Expanded Access Program of Bitopertin For Participants With EPP or XLP

Inclusion Criteria: * Written informed consent (and assent where applicable). * Age ≥12 years at time of request. * Diagnosis of erythropoietic protoporphyria (EPP) or X-linked protoporphyria (XLP), confirmed by ferrochelatase (FECH) or aminolevulinic acid synthase 2 (ALAS2) genotyping or by biochemical porphyrin analysis. Prior confirmation is acceptable; re-testing is not required if documentation of prior diagnosis is available. * Hemoglobin ≥10 g/dL at baseline. * Females of childbearing potential must have a negative pregnancy test prior to enrollment. Exclusion Criteria: * Known hypersensitivity to bitopertin or its excipients. * Patients with AST or ALT ≥3 × upper limit of normal (ULN), or total bilirubin ≥2 × ULN (unless due to Gilbert syndrome), or albumin below the lower limit of normal at screening. * Patients with a history of liver transplantation or anticipated need for liver transplantation. * Pregnancy, planned pregnancy during the program, or breastfeeding. * Inability or unwillingness to comply with contraception requirements. * Use of any of the following prohibited concomitant therapies: * Strong CYP3A4 inhibitors * Strong CYP3A4 inducers * Grapefruit or Seville orange products * Afamelanotide or dersimelagon * Chronic opioid therapy (\>7 consecutive days) * Patients who are currently participating in a bitopertin clinical study. * Patients who previously participated in a bitopertin study and discontinued the study due to an adverse event or for reasons that, in the judgement of the treating physician or Disc, would put the patient at unacceptable risk or otherwise preclude participation in the EAP. * Patients who have received another investigational therapy within 30 days. * History of suicidal ideation with intent (C-SSRS Grade 4 or 5) within the past year or suicidal behavior within the past 5 years.