Mesa, Ruben A.

Abstract Background The Janus-kinase (JAK) pathway plays a critical role in normal hematopoiesis. In two phase 3 studies, the JAK1/JAK2 inhibitor ruxolitinib (RUX) demonstrated clinical benefit over placebo (COMFORT-I) or best available therapy (COMFORT-II) in patients with intermediate-2 or high-risk myelofibrosis (MF). Anemia and thrombocytopenia, the most common adverse events associated with RUX treatment, were dose-dependent and expected based on RUX's mechanism of action. These events were successfully managed and few RUX-treated patients discontinued for anemia or thrombocytopenia (<1% for each event). The ability to identify patients who would most likely benefit from a dose adjustment may contribute to improved patient management. Therefore, an analysis was conducted in patients who received RUX in COMFORT-I to identify patient characteristics that could help select patients who would potentially benefit from closer monitoring and dose titration in the early period after initiation of therapy. Methods In COMFORT-I, starting doses in the patients randomized to RUX were 15 mg twice daily (BID) for patients with baseline platelet counts of 100–200 ×109/L (n=55) and 20 mg BID for those with platelet counts >200 ×109/L (n=100). Dose reductions were required for protocol-defined decreases in platelet counts; there was no protocol-mandated dose change for anemia. The time course of dose adjustments and the most common titrated doses by starting dose were evaluated. Logistic regression analyses with baseline hemoglobin (Hgb) level, platelet count, IPSS risk category, sex, and MF type as model effects were conducted to determine predictors of: 1) titration to a RUX dose of ≤10 mg BID within 8 weeks of starting therapy (early dose titration event); or 2) development of grade ≥3 anemia or new need for RBC transfusions (≥2 units of packed RBCs) within 12 weeks of therapy initiation (anemia event). Only baseline platelet count and Hgb emerged as significant predictors (alpha=0.05). Receiver operating characteristics (ROC) analyses were also conducted for these two predictors to determine a clinically relevant cutoff of the underlying predictor variable with a positive predictive value (PPV), true positive rate (TPR), and false positive rate (FPR) obtained at all possible cutoffs and a general goal of obtaining a TPR ≥ 50%, an FPR ≤ 10%, and a high PPV. Results Approximately 70% of patients had a dose adjustment within the first 12 weeks of initiating RUX treatment. At week 24, 77% of patients with baseline platelet counts of 100–200 ×109/L and 39% of those with baseline platelet counts >200 ×109/L had titrated to a reduced RUX dose relative to their starting dose. With longer-term follow-up (median 149 weeks), the mean dose over time in patients who continued on study was ∼10 mg BID for patients starting at 15 mg BID and ∼15 mg BID for those starting at 20 mg BID (Figure). ROC analyses identified that a baseline platelet count range of less than 150–175 x109/L may predict which patients would experience an early titration event, while a baseline Hgb level of less than 10 mg/dL may predict which patients would experience an anemia event (Table). Conclusions In COMFORT-I, most patients experienced a RUX dose adjustment in the first 12 weeks of treatment and stable doses were achieved with long-term therapy. Dose titration allowed most patients to maintain adequate platelet counts. After starting therapy at 15 or 20 mg BID, the majority of patients titrated to RUX doses of 10 mg BID or higher, which have been previously been shown to produce meaningful spleen volume reductions and symptom improvements (Mesa et al. 8th Annual Hematologic Malignancies Conference. Abstract 305; Verstovsek et al. ASH 2012. Abstract 800; Talpaz et al. ASH 2012. Abstract 176). A baseline platelet count of less than 150 ×109/L and baseline Hgb level of less than 10 g/dL may be clinically useful cutoffs for predicting which patients may benefit from closer monitoring shortly after treatment initiation of RUX and appropriate dose adjustments as needed. Disclosures: Mesa: Lilly: Research Funding; Genentech: Research Funding; NS Pharma: Research Funding; Gilead: Research Funding; Incyte Corporation: Research Funding. Komrokji:Incyte Corporation: Membership on an entity’s Board of Directors or advisory committees. Sun:Incyte Corporation: Equity Ownership; Incyte Corporation: Employment. Sandor:Incyte Corporation: Equity Ownership; Incyte Corporation: Employment. Verstovsek:Incyte Corporation: Research Funding.

