Clinical trial • Phase IV • Rare Disease|Endocrinology

BITOPERTIN for Erythropoietic Protoporphyria (EPP) | X-Linked Protoporphyria (XLP)

Phase IV trial of BITOPERTIN for Erythropoietic Protoporphyria (EPP) | X-Linked Protoporphyria (XLP). open-label, none/not specified-controlled.

Overview

Trial Therapeutic Area
Rare Disease|Endocrinology
Trial Disease
Erythropoietic Protoporphyria (EPP) | X-Linked Protoporphyria (XLP)
Trial Stage
Phase IV
Drug Modality
Small molecule
Paediatric Trial
Yes
Orphan Drug
Yes

Key dates

Initial CTIS Submission Date
17-10-2025
First CTIS Authorization Date
12-02-2026

Trial design

open-label, none/not specified-controlled Phase IV trial across 12 sites in Belgium, France, Sweden and others.

Open Label
Yes
Comparator
None/Not specified
Target Sample Size
216
Trial Duration For Participant
364

Eligibility

Recruits 216 paediatric patients.

Pregnancy Exclusion
7. If female, pregnant, planning to become pregnant, or breastfeeding.
Vulnerable Population
Adolescents (participants aged 12–17) are included. The protocol requires written informed consent and specifies "assent if necessary" for minors. Country-specific adolescent assent and parent/guardian informed consent forms are provided (multiple adolescent assent and parent/guardian ICF documents are listed for participating countries), indicating parental/legal guardian consent and adolescent assent processes are in place.

Inclusion criteria

  • {"criterion_text":"- 1. Participants with diagnosis of EPP or XLP who are participating (or who have participated) in a prior Disc bitopertin study and who have completed the randomized treatment phase and End-of- Study visit.\n- 2. Aged ≥12 years upon study consent.\n- 3. Body weight ≥32 kg for participants <18 years of age and BMI ≥18.5 kg/m2 for adult participants.\n- 4. Willing to practice highly effective methods of birth control (both males who have partners of childbearing potential and females of childbearing potential during the study, while taking study drug, and for at least 30 days after the last dose of study drug.\n- 5. Negative urine or serum pregnancy test (females of childbearing potential).\n- 6. Able to understand the study aims, procedures, and requirements, and provide written informed consent (and assent if necessary).\n- 7. Able to comply with all study procedures."}

Exclusion criteria

  • {"criterion_text":"- 1. Participants who have an ongoing serious adverse event (SAE) from a clinical study that is assessed by the investigator as related to bitopertin.\n- 10. Consumption of grapefruit/Seville orange and products containing these for 14 days prior to first dose of study drug and throughout the study.\n- 2. Other medical or psychiatric condition or laboratory finding not specifically noted above that, in the judgement of the Investigator or Sponsor, would put the participant at unacceptable risk or otherwise preclude participation in the study.\n- 3. Condition or concomitant medication that would confound the ability to interpret clinical, clinical laboratory, or participant diary data, including a major psychiatric condition that has had an exacerbation or required hospitalization in the last 6 months.\n- 4. Planned treatment with afamelanotide or dersimelagon during the study.\n- 5. Planned use of any drugs or herbal remedies known to be strong or moderate inhibitors or inducers of cytochrome P450 (CYP)3A4 enzymes throughout the study.\n- 6. Current or planned treatment with antipsychotic medication.\n- 7. If female, pregnant, planning to become pregnant, or breastfeeding.\n- 8. Participation in any other clinical protocol or investigational study, other than Disc bitopertin studies, that involves administration of experimental therapy and/or therapeutic devices within 30 days of Day 1.\n- 9. Score of PHQ-8 ≥10 at screening or imminent suicidal risk identified by the C-SSRS as defined as suicidal ideation with intent (Grade 4 or 5) within the last year or any suicidal behavior within the last 5 years."}

Endpoints

Primary endpoints

  • {"endpoint_text":"- Safety and tolerability of bitopertin, as assessed by the incidence of treatmentemergent adverse events (TEAEs), vital signs, physical examinations, and clinical laboratory parameters.","definition_or_measurement_approach":"As assessed by the incidence of treatment-emergent adverse events (TEAEs), vital signs, physical examinations, and clinical laboratory parameters."}

Secondary endpoints

  • {"endpoint_text":"- 1. Change from baseline in daylight tolerance, as assessed by total hours spent in sunlight without pain and average time to first prodromal syndrome in sunlight.","definition_or_measurement_approach":"Change from baseline evaluated by total hours spent in sunlight without pain and average time to first prodromal syndrome in sunlight."}
  • {"endpoint_text":"- 2. Percent change from baseline in whole blood metal-free PPIX concentrations.","definition_or_measurement_approach":"Percent change from baseline in whole blood metal-free protoporphyrin IX (PPIX) concentrations (bioanalytical measurement)."}
  • {"endpoint_text":"- 3. Plasma bitopertin concentrations.","definition_or_measurement_approach":"Trough and plasma concentrations of bitopertin (pharmacokinetic sampling to obtain and summarize plasma concentrations)."}

Recruitment

Planned Sample Size
216
Recruitment Window Months
33
Consent Approach
Written informed consent is required from participants; assent is required for minors. Country-specific informed consent and assent documents are provided (adult ICFs, adolescent assent forms for 12–14 and 15–17, parent/guardian ICFs, pregnancy ICFs). Documents exist in multiple country/language versions (e.g., German, French, Dutch, Italian, Swedish, Norwegian, Spanish, English), indicating language- and age-specific consent/assent materials and parent/guardian consent procedures.

Geography

Total Number Of Sites
12
Total Number Of Participants
46

Belgium

Earliest CTIS Part Ii Submission Date
26-01-2026
Latest Decision Or Authorization Date
13-02-2026
Processing Time Days
18
Number Of Sites
1
Number Of Participants
2

Sites

Site Name
UZ Leuven
Department Name
Dermatology
Principal Investigator Name
Petra De Haes
Principal Investigator Email
petra.dehaes@uzleuven.be
Contact Person Name
Petra De Haes
Contact Person Email
petra.dehaes@uzleuven.be

France

Earliest CTIS Part Ii Submission Date
07-01-2026
Latest Decision Or Authorization Date
28-04-2026
Processing Time Days
111
Number Of Sites
2
Number Of Participants
12

Sites

Site Name
Assistance Publique Hopitaux De Paris
Department Name
CIC
Principal Investigator Name
Laurent Gouya
Principal Investigator Email
laurent.gouya@aphp.fr
Contact Person Name
Laurent Gouya
Contact Person Email
laurent.gouya@aphp.fr
Site Name
Centre Hospitalier Universitaire De Nantes
Department Name
Dermatology
Principal Investigator Name
Marie Le Moigne
Principal Investigator Email
marie.lemoigne@chu-nantes.fr
Contact Person Name
Marie Le Moigne
Contact Person Email
marie.lemoigne@chu-nantes.fr

Sweden

Earliest CTIS Part Ii Submission Date
12-01-2026
Latest Decision Or Authorization Date
09-04-2026
Processing Time Days
87
Number Of Sites
1
Number Of Participants
2

Sites

Site Name
Karolinska University Hospital
Department Name
Sektionen för leversjukdomar
Principal Investigator Name
Staffan Wahlin
Principal Investigator Email
staffan.wahlin@regionstockholm.se
Contact Person Name
Staffan Wahlin

Italy

Earliest CTIS Part Ii Submission Date
15-01-2026
Latest Decision Or Authorization Date
09-04-2026
Processing Time Days
84
Number Of Sites
2
Number Of Participants
2

Sites

Site Name
Fondazione IRCCS Ca Granda Ospedale Maggiore Policlinico
Department Name
Simple Structure Hemoglobinopathies and Hereditary Disorders of Metabolism and the Immune System
Principal Investigator Name
Giovanna Graziadei
Principal Investigator Email
giovanna.graziadei@policlinico.mi.it
Contact Person Name
Giovanna Graziadei
Site Name
I.F.O. Istituti Fisioterapici Ospitalieri
Department Name
UOSD Center for Porphyrias and Rare Diseases
Principal Investigator Name
Luca Barbieri
Principal Investigator Email
luca.barbieri@ifo.it
Contact Person Name
Luca Barbieri
Contact Person Email
luca.barbieri@ifo.it

Norway

Earliest CTIS Part Ii Submission Date
10-02-2026
Latest Decision Or Authorization Date
08-04-2026
Processing Time Days
57
Number Of Sites
1
Number Of Participants
1

Sites

Site Name
Helse Bergen HF
Department Name
Norwegian Porphyria Centre
Principal Investigator Name
Aasne Aarsand
Principal Investigator Email
aasne.aarsand@helse-bergen.no
Contact Person Name
Aasne Aarsand
Contact Person Email
aasne.aarsand@helse-bergen.no

Spain

Earliest CTIS Part Ii Submission Date
23-01-2026
Latest Decision Or Authorization Date
22-04-2026
Processing Time Days
89
Number Of Sites
1
Number Of Participants
3

Sites

Site Name
Hospital Clinic De Barcelona
Department Name
Dermatology
Principal Investigator Name
Paula Aguilera
Principal Investigator Email
paguile@clinic.ub.es
Contact Person Name
Paula Aguilera
Contact Person Email
paguile@clinic.ub.es

Germany

Earliest CTIS Part Ii Submission Date
15-01-2026
Latest Decision Or Authorization Date
08-04-2026
Processing Time Days
83
Number Of Sites
2
Number Of Participants
10

Sites

Site Name
Klinikum Chemnitz gGmbH
Department Name
Porphyria
Principal Investigator Name
Ilja Kubisch
Principal Investigator Email
i.kubisch@skc.de
Contact Person Name
Ilja Kubisch
Contact Person Email
i.kubisch@skc.de
Site Name
Charite Universitaetsmedizin Berlin KöR
Department Name
Institute of Allergology (IFA)
Principal Investigator Name
Manuel Pereira
Principal Investigator Email
manuel.pereira@charite.de
Contact Person Name
Manuel Pereira
Contact Person Email
manuel.pereira@charite.de

Ireland

Earliest CTIS Part Ii Submission Date
21-01-2026
Latest Decision Or Authorization Date
28-04-2026
Processing Time Days
97
Number Of Sites
1
Number Of Participants
1

Sites

Site Name
Children's Health Ireland
Department Name
Dermatology
Principal Investigator Name
Fiona M. Browne
Principal Investigator Email
Fiona.Browne1@childrenshealthireland.ie
Contact Person Name
Fiona M. Browne

Netherlands

Earliest CTIS Part Ii Submission Date
15-01-2026
Latest Decision Or Authorization Date
02-04-2026
Processing Time Days
77
Number Of Sites
1
Number Of Participants
13

Sites

Site Name
Erasmus Universitair Medisch Centrum Rotterdam (Erasmus MC)
Department Name
Internal Medicine
Principal Investigator Name
Janneke Langendonk
Principal Investigator Email
j.langendonk@erasmusmc.nl
Contact Person Name
Janneke Langendonk
Contact Person Email
j.langendonk@erasmusmc.nl

Sponsor

Primary sponsor

Full Name
Disc Medicine Inc.
Organisation Type
Pharmaceutical company
Country Of Registered Address
United States

Contract research organisations

Name
Orion Clinical Services Limited
Responsibilities
Contract Research Organisation (CRO); Medical monitoring

Third parties

  • {"country":"United Kingdom","full_name":"Orion Clinical Services Limited","duties_or_roles":"Contract Research Organisation (CRO); Medical monitoring","organisation_type":"Pharmaceutical company"}
  • {"country":"United States","full_name":"Almac Clinical Services LLC","duties_or_roles":"IP packaging and labeling","organisation_type":"Pharmaceutical company"}
  • {"country":"United Kingdom (Northern Ireland)","full_name":"Almac Clinical Services Limited","duties_or_roles":"Drug Depot","organisation_type":"Pharmaceutical company"}
  • {"country":"United States","full_name":"Propharma Group LLC","duties_or_roles":"Pharmacovigilance","organisation_type":"Pharmaceutical company"}
  • {"country":"United Kingdom","full_name":"Acm Global Central Laboratory Limited","duties_or_roles":"Central Safety Laboratory, PPIX, PK and Biomarker kit supplies, and sample shipment","organisation_type":"Laboratory/Research/Testing facility"}
  • {"country":"United States","full_name":"Creative Proteomics","duties_or_roles":"Exploratory Hepatobiliary Biomarker Laboratory","organisation_type":"Industry"}
  • {"country":"United States","full_name":"Medrio Inc.","duties_or_roles":"ePRO; RTSM","organisation_type":"Pharmaceutical company"}
  • {"country":"Australia","full_name":"Avance Clinical Pty Limited","duties_or_roles":"eTMF; Medical monitoring","organisation_type":"Pharmaceutical company"}
  • {"country":"United States","full_name":"Alliance Pharma Inc.","duties_or_roles":"PPIX, PK Bioanalytical Laboratory","organisation_type":"Pharmaceutical company"}
  • {"country":"United States","full_name":"Scout Clinical","duties_or_roles":"Patient Travel Reimbursement","organisation_type":"Hospital/Clinic/Other health care facility"}

Investigational products

Investigational Product Name
Bitopertin
Active Substance
BITOPERTIN
Modality
Small molecule
Routes Of Administration
ORAL
Route
ORAL
Authorisation Status
Investigational (MIA(IMP) 20377)
Orphan Designation
Yes
Maximum Dose
60 mg

Related trials

Other published trials that may interest you.