week 24 endpoint evaluations prior to the full clinical hold* (ITT efficacy population). Results: 311 pts were randomized (107 PAC BID, 104 PAC QD, 100 BAT), 308 received study drug, and 221 were included in the ITT efficacy population (74 PAC BID, 75 PAC QD, 72 BAT). Demographics and baseline disease characteristics were generally balanced among the treatment arms (Table) and analysis populations. A total of 32 (44%) BAT pts in the ITT efficacy population received RUX as treatment at some point on study. Population PK analyses showed that the steady-state plasma levels achieved with BID were higher than with QD, however the Cmax levels were lower. A significantly higher percentage of pts in the pooled PAC arm achieved SVR ≥35% (18% [27/149]) vs the BAT arm (3% [2/72]; p=0.001; Figure 1A). 25% of PAC pts (37/149) had ≥50% reduction in TSS vs 14% of BAT pts (p=0.079; Figure 1B). In secondary analyses vs BAT, PAC BID demonstrated significant improvement over BAT for both efficacy endpoints with 22% achieving SVR ≥35% (BAT=3%; p=0.001) and 32% achieving ≥50% reduction in TSS (BAT=14%; p=0.011). The PAC QD arm had a significant SVR ≥35% (15% v 3%, respectively; p=0.017), but a similar proportion with ≥50% reduction in TSS (17% v 14%, respectively; p=0.652). More PAC pts reduced their red blood cell transfusion dependence at Week 24 (defined as a ≥50% reduction in average transfusions/month for 3 months relative to baseline) with 19% (7/37) in the PAC QD arm, 22% (8/36) in PAC BID, and 9% (3/35) in BAT. There was no significant difference observed in OS across the treatment arms (Figure 2). Hazard ratios for OS (95% confidence intervals) were 0.68 (0.30, 1.53) for PAC BID v BAT, 1.18 (0.57, 2.44) for PAC QD v BAT, and 0.61 (0.27, 1.35) for PAC BID v QD. PAC BID maintained this survival advantage vs BAT across nearly all demographic and MF-associated risk factors. During the course of the study, 10 (9%), 15 (14%), and 15 (14%) died on PAC BID, PAC QD, and BAT, respectively. The most common treatment-emergent adverse events (AEs) associated with PAC were gastrointestinal (diarrhea, nausea, vomiting) and hematologic (anemia and thrombocytopenia), and were generally less frequent for BID vs QD administration. Grade 3/4 cardiac AEs occurred in 7%, 13% and 9% of PAC BID, PAC QD, and BAT pts, respectively, and grade 3/4 bleeding AEs occurred in 14%, 7%, and 7%, respectively. Grade 3/4 bleeding AEs were associated with grade 3/4 thrombocytopenia, which was also more common in the PAC BID group. Nine pts had cardiac failure (2% PAC QD, 4% PAC BID, 3% BAT) and 1 (1%, PAC QD) had intracranial hemorrhage.* Conclusions: The PERSIST-2 study is the only randomized, controlled trial to date in pts with MF and thrombocytopenia (platelets ≤100,000/µL), allowed prior JAK2 inhibitor treatment exposure (including RUX), and allowed RUX as BAT comparator. Irrespective of prior JAK2 inhibitor treatment, both PAC arms were more effective at SVR than BAT; however, PAC BID appeared more active than QD dosing and achieved significance versus BAT for both SVR and TSS. The most frequent AEs with PAC were gastrointestinal and hematologic toxicities. *PAC on full clinical hold by the FDA on 2/8/2016 based on concerns around excess deaths and cardiac and hemorrhagic events in PERSIST-1. Disclosures Mascarenhas: Incyte: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; CTI BioPharma: Research Funding; Janssen: Research Funding; Roche: Research Funding; Promedior: Research