BridgeBio Pharma is having a banner week, with the Bay Area company’s encaleret acing a phase 3 trial just days after another late-stage rare disease win as its eyes an FDA review in 2026.
In the global phase 3 Calibrate trial, 34 out of 45 patients with autosomal dominant hypocalcemia type 1 (ADH1), a rare genetic disease that causes calcium deficiency, who were given encaleret achieved healthy blood and urine calcium levels, BridgeBio reported in an Oct. 29 release.
That result trounced the two out of 45 of those same patients who hit the calcium targets on standard-of-care treatment. Encaleret, an oral small molecule, hit all of its primary and key secondary endpoints, BridgeBio added, was well tolerated and caused no discontinuations in the trial.
The result comes two days after BridgeBio announced that its limb-girdle muscular dystrophy candidate BBP-418 had also hit all of its primary and secondary endpoints in an interim phase 3 analysis.
The pharma plans to file FDA approval applications for both encaleret and BBP-418 in the first half of 2026, along with launching registrational studies of encaleret in chronic hypoparathyroidism and pediatric ADH1 next year. Submission of encaleret to the European Medicines Agency will follow the FDA filing, according to the release.
In a note to clients early Wednesday, analysts with Evercore ISI said they’ve “long emphasized [BridgeBio’s] unique setup,” but this week’s series of positive readouts still came as a surprise to them. The analysts described the encaleret phase 3 result as a “clear win” that further solidifies the company’s “path to becoming a multi-product company.”
The 76% responder rate seen in the study was higher than the drug’s phase 2 result of 69%, according to the analysts, who also flagged “rapid” responses and a lack of side effects leading to discontinuations. The team at Evercore ISI is now modeling $1 billion in peak sales for the drug in the indication.
In ADH1, a genetic mutation causes disrupted calcium sensing, which makes calcium and parathyroid hormone levels in the blood too low while calcium levels in the urine are too high.
Low blood calcium levels can lead to muscle spasms and cramping, according to MedlinePlus, while too much of the mineral in urine can cause kidney stones and kidney damage.
“Unlike conventional therapy with calcium supplements and active vitamin D, encaleret not only increased and maintained both blood calcium and endogenous parathyroid hormone but also decreased and maintained urine calcium in the normal range,” Michael Mannstadt, M.D., chief of the endocrine unit at Massachusetts General Hospital, said in the release. “The consistent and clinically meaningful improvements in calcium and mineral homeostasis indicate its potential to become an important new standard of care for this patient community.”
Encaleret previously scored a phase 2 win at a precarious time for BridgeBio; the pharma’s star cardiovascular asset, acoramidis, flopped a phase 3 trial at the end of 2021, leading to rounds of layoffs and a tumbling share price. Acoramidis bounced back in later analyses, ultimately snagging FDA approval for rare heart disease transthyretin amyloid cardiomyopathy in November 2024.
BridgeBio will also be busy next year launching a registrational trial for encaleret in chronic hypoparathyroidism, after the candidate restored healthy calcium levels in patients with post-surgical hypoparathyroidism in a small phase 2 study led by the National Institutes of Health's National Institute of Dental and Craniofacial Research.
In addition to the looming FDA submissions of encaleret and BBP-418, BridgeBio’s dwarfism candidate infigratinib is set to wrap up its own phase 3 trial in achondroplasia by the end of the year. Since pivoting from cancer to dwarfism, infigratinib has topped BioMarin’s approved therapy Voxzogo in a phase 2 achondroplasia trial.