Vera Therapeutics released a 36-week per-protocol analysis of the Phase IIb trial assessing atacicept in IgA nephropathy.
Marshall Fordyce, CEO, Vera Therapeutics/courtesy of Vera Therapeutics
After the reveal of topline Phase IIb data for atacicept in IgA nephropathy (IgAN) failed to impress investors, Vera Therapeutics released a 36-week analysis Monday touting greater efficacy.
The late-stage biotech is pinning all its current hopes on the disease-modifying dual inhibitor for IgAN patients who, despite current therapies, retain persistently high levels of protein in the urine (proteinuria).
This new analysis highlights atacicept’s potential to substantially reduce proteinuria, regardless of changes to the patient’s background regimen. Vera is “confident of atacicept’s efficacy” in all subgroups, said Marshall Fordyce, CEO, in a conference call Monday morning.
The pre-specified per-protocol analysis at 36 weeks showed a group of patients dosed at 150 mg achieved a 47% mean reduction in proteinuria versus placebo and a 48% delta versus placebo.
The PP analysis included only patients who had completed treatment according to protocol.
A proteinuria reduction of 30% is considered clinically meaningful in IgAN patients, said Jonathan Barratt, Ph.D., professor of renal medicine at the University of Leicester, on the same call.
“The exciting thing for me is that actually, we probably haven’t stopped at 36 weeks. Per trajectory for proteinuria reduction is continuing,” Barratt told BioSpace in a subsequent interview.
“The more proteinuria reduction we see, the greater the amount of kidney function protection.”
A Big Year for the IgAN Market
Following the Jan. 4th topline data readout, investors seemed unconvinced the drug could stand against market competition.
Calliditas Therapeutics’ Tarpeyo is currently the only drug approved for IgAN. Net sales were estimated between $35-40 million for 2022, as Calliditas seeks approval in China. While the disease is considered extremely rare in the U.S. and Europe, it is more common in Asia and the far and Middle East.
During Monday’s call, Fordyce called the 36-week results statistically significant and “close to two-fold better than” Tarpeyo.
Chinook Therapeutics and Ionis, partnered with Roche, are both slated to take IgAN treatment candidates into Phase III this year. Chinook’s mAb reduced proteinuria by up to 66.9% at 52 weeks when given intravenously. Ionis’ candidate cut 34-hour protein levels by an average of 44% over 29 weeks.
Next Steps for Vera
Vera believes its data is “highly differentiating” as a result of atacicept’s mechanism of action, Lauren Frenz, chief business officer, told BioSpace.
Despite the competition, the biotech is putting all its money into advancing atacicept into a pivotal Phase III trial in IgAN, putting a Phase III trial of the drug for lupus nephritis, and its other pipeline program - a monoclonal antibody that neutralizes the BK virus – on hold.
Following Phase III trial design discussions with the FDA, Vera anticipates the Phase III trial will begin in the first half of 2023. Fordyce predicted a primary endpoint readout in the first half of 2025, with the expectation of submitting a BLA later that year.
The company will share full 36-week results in Q2, 2023. Barratt expects to see “even more proteinuria reduction” at this time, which he said will translate to better kidney function and protection.