Abstract Introduction Fedratinib (SAR302503), a JAK2-selective inhibitor, has demonstrated clinical improvements in splenomegaly and constitutional symptoms in patients with MF in Phase I/II trials (J Clin Oncol 2011;29:789. Haematologica 2013;98:S1113). The aim of this primary analysis was to determine the effect of fedratinib on key MF symptom burden and global assessment of HRQoL in the JAKARTA trial (NCT01437787). Methods JAKARTA is a double-blind, placebo-controlled, international, 3-arm, Phase III study, in which patients ≥18 years of age with intermediate- or high-risk MF, platelet count ≥50 × 109/L, and splenomegaly were randomized (1:1:1) to receive placebo or fedratinib at a dose of 400 or 500 mg, orally, once daily, in consecutive 4-week cycles. Total symptom score (TSS), a key efficacy end point (TSS: averaged daily total score of 6 item measures over 1 week: night sweats, pruritus, abdominal discomfort, early satiety, pain under ribs on left side, and bone or muscle pain), was assessed through a daily electronic eDiary using the modified Myelofibrosis Symptom Assessment Form (MFSAF; Cancer 2011;117:4869. Blood 2011;118:401), with symptom response defined as a ≥50% reduction in TSS at the end of Cycle 6 (EOC6). HRQoL was assessed using the EuroQOL (EQ)-5D instrument that was completed at baseline and EOC6. Patient performance was assessed using the Eastern Cooperative Oncology Group Performance Scale (ECOG PS). Spleen volume was measured by MRI or CT at baseline and EOC6. Results In JAKARTA, a total of 289 patients were randomized: median age 65 years; 59% male; 63% primary MF; 48% high-risk MF; 67% JAK2V617F positive; 16% platelet count <100 × 109/L. The symptom evaluable population comprised 261 patients (placebo [n=82]; 400 mg [n=89]; 500 mg [n=90]). The mean (SD) baseline TSS was 14.6 (11.9), 17.6, (13.5), and 16.9 (11.9) in the placebo, 400 mg, and 500 mg groups, respectively. At Week 24 (EOC6), the proportion of patients with a symptom response was significantly higher (p<0.0001) in the 400 and 500 mg groups versus placebo (Table). Symptom responses with fedratinib were also higher than placebo in the subgroup of patients with baseline platelets <100 × 109/L (Table). For individual symptoms, the greatest improvements were seen for night sweats and early satiety (Table). Baseline HRQoL (EQ-5D, mean [SD]) was similar in the three groups (placebo: 62.5 [21.2]; 400 mg: 61.3 [22.2]; 500 mg: 60.1 [20.1]). Fedratinib treatment led to improvements in HRQoL from baseline to Week 24, whereas placebo treatment led to slight worsening of HRQoL (Table). At Week 24, the degree of improvement in TSS was greatest in patients with ≥35% reduction in spleen volume from baseline (Figure). Mean TSS improvement was correlated with improvement in HRQoL (TSS reductions were greater in EQ-5D improvers versus non-improvers), and ECOG PS (TSS reductions were greater in patients with ECOG PS 1 or 2 score improvement versus those with ECOG PS worsening). Conclusions Fedratinib treatment over 24 weeks led to significant improvements in MF symptoms versus placebo. Patients treated with fedratinib also experienced substantial improvements in HRQoL versus placebo. Symptom improvements were associated with spleen responses. This study was sponsored by Sanofi. Disclosures: Mesa: Incyte, Genentech, Lilly, MS Pharma, Gilead: Research Funding. Cortes:Incyte, Sanofi: Consultancy; Incyte, Sanofi: Research Funding. Cervantes:Novartis: Speakers Bureau; Novartis and Sanofi: Membership on an entity’s Board of Directors or advisory committees. Jourdan:Sanofi: Honoraria. Vannucchi:Novartis: Membership on an entity’s Board of Directors or advisory committees. Drummond:TargeGen, Novartis: Speakers Bureau; Sanofi, Novartis, Celgene: Honoraria; Sanofi, Novartis, Celgene: Consultancy. Passamonti:Novartis, Celgene, Incyte, Sanofi, Roche: Honoraria. Neumann:Sanofi: Employment. Joulain:Sanofi: Employment. Iqbal:Sanofi: Employment. Harrison:Novartis: Research Funding; Novartis, Sanofi, YM Bioscience, Celgene, SBio, Gilead: Honoraria; Novartis, Sanofi, Shire: Speakers Bureau; Novartis, Sanofi, YM Bioscience, SBio, Gilead: Membership on an entity’s Board of Directors or advisory committees.

