BridgeBio Reports Positive Phase 3 Topline Results for Encaleret in Patients with Autosomal Dominant Hypocalcemia Type 1 (Form 8-K)

BridgeBio Reports Positive Phase 3 Topline Results for Encaleret in Patients with Autosomal Dominant Hypocalcemia Type 1

- The CALIBRATE study of encaleret for patients with ADH1 met all pre-specified primary and key secondary efficacy endpoints

- The primary endpoint was met with 76% of participants administered encaleret achieving both serum and urine calcium within the respective target ranges at Week 24 compared to 4% when on conventional therapy at Week 4 (p<0.0001)

- In a key secondary analysis, 91% of participants administered encaleret achieved intact PTH above the lower limit of the reference range at Week 24 compared to 7% of participants when on conventional therapy at Week 4 (p<0.0001)

- Encaleret was well-tolerated with no discontinuations related to study drug

- NDA submission planned in the first half of 2026 to support full approval

- BridgeBio plans to initiate registrational studies of encaleret in chronic hypoparathyroidism and pediatric ADH1 in 2026

PALO ALTO, CA - October 29, 2025 - BridgeBio Pharma, Inc. (Nasdaq: BBIO) ("BridgeBio" or the "Company"), a new type of biopharmaceutical company focused on genetic diseases, today announced positive topline results from CALIBRATE, its global Phase 3 study of encaleret in autosomal dominant hypocalcemia type 1 (ADH1). BridgeBio will host an investor call on October 29, 2025 at 8:00 am ET to discuss these results.

CALIBRATE was designed to study the efficacy and safety of encaleret, an investigational, orally-administered, negative allosteric modulator of the calcium-sensing receptor (CaSR). The primary endpoint, defined as the proportion of participants randomized to receive encaleret achieving both serum calcium (8.3-10.7 mg/dL) and urine calcium (<300 mg/day for males and <250 mg/day for females) in the respective target ranges, was achieved by 76% of encaleret-treated participants (34 of 45) compared to 4% for these same participants (2 of 45) while on conventional therapy (p-value <0.0001).

"The remarkable results of the landmark CALIBRATE study represent an important step forward for patients living with ADH1," said Michael Mannstadt, M.D., Chief of the Endocrine Unit at the Massachusetts General Hospital. "Unlike conventional therapy with calcium supplements and active vitamin D, encaleret not only increased and maintained both blood calcium and endogenous parathyroid hormone (PTH) but also decreased and maintained urine calcium in the normal range. 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."

"ADH1 is one of the most common genetic causes of hypoparathyroidism, representing a unique form of the condition and a distinct community within HPA that we serve. People living with ADH1 often face daily challenges managing low blood calcium and high urinary calcium, which can lead to seizures, tetany, heart rhythm disturbances, brain calcifications, kidney stones, and kidney damage or failure. BridgeBio's CALIBRATE Phase 3 results are promising and offer potential for a targeted therapy for people living with ADH1, including those yet to be diagnosed," said Patty Keating, Executive Director of the HypoPARAthyroidism Association (HPA).

The CALIBRATE study enrolled 70 adults with ADH1 and randomized 67 participants in a 2:1 ratio (encaleret: standard of care). The pre-specified key secondary analyses comparing encaleret to standard of care included a between group comparison on the proportion of participants achieving both target albumin-corrected serum and urine calcium (p<0.0001), and comparisons of intact PTH above the lower limit of the reference range (p<0.0001). Additional results from the clinical trial include:

65 of 67 randomized participants (97%) elected to continue in the ongoing long-term extension of the study.

"Our deepest gratitude goes out to the patients, their caregivers, investigators, and study staff who have made this groundbreaking CALIBRATE study possible and continue to contribute to this pivotal research in ADH1," said Scott H. Adler, M.D., Chief Medical Officer of Calcilytix, a BridgeBio affiliate that is focused on developing encaleret. "We are extremely encouraged by the robust and positive findings of this registrational study, which underscore the potential for encaleret to meaningfully improve the lives of people living with ADH1. We look forward to working closely with health authorities to bring encaleret to patients as quickly as possible."

The Company intends to submit its New Drug Application (NDA) to the FDA in the first half of 2026, and a Marketing Authorization Application to the EMA to follow. In addition, BridgeBio plans to initiate a registrational trial of encaleret in pediatric ADH1 in Q1 2026 and a Phase 3 study of encaleret in adults with chronic hypoparathyroidism in 2026.

¹Requirement for conventional therapy defined as oral calcium >600 mg/day and/or active vitamin D during Period 3.

Webcast Information

BridgeBio will host an investor call and simultaneous webcast to discuss the results from the Phase 3 CALIBRATE study of encaleret in patients with ADH1 on October 29, 2025, at 8:00 am ET. A link to the webcast may be accessed from the event calendar page of BridgeBio's website at https://investor.bridgebio.com/. A replay of the conference call and webcast will be archived on the Company's website and will be available for at least 30 days following the event.

About Encaleret

Encaleret is an investigational, orally administered small molecule under investigation to treat ADH1, that is designed to selectively negatively modulate the calcium sensing receptor, targeting ADH1 at its source. Encaleret has received Fast Track Designation by the U.S. FDA and Orphan Drug Designation in the U.S., European Union, and Japan.

About BridgeBio Pharma, Inc.

BridgeBio Pharma, Inc. (BridgeBio) is a new type of biopharmaceutical company founded to discover, create, test, and deliver transformative medicines to treat patients who suffer from genetic diseases. BridgeBio's pipeline of development programs ranges from early science to advanced clinical trials. BridgeBio was founded in 2015 and its team of experienced drug discoverers, developers and innovators are committed to applying advances in genetic medicine to help patients as quickly as possible. For more information visit bridgebio.com and follow us on LinkedIn, X, Facebook, Instagram, and YouTube.

BridgeBio Pharma, Inc. Forward-Looking Statements