Japanese pharmaceutical company Kowa has received Breakthrough Therapy designation from the US Food and Drug Administration (FDA) for K-808 (pemafibrate), an investigational treatment for patients with primary biliary cholangitis (PBC).
The FDA’s Breakthrough Therapy designation is intended to accelerate the development and review of drugs for serious diseases when preliminary clinical evidence indicates the potential for substantial improvement over existing therapies in one or more clinically meaningful endpoints.
Primary biliary cholangitis is a rare, chronic and progressive autoimmune liver disease characterised by inflammation and destruction of the intrahepatic bile ducts. Disease progression can lead to fibrosis, cirrhosis and liver failure. Patients may also experience symptoms including fatigue and pruritus (itching), which can be extremely severe in some patients. The condition predominantly affects women.
According to Kowa, the designation was supported by preliminary findings from the ongoing Phase II K-808-2.01 clinical trial, which demonstrated a reduction in alkaline phosphatase (ALP) levels — a key marker used to assess disease activity in PBC.
Preliminary data from the study were presented at the European Association for the Study of the Liver (EASL) Congress in May 2026.
Kowa said it is advancing global development of K-808 with the goal of securing regulatory approval in markets including the United States and Japan. The company is evaluating the therapy both in combination with ursodeoxycholic acid (UDCA) for adult patients who do not respond adequately to standard treatment and as monotherapy in patients unable to tolerate UDCA.
Pemafibrate is a selective peroxisome proliferator-activated receptor alpha (PPARα) modulator developed by Kowa to improve lipid metabolism by regulating genes involved in lipid and glucose metabolism in the liver. In Japan, the company launched Parmodia Tablets in June 2018 for the treatment of hyperlipidaemia.
For PBC, Kowa is developing pemafibrate aimed at delaying disease progression. The drug is expected to work through multiple mechanisms, such as micellization of hydrophobic bile acids, anti-inflammatory effects resulting from the activation of the nuclear receptor PPARα, and inhibition of bile acid synthesis.