Funding. Talpaz:CTI BioPharma: Research Funding; Pfizer: Research Funding; Incyte Corporation: Research Funding; Ariad: Other: Expense reimbursement, travel accomodation expenses, Research Funding; Gilead: Other: Travel, Accommodations, Expenses, Research Funding; BMS - Canada: Consultancy. Gerds:CTI BioPharma: Research Funding; Astra-Zeneca: Research Funding; Roche: Research Funding; Incyte: Research Funding. Stein:Incyte Corporation: Consultancy. Gupta:Incyte Corporation: Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding. Drummond:CTI BioPharma: Honoraria; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; BMS: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Other: Travel, Accommodations, Expenses, Research Funding, Speakers Bureau; Roche: Speakers Bureau. Granston:CTI BioPharma Corp.: Employment. Daly:CTI BioPharma Corp.: Employment. Dean:CTI BioPharma Corp.: Employment, Equity Ownership. Al-Fayoumi:CTI BioPharma Corp.: Employment, Equity Ownership. Callahan:CTI BioPharma: Employment. Singer:CTI BioPharma Corp.: Employment, Equity Ownership, Other: Leadership . Gotlib:Novartis: Other: Travel, Accommodations, Expenses; Steering Committee Chairman, Research Funding; Promedior: Research Funding; CTI BioPharma: Research Funding; Gilead: Research Funding; Incyte: Consultancy, Honoraria, Other: Travel, Accommodations, Expenses, Research Funding. Jamieson:GSK: Research Funding; Johnson & Johnson: Research Funding; CTI BioPharma: Research Funding. Harrison:Novartis: Consultancy, Honoraria, Other: Travel, Accommodations, Expenses, Research Funding, Speakers Bureau; CTI BioPharma: Consultancy, Honoraria, Speakers Bureau; Baxter: Consultancy, Honoraria; Shire: Speakers Bureau; Gilead: Speakers Bureau; Incyte: Speakers Bureau. Mesa:Novartis: Consultancy, Honoraria; Incyte: Research Funding; Gilead: Research Funding; CTI BioPharma: Research Funding; Celgene: Research Funding; Genetech: Research Funding; Promedior: Research Funding. Verstovsek:CTI BioPharma Corp: Research Funding.

Abstract Background: NS-018 is an oral, selective, small molecule inhibitor of Janus kinase 2 (JAK2).In the previously-reported Phase 1 portion, patients with myelofibrosis (MF) who received NS-018 achieved steady-state plasma levels above the IC50 for JAK2 at all doses (75mg QD - 400 mg BID). 300 mg QD was chosen as the recommended dose (RD) for Phase 2 portion of the study. OBJECTIVE: The purpose of this study was to determine the safety, tolerability and efficacy of orally-administered NS-018 in patients with PMF, post-PV MF, or post-ET MF. METHODS: This multicenter, Phase 1/2, 3+3 dose-escalation study of NS-018 enrolled patients with IPSS intermediate-1, intermediate-2, or high risk PMF, post-PV MF, or post-ET MF. NS-018 was dosed orally daily (QD) or twice daily (BID) in 28-day cycles. In Phase 1, changes in spleen size were assessed by manual palpation, quality of life with the Myelofibrosis Symptom Assessment Form (MF-SAF), and responses according to the IWG-MRT/ELN consensus criteria. Bone marrow fibrosis was evaluated by biopsy, according to standard practice at the sites. Changes from baseline in grade of BM fibrosis were categorized as improvement, stabilization, or worsening. The Phase 1 portion of the study is complete. In the ongoing Phase 2 portion, spleen size is being assessed by palpation and by centrally-read MRI, and quality of life evaluated by the Myeloproliferative Neoplasm Symptom Assessment Form (MPN-SAF). RESULTS: 48 patients were enrolled across 