Abstract Background: A diagnosis of cancer leads to significant information requirements to facilitate health care decision making, understand management options, and health care system navigation. Many patients demonstrate a knowledge deficit that can lead to decreased quality of life and poor health care compliance. This study sought to evaluate the impact of a patient centered cancer symposium on knowledge level, symptom burden, and desired information in a broad population of cancer patients. Methods: Surveys were distributed to attendees of the Mayo Clinic "Living with and Surviving Cancer" patient symposium in January 2015. A follow up survey was sent to participants 3 months after the symposium. Surveys included demographic data, questionnaire evaluating disease comprehension, symptom burden, desired information and quality of life. Results: Demographics: 113 patients completed the pre-intervention survey. Average age of participants was 64.7 years. Disease types represented included hematologic malignancies (N=50), specifically multiple myeloma (N=24), lymphoma (N=17), leukemia (N=6), MPN/MDS (n=3), as well as solid tumor malignancies (N=77). Highest knowledge topics were disease (80%), screening tests (74%), and monitoring tools (72%). Lowest knowledge topics were financial management (13%), legal issues (13%), and pain management (35%). Pre and Post Analysis: Of the 113 initial participants, 79 patients completed the pre- and post-symposium surveys. In the post-symposium setting significant improvement was noted in understanding of disease (pre 80% vs post 92%), treatment options (pre 60% vs post 76%), nutrition (pre 68% vs post 84%) and legal issues (pre 15% vs post 32%). Non-significant knowledge improvement was noted in areas of risk factors and symptoms, screening/monitoring tools, disease side effects, managing stress/fatigue, end of life decision making and health care navigation. Most patients desired increased understanding regarding disease, screening tests, nutrition, and stress and fatigue management. The level of patient reported desire for information of these topics decreased in the post-symposium setting, statistically significant decrease noted in 4 of 5 topics assessed. In hematology patients who completed pre and post surveys (N=36), a higher level of baseline knowledge was reported regarding disease understanding (89%), tools monitoring response (83%) and recurrence (75%), symptoms (83%), relapse symptoms (64%) and treatment options (72%). In this group the decrease in desire for information was less prominent in the post-symposium setting. Discussion: This data demonstrates improved patient reported understanding on a variety of topics with durable response at 3 months. A majority of patients reported adequate baseline knowledge of many topics prior to the symposium but also a desire of increased cancer specific information. Knowledge deficit in cancer care includes disease specific topics, social stressors and health care navigation. The percentage of participants reporting a high desire for more information remained high but did decrease, suggesting decreased knowledge deficit in the post-symposium setting. Patient education should strive to be accessible, all-inclusive and reactive to patient needs. Table 1.Reported "quite a bit" or "very much" understanding and desired information regarding cancer carePrePostP-valueN=79(%)N=79(%)I understand…How to manage financial considerations of my disease/treatment39(51)41(53)0.85How to manage my pain24(34)23(32)0.81Risk factors that can lead to my disease37 (49)42 (56)0.56How to navigate the health care system43(55)47(60)0.56How to manage fatigue38(50)43(56)0.54Process of making end of life decisions33(47)41(53)0.52Screening tests60 (76)63 (81)0.5Symptoms associated with relapse35(45)42(54)0.27Disease symptoms54(70)60(76)0.2Tools monitoring recurrence49(62)56 (72)0.19Tools monitoring response56(71)63(81)0.15How to manage stress46(60)56(71)0.12Legal issues of my disease11(15)24(32)<0.05Treatment options47(60)60(76)<0.05What to eat49(68)66(84)<0.05My disease62(80)71(92)<0.05I desire increased understanding…Of my disease59(77)53(70)0.4Of managing stress50(65)35(51)<0.05Regarding nutrition64(84)54(70)<0.05Of the screening tests62(79)43(57)<0.05How to manage fatigue54(72)42(54)<0.05 Disclosures Tibes: TetraLogic Pharmaceuticals: Research Funding. Mesa:Novartis. Research- incyte, Gilead, cti, Genentech, promedior, NS Pharma: Consultancy.

