BACKGROUND: Hypomethylating drugs are useful in the management of myelodysplastic syndrome (MDS). Two of these drugs, azacitidine and decitabine, have received FDA approval for the treatment of MDS and chronic myelomonocytic leukemia (CMML). However, phase 2 and 3 studies that assessed these agents in MDS included only a small number of patients with CMML. The objective of this study was to evaluate the efficacy and safety of azacitidine in the treatment of CMML. METHODS: The records of thirty-eight patients diagnosed with CMML and treated with azacitidine at our institution were reviewed. Azacitidine was administered at 75 mg/m 2 /day for 7 days or 100 mg/m 2 /day for 5 days every 4 weeks. Patients who received at least 1 cycle of the drug were considered evaluable for response. RESULTS: Response was assessed by the modified International Working Group (IWG) criteria. The overall response rate was 39% (14 of 36); complete response (CR) rate was 11% (4 of 36); partial response (PR) rate was 3% (1 of 36); hematologic improvement (HI) was 25% (9 of 36). The median overall survival was 12 months. There was a statistically significant overall survival advantage in responders compared with nonresponders: 15.5 months versus 9 months, respectively (P ¼ .04). Treatment was generally well tolerated. One of 2 patients had complete resolution of a skin rash that was due to monocytic infiltration. CONCLUSIONS: Azacitidine is active in the treatment of CMML. The therapy-associated toxicity is acceptable. Our results support further investigation of azacitidine in CMML, particularly in combination with other agents.

BACKGROUNDPatients older than 55 years of age with acute myelogenous leukemia (AML) are less likely to achieve complete remission and more likely to experience toxicity with conventional induction chemotherapy than younger patients. Azacitidine administered in the outpatient setting is well tolerated and can induce complete hematological remission in patients with myelodysplastic syndromes (MDS). At higher doses, azacitidine has activity in AML.METHODSTwenty patients were retrospectively identified who had been treated with azacitidine with bone marrow blast counts between 21 and 38%. Patients with blast counts up to 29% were initially treated as MDS, but by WHO now meet criteria for AML. Patients with blast counts over 29% were treated with azacitidine after being deemed poor candidates for induction chemotherapy. Azacitidine 75 mg/m2/day was administered subcutaneously for 7 days every 4 weeks, which was defined as 1 cycle.RESULTSThe overall response rate was 60% (12/20): complete response (CR; n = 4; 20%); partial response (PR; n = 5; 25%); hematologic improvement (HI; n = 3; 15%). The median survival of responders was 15+ months compared with 2.5 months for nonresponders (P = .009). During therapy, responders had an Eastern Cooperative Oncology Group (ECOG) performance status of 1 or 0. The most common toxic event was infection (n = 8). Four patients were hospitalized during the first cycle of treatment.CONCLUSIONSAzacitidine administered in the outpatient setting can induce remission in AML. The therapy is well tolerated and might be an alternative for patients unlikely to tolerate standard induction chemotherapy. Cancer 2006. © 2006 American Cancer Society.

Myelodysplastic syndromes (MDS) are a heterogeneous group of clonal hematopoeitic disorders characterized by ineffective hematopoiesis and potential transformation to acute myeloid leukemia (AML). For decades, the mainstay of treatment for MDS was supportive care, including transfusion of blood products and growth factors. Further understanding of disease biology led to the discovery of a high prevalence of hypermethylation of tumor suppressor genes in high-risk MDS and secondary leukemias. Hence, the role of irreversible DNA methlytransferase inhibitors such as azacitidine was investigated with promising outcomes in the treatment of MDS. Azacitidine was initially approved in the USA by the Food and Drug Administration (FDA) in 2004 for the treatment of all subtypes of MDS and was granted expanded approval in 2009 to reflect new overall survival data demonstrated in the AZA-001 study of patients with higher-risk MDS. Azacitidine has demonstrated significant and clinically meaningful prolongation of survival in higher-risk patients with MDS and has changed the natural history of these disorders. The agent maintains a relatively safe toxicity profile, even in older patients. The role of azacitidine has been explored in the treatment of AML and chronic myelomonocytic leukemia and has also been studied in the peritransplant setting. Azacitidine has been combined with other novel agents such as lenalidomide, histone deacetylase inhibitors and growth factors in the hope of achieving improved outcomes. Currently, both intravenous and subcutaneous forms of azacitidine are approved for use in the USA with the oral form being granted fast track status by the FDA.