10 dosing cohorts (75-400 mg QD/100-400 mg BID) in Phase 1. Patient characteristics: 37 PMF, 5 post-PV MF, 6 post-ET MF; median age (range) 69.5 yrs (38-83); M/F:29/19; 35 JAK2V617F+, and 23 previously treated with a different JAK2 inhibitor. The data cutoff for this analysis was June 30, 2016 (median follow-up time of 279.5 [range 5-1806] days from screening), at which time 10 patients remained on treatment. The median number of treatment cycles was 10 (1-65). Reasons for treatment discontinuation were disease progression (PD, n = 13), adverse events (AE, n = 8), physician consideration (n = 6), patient request (n = 4), and protocol non-compliance (n = 1). The 300 mg QD dose was selected as the phase 2 recommended dose (P2RD) in terms of tolerability and efficacy. For the 48 patients, reductions in MF-SAF score were observed for all symptoms after 3 cycles, including patients with priorJAK2 inhibitor treatment. Among 36 splenic-evaluable patients with baseline splenomegaly > 5 cm and treatment for > 1 cycle, 20 (56%) showed > 50% reduction in spleen size (confirmed for > 8 weeks in 16 patients), including 9/19 (47%) patients with prior JAK2 treatment. According to IWG criteria, 14/36 (39%) patients showed splenic clinical improvement for > 8 weeks, 4 with hemoglobin CI, and 1 with platelet CI. Twenty-nine patients with prior JAK inhibitor treatment have been enrolled into the phase 2 portion of the trial. Patient characteristics: 13 PMF, 12 post-PV MF, 4 post-ET MF; median age (range) 67 yrs (48-86). The reason for discontinuation of prior JAK2 inhibitor treatment: AEs (62%) and PD (38%). To date, the median number of treatment cycles is 6 (1-20). The majority of grade 3/4 AEs were hematologic and the most common hematologic toxicities were anemia (21%) and thrombocytopenia (17%). Non-hematologic AEs were mostly grade 1/2, and the other AEs shown in > 10% of patients was nausea (14%). Updated Phase 2 efficacy and safety data will be presented at the meeting. CONCLUSIONS: The RP2D dose of NS-018 was 300 mg QD. This dose provided a durable dosing schedule, an acceptable safety profile, splenic size reductions and clinical symptom improvement. Phase 2 is ongoing and includes patients previously treated with a different JAK2 inhibitor. Disclosures Talpaz: Novartis: Research Funding; Incyte Corporation: Other: Travel expense reimbursement, Research Funding; Ariad: Other: Expense reimbursement, travel accomodation expenses, Research Funding; Pfizer: Consultancy, Other: travel accomodation expenses, Research Funding. Ritchie:Pfizer: Honoraria; Arian: Speakers Bureau; Celgene: Speakers Bureau; Novartis: Honoraria; Incyte: Speakers Bureau. Odenike:Suneisis: Honoraria, Membership on an entity's Board of Directors or advisory committees; CTI/Baxter: Honoraria, Membership on an entity's Board of Directors or advisory committees; Geron: Research Funding; Spectrum: Honoraria, Membership on an entity's Board of Directors or advisory committees; Algeta: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi-Aventis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees. Jamieson:GlaxoSmithKline: Research Funding; CTI Biopharma: Research Funding; Johnson & Johnson: Research Funding. Stein:Incyte: Membership on an entity's Board of Directors or advisory committees. Mesa:CTI: Research Funding; Promedior: Research Funding; Celgene: Research Funding; Gilead: Research Funding; Incyte: Research Funding; Galena: Consultancy; Ariad: Consultancy; Novartis: Consultancy.