A 69-year-old man presents with a Dynamic International Prognostic Scoring System (DIPSS) intermediate-risk 2 post polycythemia vera myelofibrosis with significant splenomegaly, 30 pound weight loss, constitutional symptoms, and 2% peripheral blood blasts. He has no other significant past medical history and no other major comorbid conditions. You are asked by the hematology fellow you are supervising whether or not treating this patient with a Janus kinase (JAK) inhibitor will decrease major morbid events.

Abstract Background : CC-5013 (Revlimid™) is an immunomodulatory analog of thalidomide that is substantially more potent than the parent drug in terms of both anti-angiogenic and anti-TNF-α activity. CC-5013 has shown therapeutic activity in thalidomide-responsive hematological malignancies including relapsed multiple myeloma (Blood2002;100:3063) and myelodysplastic syndrome (Blood2002;100:96a). Myelofibrosis with myeloid metaplasia (MMM) has also been shown to respond to thalidomide (BJH2002;117:288). Furthermore, both angiogenesis and altered TNF-α activity have been pathogenetically implicated in MMM. Methods : The current report considers the first 15 patients in an ongoing phase II treatment trial of single agent CC-5013 in MMM based on a minimum of 3 month follow-up from day 1 of protocol treatment. Study eligibility criteria included no concomitant MMM-directed therapy, a hemoglobin (Hgb) level of < 10 g/dL, an absolute neutrophil count (ANC) of ≥ 1 x 109/L, and a platelet count of ≥ 100 x 109/L. Previous thalidomide therapy in the absence of high-grade skin toxicity was allowed. All patients were started with daily oral CC-5013 (10 mg/day) to be taken for three 28-day treatment cycles. Three additional treament cycles were planned in case of anemia response. Results : Median age was 64 years (range, 40–75) and 10 pts were males. Twelve of the 15 study pts (80%) were red cell transfusion-dependent, 14 (93%) were previously treated including 12 with cytoreductive and 4 with thalidomide therapy. The spleen was palpably enlarged in 13 pts (median 18 cm, range 7–23). Eight of the 15 pts (53%) successfully completed 3 months of protocol treatment. Treatment was discontinued in the remaining 7 pts because of drug toxicity (2 pts), disease progression (1 pt), other co-morbid condition (3 pts), or patient discretion (1 pt). Treatment response data : Clinically relevant responses were documented in 4 patients (27%) and consisted of measurable improvements in anemia (2 pts), splenomegaly (2 pts), and/or constitutional symptoms (3 pts). One pt experienced an increase in Hgb level from 8.3 to 13.4 g/dL, a decrease in leukocyte count from 66.2 to 7.7 x 109/L, and complete resolution of myelophthisis including disapperance of circulating blasts that measured 9% before treatment. Another pt became transfusion-independent (Hgb level increased to > 10 g/dL) as well as enjoyed a profound improvement in constitutional symptoms. Interestingly, serum lactate dehydrogenase (LDH) level decreased in 11 pts (73%) to either within the normal ramge (5 pts) or by more than 30 % (6 pts). Treatment toxicity data : Grade 3 or 4 adverse events that were possibly, probably, or definitely attributed to CC-5013 included rash (2 pts), neutropenia (5 pts), thrombocytopenia (3 pts), and fatigue (2 pts). In addition, 3 patients experienced drug-associated extreme thrombocytosis while a histologically-proven disseminated extramedullary hematopoiesis was documented in one patient after one month of CC-5013 treatment. Conclusion : The current preliminary report suggests a substantial biological activity of CC-5013 in MMM with a therapeutic potential for a subset of patients. Additional studies with a longer duration of therapy, different dose schedules, and combinations of CC-5013 and corticosteroids are warranted.

