Extension Study to PTR-01-002 (A Study in Recessive Dystrophic Epidermolysis Bullosa (RDEB) Patients Previously Treated With PTR-01)

A Phase 2b Open-Label Study of PTR-01 in Recessive Dystrophic Epidermolysis Bullosa (RDEB) Patients Previously Treated With PTR-01 in Study PTR-01-002

A sub-set of patients who participated in PTR-01-002 will be enrolled in an open-label study, if they meet the study eligibility criteria.

Protocol PTR-01-003 is a 4-part Phase 2, open-label study of PTR-01 in patients who satisfactorily completed study PTR-01-002 and meet current enrollment criteria.

In Part 1, patients will be monitored monthly for up to 2 months with patient-reported and Investigator assessments. In Part 2, patients will receive a dose of 3.0 mg/kg every week for a total of 4 doses. This will be followed by Part 3 in which patients will receive a dose of 3.0 mg/kg monthly for a total of 5 additional doses. At the end of each dosing period, efficacy assessments will be performed. During Part 4, patients will be evaluated at Months 1 and 3 after completion of dosing to assess the durability of wound healing and other efficacy parameters. Safety will be assessed continuously throughout the study.

Inclusion Criteria:

1. Willing to provide informed consent form, or if 12 to <18 years of age, legal guardian has provided informed consent form and the minor has signed an assent form acknowledging that they understand and agree to study procedures.

2. Has satisfactorily completed participation in PTR-01-002.

3. Agrees to use contraception as follows:

   • For women of childbearing potential (WOCBP) agrees to use highly effective contraceptive (including abstinence) methods from Screening, through the study, and for at least 10 weeks after the last dose of study drug. Non-childbearing potential is defined as a female who meets either of the following criteria: age ≥50 years and no menses for at least 1 year or documented hysterectomy, bilateral tubal ligation, or bilateral oophorectomy.
   • For males, agrees to use a condom with any WOCBP sexual partner from Day 1 of study treatment, through the study, and at least 10 weeks after the last dose of study drug.

4. Be willing and able to comply with this protocol.

Exclusion Criteria:

1. Has known systemic hypersensitivity to any of the inactive ingredients in PTR-01.
2. Has previously had an anaphylactic reaction to PTR-01.
3. Is pregnant or nursing.
4. Has received in the last six months any investigational gene therapy product or in the last three months any non-gene therapy investigational products (other than PTR-01).
5. Is anticipated to receive new regimens of antibiotics or other anti-infectives during the trial.
6. Has any other medical or personal condition that, in the opinion of the Investigator, may potentially compromise the safety or compliance of the