Abstract Background We previously reported that patients with MF enrolled in a randomized Phase II study of fedratinib (SAR302503) (ARD11936; NCT01420770) had clinically meaningful reductions in splenomegaly and improvements in MF-associated constitutional symptoms after 24 weeks of treatment (Haematologica 2013;98:S1113). Here, we report updated efficacy and safety results from this study after 48 weeks of treatment (end of Cycle 12). Methods Patients with intermediate risk-2 or high-risk MF were randomized to receive once-daily fedratinib at doses of 300 mg, 400 mg, or 500 mg, for consecutive 4-weekly cycles, until disease progression or unacceptable toxicity. Eligible patients were aged ≥18 years, with palpable splenomegaly (5 cm below costal margin), and a platelet count ≥50 × 109/L. The primary measure for this study was percent change in spleen volume from baseline at the end of Cycle 3 (Blood 2012:120;Abstract 2837. Haematologica 2013;98:S1113). Endpoints for the current analysis included spleen response (≥35% reduction in spleen volume from baseline, assessed by a blinded independent central review by MRI), safety, and changes in bone marrow fibrosis (BMF). Results A total of 31 patients were randomized and treated: median age 63 years, 52% male, 58% primary MF, 58% high-risk MF, 90% JAK2V617F positive. The median numbers of treatment cycles were 12, 14, and 13 in the 300 mg, 400 mg and 500 mg dose groups, respectively, with median durations of exposure of 48.2, 56.2, and 52.4 weeks. At the cut-off date for this analysis, 21 patients (68%) remained on treatment; the most common reasons for treatment discontinuation were adverse events (AEs) (n=5) and withdrawal of consent (n=2). Overall, 58% (18/31) of patients achieved a spleen response at any time during treatment. The median spleen response duration was >35 weeks at all doses (Table). At Week 48, a spleen response was achieved by 30% (3/10), 80% (8/10), and 45% (5/11) of patients in the 300 mg, 400 mg, and 500 mg groups, respectively. Responses were generally maintained across all treatment groups. From Week 24 to Week 48 two additional patients achieved a spleen response (both in the 400 mg group), while one patient in the 500 mg group did not maintain a response (this patient had a fedratinib dose reduction to 200 mg). Changes in BMF up to Week 48 are being evaluated. The most common non-hematologic AE was diarrhea, with a Grade 3 rate of 13% (4/31 patients) but no Grade 4 cases were recorded. The rates of diarrhea decreased after the first cycle of treatment; from Cycle 2, the incidence of diarrhea (any grade) did not exceed 16% (5/31) at any cycle, and only one case of diarrhea was reported at Week 48 (end of Cycle 12). Anemia was the most-common hematologic toxicity, with a Grade 3 rate of 58% (18/31); no Grade 4 cases were reported. All Grades thrombocytopenia occurred in 55% (17/31) of patients, Grade 3 in three patients, and Grade 4 in two patients. Discontinuation of treatment due to AEs occurred in five patients over the 48 weeks (300 mg [n=2]; 400 mg [n=2]; 500 mg [n=1]), with two cases reported after Week 24 (dyspnea and leukocytosis [400 mg]; anemia and thrombocytopenia [500 mg]). There were 2 deaths (one in the 300 mg group due to unknown reasons [85 days after fedratinib discontinuation] and one in the 500 mg group due to disease progression [36 days after fedratinib discontinuation]). No cases of leukemic transformation were reported. Conclusions This updated analysis of the ARD11936 Phase II trial shows that treatment with fedratinib results in durable reductions in splenomegaly in patients with MF. No additional safety signals were observed with prolonged exposure to fedratinib. This study was sponsored by Sanofi. Disclosures: Pardanani: Sanofi, Bristol Myers Squibb, PharmaMar and JW Pharma: Clinical trial support Other. Jamieson:J&J, Roche: Research Funding; Sanofi: Membership on an entity’s Board of Directors or advisory committees. Lebedinsky:Sanofi: Employment. Gao:Sanofi: Employment. Talpaz:Novartis, Bristol-Myers Squibb, Ariad, Deciphera: Research Funding; Novartis, Bristol-Myers Squibb, Ariad, Deciphera: Speakers Bureau.