Abstract Background: Myelofibrosis with myeloid metaplasia (MMM) is a progressive and fatal myeloproliferative disorder with limited therapeutic options. R115777 is a non-peptidomimetic enzyme-specific inhibitor of farnesyl protein transferase (FT) which we recently reported has in vitro activity against aberrant myeloid progenitors from MMM patients (Leukemia2003;17:849). This observation, coupled with the clinical activity demonstrated in high risk acute myeloid leukemia (Blood2001;97:3361) and chronic myeloid disorders (Blood2003;101:1692) led us to perform a Phase II trial in patients (pts) with MMM. Methods: Eligible pts had histologically confirmed MMM and were symptomatic, defined by anemia (hemoglobin<10g/dL or transfusion dependent) or palpable hepatosplenomegaly. Pts received 300 mg of R115777 orally twice daily for the first 21 days of a 28 day cycle. Dose escalations (up to 1200mg/day) and reductions (down to 100mg/day) were allowed based on activity and toxicity. The primary endpoint was response as defined by improvement in either anemia or organomegaly. Results: 34 pts (median age 65 yrs, range 55–80; 71% male) were enrolled in the trial. All pts displayed symptomatic disease at enrollment, with 10 who were erythrocyte transfusion dependent; and 19 (56%) had a Lille MMM prognostic score ≥1; no pts were significantly thrombocytopenic at entry by enrollment criteria. Median pre-study spleen and liver sizes were 12 cm (range: 0–35) and 2 cm (range: 0–15) below the left and right costal margin, respectively. Median time to discontinuation of therapy was 5.5 months (95% CI:2.9–6.4). Reasons for early termination were progression (7), adverse reactions (5), co-morbidities (2), refusal of further treatment (2), and death on study (1). One pt died of grade 5 pneumonitis two weeks after study enrollment, which was felt to be unrelated to study treatment. Significant toxicities (≥ grade 3) were seen for myelosuppression (n=13), neuropathy (n=2), fatigue (n=1), rash (n=1) and hyponatremia (n=1). Overall, R115777 resulted in little improvement in anemia, with the exception of one anemia-based partial response. However, the myelosuppressive aspects of the agent may have masked improvements in cytopenias. In contrast, R115777 did result in clinically relevant decreases in organomegaly in 11 pts (33%) (splenomegaly in 3 pts, hepatomegaly in 5 pts, and both in an additional 3 pts.) Across all pts who had some reduction in splenomegaly, the median maximal reduction was 42.5% (of palpable component; range: 8–100%). Likewise, all patients with baseline hepatomegaly had resolution of this problem at some point during therapy. Four pts remain on the agent (from 14 to 22 months) for continued and sustained improvement in organomegaly. Responses observed did not significantly correlate with reductions in bone marrow fibrosis, osteosclerosis, neoangiogenesis, or resolution of baseline karyotypic abnormalities. Conclusions: R115777 has demonstrated preliminary activity against MMM associated organomegaly. Whether this latter benefit is independent of R115777 induced myelosuppression is unclear. The myelosuppression observed was generally mild and without clinical consequence, although it was difficult to differentiate between myelosuppression versus disease progression. Pts continue to be followed to evaluate durability of observed responses, long term effects on anemia and intramedullary manifestations of the disease.

Abstract Background: Philadelphia chromosome negative myeloproliferative neoplasms (MPN) include myelofibrosis (MF), polycythemia vera (PV), and essential thrombocythemia (ET). Pertinent to these disorders is the high persistence, prevalence, and severity of fatigue. Overall, excessive fatigue compared to age and gender matched controls occurs in greater than 95% of MPN patients (Blood. 2011;118(2):401-8). Physiologic etiologies of fatigue in these patients include cytokine dysregulation and impaired hematopoiesis, however to date no one has investigated the impact that cofounding medical illnesses have on MPN fatigue burden. Methods: A 70-item internet-based survey was developed by a team of MPN investigators, patient advocates from MPN Forum, and hosted by the Mayo Clinic Survey Research Center. The survey was promoted online via multiple MPN-related webpages including the MPN Forum, MPN Net, MPN Research Foundation, and MPN Voice during late February to March of 2014. Surveyed data included disease demographics such as splenomegaly, thrombosis, hemorrhage transfusions, medications, and phlebotomies. The MPN-SAF (including the MPN 10) was utilized including the 10-item brief fatigue inventory was used to assess disease burden (Blood. 