The US FDA has approved Ironwood Pharma’s combination gout therapy Duzallo, but with a warning that it can cause serious kidney failure.
Ironwood bought rights to Duzallo (allopurinol and lesinurad) and single-agent Zurampic (lesinurad) from AstraZeneca last year in a $265m deal, including $100m upfront, which came amid a massive slimming down exercise at AZ as it focused on core therapy areas.
The approval for the once-daily combination gives Ironwood another product in a franchise that according to some analysts could make sales of $300m or more a year in the US alone – perhaps modest for AZ but significant for Ironwood which made $274m in total revenues last year.
Gout is a painful form of inflammatory arthritis caused by elevated levels of uric acid (UA) in the blood, and the FDA has approved Duzallo for “hyperuricemia associated with gout in patients who have not achieved target [UA] levels with a medically appropriate daily dose of allopurinol alone”.
The fixed-dose combination “provides a dual mechanism of action in a single tablet that can address both underlying causes of hyperuricemia – over-production and under-excretion of serum uric acid”, according to Ironwood, which has said it intends to launch the drug onto the market in the fourth quarter of this year.
The approval of Duzallo was based on the results of two phase III trials, CLEAR 1 and CLEAR 2, which supported the approval of Zurampic, plus a third trial which showed that the combination was as effective as giving lesinurad and allopurinol separately.
In adult patients with gout who failed to achieve target serum UA levels on allopurinol alone, lesinurad in combination with allopurinol nearly doubled the number of patients who achieved targets after six months.
The new product has however been approved with a black box warning – the highest level that can be added to a drug’s label – that lesinurad can cause acute renal failure.
That’s also on the label of Zurampic, which has so far failed to grow as quickly as hoped with sales of $0.5m in the second quarter of the year and Barclays analysts predicting it will make only around $10m for the full year, rising to $75m in 2018.