On December 12, 2021 Imago BioSciences, Inc. ("Imago") (Nasdaq: IMGO), a clinical stage biopharmaceutical company discovering new medicines for the treatment of myeloproliferative neoplasms (MPNs), reported that positive data from its ongoing global Phase 2 clinical study evaluating bomedemstat in patients with essential thrombocythemia (ET) (Press release, Imago BioSciences, DEC 12, 2021, View Source [SID1234596827]). The data were presented in an oral session during the 63rd American Society of Hematology (ASH) (Free ASH Whitepaper) Annual Meeting and Exposition, taking place December 11-14, 2021. Previously, a Phase 2 data set with a cut-off date of May 18, 2021 was presented at the European Hematology Association (EHA) (Free EHA Whitepaper) 2021 Virtual Congress.

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Updated Highlights (as of November 1, 2021 cutoff):

Of the 29 patients treated with bomedemstat for more than 6 weeks:
100% (29/29) of patients experienced platelet count reduction to within normal ranges (150 – 400 x 109/L).
90% (26/29) of patients achieved a platelet count of less than 400 x 109/L without thromboembolic events, the primary composite endpoint of this study.
Of the 17 evaluable patients at 24 weeks:
71% (12/17) showed a decrease in Total Symptom Score (TSS).
53% (9/17) showed a ≥50% decrease in TSS.
Patients with all genotypes identified in the study (CALR, JAK2V617F, Triple Negative) responded to bomedemstat.
"As of the most recent data cut-off in this Phase 2 trial, bomedemstat as a monotherapy in a 2nd line ET population demonstrated significant and durable hematologic control and symptom improvement while maintaining normal hemoglobin levels. I am delighted with the progress we are making with this study and would like to take this opportunity to thank all of the investigators and patients involved," said Hugh Young Rienhoff, Jr., M.D., CEO, Imago BioSciences. "Even with only 36 of the up-to 60 patients we plan to enroll, we have commenced planning for a registrational clinical trial for ET. We expect an End-of-Phase 2 meeting and discussion of the Phase 3 Protocol in the second half of 2022."

Safety & Tolerability

Bomedemstat was generally well-tolerated.
The most common AEs (>20%) were dysgeusia (altered taste), constipation, arthralgia, and fatigue.
4 patients have discontinued due to AEs.
"We are pleased with the safety and tolerability of Bomedemstat in this trial in a patient population, most of whom were intolerant or resistant to hydroxyurea," said Wan-Jen Hong, M.D., CMO, Imago BioSciences. "In addition, the data presented provide evidence of continued durability of the response."

Details on Imago’s ASH (Free ASH Whitepaper) Presentation

Oral Presentation Title: A Phase 2 Study of the LSD1 Inhibitor IMG-7289 (Bomedemstat) for the Treatment of Essential Thrombocythemia (ET)
Session: Myeloproliferative Syndromes: Clinical and Epidemiological: Non-JAK inhibitor Therapies for Myelofibrosis
Presenter: Francesca Palandri, M.D., Ph.D., Institute of Hematology "L. & A. Seràgnoli," Sant’Orsola-Malpighi University Hospital, Bologna, Italy
Date and Time: Sunday, December 12, 2021, at 9:45 AM ET

For further details, please see the ASH (Free ASH Whitepaper) 2021 abstract and presentation on the Imago website here.

About Imago’s Phase 2 Essential Thrombocythemia Program

Essential thrombocythemia (ET) is a rare blood cancer resulting from the overproduction of platelets, which increases the risk of blood clots and bleeding. It is one of the myeloproliferative neoplasms (MPN) family of rare bone marrow diseases, and affects approximately 80,000 – 100,000 patients in the U.S. Imago BioSciences is developing bomedemstat (IMG-7289), an orally administered LSD1 inhibitor, as a potential therapy for patients with ET.

This Phase 2b multi-center, open-label study is designed to assess the safety, efficacy, and pharmacodynamics of bomedemstat, an oral inhibitor of the epigenetic enzyme lysine-specific demethylase 1 (LSD1) (www.clinicaltrials.gov Identifier NCT04254978). Eligible patients aged 18 or older with ET who have failed at least one standard therapy and require treatment in order to lower their platelet count will be considered for participation in this study. Exploratory assessments include the serial measurement of mutant allele frequencies and changing plasma cytokine profiles. The trial is being conducted in the United States, the United Kingdom, Europe, New Zealand, and Australia. Imago BioSciences announced first patient dosed on October 1, 2020. As of November 1, 2021, the trial has enrolled 36 of up to 60 planned study participants.