Abstract Background: NS-018 is an oral, selective, small molecule inhibitor of Janus kinase 2 (JAK2). Pre-clinically NS-018 inhibited JAK2 kinase with an IC50 value in the subnanomolar range and demonstrated splenomegaly reduction at low doses in a JAK2V617F-bearing mouse model (Blood Cancer J 2011; 1: e29.). Methods: This multicenter, Phase 1/2, 3+3 dose-escalation study of NS-018 enrolled patients with IPSS intermediate-1, intermediate-2, or high risk PMF, postPV MF, or postET MF. Patients were ≥ 18 years, had ECOG PS ≤ 2 and required therapy but were not required to have splenomegaly in Phase 1. NS-018 was dosed orally daily (QD) or twice daily (BID) in 28-day cycles. Responses were assessed according to IWG consensus criteria, changes in spleen size by manual palpation and quality of life with the Myelofibrosis Symptom Assessment Form (MF-SAF). The Phase 1 portion of the study completed enrollment and is presented here. Results: Patients: 42 patients were enrolled across 10 cohorts. Patient characteristics: 33 PMF, 5 postPV MF, 4 postET MF; median age (range) 69 yrs (43-83); M/F:28/14; 31 JAK2V617F+, and 17 previously treated with a different JAK inhibitor. Dosing and tolerability: Dose levels included 75, 125, 200, 300 and 400 mg QD and 100, 200, 250, 300 and 400 mg BID. Systemic exposures based on Cmax were approximately dose proportional across the tested range from 75 to 400 mg. The recommended Phase 2 dose (RP2D) was 300 mg BID, based on drug-related neurological adverse events (AEs) at 400 mg BID including dizziness (Grade 2 or 3), dysphagia (Grade 2) or hypoesthesia (Grade 1) in one patient each that led to dose reduction or drug discontinuation. Study drug-related serious AEs (SAEs) included non-cardiac chest pain (Grade 2, 200 and 300 mg BID), lower GI hemorrhage (Grade 3, 300mg BID), paresthesia (Grade 3, 300mg BID), increased lipase (Grade 2, 300mg BID), and dizziness (Grade 3, 400 mg BID) in one patient each. For the 300 mg BID cohort (n=11), the most frequent drug-related AEs across all grades were nausea (Grade 1, 18%), decreased platelet count (≤ Grade 2, 18%), and dizziness (≤ Grade 2, 27%); Grade 3 related AEs included anemia, lower GI bleed, leukopenia, neutropenia or paresthesia (1 patient each, 9%); and no Grade 4 AEs. Overall, 22 patients (52%) discontinued treatment due to AEs (n=7), progressive disease (PD) (n=7), or MD/patient decision (n=8). The AEs leading to discontinuation included thrombocytopenia (Grade 4), transient ischemic attack (Grade 2), muscle contraction involuntary (Grade 2), light headedness (Grade 1), insomnia (Grade 1), hemolytic anemia (Grade 3), dizziness (Grade 2), dysphagia (Grade 2), and hypoesthesia (Grade 1). Nine patients had a hemoglobin decrease ≥ 2 g/dL and 8 patients a platelet decrease ≥ 50%. Responses: Of 33 evaluable patients with baseline splenomegaly ≥ 5 cm and treatment for ≥ 1 cycle, 16 (48%) patients showed ≥ 50% reduction in spleen size (confirmed for ≥ 8 weeks in 11 patients). In addition, 11 patients showed splenic clinical improvement (CI, for ≥ 8 weeks), 3 patients hemoglobin CI, and 2 patients platelet CI. Median (range) time to splenic response and duration of response: 1.5 cycle (1-12) and 4.5 cycles (1-29). Splenic reductions ≥50% are shown in the Table for the specified patient groups. Changes in MF-SAF and PK and PD results will be presented. Table Splenic reduction(in evaluable patients) All doses 16/33 (48%) 300mg BID 3/6 (50%) 300mg QD 4/7 (57%) Prior different JAK inhibitor treated 8/16 (50%) Conclusions: The dose of NS-018 determined to be the RP2D in Phase 1 was 300 mg BID. This dose provided a durable dosing schedule with an acceptable safety profile, and was associated with splenic size reduction and clinical improvements. The Phase 2 portion of the study is ongoing and includes only patients previously treated with a different JAK inhibitor. Disclosures Verstovsek: NS Pharma, Inc: Research Funding. Talpaz:Ariad, BMS, Sanofi, Pfizer, Incyte: Research Funding. Ritchie:Celgene, Incyte: Speakers Bureau. Odenike:Suneisis Pharmaceuticals, Incyte, Sanofi-Aventis, Algeta Pharmaceuticals, Spectrum Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees. Jamieson:Roche, Johnson&Johnson, CTI: Research Funding. Stein:Incyte Corporation: Honoraria, Speakers Bureau; Sanofi Oncology: Honoraria. Tomonori:NS Pharma, Inc.: Employment. Mesa:Incyte, CTI, NS Pharma, Inc., Gilead, Celgene: Research Funding.

