Onconic Therapeutics announced on November 23 that its Chinese partner, Livzon Pharmaceutical Group, has initiated patient dosing in a Phase 3 clinical trial for the gastroesophageal reflux disease (GERD) treatment Zastaprazan (marketed in Korea as Jaqbo). Following this milestone, Onconic has filed a $3 million (approximately KRW 4.39 billion) milestone payment claim with Livzon, a sum exceeding 10% of Onconic’s 2022 revenue of KRW 21 billion. The payment is expected to be received within 30 days.

Zastaprazan, the 37th domestically developed new drug in Korea, belongs to the P-CAB (potassium-competitive acid blocker) class and represents a breakthrough in GERD treatment. Known for its rapid onset and high efficacy, Zastaprazan demonstrated a treatment success rate of 97.9% after eight weeks of administration in clinical trials, outperforming the commonly used PPI (proton pump inhibitor) esomeprazole by 7.44%. Its long half-life provides sustained acid suppression, effectively alleviating nighttime symptoms like heartburn, and its convenience of administration—unaffected by meals—improves patient adherence.

Livzon obtained exclusive rights in March 2022 to develop, manufacture, and commercialize Zastaprazan in the Greater China region (China, Taiwan, Hong Kong, and Macau) through a licensing deal worth $127.5 million, including an upfront payment of $15 million. Livzon has since been conducting clinical trials for various indications.

The current Phase 3 trial, approved by China’s National Medical Products Administration (NMPA) last month, is a multicenter, randomized, double-blind study. It will evaluate the efficacy of Zastaprazan compared to esomeprazole in GERD patients. The first patient was dosed on November 5, signaling the progression of this pivotal trial.

Onconic’s Jaqbo was launched in Korea on October 1, 2024, and has quickly gained traction in the domestic market as an innovative GERD solution. With its rapid onset of action, superior efficacy, and enhanced patient convenience, Jaqbo is poised to set a new standard in GERD treatment.

CEO John Kim of Onconic expressed optimism about the drug’s future, stating, "This milestone not only demonstrates the global potential of Zastaprazan but also reinforces our commitment to delivering innovative therapies to improve patient outcomes worldwide. We will continue to advance our efforts to establish Jaqbo as a leading treatment in the GERD market."

The initiation of this Phase 3 trial and the accompanying milestone payment highlight the growing global recognition of Zastaprazan’s therapeutic value and Onconic's capability in advancing groundbreaking treatments on an international scale.