Valemetostat, a potential first-in-class drug from Daiichi Sankyo, led to durable tumor response in patients with peripheral T-cell lymphoma (PTCL) and adult T-cell leukemia/lymphoma (ATL) in a Phase 1 study.
The company presented highlights from the trial at the European Hematology Association (EHA) 2021 Virtual Congress today.
In the study, the objective response rate was 54.5% in 44 patients with PTCL. That tally included 12 complete responses and 12 partial responses. The median duration of response was 56 weeks.
Valemetostat inhibits two enzymes known as enhancer of zeste homolog 1 and 2 (EZH1/EZH2). As a Daiichi-Sankyo clinical trial synopsis explains, “EZH1/EZH2 are part of polycomb protein complexes and act through histone methylation to regulate expression of genes involved in maintaining hematopoietic stem cells.”
Researchers have observed altered EZH2 expression in the development and progression of blood cancers such as non-Hodgkin lymphomas (NHLs) and adult T-cell leukemia/lymphoma (ATL). EZH1 also plays a role in hematologic cancer progression.
Daiichi Sankyo has noted that valemetostat has shown promise against hematologic malignancies in preclinical studies.
Based on the most recent research, the company plans to launch a pivotal Phase 2 study known as VALENTINE-PTCL01 to further test valemetostat in patients with relapsed or refractory PTCL and ATL. The trial name is an abbreviation of Valemetostat Tosylate (DS-3201b), an Enhancer of Zeste Homolog (EZH) 1/2 Dual Inhibitor, for Relapsed/Refractory Peripheral T-Cell Lymphoma.
The prognosis for patients with PTCL and ATL is generally poor. The five-year overall survival rate for two common types of PTCL is 32% for PTCL-NOS (peripheral T-cell lymphoma not other specified) and AITL (angioimmunoblastic T-cell lymphoma), while it is 14% for ATL.
Most patients with PTCL experience disease progression after multi-drug chemotherapy.
Filed Under: clinical trials, Drug Discovery, Oncology