Abstract Abstract 755 Background: TG101348 is a potent, orally bioavailable, JAK2-selective small molecule inhibitor, that is currently being evaluated in a Phase I study for the treatment of myelofibrosis. Data from the dose escalation cohort (n=28; 30-800mg administered as a single daily dose) showed dose-linear plasma exposure, with mean elimination T1/2 at steady state ranging from 20 to 52 hours. The dose-limiting toxicity was asymptomatic grade 3 or 4 amylasemia/lipasemia that was reversible, and the maximum tolerated dose (MTD) was 680mg. The most frequent non-hematological toxicities were mild nausea, vomiting, and/or diarrhea that were easily controlled or resolved spontaneously. Grade 3/4 neutropenia and thrombocytopenia were observed in 14% and 25% of patients, respectively. TG101348 had activity in reducing spleen size, leukocyte count, and JAK2V617F (VF) allele burden. Here, we present updated results with a focus on data from the dose confirmation cohort who initiated treatment at a dose of 680mg/day. Results: Fifty nine patients (median age=66 years; range 43-86) have been treated – 28 in the dose escalation phase, and 31 in the dose confirmation phase. Overall, 44 patients had PMF, 12 post-PV MF, and 3 post-ET MF; 86% were VF-positive. Median palpable spleen size was 18cm and 22 patients were RBC transfusion-requiring at study enrollment. After a median follow-up of 12 weeks (range <1-76), 18 (31%) patients have discontinued treatment due to toxicity (n=7; thrombocytopenia=3, neutropenia=1), comorbidities (n=5), withdrawal of consent (n=4), or non-compliance/lack of response (1 each). The remaining 41 patients are currently at the following dose levels: 680mg (n=14), 520-600mg (n=16), 360-440mg (n=10), and 240mg (n=1). The cumulative drug exposure to date is 362 patient-months; exposure at or above MTD (≥680mg) is 154 patient-months. Forty patients (68%) started treatment at ≥680mg. Toxicity: TG101348 is well tolerated. Of the patients who started at ≥680mg, Gr3/4 neutropenia was observed in 15/0% and Gr3/4 thrombocytopenia in 20/10%. Twenty four (60%) patients did not require RBC transfusions at baseline (median Hgb=9.6g/dL; range 7.4-13.1); of these, 42% and 8% of patients developed Gr3 and Gr4 anemia, respectively. The majority of patients who started at ≥680mg developed mild nausea (1 Gr3), vomiting (1 Gr3), and/or diarrhea (3 Gr3) that were self-limited or easily controlled. Other non-hematological toxicities included Gr1/2 transaminitis (38%), Gr1/2 serum creatinine elevation (38%), and asymptomatic hyperlipasemia (33%). Efficacy: Thirty three patients who started at ≥680mg have completed at least 3 cycles of treatment; at 3 months, reduction in palpable spleen size (baseline median=18cms; range 6-32) was at least 50% in 22 (67%) patients; the spleen became non-palpable in 9 (27%) patients. All 21 patients with leukocytosis at baseline (WBC range 11 to 203 ×109/L) who started at ≥680mg have experienced a marked reduction in their WBC count (range 4 to 90); 70% had a normal WBC count at their last follow-up visit. Overall, 48 of the 51 VF-positive patients completed at least 1 cycle and were evaluable for response in VF allele burden; at last available follow-up, the median decrease in granulocyte mutant allele burden was 48%; 21 (44%) patients have had a ≥50% reduction, and in the group who started treatment