2011 Jul 14;118(2):401-8). Comorbid conditions were assessed, including hypothyroidism, anemias, sleep disturbances, obesity, and heart and lung disorders. Data: Demographics. Overall 1788 MPN patients participated in the survey. Of these, 1676 consented to participate and provided additional data (i.e., completed at least 10 questions). Of these, 555 (33%) patients had ET, 651 (39.0%) had PV, and 417 (25.0%) had MF. Among MF patients, 44.1% had primary MF, 29.7% had post-PV MF, and 26.2% had post-ET MF. Respondents were 68% female with a mean age of 59. Overall brief fatigue inventory score had a mean of 4.4 (range 0-10). MPN-10 score average was 28.4 (range 0-83). Medical Comorbidities. Overall, many patients endorsed having comorbid medical diseases that could contribute to overall fatigue (Table1). Overall 20.2% of patients endorsed having low thyroid function, with 10% indicating they obtained this diagnosis in the last six months. Twenty three percent endorsed having a new sleep disturbance in the last six months. On average, patients tended to have an average to above average BMI (mean =26.3, median = 25.0). However, many patients also experienced a high rate of unintended weight loss (11.8% with >11lb weight loss in the last 6 months). Cytopenias were also frequently encountered, with 14.7% of participants having required previous transfusions. Among these, 46% required transfusions in the last 6 months. Thrombosis (18.3%), hemorrhage (14.7%), and anemia (48.0%) were relatively common. In the last six months, 11.1% of patients required iron supplementation and 2.2% required erythropoietin injections. Many patients also endorsed the use of medications that could contribute to overall fatigue. Correlations. Items significantly correlated with worsened fatigue score (BFI greater than or equal to four) included female gender (<0.001), age (p=0.0047), lower education level (<0.001) and lower BMI (<0.001). Current use of alcohol and tobacco was also significantly associated with greater burden of fatigue (<0.001 and 0.0025, respectively). Items not significantly associated with fatigue included DIPSS (MF only), IPSET (ET only) or PV risk scoring. Conclusions Overall patients with MPN experience an exclusive pattern of disabling fatigue. Many fatigue-related medications and medical comorbidities may contribute to the debilitating fatigue seen among MPN patients, although no specific comorbidities could account for the high prevalence of fatigue. Rates of comorbid disease burden varied widely compared to the general population. For some diseases including diabetes, rates among MPN populations were less than the general population (National Diabetes Statistics Report, 2014), however the rates of other comorbidities, such as hypothyroidism, were higher (J Clin Endocrinol Metab 2002;87:489–99). Similar to our previous studies, females tended to suffer from a higher mean fatigue burden than males (Geyer ASH 2014). Clinical and research-related determination of fatigue should take into account cofounding comorbid medical conditions that can contribute to overall fatigue burden. Disclosures Harrison: Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau; Sanofi: Honoraria, Speakers Bureau; Shire: Speakers Bureau; CTI: Consultancy; YM Bioscience: Consultancy; Gilead: Consultancy; SBio: Consultancy. Mesa:Incyte: Research Funding; Novartis: Consultancy; Gilead: Research Funding; Genentech: Research Funding; Promedior: Research Funding; Ns Pharma: Research Funding; Celgene: Research Funding; Lilly: Research Funding; Cti: Research Funding.

Abstract Background: Histone deacetylase (HDAC) inhibitors (HDIs) vorinostat (SAHA) and romidepsin are approved for the treatment of cutaneous T-cell lymphoma, while belinostat has recently been approved for the treatment of peripheral T-cell lymphoma. SAHA exhibits clinical activity in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML), although insufficient to justify single-agent therapy for these indications. The precise clinical mechanism of SAHA and other HDIs remains incompletely characterized, impeding the design and implementation of rational HDI-based therapeutic combinations for myeloid malignancies. To circumvent this lack of mechanistic understanding, we conducted RNA-interference (RNAi) modifier screens of the kinome and phosphatome to identify signaling pathways that modulate SAHA (HDI) anti-leukemic activity in AML cell lines TF-1, HEL and THP-1 for rapid translation of findings from ex vivo validation to clinical application. Results: Multiple screen hits (both kinases and phosphatases) converge on distinct points of the p38-SAPK/JNK signaling pathways, suggesting involvement of these stress-activated pathways in SAHA anti-leukemic activity. However, the most well characterized p38α/β inhibitors SB202190 and LY2228820 do not augment SAHA anti-leukemic activity at any dose across the broad dose ranges tested. Similarly, the JNK inhibitor SP600125 does not modulate SAHA activity at doses that inhibit JNK. However, the putative MK2a substrate-selective p38 inhibitor CMPD1 (Boehringer-Ingelheim; Davidson, W., et. al., Biochemistry 2004 Sep 21;43(37):11658-71) selectively potentiates the activity of SAHA in all AML cell lines tested (N=8), as well as in ex vivo cultures of primary myeloid malignancies (N=14), including polycythemia vera, chronic myelomonocytic leukemia, MDS/myeloproliferative neoplasm overlap syndrome, MDS transformed to AML, and de novo AML. The observed dose-dependent synergy occurs at nanomolar doses consistent with the reported apparent inhibitory constant for CMPD1 inhibition of p38-dependent phosphorylation of MK2a. Further, SAHA + CMPD1 synergy is significantly greater in CD34+-selected