BridgeBio Builds ATTR

Jul 18, 2023

Published: Aug 28, 2023 By Tristan Manalac

Pictured: Ultrasound machine used to obtain images of the heart/iStock, sudok1

Detailed results from the Phase III ATTRibute-CM study showed that BridgeBio Pharma’s acoramidis met its primary endpoint, inducing significant improvements in patients with transthyretin amyloid cardiomyopathy (ATTR-CM), the company announced Sunday.

ATTRibute-CM is a randomized and double-blinded study with over 630 patients enrolled. Its primary endpoint is a combination of all-cause mortality, frequency of cardiovascular-related hospitalizations and changes from baseline in NT-proBNP levels and six-minute walk distance (6MWD) performance.

Acoramidis achieved a “highly statistically significant result” compared with placebo, BridgeBio wrote in its announcement, touting a Win Ratio of 1.8 with a p-value less than 0.0001. This effect was consistent across NYHA functional classes and between wild-type and variant transthyretin amyloid cardiomyopathy (ATTR-CM) patient subgroups.

BridgeBio presented the findings at the 2023 Congress of the European Society of Cardiology, held in Amsterdam over the weekend.

The data “further substantiate our hypothesis that highly potent TTR stabilization has the potential to deliver differential benefits to patients,” Jonathan Fox, president and CMO of BridgeBio Cardiorenal, said in a statement.

The company will present the data to health authorities in its bid to secure regulatory approvals for acroamidis, Fox said. BridgeBio aims to submit a New Drug Application to the FDA before the year ends and make other regulatory filings next year.

Monday’s data drop follows topline results unveiled in July 2023, demonstrating that at the 30-month follow-up, 81% of treated ATTR-CM patients were still alive, as opposed to only 74% of placebo comparators. This 25% relative risk reduction in mortality was accompanied by a 50% decrease in the relative risk of cardiovascular-related hospitalizations.

Thirty-month data published Monday also demonstrated that acoramidis outperformed placebo in terms of serum and functional biomarkers. A higher proportion of treated patients saw improvements in both NT-proBNP levels and 6MWD performance than in the placebo group.

“45% of completers displayed improvement from baseline in NT-proBNP, and 40% walked farther in six minutes at study end compared to baseline,” Fox said in a statement with Monday’s data release. These are “remarkable observations” especially given the progressive nature of ATTR-CM.

Acoramidis is an orally available small molecule drug that mimics a naturally occurring variant of the TTR protein, thereby stabilizing it. This protein is mutated in patients with ATTR-CM, causing them to form amyloid clumps that accumulate in and ultimately damage various organs in the body including the heart.

Acoramidis’ mechanism of action allows it to minimize this buildup in patients carrying the disease-causing TTR mutations.

If approved, acoramidis will compete with Pfizer’s Vyndamax (tafamidis) and Vyndaqel (tafamidis meglumine), currently the only authorized treatments for ATTR-CM.

Tristan Manalac is an independent science writer based in Metro Manila, Philippines. He can be reached at [email protected] or [email protected].

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