Ribitol (BBP-418)
An investigational treatment for Limb-Girdle Muscular Dystrophy.
The same compound appears under different names depending on the context. Here is how to identify Ribitol (BBP-418) wherever you encounter it, plus the key facts at a glance.
- Generic name
- Ribitol (BBP-418)
- Development codes
- BBP-418, MLB-01
- Drug class
- Glycosylation substrate therapy
- Manufacturer
- BridgeBio Pharma (ML Bio Solutions)
- How it's taken
- In the trial, granules from a packet were mixed with water and taken by mouth twice a day: 9 g twice a day for people over 30 kg up to 50 kg, and 12 g twice a day above 50 kg.
An investigational twice-daily oral powder of ribitol, a natural sugar alcohol, for limb-girdle muscular dystrophy type 2I/R9 (LGMD2I/R9), under FDA priority review with a decision due November 27, 2026. If approved, BridgeBio says it would be the first treatment for LGMD2I/R9 and possibly the first for any form of LGMD.
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How Ribitol (BBP-418) works
In LGMD2I/R9, changes in both copies of the FKRP gene leave the FKRP enzyme only partly working, so alpha-dystroglycan, the protein that anchors muscle cells during contraction, gets a thin sugar coat and muscle cells are damaged with use. Ribitol is converted in the body to CDP-ribitol, the building block FKRP attaches. BBP-418 is designed to flood the partly working enzyme with that building block, so more of the coat gets finished.
Mechanism: Oral glycosylation substrate: ribitol, which the body turns into CDP-ribitol, the building block the FKRP enzyme uses to finish the sugar coat on alpha-dystroglycan
Side effects and safety
In the Phase 3 FORTIFY trial's 12-month analysis, side effects were about as common as on placebo. The most common on BBP-418 were diarrhea (39.2% vs 52.6% on placebo, all mild to moderate), pain after a study procedure (20.3% vs 10.5%), falls (18.9% vs 26.3%), common cold symptoms (17.6% vs 21.1%), nausea (16.2% vs 7.9%) and joint pain (14.9% vs 10.5%). Serious side effects occurred in 5.4% vs 7.9% on placebo, none judged related to the drug, and no one died (BridgeBio, March 2026).
This is not a complete list of side effects. Talk to your doctor or pharmacist about what to expect and when to seek medical attention.
Taking Ribitol (BBP-418)
In the trial, granules from a packet were mixed with water and taken by mouth twice a day: 9 g twice a day for people over 30 kg up to 50 kg, and 12 g twice a day above 50 kg. It can be taken with or without food. The approved dose, if it is approved, will be set by the FDA label.
Clinical trial results
FORTIFY (NCT05775848) is a 3-year Phase 3 trial of 112 people aged 12 to 60 with LGMD2I/R9, randomized 2 to 1 to BBP-418 or placebo at 21 sites, 13 in the US. At its 12-month interim analysis, glycosylated alpha-dystroglycan rose about 1.8 times by month 3, creatine kinase fell 82%, walking speed on a 100-meter timed test rose 0.14 m/s against a 0.12 m/s decline on placebo, and lung function (FVC) rose about 3 points of predicted against about 5 points better than placebo.
In an exploratory heart analysis, every evaluable person on BBP-418 whose high-sensitivity troponin I was raised at the start was back in the normal range at month 12, against 40% on placebo. These results are company-reported and not yet published in a journal.
Main registered trial: NCT05775848 on ClinicalTrials.gov. Check it for the current status, sites and contacts before asking about enrollment.
Development history
Developed by ML Bio Solutions, a BridgeBio company. An open-label Phase 2 study in 14 people at Virginia Commonwealth University (NCT04800874) showed creatine kinase falling more than 75%. BridgeBio submitted its application to the FDA on March 30, 2026 for traditional approval, and announced on May 27, 2026 that the FDA had accepted it with priority review and a target date of November 27, 2026, with no advisory committee planned.
BBP-418 holds Orphan Drug, Fast Track and Rare Pediatric Disease designations in the US. BridgeBio plans studies in children under 12 in the first half of 2027.
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Common questions about Ribitol (BBP-418)
▸What is Ribitol (BBP-418)?
An investigational twice-daily oral powder of ribitol, a natural sugar alcohol, for limb-girdle muscular dystrophy type 2I/R9 (LGMD2I/R9), under FDA priority review with a decision due November 27, 2026. If approved, BridgeBio says it would be the first treatment for LGMD2I/R9 and possibly the first for any form of LGMD.
▸How does Ribitol (BBP-418) work?
