Data Presented At 24th Congress of the European Hematology Association Demonstrates Clinical Safety, Early Efficacy of Imago BioSciences’ IMG-7289 in Myelofibrosis Patients

Data Informs Expansion of Study into Phase 2b and Considerations for Clinical Studies of IMG-7289 in Additional Myeloid Diseases

San Francisco, California, June 17, 2019 – Imago BioSciences, Inc., a clinical-stage biotechnology company developing innovative treatments for myeloid diseases, today announced that positive safety and early efficacy clinical data regarding its lysine-specific demethylase (LSD1) inhibitor, IMG-7289, were presented at the 24th Congress of the European Hematology Association (EHA). Based on the findings, Imago has expanded the study into a Phase 2b trial and is evaluating clinical investigations in additional myeloid diseases.

The data, from the ongoing IMG-7289-CTP-102 Phase 1/2a clinical trial, showed that IMG-7289 was well-tolerated in patients with high or intermediate-2 risk myelofibrosis resistant to or intolerant of approved therapy. In addition, the therapy was effective in reducing spleen volumes and substantially improved symptom scores in a majority of evaluable patients. The expanded Phase 2b study, expected to enroll 35 additional patients, will utilize a modified dosing schedule of IMG-7289 that safely optimizes efficacy. Additional trial sites have been added in the US, EU and UK (see clinicaltrials.gov NCT03136185).

“IMG-7289 has shown tremendous promise to be a meaningful treatment option for myelofibrosis patients, and these data support our clinical program,” said Hugh Young Rienhoff, Jr. M.D., chief executive officer of Imago BioSciences. “These data, particularly the strong safety and efficacy signals, have informed our Phase 2b dosing strategy and encourage us to explore additional indications in myeloproliferative diseases.”

The data presented is from a cohort of 16 enrolled patients, 15 of whom had received one or more prior treatments including ruxolitinib. All patients began treatment with a sub-therapeutic dose of 0.25 mg per kg, with doses increasing until platelet count rested between 50 and 100K/μL. Twelve patients (75%) sustained a platelet count within this target zone at a dose of 0.81 mg/kg, with 14 patients (88%) completing the 85-day study. Nine patients were evaluable for efficacy, with six (66%) showing a reduction of spleen volume via imaging and five (56%) recording a greater than 50% reduction in total symptom score (TSS) and two (22%) recording an improved bone marrow fibrosis score at 12 weeks.

The study has not shown safety signals, dose-limiting toxicities, or patient deaths with a median duration of treatment at 156 days. Fourteen patients in the study reported a total of 239 adverse events.

“LSD-1 inhibition has shown positive preclinical potential for treating myelofibrosis. This first report of clinical data suggesting that IMG-7289 is safe and tolerable in patients is cause for optimism in this terrible disease,” said Kristen Pettit, M.D., Assistant Professor of Medicine at the University of Michigan and a principle investigator of the study. “Even with a conservative dosing approach to evaluate safety, we saw encouraging improvements in patients’ symptoms and spleen sizes. Continued evaluation of this therapeutic candidate under the modified clinical trial design with a more aggressive dosing approach will be a critical next step.”

A summary of the presentation is available in the “News” section of Imago’s website.

About IMG-7289

IMG-7289 is a small molecule discovered by Imago BioSciences that inhibits lysine-specific demethylase 1 (LSD1 or KDM1A), an enzyme regulating cytokine expression, myeloid differentiation and sustaining self-renewal in malignant hematopoietic stem/progenitor cells. In non-clinical studies, IMG-7289 demonstrated robust in vivo efficacy as a single agent and in combination with other therapeutic agents across a range of myeloid malignancies models including the myeloproliferative neoplasms which encompass myelofibrosis, essential thrombocythemia and polycythemia vera. IMG-7289 also shows activity against solid tumors in combination with checkpoint inhibitor agents in non-clinical models. IMG-7289 is under evaluation for the treatment of acute myeloid leukemia (see clinicaltrials.gov NCT02842827), with additional clinical studies in myeloid diseases under evaluation.

About Imago BioSciences

Imago BioSciences is a clinical-stage, venture-backed pharmaceutical company whose investors include a fund managed by Blackstone Life Sciences, Frazier Healthcare Partners, Omega Funds, Amgen Ventures, MRL Ventures Fund, HighLight Capital, Pharmaron, Greenspring Associates and Xeraya Capital as well as other corporate and venture investors. Imago is focused on improving the management of malignant and life-threatening diseases of the bone marrow and modulation of the immune system. The Company is currently focused on neoplastic diseases of the bone marrow including acute myeloid leukemia, myelodysplastic syndrome, polycythemia vera, myelofibrosis and essential thrombocythemia. The Company is based in California.

Please see the website at www.imagobio.com for additional information.