Daewoong Pharmaceutical has dropped its first Korean-made P-CAB in India, teaming up with Sun Pharmaceutical to launch Fexuclue  (fexuprazan) and take a swing at the world’s fourth-largest anti-ulcer drug market.

The move puts Fexuclue, a potassium-competitive acid blocker, head-to-head with entrenched proton pump inhibitors (PPIs) in a 1.4 billion won ($955 million) GERD segment that trails only China, the U.S., and Japan, per IMS data from 2023. 

The move marks the first time a Korean-developed drug in this class has landed in India. The launch follows a speedy regulatory sprint that began with a tech transfer deal in December 2023 and wrapped with full market clearance from Indian regulators.

Under the agreement, Sun Pharma picked up manufacturing and commercial rights in India. Daewoong is set to receive upfront and milestone payments plus royalties, according to Sun Pharma’s Monday release.

While the companies didn’t disclose pricing, Sun Pharma’s India chief Kirti Ganorkar framed the product as filling a clinical gap: Despite available treatments, there remains a significant unmet need in erosive esophagitis management, he said. "Fexuclue is a best-in-class option with the potential to bridge this gap,” he added..

Fexuclue first launched in Korea in 2022, billed as a next-gen GERD drug with faster onset, longer duration, and no need for food-timing—areas where traditional PPIs like esomeprazole fall short. Sun Pharma cited studies showing that erosive esophagitis affects about 9 percent of GERD patients in India and remains difficult to fully manage in a significant subset.

That pitch held up in a local phase 3 trial, where Fexuclue went head-to-head with esomeprazole. After eight weeks, 95.05 percent of patients on Fexuclue showed mucosal healing versus 92.93 percent in the PPI group. The difference—2.12 percent (95% CI: -4.47%, 8.71%)—cleared the bar for non-inferiority and mirrored Korean data.

Fexuclue also posted stronger night-time symptom relief, with up to 13.8 percentage points more symptom-free nights compared to esomeprazole. On the CGI-I clinical improvement scale, 96.2 percent of Fexuclue patients were rated “very much” or “much improved,” beating out esomeprazole’s 87.8 percent.

The drug has already broken the 100 billion won annual sales mark in Korea by its third year on the market. With the India rollout, it’s now available in six countries: Korea, Mexico, Chile, Ecuador, the Philippines, and India. Daewoong says filings are in place for 19 more, and deals signed in five additional countries, targeting entry into 30 total.

The company is gunning for 100-country reach by 2027 and a 1 trillion won revenue target by 2030.