as compared to CD34+-depleted cell populations ex vivo. Furthermore, CMPD1 is similarly synergistic with the HDI panobinostat in vitro, but interacts antagonistically with cytarabine and additively with 5-azacitidine. This suggests that CMPD1 interacts specifically with SAHA and panobinostat in AML. The synergistic interaction between CMPD1 and SAHA is independent of ROS induction, as pretreatment with N-acetylcysteine does not abrogate synergy, despite reducing single-agent SAHA activity. While CMPD1 is reported to be an MK2a substrate-selective p38 inhibitor, CMPD1 does not affect the regulation of several canonical MK2 targets at doses that are potently synergistic in AML cell lines, including the phosphorylation of HSP27 or AATF. To begin to probe the mechanism of CMPD1 and SAHA synergy more extensively, mRNA expression was measured by next-generation sequencing after SAHA and CMPD1 treatment alone and in combination in the AML cell line TF-1. Sequencing data is currently being analyzed and findings will be presented. Conclusion: RNAi knockdown of several p38-SAPK/JNK pathway components modulates SAHA activity in malignant myeloid cells; however, common pharmacological sensitizing targets remain elusive. We hypothesize that MK2 and/or a yet unrecognized pathway modulated by CMPD1 can be targeted for HDI combination therapy in malignant myeloid cells. Current and ongoing results from this study will provide validated targets for rational HDI combination in myeloid malignancies. Disclosures Off Label Use: LDE225/Sonidegib as investigational agent. Mesa:Incyte, CTI, NS pharma, Gilead, Celgene: Research Funding.

Abstract BACKGROUND: Our group has periodically analyzed (Silverstein et. al. JAMA1974;227(4):424 to Tefferi et. al. Blood2000;95(7):226) presentation, peri-operative and long-term outcomes from splenectomy for myelofibrosis with myeloid metaplasia (MMM) in an attempt to improve patient selection and management. We now report on an additional 91 patients (pts) to see if control of post splenectomy thrombocytosis, and modern techniques, have diminshed morbidity and mortality. Additionally, we provide long-term follow-up on prior cohorts across a twenty-eight year period. METHODS: A comprehensive retrospective analysis of presentation, peri-operative and long-term outcomes in a single institution experience with splenectomy in pts with MMM from 1976–2004. RESULTS: Presplenectomy : 314 MMM pts (171 men 54%; 208 (66%) with agnogenic myeloid metaplasia) were included. Presplenectomy 55% of pts presented with a Lille MMM prognostic score of ≥1, 90 pts (29%) failed a prior therapy for splenomegaly and pre-operatively had median spleen size of 20cm below the left costal margin (95%CI 18.7–20.4). Perioperative Outcomes : Pts were splenectomized (1976–1985 (Decade 1(D1)) (n=90 (29%)); 1986–1996 (D2) (n=133 (42%)); 1997–2004 (D3) (n=91 (29%)) a median of 27 months (range 0–389 months) after the diagnosis of MMM (age at diagnosis (median 65 (range 19–83)) with a median splenic mass 2700 gm (range 300–11750)). Primary indication for surgery included mechanical symptoms n=156 (49%), anemia n=78 (25%)), portal hypertension n=47 (15%), or thrombocytopenia n=33 (11%). Peri-operative complications occured in 103 pts (33%) and included infection (n=30), thrombosis (n=34), and bleeding (n=48; 37 required a second laparotomy) of which 28 (9% of all pts) were fatal (30 day mortality (D1=10%, D2=9%, D3=7.7% (p=NS)). Overall length of hospital stay (D3) was median of 8 days (range 3–63), during which 6 pts (7%) required platelet pheresis (1–8 times; for platelet counts of 870–2400 x 109/L) and/or acute platelet lowering agents (n=12; 13%), respectively. Additionally, median post-splenectomy increases in leukocyte and platelet count were 8 x 109/L (range −65 to 190.2) and 127 x 109/L (range −270 to 1221), respectively. Long-Term Outcomes and Survival : Amongst the recent cohort (n=91) 69 pts (76%) experienced a palliative benefit for their primary surgical indication for a median of 12 months (range 1–91). Post splenectomy rates of thrombocytosis (21%), accelerated hepatomegaly (8%), and leukemic transformation (11%) did not vary across the three decades analyzed. Overall survival (n=263 (84%) have expired)) from the diagnosis of MMM and splenectomy was 62 months (95%CI 54–66) and 19 months (95%CI 14–22), respectively. Survival after splenectomy was not significantly different by type of MMM, surgical indication, Lille MMM prognostic score, leukemic transformation or decade performed. However, patients with preoperative thrombocytopenia (<50 x 109//L (p<0.0001) or <100 x 109/L (P=0.006)) clearly had a decrease in survival, although this was independent of the development of peri-operative complications. CONCLUSIONS: Splenectomy for MMM remains a procedure with significant peri-operative risks, but potential for palliating symptoms. Decreased survival in thrombocytopenic pts probably arises from advanced disease as opposed to increased complications. The lack of improvement in overall post-splenectomy survival across the study period may not be attributable to peri-operative issues but a reflection on the failure of medical therapy to improve survival in MMM.

