Pfizer, Astellas amend clinical research protocols for two phase 3 trials of Enzalutamide

These amendments accelerate timelines for the anticipated primary completion dates of both trials.

ARCHES is a randomized Phase 3 study evaluating the efficacy and safety of enzalutamide plus androgen deprivation therapy (ADT) versus ADT alone in metastatic HSPC patients. The primary endpoint of the trial is radiographic progression-free survival (rPFS).

Changes to the protocol include revision of the planned analyses of the primary and secondary endpoints. Enrollment was completed earlier this year. The companies now anticipate the primary completion date for the ARCHES clinical trial to be in late 2018. The previously expected primary completion date was April 2020.

Revisions were also made to the protocol for EMBARK, a randomized Phase 3 study of enzalutamide plus leuprolide, enzalutamide monotherapy, and leuprolide alone in men with high-risk non-metastatic HSPC. The primary endpoint of the trial is metastasis-free survival (MFS).

 The main purpose of the amendment is to revise the planned analyses of the primary and several secondary endpoints, which reduced the target sample size.

Enrollment was completed earlier this year. With these changes, the estimated primary completion date for the EMBARK clinical trial is mid-2020. Previously, the expected primary completion date for EMBARK was March 2021.

Astellas oncology development global therapeutic area head and senior vice president Dr Steven Benner said: “We continually strive to design and implement clinical trials that bring innovations to people with the greatest need.

“With the amendments to ARCHES and EMBARK, we will be able to evaluate the potential of XTANDI for men with hormone-sensitive prostate cancer sooner, including for those with non-metastatic disease in which there are no currently approved oral treatment options.”

Pfizer global product development oncology chief development officer Dr Mace Rothenberg said: “With a large body of evidence demonstrating the activity of XTANDI in men with castrate-resistant prostate cancer, ARCHES and EMBARK are designed to extend the evaluation of XTANDI to men with hormone-sensitive prostate cancer.

“Our goal is to build upon the body of clinical evidence for enzalutamide in an effort to help address the unmet needs of an even broader spectrum of prostate cancer patients.”

XTANDI is approved by the U.S. Food and Drug Administration for the treatment of castration-resistant prostate cancer.

Source: Company Press Release