BridgeBio Pharma (BBIO) dosed its first patient in a phase 3b/4 study evaluating the long-term effects of its drug Acoramidis on disease regression in patients with transthyretin amyloid cardiomyopathy, the company said Wednesday.

The study is expected to enroll about 150 participants, who will undergo annual cardiovascular magnetic resonance and echocardiography assessments, with the primary efficacy endpoint to measure whether patients show improved heart function after 36 months.

The current study follows a phase 3 trial which suggested treatment with acoramidis may improve cardiac structure and function and showed evidence of amyloid regression in a subset of patients, raising the possibility that the disease progression could be reversed, the company said.

The current trial is meant to determine whether long-term treatment can lead to sustained improvement in disease damage, the company said.

Shares of the company were up 0.2% in recent premarket trading.