Abstract Background: JAK2 inhibitors have been shown to improve symptoms and produce durable reductions in splenomegaly in patients with myelofibrosis (MF), and ruxolitinib has been shown to improve survival in MF patients (Cervantes et al., 2013; Verstovsek et al., 2013). Current prognostic models such as DIPSS plus (Gangat et al., 2011) predict survival in MF based on clinical, laboratory, and cytogenetic information, but their value in predicting clinical response or survival during treatment with JAK2 inhibitors remains unknown. We hypothesized that clinical features such as bone marrow fibrosis and splenomegaly may have independent effects on therapy response. Therefore, we conducted a retrospective analysis to create a new model to risk stratify patients with respect to their likelihood of responding to oral JAK2-inhibitor therapy. Methods: We studied a cohort of 203 patients with bone marrow biopsy-proven MF seen at University of Michigan, Stanford University, and Mayo Clinic in Scottsdale, AZ. These patients were all treated with ruxolitinib or an experimental JAK2 inhibitor. Our primary endpoint was defined as IWG-MRT criteria for splenic response by palpation (Tefferi et al., 2013). Response in patients with spleen size of less than 5 cm was defined as complete resolution of splenomegaly. Of the 203 patients studied, splenic response was evaluated after 3 months of therapy in 167 patients and after 6 months of therapy in 138 patients; 127 patients were in both groups. A logistic regression was performed to identify factors that would predict clinical response. Results: The following characteristics were significantly associated with spleen response at 3 and 6 months: initial spleen size, European consensus criteria grading of MF on bone marrow biopsy, initial DIPSS plus score, and initial WBC count. Cellularity on marrow biopsy was not significant. We enriched a baseline logistic model of initial dose of oral JAK2 therapy and DIPSS plus score with additional prognostic factors. We found the following clinical characteristics to be jointly associated with splenic response: normalized initial dose of oral JAK2 inhibitor, initial spleen size, DIPSS plus score, degree of fibrosis by European consensus criteria. Duration of disease from time of diagnosis to time of treatment initiation was not prognostic for splenic response. We used this model to calculate the probability of splenic response based on a risk score: Risk score = –1.18(Dose) + 0.09(Initial Spleen Size in cm) + 0.20(DIPSS-plus Points) +0.92 (if fibrosis is MF-3). The probability at 6 months can then be calculated from the risk score as follows: [1/(1+e(risk score-2.6))]. The figure demonstrates the prognostic gain of our model over a model based on DIPSS plus alone. Conclusion: With this observational study, we propose a predictive model which may serve as a clinical tool to identify which patients are most likely to benefit from JAK2 inhibitor-based therapies. Further validation in independent data sets will be required before this model can be more widely applied. Disclosures Mesa: Incyte Corporation, CTI, NPS Pharma, Inc., Gilead Science Inc., Celgene: Research Funding. Gotlib:Incyte: Consultancy, Honoraria, Research Funding, Travel Reimbursement Other; Gilead: Research Funding; Sanofi: Research Funding; Novartis: Research Funding, Travel Reimbursement, Travel Reimbursement Other. Talpaz:ARIAD Pharmaceuticals, Inc., BMS, Sanofi, Incyte, Pfizer: Research Funding.