FDA Approves Ardelyx Tenapanor (Ibsrela) for IBS-C

September 25, 2019

Impact: High

Ardelyx received FDA approval for tenapanor for the treatment of IBS-C in adults. The approval was based on two phase 3 clinical trials, T3MPO 1 and T3MPO2. The brand name for the drug will be Ibsrela. The label contains a black box warning on the risk of serious dehydration in pediatric patients, which is due to a class effect of NHE3 sodium transport inhibitors.

Ardelyx has decided not to commercialize the drug for IBS-C indication themselves and is awaiting a commercial partner who would also be interested in developing the drug for CIC. The company did not disclose details of ongoing partnership conversations during the call following tenapanor’s approval.

inThought Analysis

The approval of tenapanor, the black box warning for pediatric patients, and Ardelyx’s decision to not commercialize the drug are all in line with expectations. Ardelyx sees a significant market for tenapanor in patients who are not responsive to GC-agonists like Linzess and Trulance. Ardelyx is also developing tenapanor for hyperphosphatemia and intends to commercialize it under a different undisclosed brand name. inThought does not anticipate significant off-label use in IBS-C in case the drug comes into market for hyperphosphatemia first due to differences in dosing, brand names and NDC numbers for the two indications.

Sources: Ardelyx Press Release, Ardelyx Conference Call