at ≥680mg, 48% have had a ≥50% reduction. Of those evaluable, there was clinically significant benefit or resolution of constitutional symptoms, including early satiety, fatigue, cough, pruritus, and night sweats. Conclusions: TG101348 continues to be well tolerated in patients with myelofibrosis. Spleen and leukocyte responses are frequent, observed early, and produce substantial clinical benefit for patients. These responses are associated with significant decrease in VF allele burden and point to activity of TG101348 against the malignant clone in myelofibrosis. Disclosures: Pardanani: TargeGen: Research Funding; Cytopia: Research Funding. Off Label Use: Data from ongoing clinical trial will be presented. Gotlib:TargeGen: Research Funding. Jamieson:Merck: Research Funding; Pfizer: Research Funding; Wintherix: Consultancy; TargeGen: Research Funding; Celgene: Research Funding. Cortes:Targegen: Research Funding. Stone:Cephalon: ad hoc advisory board. Silverman:TargeGen: Consultancy. Shorr:TargeGen: Employment, Equity Ownership. Gilliland:Merck: Employment. Tefferi:TargeGen: Research Funding.

7061 Background: Glasdegib is a small molecule inhibitor of the Sonic Hedgehog pathway, and data from the single arm, lead-in cohort of a phase 1b/2 trial in myelofibrosis (MF) are shown. Methods: Patients (age ≥18 yrs) with primary/secondary MF previously-treated with ≥1 Janus Kinase inhibitor (JAKi) were enrolled and received glasdegib 100 mg QD orally in 28 day cycles. AEs and laboratory abnormalities were assessed. Key efficacy endpoints were proportion of patients with spleen volume reduction (SVR) ≥35% and ≥50% reduction in total symptom score (TSS) measured by the MPN Symptom Assessment Diary (MPN-SAD) at Week 24. Results: 21 patients were enrolled between Oct '14-Oct '15 in this ongoing study. Mean age was 69.3 yrs (range 58-83). Median duration of treatment was 85 days (22-343). 52% were refractory patients with inadequate response to prior JAKi. Baseline symptoms were mostly mild (1-4), except fatigue (>4). No patients achieved SVR ≥35%, 5 patients had some SVR (maximum 2.3-21.4% reduction from baseline), and no progressive disease prior to Day 71. At week 24, 1 patient had ≥50% reduction in TSS, but 3/21 and 4/21, respectively showed 30% and 20% TSS reduction. Of 14 patients with severe baseline symptoms (1 with ≥5, or ≥2 with ≥3), 1, 1, and 2 achieved 50%, 30%, and 20% TSS reduction, respectively at week 24. TSS, spleen-related, and constitutional symptom scores showed a trend of reduction over 24 weeks with spleen-related symptoms, inactivity, and fatigue showing greatest improvement (52%, 58%, and 36%, respectively). Dysgeusia (N=13), muscle spasms (N=12), alopecia (N=8), decreased appetite (N=7), fatigue (N=7), lipase increase (N=5), and weight decrease (N=5) occurred in ≥20% patients. None, except 1 episode of fatigue, were considered serious AEs. Glasdegib steady state PK was consistent with previous single agent data. Conclusions: Glasdegib has an acceptable toxicity profile in patients with primary/secondary MF previously treated with JAKi. Symptom responder definition for refractory patients may not be the same as for JAKi naïve patients. Patient reported symptom improvement may be a more sensitive indicator of treatment benefit vs SVR. Further study of glasdegib may be warranted. Clinical Trial Information: NCT02226172.