BridgeBio’s Attruby preserves kidney function in patients with transthyretin amyloidosis cardiomyopathy, an effect that is “distinct” from other drugs in this space, according to Jefferies.
BridgeBio’s protein stabilizing therapy Attruby appears to protect kidney function in patients with transthyretin amyloidosis cardiomyopathy—a key clinical benefit that analysts say could help the drug stand out in a crowded market for this indication.
The findings come from a posthoc analysis released Thursday that drew data from a Phase 2 study of Attruby, as well as the Phase 3 ATTRibute-CM trial, results from which led to the drug’s approval in November 2024.
The posthoc evaluation found that patients on Attruby saw an initial but reversible decrease in estimated glomerular filtration rate (eGFR), a common measure used to quantify kidney function, with decreasing values suggesting worse filtering. At 30 months of follow-up, however, the slope of eGFR changes showed sustained and significant placebo-adjusted improvements, according to BridgeBio, suggesting “direct kidney-protective effects” in patients.
“The acute dip in eGFR following initiation of [Attruby] may represent a beneficial kidney effect,” the biotech said on Thursday. Alongside these eGFR changes, BridgeBio documented significant and sustained reductions in urinary albumin-to-creatinine ratio, an indicator of kidney damage, though 30 months.
Jefferies was positive on the news, telling investors in a Thursday note that the posthoc assessments “point to cardiorenal protective benefits” for Attruby. “The degree of kidney function protection”—as measured by the positive changes in eGFR slope—“looks competitive to kidney-targeted therapies,” the analysts added. “Ultimately, slowing down kidney progression could improve hospitalization/mortality outcomes.”
More broadly, the posthoc analysis “adds differentiation” to Attruby in transthyretin amyloidosis cardiomyopathy (ATTR-CM), Jefferies said, noting that the “cardiorenal protective effects seem distinct from other therapies” in this space. In particular, the firm pointed to Pfizer’s Vyndaqel/Vyndamax, which was approved in 2019 and last year grew 16% to $6.4 billion in worldwide sales.
Also looking to compete in ATTR-CM are AstraZeneca and Ionis, which are testing their antisense oligonucleotide Wainua, currently approved to treat polyneuropathy caused by hereditary transthyretin-mediated amyloidosis (hATTR-PN), for a possible expansion into ATTR-CM. The partners are expected to release Phase 3 data for the asset in late August, Jefferies said Thursday.
For BridgeBio, the posthoc data come after a late-stage win in achondroplasia last week. The company’s oral drug infigratinib not only boosted growth in children but also significantly improved body proportionality. As in the case of Attruby, analysts see this achondroplasia outcome as a key differentiator for BridgeBio in the space.
“Other players do not seem to hit stat-sig” in body proportionality, Jefferies told investors in a June 28 note. “We think proportionality drives meaningful outcomes in daily activities and mobility,” the analysts wrote. “We are optimistic proportionality will be included in the label.”
