China’s Hybio Pharmaceutical announced that the U.S. Food and Drug Administration has accepted its abbreviated new drug applications (ANDAs) for generic versions of Eli Lilly’s popular weight-loss medication, tirzepatide injection. This marks the company’s first public disclosure of such a filing, despite the original drug’s primary U.S. patent remaining valid until 2036. Following the news, Hybio’s stock experienced a significant increase.
Shares in Hybio closed at CNY23.93 (approximately USD3.30), reflecting an 8.4% gain, after reaching a peak intraday increase of 9.1%. Meanwhile, the broader Shenzhen ChiNext Index declined by 1.9%.
The applications submitted include Paragraph IV patent certifications that challenge Eli Lilly’s patents — a move that is likely to lead to patent litigation. If Hybio successfully wins in court, it could potentially launch its generic version before the patents expire, earning a 180-day period of exclusive rights to sell the generic in the U.S.
The company revealed that it had submitted two ANDAs for tirzepatide injection and received formal acceptance notices from the FDA. Hybio also stated that it has developed proprietary synthesis technology along with large-scale manufacturing capabilities for the drug’s active pharmaceutical ingredient (API). Notably, it is the first supplier to have its tirzepatide API Drug Master File (DMF) pass the FDA’s completeness review.
Tirzepatide, a once-weekly injectable medication, acts as a dual agonist targeting both the glucagon-like peptide-1 receptor (GLP-1R) and the glucose-dependent insulinotropic polypeptide receptor (GIPR), developed by Eli Lilly. It is marketed under the names Mounjaro for adults with Type 2 diabetes and Zepbound for long-term weight management in overweight or obese adults. To date, no generic versions have been introduced globally.
The main U.S. patent for the drug’s core compound is set to expire on January 5, 2036, with various secondary patents extending further, with the latest extending to 2041 according to public patent records.
The surge in weight-loss treatment popularity has made tirzepatide one of Eli Lilly’s top revenue generators. The company’s 2025 annual report indicated global sales of the drug reached USD36.51 billion last year, with nearly USD23 billion generated from Mounjaro and around USD13.54 billion from Zepbound. U.S. sales accounted for approximately USD32 billion, nearly 88% of the total.
Industry analysts expect that Hybio’s Paragraph IV filing will likely trigger patent infringement litigation from Eli Lilly. Under U.S. law, the first company to successfully challenge a patent via Paragraph IV can receive 180 days of market exclusivity for its generic version, during which the FDA generally cannot approve rival generics except for any authorized generics the original manufacturer may market.