A phase 3 trial is expected to begin by the end of the second quarter.
The FDA granted breakthrough therapy designation (BTD) to Acer Therapeutics for Edsivo (celiprolol) for patients with the rare disease COL3A1-positive vascular Ehlers-Danlos syndrome (vEDS).
EDS is an inherited disorder caused by mutations in the genes responsible for the structure, production, or processing of collagen. The most serious form is vascular Ehlers-Danlos syndrome, also known as vEDS type IV, which is generally caused by a mutation in the COL3A1 gene resulting in reduced collagen levels, Acer said in a press release.
vEDS causes abnormal fragility in blood vessels, which can give rise to aneurysms, abnormal connections between blood vessels known as arteriovenous fistulas, arterial dissections, and spontaneous vascular ruptures. Arterial rupture or dissection events occur in about 25% of patients before the age of 20 but increase to roughly 90% of patients by the age of 40.
The median survival age of vEDS patients in the United States is 51 years, with arterial rupture being the most common cause of sudden death.
“With no currently approved treatments for vEDS anywhere in the world, this designation by FDA marks an important step forward in support of our goal to provide treatment options like Edsivo to rare disease patients, who are often overlooked or underserved,” said Adrian Quartel, M.D., chief medical officer of Acer.
In December 2021, Acer submitted a protocol for its proposed prospective pivotal trial, along with an IND, which received FDA clearance in January 2022.
Meanwhile, Acer is working with FDA to reach agreement on a special protocol assessment (SPA), a process in which sponsors may ask to meet with FDA to reach agreement on the design and size of certain clinical trials, clinical studies, or animal studies.
The company anticipates that the trial would enroll approximately 150 COL3A1-positive vEDS patients in the United States, and the duration of the clinical trial is estimated to be around 3.5 years to completion.
“We look forward to continuing our discussions with FDA, through the SPA process, to seek agreement on the protocol design of the proposed pivotal phase 3 DiSCOVER trial that we plan to initiate by the end of Q2 2022 once agreement is reached,” Quartel said.
Edsivo is a new chemical entity (NCE), which received FDA orphan drug designation for the treatment of vEDS in 2015. The Edsivo new drug application was originally submitted based on data obtained from the BBEST trial and accepted for filing in October 2018 with priority review.
However, Acer received a complete response letter (CRL) from the FDA in June 2019 stating that it will be necessary to conduct an adequate and well-controlled trial to determine whether Edsivo reduces the risk of clinical events in patients with vEDS.
Acer subsequently appealed the FDA decision and while FDA denied the appeal, it described possible paths forward for Acer to explore.