As discussed at the 2016 MSUD Symposium and in the previous issue of this newsletter, Acer Therapeutics is following up on the research initiated by Dr. Lee on phenylbutyrate and its potential to aid in the control of branched chain amino acid levels in those with MSUD. I was asked to provide a quick update on ACER-001 – the taste-masked, immediate release formulation of sodium phenylbutyrate – that we at Acer are developing for the treatment of MSUD.

We’ve spent the better part of the past year optimizing the formulation, ensuring that it is completely taste-masked, yet behaves like regular sodium phenylbutyrate once it’s in the body. It’s really important that we get this right, so that patients taking ACER- 001 get the maximum benefit of the drug, while not detecting the horrific taste of phenylbutyrate! While this has been an incredibly challenging project, we believe we now have the best formulation developed to take into the clinic.

Before we begin the phase 2 clinical trial for MSUD, we need to run a quick study in healthy volunteers to make sure the drug is completely taste-masked, safe, and behaves similarly to regular phenylbutyrate in the body. This is a very quick study that should be completed in the fall. Assuming everything goes well with this study, we will begin the MSUD trial shortly afterward.

As a reminder, the MSUD phase 2 trial will enroll approximately 60 patients at 10-15 clinics across the US. Once a patient begins the study, they will be required to maintain a very tightly-controlled diet for about a month. ACER-001 will be added on top of their diet for about two weeks, to determine if ACER- 001 + diet can lower levels of leucine by a meaningful amount over diet alone.

We invite you to visit our recently updated website, where you can access patient resources, subscribe to our mailing list to receive program updates and clinical trial information, or ask questions directly to the company. Please visit:

We look forward to hearing from you, and keeping you updated on our progress!


The MSUD Family Support Group is currently funding several research projects and we are proactively looking for researchers interested in developing new treatments or finding a cure for MSUD. Significant funding is necessary if we are to accomplish this goal.
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