At two external conferences (VAC in Berlin and ISSVA in Paris), we had an exhibition booth. Nearby, there was a booth from the American company Relay. During these conferences, we had extensive contact with Relay staff, and they shared with us information about the development of new medication.
A Q&A with Brenton Mar from Relay Therapeutics (May 2025)
About Brenton Mar: Brenton runs clinical development at Relay Therapeutics, which means he leads the team that creates and runs Relay’s clinical trials. By training, he is a pediatric hematologist/oncologist and has spent many years doing research and clinical care.
Who is Relay Therapeutics?
Brenton: Relay Therapeutics is a small biotech company that focuses on discovering and developing new medicines for rare disease and oncology communities with significant unmet needs.
We were founded in 2016, and you can find most of us in Cambridge, Massachusetts where Relay is based.
Can you tell us more about your PIK3CA-driven vascular malformations program?
Brenton: One of Relay’s programs is focused on PIK3CA-driven vascular malformations, including PIK3CA Related Overgrowth Spectrum, known as PROS, and PIK3CA-driven lymphatic malformations.
As you know, PROS includes syndromes such as Klippel-Trenaunay, CLOVES, FAVA, MCAP and many more.
I’ve mentioned PIK3CA a few times now. PIK3CA is a gene that creates a protein, called PI3Kα. PI3Kα is involved in your body’s natural cell growth and metabolism. However, mutations or changes in the PIK3CA gene can lead to a malfunctioning, mutated PI3Kα protein, which is the most common cause of vascular malformations and other overgrowth syndromes.
The therapy Relay is investigating in clinical trials, which is called RLY-2608, specifically targets the mutated PI3Kα protein.
What is the investigational therapy RLY-2608?
Brenton: The investigational study drug being evaluated is called RLY-2608. It is a drug that is taken orally and is designed to specifically target and hinder the mutated PI3Kα protein that can cause PIK3CA-driven vascular malformations. By selectively targeting the mutated protein, and limiting impact on the non-mutated proteins, the study drug aims to be an effective treatment that reduces side effects that are caused by hindering the normal protein, including diarrhea, increased blood sugar, rash, mouth sores, and others.
It’s important to note that RLY-2608 has not yet been evaluated in individuals living with vascular malformations, as Relay is just starting this clinical trial.
Relay has seen encouraging interim results from our ongoing clinical trial of RLY-2608 in breast cancer, which we shared in December 2024. This breast cancer trial has been running since early 2022.
Can you tell us more about Relay Therapeutics’ clinical trial for PIK3CA-driven vascular malformations?
Brenton: Earlier this year, Relay started a Phase 2 clinical trial for eligible individuals living with PIK3CA-driven vascular malformations. The trial will evaluate the safety and effectiveness of the investigational medicine, RLY-2608.
We’re excited to say that we’ve just opened our first site in the USA in April, and we expect many more sites in the USA to open as the year goes on. The trial is a global trial, and we expect to open sites in additional countries in the future.
How can people learn more?
Brenton: Please feel free to reach out to Relay Therapeutics with any questions at clinicaltrials@relaytx.com. You can learn more about the clinical trial on https://clinicaltrials.gov/study/nct06789913.
Thank you to the patient advocacy groups we have had the opportunity to work with over the past year. We are looking forward to meeting more people in the community throughout the year. Please do not hesitate to reach out.