In LGMD2I/R9, changes in both copies of the FKRP gene leave the FKRP enzyme only partly working, so alpha-dystroglycan, the protein that anchors muscle cells during contraction, gets a thin sugar coat and muscle cells are damaged with use. Ribitol is converted in the body to CDP-ribitol, the building block FKRP attaches. BBP-418 is designed to flood the partly working enzyme with that building block, so more of the coat gets finished.
▸What are the side effects of Ribitol (BBP-418)?
In the Phase 3 FORTIFY trial's 12-month analysis, side effects were about as common as on placebo. The most common on BBP-418 were diarrhea (39.2% vs 52.6% on placebo, all mild to moderate), pain after a study procedure (20.3% vs 10.5%), falls (18.9% vs 26.3%), common cold symptoms (17.6% vs 21.1%), nausea (16.2% vs 7.9%) and joint pain (14.9% vs 10.5%). Serious side effects occurred in 5.4% vs 7.9% on placebo, none judged related to the drug, and no one died (BridgeBio, March 2026).
▸How is Ribitol (BBP-418) taken?
In the trial, granules from a packet were mixed with water and taken by mouth twice a day: 9 g twice a day for people over 30 kg up to 50 kg, and 12 g twice a day above 50 kg. It can be taken with or without food. The approved dose, if it is approved, will be set by the FDA label.
▸Is Ribitol (BBP-418) FDA approved?
Not yet. Ribitol (BBP-418) is under FDA review for Limb-Girdle Muscular Dystrophy; BridgeBio Pharma has filed an application and a decision is due November 27, 2026. The FDA calendar page tracks the outcome.
▸When will the FDA decide on BBP-418?
The FDA's target date is November 27, 2026, under priority review. BridgeBio said the FDA was not planning an advisory committee meeting.
▸Who was BBP-418 tested in?
FORTIFY enrolled people 12 to 60 years old (18 to 60 in Europe) who weighed more than 30 kg and had a genetically confirmed LGMD2I/R9 diagnosis with 2 FKRP changes. Studies in children under 12 are planned for the first half of 2027.
▸Is BBP-418 the same as a ribitol supplement?
BBP-418 is ribitol made and tested as a drug, at 9 or 12 grams twice a day by weight, with medical monitoring in its trials. The trial results apply only to BBP-418 as studied. Talk to a neuromuscular specialist before taking any supplement.
▸Does BBP-418 help the heart?
An exploratory analysis presented on October 5, 2026 found that among FORTIFY participants with a raised troponin, a blood sign of heart injury, every evaluable person on BBP-418 was back in the normal range at 12 months, against 40% on placebo, and heart pumping was stable or better in 54% against 25%. BridgeBio notes the groups were small.
Sources and references
Every factual claim on this page is drawn from the public sources listed below. Click any reference to open the original document.
- BridgeBio Pharma via BioSpace · 2026-05-27. BridgeBio Announces FDA Acceptance and Priority Review of NDA for BBP-418 for LGMD2I/R9. https://www.biospace.com/press-releases/bridgebio-announces-fda-acceptance-and-priority-review-of-nda-for-bbp-418-for-lgmd2i-r9
- BridgeBio Pharma · 2025-10-27. BridgeBio Reports Positive Phase 3 Results for Small Molecule BBP-418 in LGMD2I/R9 FORTIFY Study. https://s205.q4cdn.com/224494602/files/doc_news/BridgeBio-Reports-Positive-Phase-3-Results-for-Small-Molecule-BBP-418-in-LGMD2IR9-FORTIFY-Study-2025.pdf
- BridgeBio Pharma · 2026-03-11. BBP-418 Demonstrates Consistent Efficacy and Favorable Safety Profile in Phase 3 FORTIFY Interim Analysis in LGMD2I/R9. https://s205.q4cdn.com/224494602/files/doc_news/BBP-418-Demonstrates-Consistent-Efficacy-and-Favorable-Safety-Profile-in-Phase-3-FORTIFY-Interim-Analysis-in-LGMD2IR9-2026.pdf
- BridgeBio Pharma · 2026-10-05. BBP-418 Demonstrates Potential to Be Disease Modifying Therapy, Restoring Cardiac and Disease Markers to Unaffected Levels. https://s205.q4cdn.com/224494602/files/doc_news/BBP-418-Demonstrates-Potential-to-Be-Disease-Modifying-Therapy-Restoring-Cardiac-and-Disease-Markers-to-Unaffected-Levels-2026.pdf
- ClinicalTrials.gov. FORTIFY: BBP-418 in LGMD2I/R9 (Phase 3). https://clinicaltrials.gov/study/NCT05775848
- Clinical Pharmacology in Drug Development · 2026-08. Safety, Tolerability, Pharmacokinetics, Food Effect of Ribitol, and Its Effect on QTcF in Healthy Adults. https://doi.org/10.1002/cpdd.70082