By Don Tracy, Associate Editor

DSP-5336 targets the menin and mixed-lineage leukemia protein interaction, crucial in various biological processes, including cell growth and genomic stability.

Image Credit: Adobe Stock Images/Pichitchai

The FDA has granted Fast Track Designation to Sumitomo Pharma America’s DSP-5336, an investigational small molecule inhibitor for the treatment of relapsed or refractory acute myeloid leukemia (AML) with KMT2A rearrangement (MLLr) or nucleophosmin mutation (NPM1m). According to the company, DSP-5336 targets the menin and mixed-lineage leukemia (MLL) protein interaction, which is considered vital in a variety of biological processes, including cell growth and genomic stability.1

"For patients and families facing a diagnosis of relapsed or refractory acute myeloid leukemia, significant unmet medical needs remain—and we share in their urgency to identify and advance new treatment pathways," said Tsutomu Nakagawa, PhD, president, CEO, SMPA, in a press release. "We are encouraged by FDA's decision and look forward to working closely with the agency as we continue our clinical development of DSP-5336."

Promising data from an ongoing Phase I/II study, which was presented at the European Hematology Association 2024 Hybrid Congress, demonstrated an objective response rate of 57% and a 24% rate of complete remission or partial hematologic recovery. There were no reports of dose-limiting toxicity or significant adverse events, and the treatment was well tolerated. Additionally, there were no reports of serious drug-drug interactions or need for differentiation syndrome prophylaxis. Further, only three cases of differentiation syndrome were reported, which were all manageable and did not result in intensive care unit stays or discontinuation of DSP-5336.1

One out of every three adults in the United States with leukemia has been diagnosed with AML; however, it only accounts for approximately 1% of all cancers. This year, the American Cancer Society estimated that around 20,800 people in the United States will be diagnosed with AML, with most cases occurring in adults. Approximately 11,220 patients with AML will die as a result. While children can develop AML, it is uncommon in people under the age of 45 years. On average, the lifetime risk of being diagnosed with AML is half of 1%.2

According to Medical News Today, relapse is common for patients with AML, with an estimated two-thirds of patients with AML experiencing a relapse after first being treated. In younger patients, 40%-50% will experience a relapse compared to the larger population of older patients.3

“According to the LLS, from 2010 to 2016, the 5-year relative survival rate for adults with AML was 29.8%,” reports Medical News Today. “People under the age of 15 years had a 5-year relative survival rate of 70.6%. However, research in the journal Current Treatment Options in OncologyTrusted Source notes that outcomes vary depending on how long a person was in remission before relapsing and whether doctors recommend a stem cell transplant.”

The FDA previously granted Orphan Drug Designation for DSP-5336 for the indication of acute myeloid leukemia in June 2022.1

"Management of AML continues to be challenging with limited options for which there are currently no approved targeted therapies to treat AML with KMT2A (MLL) rearrangements or NPM1 mutations, leaving a serious unmet medical need," said Jatin Shah, MD, chief medical officer—oncology, SMPA, in a press release. "DSP-5336 has shown promising clinical activity, and menin inhibitors have tremendous potential to impact the outcomes of these types of acute leukemia. We are excited by these early results and FDA Fast Track Designation and look forward to working closely with the agency and our collaborators to rapidly advance this program with the goal of providing a well-tolerated and effective targeted treatment option for patients with relapsed or refractory acute myeloid leukemia."