FibroGen’s pamrevlumab disappointing results marks second failure in a row

FibroGen’s lead candidate pamrevlumab failed to meet its primary and secondary endpoints in the Phase III trial in ambulatory Duchenne muscular dystrophy (DMD) patients aged 6 to 12 years.

This news is in line with the previous trial failure of pamrevlumab, where the drug failed to meet its primary endpoint in the Phase III trial (NCT04371666) with patients with DMD aged 12 years or older.

Although the company put on a brave face, stating it is looking to evaluate the totality of the data from the trial before determining any steps for the programme, its share price saw a drop in value. FibroGen shares were down over 22% in pre-market trading on 30 August, compared to market close on the previous day.

Moreover, in May, FribroGen received $150m in non-dilutive funding from Morgan Stanley Tactical Value for pamrevlumab commercialisation.

Pamrevlumab is a monoclonal antibody that inhibits the activity of connective tissue growth factor (CTGF), which is involved in multiple tumour development and tissue fibrosis pathologies. The drug was granted paediatric disease designation for DMD treatment by the US Food and Drug Administration (FDA), along with an orphan drug designation and a fast-track designation.

DMD is a rare genetic neuromuscular disease that primarily affects males. The Muscular Dystrophy Association approximates the prevalence of DMD in Europe and North America at six per 100,000 individuals.

The primary endpoint for the randomised, placebo-controlled Phase III trial (NCT04632940) was the change in the functional motor abilities of the ambulant children with DMD from baseline, which was measured using the North Star Ambulatory Assessment (NSAA).

The secondary endpoints of the trial included various tests to measure motor functions such as four-stair climb velocity, 10m walk/run test, time to stand, and time to loss of ambulation.

The trial assessed 73 male patients who were given either pamrevlumab or placebo in combination with the standard corticosteroid therapy.

The adverse effects of the drug were mild to moderate in severity, with 8.3% of patients reporting these events in the treatment arm compared to 2.8% in the placebo arm.

Pamrevlumab is also being evaluated in a Phase III trial (NCT03941093) for locally advanced unresectable pancreatic cancer and a Phase III trial (NCT04229004) for metastatic pancreatic cancer.