Otsuka joins IgAN market with Voyxact approval in US

Otsuka has claimed FDA approval for its IgA nephropathy (IgAN) therapy Voyxact, joining an increasingly crowded market and beating rival Vera Therapeutics to the punch.

Anti-APRIL antibody Voyxact (sibeprenlimab) has been approved by the US regulator to reduce proteinuria in adults with primary IgAN – a life-threatening kidney disease – who are at risk of disease progression. It is administered as a subcutaneous injection once a month and is the first APRIL-targeting drug to be approved in the US.

The FDA's decision comes after a priority review and means that Otsuka will be able to bring Voyxact to market months before its closest rival in the APRL space, Vera Therapeutics, whose dual BAFF/APRIL inhibitor ataticept, given by injection once a week, was submitted for FDA approval earlier this month.

Otsuka has not yet revealed its launch and pricing plans for Voyxact in the US, which is believed to be the first market to grant regulatory approval for the product.

The accelerated approval for Voyxact follows positive results in the phase 3 VISIONARY trial, which showed a 51.2% reduction in proteinuria at nine months with once-monthly, self-administration of the drug.

Proteinuria is a marker for kidney function and is a surrogate marker for drug activity in IgAN, which occurs when antibodies accumulate in the kidneys, causing inflammation and scarring and potentially leading to chronic kidney disease (CKD). Upgrading to full approval will require follow-up data from the study that demonstrated Voyxact can also slow kidney function decline.

Voyxact launches into a market that had no FDA-approved therapies until 2021, when Calliditas Therapeutics got the green light for its steroid-based Tarpeyo (budesonide).

Since then, three more treatments have been launched, namely Travere Therapeutics' endothelin-1/angiotensin-2 inhibitor Filspari (sparsentan), as well as Novartis' Factor B inhibitor Fabhalta (iptacopan) and endothelin A receptor antagonist entrant Vanrafia (atrasentan).

Meanwhile, Novartis has a third candidate – anti-APRIL drug zigakibart – in phase 3 trials, and several other drugs are coming through the late-stage industry pipeline for IgAN. Those include AstraZeneca's already marketed complement C5 inhibitor Ultomiris (ravulizumab), Vertex's BAFF/APIL antagonist povetacicept, Ionis/Roche's antisense-based Factor B inhibitor IONIS-FB-LRx/RG6299, and Biogen's anti-CD38 antibody felzartamab.

Otsuka said there is still a need for new therapies for IgAN because, despite standard care, patients can still go on to develop end-stage kidney disease.

"We're thrilled to hear the news about the accelerated approval of Voyxact," commented Bonnie and Ed Schneider, co-founders of the IgA Nephropathy Foundation in the US.

"It's important for patients who are managing IgAN to have new treatment options."