FDA Grants Rare Pediatric Disease Designation to Chinook’s Treatment of Primary Hyperoxaluria

Rare Daily Staff

The U.S. Food and Drug Administration granted Rare Pediatric Disease designation to Chinook Therapeutics’ CHK-336 for the treatment of primary hyperoxaluria, a group of ultra-rare genetic kidney diseases.

Primary hyperoxaluria (PH) is caused by enzyme mutations that result in excess oxalate production in the liver, a potentially toxic metabolite typically filtered by the kidneys and excreted as a waste product in urine. Symptoms of PH include recurrent kidney stones, severe pain, blood in the urine, and urinary tract infections. In its most severe forms, PH can lead to end-stage kidney disease at a young age. When left untreated, PH can result in kidney failure requiring dialysis or dual kidney/liver transplantation.

CHK-336 is a first-in-class, liver-targeted oral small molecule LDHA inhibitor for the treatment of PH. LDHA catalyzes the final step in the production of oxalate from glyoxalate in the liver, therefore LDHA inhibition has the potential to treat all forms of PH as well as other disorders arising from excess oxalate.

CHK-336 also has the potential for robust efficacy by rapidly distributing to the site of oxalate production, while minimizing systemic exposures and potential for off-target activity, to facilitate a favorable tolerability profile required in this chronic disease. In PH1 mouse models, CHK-336 demonstrated significant and dose-dependent reductions in urinary oxalate, with the majority of CHK-336-treated mice reaching the normal range seen in wild-type mice. CHK-336 is currently progressing through IND-enabling studies with phase 1 initiation planned for the second half of 2021.

“Through the development of CHK-336 for all forms of PH, we aim to address the significant unmet need and burden affecting patients and caregivers,” said Alan Glicklich, chief medical officer at Chinook.

The FDA grants rare pediatric disease designation for serious and life-threatening diseases that primarily affect children ages 18 years or younger and fewer than 200,000 people in the United States. The designation makes each CHK-336 eligible for a Rare Pediatric Disease Priority Review voucher upon approval of the therapy by the FDA.

The vouchers can be used to reduce the time of an FDA new drug approval review to six months from ten months. The vouchers are potentially lucrative because they are transferable. Most recently, Rhythm Pharmaceutics sold its priority review voucher for $100 million in January 2021 to Alexion Pharmaceuticals.

Photo: Alan Glicklich, chief medical officer at Chinook