Clinical trials

PATHWAY is a Phase 2b/3 clinical study with an Open-Label Extension (OLE). It tests PORT-77 in patients with EPP, EPP2, and XLP. The study has three parts: Part 1: Phase 2b * Find the right dose of PORT-77 to lower PPIX levels in the blood * Test if PORT-77 lowers PPIX levels better than placebo * Check the safety of each dose Part 2: Phase 3 * Test if PORT-77 lowers PPIX levels better than placebo * Test if PORT-77 increases the amount of time patients spend in sunlight each day without pain compared to placebo * Check the safety of PORT-77 Part 3: Open-Label Extension (OLE) * Test the long-term effect of PORT-77 on PPIX levels and time in sun * Monitor long-term safety

The purpose of this study is to collect information about the effects of EPP/XLP in adults and adolescents. This is an observational study in which participants will not receive any treatment. Study details include: * The study duration will be up to 6 months for each participant. * After Screening, participants will have a Baseline (Day 1) visit and return for visits every 4 weeks through 24 weeks. * Assessments to evaluate EPP/XLP will include clinical laboratory tests, physical exams, vital signs measurement, blood draws for PPIX concentration, reporting of EPP/XLP-related symptoms (including completion of a daily diary), light dosimetry.