Ardelyx has taken the unusual step of buying back rights to a drug candidate from its big pharma development partner – AstraZeneca (AZ) – on the grounds that it needs to speed up development.
The two companies have been working together on the NHE3 inhibitor tenapanor and other drugs in the same class since 2012, when AZ licensed the portfolio in a deal valued at up to $273m.
Now, Ardelyx is paying $25m back to AZ in order to reclaim rights to the programme and “accelerate the clinical development path” for drug. It says a phase III trial in constipation-predominant irritable bowel syndrome (IBS-C) is due to start before the end of the year with a second, phase IIb dose-ranging trial in elevated blood phosphate levels (hyperphosphataemia) also planned.
Tenapanor is a minimally absorbed small molecule inhibitor of NHE3, a transporter of sodium in the gastrointestinal tract. Orally administered tenapanor has been shown in clinical trials to reduce the intestinal absorption of both dietary sodium and phosphorus.
AZ’s willingness to give up rights could stem from the revelation last month that a phase IIa trial of tenapanor in diabetic patients with stage 3 chronic kidney disease and albuminuria (protein in the urine) failed to meet its objectives.
Ardelyx’ chief executive Mike Raab discussed the possibility of AZ terminating its involvement after revealing that data but – facing a downgrade in priority at its big pharma partner – has clearly decided to take the initiative.
A phase IIb clinical trial in IBS-C reported last October was more encouraging, showing that q twice-daily dose of the drug help restore normal bowel movements and reduced abdominal pain.
“By regaining the worldwide rights to tenapanor, we now have a late-stage clinical asset that has demonstrated significant promise for the treatment of IBS-C and hyperphosphataemia, both of which are conditions where we believe tenapanor could potentially transform the treatment paradigm,” he said.
Ardelyx still has a $200m partnership in place with Sanofi for NaP2b inhibitors used in the treatment of hyperphosphataemia in end-stage renal disease patients.
Separately, Ardelyx said it would pursue approval of new candidate RDX022, a non-absorbed polystyrene sulfonate polymer designed to reduce elevate blood levels of sodium (hyperkalaemia) that should start clinical trials later in 2015.