Jacuvo upends P-CAB rankings, overtaking Fexuclue for No. 2 as Kecab holds firm

South Korea's next-generation acid suppressant market — dominated by domestically developed drugs known as P-CABs, or potassium-competitive acid blockers — is being rapidly reshuffled.

HK Inno.N's Kecab holds an overwhelming lead as the market's dominant player, but a late entrant backed by Dong-A ST and Jeil Pharmaceutical, Jacuvo, has climbed to second place by monthly prescription value, intensifying a three-way battle with Daewoong Pharmaceutical's Fexuclue. All three products are widely cited as benchmarks of the maturing independent research and development capabilities of South Korean pharmaceutical companies.

The structural shift away from conventional proton pump inhibitors, or PPIs, toward P-CABs is rooted in clear pharmacological advantages.

PPIs can take several days to reach peak effect and must be taken before meals, while P-CABs deliver rapid acid suppression from the first day of use and can be taken at any time regardless of meals. Their longer half-life also gives them a distinct edge in suppressing nighttime acid secretion — a major source of patient discomfort — improving quality of life for those with gastroesophageal reflux disease and driving a broad shift in prescribing patterns.

The most striking development in this competitive landscape is the rapid rise of Jacuvo. The drug recorded 7.55 billion won (approximately $4.88 million) in outpatient prescriptions in May, claiming second place in the P-CAB market.

Jacuvo received Ministry of Food and Drug Safety approval in April 2024 — becoming South Korea's 37th domestically approved new drug — and launched commercially on Oct. 1 of that year. It took just 19 months to overtake Fexuclue for second place. The drug finished 2025 in third place with 44.3 billion won in annual outpatient prescriptions, but has since staged a complete monthly ranking reversal this year.

The key driver behind Jacuvo's ascent is the synergy of a dual sales network between two established pharmaceutical companies. The drug, developed by biotech venture Onconic Therapeutics, has been jointly marketed by Jeil Pharmaceutical and Dong-A ST under a co-promotion agreement signed in September 2024. Dong-A ST's nationwide hospital and clinic sales network, combined with Jeil Pharmaceutical's long-cultivated marketing expertise in gastroenterology, has rapidly expanded the drug's reach among physicians.

Jacuvo is also moving quickly to broaden its approved indications. After securing approval for gastric ulcer treatment in June 2025, the drug is now running Phase 3 trials for four additional indications: prevention of NSAIDs-induced peptic ulcers, treatment of non-erosive gastroesophageal reflux disease, maintenance therapy following treatment of erosive gastroesophageal reflux disease, and combination antibiotic therapy for Helicobacter pylori eradication. Sequential approval of these indications is expected to narrow the gap with market leaders at an accelerating pace.

Kecab, the market pioneer and undisputed leader, continues to raise the bar on the strength of its first-mover advantage. The drug posted 217.9 billion won in annual prescriptions in 2025, commanding more than 50 percent of the P-CAB market.

Kecab also leads on approved indications, holding five compared with four for Fexuclue and two for Jacuvo. It has also accumulated 159 clinical studies — the largest body of evidence among domestic P-CAB drugs — reinforcing prescribing inertia among physicians.

Daewoong Pharmaceutical is pushing back with differentiated clinical data for Fexuclue. The Ministry of Food and Drug Safety granted final approval on May 4 for Fexuclue 40 mg's indication for combination antibiotic therapy for H. pylori eradication. That brings Fexuclue's total approved indications to four, alongside treatment of erosive gastroesophageal reflux disease, improvement of gastric mucosal lesions in acute and chronic gastritis, and prevention of NSAIDs-induced peptic ulcers.

The approval drew particular attention for its quantitative data in patients with antibiotic-resistant strains — a growing concern in clinical practice. In a trial involving clarithromycin-resistant patients, Fexuclue-based eradication therapy achieved an eradication rate of 54.76 percent, demonstrating statistically significant superiority over lansoprazole-based therapy at 28.57 percent — a margin of roughly 26 percentage points. Daewoong is positioning Fexuclue as a definitive treatment option for the gastroenterology community grappling with antibiotic resistance, with the aim of recapturing market share.

The three-way domestic rivalry is now extending beyond South Korea to the world's most competitive markets. Leading the global push is Kecab. Braintree Laboratories, HK Inno.N's US partner, filed a new drug application with the US Food and Drug Administration for tegoprazan — Kecab's active ingredient — on Jan. 9 local time. The primary target is simultaneous approval for three indications in the US market, including treatment of non-erosive gastroesophageal reflux disease.

HK Inno.N presented full Phase 3 trial data from a 24-week maintenance therapy study following erosive esophagitis healing at the 2026 Digestive Disease Week conference. The company highlighted the results as the first global demonstration of long-term clinical superiority over PPIs among P-CAB therapies, drawing attention from international buyers. Kecab has already concluded major export agreements with 55 countries. Should the FDA grant approval and a commercial launch in the second half of the year become a reality, the drug is widely expected to emerge as a global blockbuster leading the K-biotech wave.