KAR101 (Ramatroban), an orally bioavailable small molecule is a dual, reversible and potent antagonist of two G protein coupled receptors (i) Prostaglandin D2 (PGD2) receptor subtype DP2 (D prostanoid receptor 2; previously known as CRTH2) and (ii) thromboxane A2 (TxA2) receptors. Ramatroban (Baynas®, Bayer, Japan; dose: 50 mg and 75 mg tablets oral BID), also available as a generic from Kotobuki Pharma, Japan, has been safely and effectively used for the treatment of allergic rhinitis in Japan for the past 20 years. Given the scientific mechanisms and great potential that Ramatroban holds, KARE Biosciences aims to repurpose this drug for a variety of indications including COVID-19, sickle cell disease, Alzheimer's disease and silicosis.
Ramatroban (KAR101) is currently being tested in a randomized placebo-controlled trial of hospitalized COVID-19 patients in India (RAMBAN-1).