FDA agrees to downsized trial for Calliditas' rare disease drug

The FDA has just made it easier for Sweden’s Calliditas to develop Nefecon for a rare kidney disease, accepting a faster readout that should hasten development of the drug.

The Stockholm-based biotech said it received written feedback following negotiations with the FDA that it should expedite a phase 3 trial in the autoimmune disease IgA Nephropathy (IgAN).

In a letter the FDA said it would accept a two-year readout of kidney filtration rates from the NeflgArd trial, reducing the overall trial duration from up to six years to around 3.5 years.

Study size has also been cut from 460 to 350 patients for both parts of the trial, cutting costs and recruitment time.

Patients assigned to the placebo arm will also be allowed to cross over on to treatment after the two year pivotal study is completed, generating additional data about the drug’s disease-modifying effect.

The NefIgArd trial is studying the effect of Nefecon versus placebo on proteinuria in patients with IgAN at approximately 140 sites in 19 countries.

The first patient dosed was in November of 2018, and results from the top line readout of 200 dosed patients are expected in the second half of 2020 followed by regulatory filings.

NeflgArd is essentially a larger version of the phase 2 NEFIGAN trial of 150 patients, which were published in the Lancet in 2017.

In June, Calliditas licensed Nefecon to Everest Medicines for China for up to $121m, including a $15m upfront payment, royalties and a $20m option to develop Nefecon in other potential indications outside IgA nephropathy.

Calliditas also in-licensed the autoimmune drug Budenofalk from Germany’s Dr. Falk Pharma, for the US market.

This year it also raised 210 million Swedish kroner ($22.5m) from Swedish institutional investors with the aim of expanding ongoing research programmes and accelerating activities to further develop the project portfolio.

The Swedish biotech, formerly known as Pharmalink before a name change in 2017, raised more than $81 million with its IPO on the country’s NASDAQ stock exchange last July.

Nefecon is a formulation of the established immunology drug budesonide that dissolves only when it reaches the ileum – the last part of the intestine.

This stops organs in the ileum wall known as Peyer’s patches from producing faulty IgA antibodies which are thought to cause the disease.

Although classified as an orphan disease, the company estimates that there are about 130,000-150,000 people in the US and about 200,000 people in Europe with the condition.

This comparatively large patient population could translate into sales in excess of $1 billion annually if approved by regulators, according to the company’s estimates, and there are no specially approved competitors.

Renée Aguiar-Lucander, CEO of Calliditas, said: “We are extremely pleased with the outcome of our interactions with the FDA, which will have a very positive impact on the conduct of our pivotal study.

“This is great news for patients as well, as it will enable us to complete the confirmatory part of the trial in a timely manner without potential impact on patient access to the marketed drug. It also has significant benefit with regards to the overall cost and timelines of the programme.”