HERO Study
Are you a hero with MMA or PA? Consider participating in a clinical study

The HERO (Help Reduce Organic Acids) Study is evaluating an experimental drug for methylmalonic acidemia (MMA) and propionic acidemia (PA). The study drug, called HST5040, is an oral therapy designed to correct metabolic abnormalities associated with MMA and PA.

Connect with a Patient Advocate

The HERO study has partnered with the KnowRare organization to assist families considering clinical trials. KnowRare advocates can help you understand the process and connect you with study sites.


HERO Goals

The HERO Study will recruit at least 12 subjects with MMA and PA to participate in clinical research. The study drug HST5040 will be taken daily orally or through gastrostomy tube. Participants will have the opportunity to continue to take the drug until it is approved for use or the study ends. 

The goals of the study are to:

  • Assess the safety of HST5040
  • Understand how HST5040 is absorbed and processed in the body 
  • Evaluate if HST5040 
    • Lowers toxins related to MMA and PA in the body 
    • Reduces the frequency of acute metabolic decompensations, hospital visits and home emergency protocol use 
    • Improves patient and family quality of life

More detailed information about the study can be found on clinicaltrials.gov.

All study drugs, study visits and study assessments will be provided at no cost. Participants will receive stipends to cover meals and travel related to study visits.

The safety and effectiveness of HST5040 for the treatment of MMA or PA have not been established.

Who Can Be a HERO?

The HERO Study is recruiting children and adults age 2 and older with MMA (mutase deficient) or PA who meet the study criteria. The study is not enrolling patients who have had transplants at this time.

Learn how methylmalonic acidemia and propionic acidemia affect the body and about experimental drug HST5040 being developed to treat these rare diseases.


About HST5040

HemoShear’s drug HST5040 is designed to correct metabolic abnormalities associated with MMA and PA. HST5040 may distribute to multiple affected tissues and may have the potential to be active throughout the body, including the kidney, liver, brain, heart and muscles.

Assessing the safety of HST5040 in MMA and PA patients is a critical objective of the HERO Study. In previous clinical studies for unrelated diseases, HST5040 was shown to be well tolerated at doses higher than planned to be used in the HERO Study.

Study Locations

HERO is being conducted at several leading children’s research centers in the United States.  Please contact a study site near you for more information. Travel and associated expenses will be covered for eligible participants. 

This map currently lists some study sites, and more will be added soon. A full list of sites can be found on clinicaltrials.gov.


Hover over the dots for study contact information.

United States Map

Learn from The Experts

HemoShear, the Organic Acidemia Association and the Propionic Acidemia Foundation hosted a webinar in April 2021 for MMA and PA patients and caregivers. Watch this video to hear from the experts about current treatment approaches for MMA and PA, how the clinical research process works, how experimental oral drug HST5040 was developed and the design of our HERO clinical trial.

Meet HemoShear

At HemoShear Therapeutics we are driven to apply our scientific insights to develop medicines that improve the lives of patients with rare metabolic diseases. We are committed to understanding and helping to meet the needs of patients and their families.