Sutro Biopharma has announced the initiation of the REFRαME-P1 trial, a pivotal study designed to evaluate luveltamab tazevibulin (luvelta) in pediatric patients suffering from CBFA2T3::GLIS2 (CBF/GLIS) acute myeloid leukemia (AML). This global study aims to address a critical unmet need in a rare and aggressive form of leukemia that primarily affects infants and young children.
The REFRαME-P1 trial is a registration-directed study, meaning its results are intended to support regulatory approval of luvelta for this indication. The trial's initiation follows encouraging data from a compassionate use program, where luvelta demonstrated a 42% complete remission rate in patients with ≥5% blasts. These responses enabled some patients to proceed to hematopoietic stem cell transplant, a potentially curative therapy.
High Unmet Need in CBF/GLIS AML
CBF/GLIS AML is a rare and highly lethal subtype of AML, predominantly found in infants and young children with an average onset age of 18 months. This form of leukemia is characterized by resistance to conventional chemotherapy, with induction failure rates exceeding 80%. The lack of effective treatment options results in a dismal two-year survival rate for affected children.
Anne Borgman, M.D., Sutro’s Chief Medical Officer, stated, "We are excited to announce the initiation of our second pivotal trial, the registration-enabling clinical trial of luvelta in infants and toddlers with a rare and aggressive form of leukemia. We look forward to bringing this promising targeted therapy to a pediatric patient group with limited effective treatment options."
Luvelta: A Targeted Approach
Luveltamab tazevibulin (luvelta), formerly known as STRO-002, is an antibody-drug conjugate (ADC) that targets folate receptor alpha (FRα). Recent studies have indicated that FOLR1, the gene encoding FRα, is uniquely induced by the CBF/GLIS gene fusion, making it a specific target for this AML subtype.
Soheil Meshinchi, M.D., Ph.D., who presented compassionate use data at the American Society of Hematology Annual Meeting and Exposition in December 2023, commented, "Beginning this trial is an important next step in the clinical development pathway for luvelta, as it has the opportunity to address the unmet need in many types of cancer that express Folate Receptor-α (FRα) beyond ovarian." He added, "With my focus on the biology of AML, I am honored to have been a part of making this medicine available to patients in dire need via a compassionate use mechanism sponsored by Sutro, through which we have seen encouraging results in this devastating disease."
Trial Design and Objectives
The REFRαME-P1 trial will evaluate the efficacy and safety of luvelta in infants and children under 12 years of age diagnosed with CBF/GLIS AML. Sutro Biopharma plans to activate the majority of clinical trial sites by the end of the year, facilitating global participation in this crucial study.
