Abstract 495TiP
Background
ENV-101 is a Hh pathway inhibitor (Smo inhibitor) originally developed as a treatment for patients with advanced solid tumors. Clinical responses have been reported in patients with gene mutations affecting PTCH1 treated with other Hh pathway inhibitors. Endeavor is studying ENV-101 in advanced cancer patients with solid tumors harboring PTCH1 loss of function mutations. This study aims to evaluate dose as well as the efficacy and safety of ENV-101, a potent Hh pathway inhibitor, in patients with refractory advanced solid tumors characterized by loss of function mutations in the PTCH1 gene. Two distinct mechanisms are responsible for inappropriate and uncontrolled Hh pathway activation in human malignancies: ligand-dependent, due to overexpression of Hh ligand, and ligand-independent, resulting from genetic mutations in pathway components such as Ptch and Smo. The ligand-dependent mediated Hh pathway activation is implicated in a number of malignancies, including basal cell carcinoma (BCC), medulloblastoma, rhabdomyosarcoma, breast cancer, esophageal cancer, gastric cancer, pancreatic cancer, prostate cancer, small cell lung cancer, bladder cancer, oral cancer, and melanoma. Hedgehog pathway activation due to the ligand-independent mechanism involving Ptch1 loss of heterozygosity (LOH) or Smo mutations are primarily reported in medulloblastoma and BCC. However, data indicate that these mutations may be present in other solid tumors as well. In addition, as the Hh pathway is known to be primarily active in embryonic development and is not required for survival in adults, this type of targeted therapy should provide improved outcomes to defined cancer patient populations.
Trial design
This is a Simon 2 stage design that aims to evaluate the efficacy and safety of ENV-101, a potent Hedgehog (Hh) pathway inhibitor, in patients with refractory advanced solid tumors characterized by loss of function (LOF) mutations in the PTCH1 gene. Stage 1 (phase IIa) of this protocol will enroll a total of 44 patients randomized between two dose levels. In the presence of acceptable efficacy, stage 2 (phase IIb) of this protocol will expand enrollment using a single dose level.
Clinical trial identification
NCT05199584 January 20, 2022.
Editorial acknowledgement
Legal entity responsible for the study
Endeavor Biomedicines.
Funding
Endeavor Biomedicines.
Disclosure
All authors have declared no conflicts of interest.