FDA Grants Fast Track Designation to Aptose’s HM43239 for Acute Myeloid Leukemia

The FDA has granted fast track designation to HM43239 (Aptose Biosciences), an oral myeloid kinome inhibitor, for the treatment of individuals who have relapsed or refectory (R/R) acute myeloid leukemia (AML) with FLT3 mutation.¹

“Fast track status acknowledges HM43239’s potential to fill an unmet need for AML patient populations and supports our efforts as we advance it toward a potential registration study,” William Rice, PhD, chairperson, president, and CEO of Aptose Biosciences, said in a statement.¹

“HM43239, which potently inhibits all tested forms of FLT3 and the SYK and JAK driven pathways, already has delivered complete remissions in a broad diversity of relapsed or refractory AML patients in an ongoing phase 1/2 clinical trial, including patients with prior failure of other FLT3 inhibitor agents. Fast track designation will help facilitate the drug’s development,” Rice said.¹

An international phase 1/2 clinical trial is ongoing for HM43239 for individuals with R/R AML. The trial was designed to assess the pharmacodynamic response, pharmacokinetics, safety, and tolerability of the drug as a single agent.¹

HM43239 has delivered complete remission in a diversity of individuals with R/R AML and continues to be a well-tolerated oral agent.¹

The drug was being administered once daily, over a 28-day cycle during the trial, according to the company website.²

The study design was a 3+3 dose escalation that gave investigators the option to expand the enrollment at each dose level.²

HM43239 may be transitioned, as appropriate, to single-agent expansion cohorts for AML, as well as in combination studies, according to the company’s website.²

The trial started March 11, 2019, and the estimated primary completion date is expected in January 2023. The estimated enrollment is 120 individuals.³

Fast track designation is designed to help facilitate the development and expedite the review of drugs to treat serious conditions and fill unmet medical needs. HM43239 received orphan drug designation from the FDA for the treatment of AML in 2018.¹

The American Cancer Society estimates that there will be 60,650 new cases of leukemia diagnosed in 2022, with 20,050 being new cases for AML, mostly in adults.⁴

Additionally, it is estimated that there will be 24,000 deaths from all leukemia with 11,540 deaths from AML, mostly in adults. AML is 1 of the most common types of leukemia in adults. However, it only accounts for 1% of all cancers.⁴

Furthermore, AML is uncommon before aged 45 years, with the average age of individuals diagnosed at about 68 years, but AML can also occur in children and teens.⁴

References

1. Aptose receives fast track designation for HM43239 in relapsed/refractory AML patients and FLT3 mutation. Aptose Biosciences. News release. May 4, 2022. Accessed May 5, 2022. https://www.aptose.com/news-media/press-releases/detail/230/aptose-receives-fast-track-designation-for-hm43239-in

2. Aptose Biosciences. HM43239 for AML. Pipeline. Accessed May 5, 2022. https://www.aptose.com/product-pipeline/hm43239

3. Aptose Biosciences. HM43239 for AML. Clinical Trials. Accessed May 5, 2022. https://www.aptose.com/product-pipeline/hm43239

4. American Cancer Society. Key Statistics for Acute Myeloid Leukemia (AML). Updated January 12, 2022. Accessed May 5, 2022. https://www.cancer.org/cancer/acute-myeloid-leukemia/about/key-statistics.html