Ruxolitinib (Jakafi®) is the one approved therapy for myelofibrosis (MF) based on reduction of splenomegaly and symptoms but JAK inhibition has not proven to significantly modify disease progression. There remains the need for novel therapies with distinct modes of action that can improve the patient experience of MF and impact progression. Lysine-specific demethylase, LSD1, is an epigenetic enzyme critical for self-renewal of malignant myeloid cells and differentiation of myeloid progenitors. LSD1 bound to GFI1b permits maturation of progenitors to megakaryocytes and enables their normal function. IMG-7289 (bomedemstat) is an orally available LSD1 inhibitor. In mouse models of myeloproliferative neoplasms (MPN), IMG-7289 reduced elevated peripheral cell counts, spleen size, inflammatory cytokines, mutant allele frequencies, and marrow fibrosis (Jutzi et al. 2018) supporting its clinical development. IMG-7289-CTP-102 is an ongoing, multi-center, open-label study that recently transitioned from a Phase 1/2a dose-range finding study to a Phase 2b study of IMG-7289 administered orally once-daily in adult patients with intermediate-2 or high-risk MF resistant to or intolerant of ruxolitinib. The key objectives are safety, PD, changes in spleen volume (MRI/CT) and total symptoms scores (TSS) using the MPN-SAF instrument. Inclusion criteria included a platelet count ≥100K/μL. Bone marrow (BM) biopsies and imaging studies (both centrally-read) were conducted at baseline and during washout (post-Day 84). The MPN-SAF was self-administered weekly. Phase 1/2a patients were treated for 84 days followed by a washout of up to 28 days. Patients demonstrating clinical benefit could resume treatment for additional 12 week cycles. Dosing was individually tailored using platelet count as a biomarker of effective thrombopoiesis. Patients were started at a presumed sub-therapeutic dose of 0.25 mg/kg/d and up-titrated weekly until the platelet count rested between 50 and 100K/μL. This preliminary analysis includes 20 patients; 18 enrolled in the Phase 1/2a study, 2 in the Phase 2b portion. 50% had PMF, 35% Post-ET-MF, 15% Post-PV-MF. The median age was 65 (48-89) with 70% males. The median baseline platelet count was 197 k/μL (102-1309k/μL). 12 patients (56%) were transfusion-dependent at baseline. Sixty percent were IPSS-classified as high risk, the remainder, intermediate risk-2. 71% had more than 1 mutation of the 261 AML/MPN genes sequenced of which 63% were high molecular risk (ASXL1, U2AF1, SRSF2) mutations; 31% had abnormal karyotypes. Sixteen patients completed the first 12 weeks; 4 patients withdrew, one due to fatigue (Day 33), one for progressive disease (Day 39), one due to physician decision (Day 76), one for an unrelated SAE of cellulitis (Day 83). All patients were up-titrated from the starting dose 0.25 mg/kg to an average daily dose of 0.89 mg/kg ± 0.20 mg/kg, the dose needed to achieve the target platelet count range; 17 achieved the target platelet range in a mean time of 45 days. Of patients evaluable for response after cycle 1 in Phase1/2a (N=14), 50% had a reduction in spleen volume from baseline (median SVR: -14%; -2% to -30%). Further, 79% (N=11) recorded a reduction in TSS (mean change -28%; -13% to -69%); for 21% of patients (N=3), the change was >-50%. Improved BM fibrosis scores at Day 84 were observed in 2/13 patients. Two patients had improvement in transfusion requirements. Plasma IL-8 levels were significantly elevated in 6/14 patients at baseline and dropped in a dose-dependent manner over 21 days in 5/6 patients. The mean duration of treatment is 166 days (14-539) at the census point in this ongoing study. Nineteen patients (95%) reported 358 AEs of which 22 were SAEs. Of the SAEs, 2 were deemed by investigators as possibly related: painful splenomegaly and heart failure. There have been no safety signals, DLTs, progression to AML, or deaths. This is the first clinical study of an LSD1 inhibitor in patients with MPNs. Once-daily IMG-7289 was well-tolerated in a heterogeneous population of patients with advanced MF and limited therapeutic options. Despite under-dosing and slow dose escalation, IMG-7289 improved symptom burdens in most patients and modestly reduced spleen volumes in a subset of patients. The Phase 2b 24-week expansion study with more aggressive dosing aimed at preserving safety and enhancing efficacy is open for enrollment in the US, UK and EU. Figure Disclosures Pettit: Samus Therapeutics: Research Funding. Gerds:Imago Biosciences: Research Funding; Celgene Corporation: Consultancy, Research Funding; CTI Biopharma: Consultancy, Research Funding; Roche: Research Funding; Sierra Oncology: Research Funding; Incyte: Consultancy, Research Funding; Pfizer: Consultancy. Yacoub:Hylapharm: Equity Ownership; Agios: Speakers Bureau; Novartis: Consultancy, Speakers Bureau; Seattle Genetics: Honoraria, Speakers Bureau; Incyte: Consultancy, Honoraria, Speakers Bureau; Ardelyx: Equity Ownership; Cara: Equity Ownership; Dynavax: Equity Ownership. Watts:Pfizer: Membership on an entity's Board of Directors or advisory committees; Takeda: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Bradley:AbbVie: Other: Advisory Board. Shortt:Celgene: Consultancy, Speakers Bureau; BMS: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; Astex: Research Funding; Amgen: Research Funding; Gilead: Speakers Bureau; Takeda: Speakers Bureau. Natsoulis:Imago BioSciences: Consultancy, Equity Ownership. Jones:Imago BioSciences: Employment, Equity Ownership. Talpaz:Samus Therapeutics: Research Funding; Novartis: Research Funding; Incyte: Research Funding; Constellation: Research Funding; Imago BioSciences: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; CTI BioPharma: Research Funding. Peppe:Imago BioSciences: Employment, Equity Ownership. Ross:Novartis: Consultancy, Honoraria, Research Funding; Celgene: Honoraria, Research Funding; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees. Rienhoff:Imago Biosciences: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties.