HELIOS: Long-term study of DISC-1459 (or Bitopertin) in patients with Erythropoietic Protoporphyria (EPP) or X-Linked Protoporphyria (XLP).

Overview

Sponsor-declared trial summary

Key facts

Sponsor

Disc Medicine Inc.

Participant type

Pediatric, Patients

Age range

0-17 years, 18-64 years, 65+ years

Gender

Male and Female

Therapeutic area

Diseases [C] - Nutritional and Metabolic Diseases [C18]

Decision date (initial)

2026-02-13

Transition trial

No

Low-intervention

No

Rare-disease indication

Yes

Vulnerable population

Yes

Funding sources

Disc Medicine, Inc.

External identifiers

EU CT number

2025-523275-27-00

ClinicalTrials.gov

NCT05883748

Trial design

CTIS Part I — objectives, methods, condition coding

Main objective

Scope: Safety, Others, Efficacy

To assess the long-term safety and tolerability of bitopertin in participants with EPP (any FECH and ALAS2 genotypes) or X-linked protoporphyria (XLP).

Secondary objectives 3

1. 1. To assess the long-term efficacy of bitopertin in participants with EPP or XLP.
2. 2. To assess changes in PPIX concentrations in response to long-term bitopertin treatment.
3. 3. To obtain and summarize trough plasma bitopertin concentrations.

Conditions and MedDRA coding

X-Linked Protoporphyria (XLP)

Regulatory references

Plan to share IPD

No

Eligibility criteria

Principal inclusion / exclusion criteria as submitted by sponsor

Inclusion criteria 7

1. 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.
2. 2. Aged ≥12 years upon study consent.
3. 3. Body weight ≥32 kg for participants <18 years of age and BMI ≥18.5 kg/m2 for adult participants.
4. 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.
5. 5. Negative urine or serum pregnancy test (females of childbearing potential).
6. 6. Able to understand the study aims, procedures, and requirements, and provide written informed consent (and assent if necessary).
7. 7. Able to comply with all study procedures.

Exclusion criteria 10

1. 1. Participants who have an ongoing serious adverse event (SAE) from a clinical study that is assessed by the investigator as related to bitopertin.
2. 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.
3. 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.
4. 4. Planned treatment with afamelanotide or dersimelagon during the study.
5. 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.
6. 6. Current or planned treatment with antipsychotic medication.
7. 7. If female, pregnant, planning to become pregnant, or breastfeeding.
8. 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.
9. 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.
10. 10. Consumption of grapefruit/Seville orange and products containing these for 14 days prior to first dose of study drug and throughout the study.

Endpoints

Primary and secondary outcome measures (English text)

Primary endpoints 1

1. Safety and tolerability of bitopertin, as assessed by the incidence of treatmentemergent adverse events (TEAEs), vital signs, physical examinations, and clinical laboratory parameters.

Secondary endpoints 3

1. 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.
2. 2. Percent change from baseline in whole blood metal-free PPIX concentrations.
3. 3. Plasma bitopertin concentrations.

Investigational products

Investigational medicinal products (IMPs), comparators, placebo, auxiliary

Test 1

Sponsors and contacts

Sponsor organisations, regulatory contacts, third parties

Disc Medicine Inc.

Sponsor organisation

Disc Medicine Inc.

Address

321 Arsenal Street Suite 101

City

Watertown

Postcode

02472-5710

Country

United States

Scientific contact point

Organisation

Disc Medicine Inc.

Contact name

Disc Medicine Clinical Trials

Public contact point

Organisation

Disc Medicine Inc.

Contact name

Disc Medicine Clinical Trials

Third parties 10

Locations

9 EU/EEA countries · 12 investigational sites

By country

Investigational sites

Results and documents

Annex IV summary of results, Annex V layperson summary, and all documents registered in CTIS for this trial

Documents 100 files

Public protocol annexes, IB summaries, regulatory submissions and post-authorisation documents registered in CTIS.

Application history

3 submissions — initial application plus substantial / non-substantial modifications