ER-004 Receives Breakthrough Therapy Designation for XLHED


According to a recent press release, EspeRare received Breakthrough Therapy Designation for its investigational therapy ER-004, designed for the prenatal treatment of X-linked hypohidrotic ectodermal dysplasia (XLHED). Ultimately, this will help meet an unmet need within this community.


X-linked hypohydrotic ectodermal dysplasia (XLHED) is a rare genetic disorder resulting from EDA gene mutations. However, it may also result from EDAR, EDARADD, and WNT10A mutations. According to the National Federation of Ectodermal Dysplasias (NFED), these genetic mutations prevent the body from making functional proteins to develop healthy teeth, sweat glands, hair, and skin. As XLHED is X-linked, males are generally more affected than females.

Symptoms and characteristics include:

  • Fine, sparse hair
  • Hypohidrosis, or an impaired ability to sweat
  • Dry, scaly, or peeling skin
  • Missing teeth or small, pointed teeth
  • Dry eyes
  • Asthma and other respiratory issues
  • Sinusitis
  • Low saliva production
  • Dark, thin skin under the eyes
  • Difficulty regulating temperature and/or frequent fevers
  • Impacted ear wax
  • Seizures
  • Pneumonia

Learn more about XLHED here.


This experimental therapy was developed by EspeRare, a nonprofit organization whose focus is meeting unmet treatment needs within the rare disease community. ER-004 is delivered through amniotic fluid to replace missing EDA protein.

The FDA granted Breakthrough Therapy Designation after results from a study in the New England Journal of Medicine. During this study, researchers administered ER-004 to three infants within and outside of the womb. According to researchers, ER-004 allowed all 3 infants to sweat normally. Additionally, XLHED symptoms failed to develop by 22 months.

So, what is Breakthrough Therapy Designation? Says the FDA, the program:

[expedites] the development and review of drugs for serious or life-threatening conditions. The criteria for breakthrough therapy designation requires preliminary clinical evidence that demonstrates the drug may have substantial improvement on at least one clinically significant endpoint over available therapy.

Once an organization receives Breakthrough Therapy Designation for their treatment, they also receive a variety of benefits, including:

  • Eligibility for priority and rolling reviews
  • Guidance from the FDA during drug development
  • Additional meetings and communication with the FDA

Additionally, EspeRare received Fast Track and Orphan Drug Designation for ER-004 within the US and Priority Medicines and Orphan Drug Designation within Europe.

Moving forward, EspeRare hopes to begin a clinical trial on ER-004. Ultimately, the goal is to enroll patients by the end of 2021.

Jessica Lynn

Jessica Lynn

Jessica Lynn has an educational background in writing and marketing. She firmly believes in the power of writing in amplifying voices, and looks forward to doing so for the rare disease community.

Follow us