Tracking symptoms, blood PPIX, and light exposure in adults and adolescents with EPP and XLP

Prospective Clinical Assessment Study in Adolescents and Adults With Erythropoietic Protoporphyria (EPP) and X-Linked Porphyria (XLP) (STEPP)

This project will track symptoms, blood PPIX levels, and light exposure over six months in people aged 12 and older with EPP or XLP to see how the conditions affect daily life.

Quick facts

• Study type: Observational
• Enrollment: 50 (estimated)
• Ages: 12 Years and up
• Sex: All
• Sponsor: Portal Therapeutics, Inc. (Industry-sponsored)
• Locations: 19 sites (Boston, Massachusetts and 18 other locations)
• Trial ID: NCT07567131 on ClinicalTrials.gov

What this trial studies

This is an observational, non‑treatment study that follows adolescents and adults with genetically or biochemically confirmed EPP or XLP for up to 24 weeks. After screening and a baseline visit, participants return every four weeks for clinical labs, physical exams, vital signs, and blood draws for protoporphyrin IX (PPIX) measurements. Participants will record daily symptoms in a diary and wear a light dosimeter to capture real-world light exposure; some visits include controlled provocative sunlight exposure with prior skin coverage. No investigational treatments are given; the protocol is designed to characterize symptom patterns, biomarker levels, and light exposure relationships.

Who should consider this trial

Good fit: Ideal candidates are people aged 12 and older with genetic confirmation of EPP (FECH) or XLP (ALAS2), or elevated free PPIX consistent with EPP/XLP, who currently have symptoms and can wear a light dosimeter and complete a daily diary.

Not a fit: People seeking therapeutic intervention, those without current EPP/XLP symptoms, or those unwilling to wear a dosimeter or keep a daily diary are unlikely to receive direct benefit from participation.

Why it matters

Potential benefit: If successful, the data could help clarify symptom patterns and light exposure triggers to inform patient counseling and guide future treatment research.

How similar studies have performed: Previous natural-history and biomarker studies in EPP/XLP have provided useful insights into PPIX levels and symptom timing, but real-world light dosimetry linked to daily symptom diaries is less commonly reported.

Eligibility criteria

Inclusion Criteria:

1. Aged 12 years and older.
2. Confirmed diagnosis of EPP or XLP as follows:

   1. Genetic confirmation of EPP (FECH mutation with reduced ferrochelatase activity) OR
   2. Genetic confirmation of XLP (ALAS2 gain-of-function mutation) OR
   3. Elevated free PPIX levels in RBCs consistent with EPP/XLP, supported by clinical and/or family history.
3. Currently has symptoms of EPP/XLP.
4. History of consistent, non-painful prodrome within approximately 45 minutes of sunlight exposure and prior to phototoxic attacks, as self-reported by the participant.
5. Willing and able to wear a light dosimetry device during the study.
6. Willing and able to complete a daily diary of EPP/XLP symptoms.
7. Willing and able to keep skin sites chosen for provocative sunlight exposure testing covered by opaque material when outside or exposed to potentially triggering light beginning 2 days prior to testing.
8. Willing and able to provide informed consent and/or assent for the study.
9. Study participants and LAR (as appropriate) are willing and able to comply with study visits and study procedures.

Exclusion Criteria:

1. Diagnosis of another porphyria or another photodermatosis that may confound the characterization of EPP/XLP.
2. Has a clinically significant disease or condition that, at the discretion of the Investigator or Sponsor, would interfere with the evaluation of EPP/XLP or study participation, or would make study participation not in the best interest of the participant.
3. Is taking, or has taken within 60 days of Day 1, any medication, vitamin, or supplement that alters sensitivity to light exposure (eg, afamelanotide, melanotan, beta carotene, dersimelagon, or bitopertin).
4. Concurrent or anticipated participation in an interventional clinical trial during the study period.

Where this trial is running

Boston, Massachusetts and 18 other locations

• Massachusetts General Hospital — Boston, Massachusetts, United States (Recruiting)
• Mount Sinai School of Medicine — New York, New York, United States (Recruiting)
• Wake Forest University Baptist Health - Dept of Gastroenterology — Wake Forest, North Carolina, United States (Recruiting)
• Temple University — Philadelphia, Pennsylvania, United States (Not_yet_recruiting)
• University of Texas Health - Ertan Digestive Disease Center — Houston, Texas, United States (Recruiting)
• UZ Leuven — Leuven, Belgium (Not_yet_recruiting)
• University of Alberta Hospital — Edmonton, Canada (Not_yet_recruiting)
• Centre Hospitalier Universitaire de Bordeaux - Hopital Saint - Andre — Bordeaux, France (Not_yet_recruiting)
• AP-HP Hopital Bichat - Claude Bernard — Paris, France (Not_yet_recruiting)
• Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico di Milano — Milan, Italy (Not_yet_recruiting)
• Azienda Ospedaliero-Universitaria di Modena — Modena, Italy (Not_yet_recruiting)
• Haukeland University Hospital — Bergen, Norway (Not_yet_recruiting)
• Hospital Universitario 12 de Octubre — Madrid, Spain (Recruiting)
• Consorcio Hospital General Universitario de Valencia — Valencia, Spain (Not_yet_recruiting)
• Gazi University Faculty of Medicine — Ankara, Turkey (Türkiye) (Not_yet_recruiting)
• University Hospital of Wales — Cardiff, United Kingdom (Recruiting)
• Ninewells Hospital — Dundee, United Kingdom (Recruiting)
• Guy's Hospital — London, United Kingdom (Recruiting)
• Salford Royal Hospital — Manchester, United Kingdom (Recruiting)

Study contacts

• Study coordinator: GondolaBio Inquiries

Conditions Erythropoietic Protoporphyria; X-Linked Porphyria; EPP; XLP