KINTOR PHARMA-B (09939) announced that its independently developed novel high-efficiency tyrosinase inhibitor KT-939, which inhibits melanin production, has recently completed enrollment of all 130 subjects in its human long-term safety trial. KT-939 can precisely target tyrosinase, effectively blocking the oxidation process of tyrosine, thereby effectively inhibiting melanin production while also possessing antioxidant and anti-inflammatory properties, demonstrating outstanding advantages in cosmetic efficacy and safety.
According to the "Cosmetics Supervision and Administration Regulation" promulgated in 2021, the approval and registration of new cosmetic ingredients by China's National Medical Products Administration requires completion of more than ten trials including safety and efficacy studies, among which the one-year human long-term safety trial involving 100 subjects is a critical study. Based on the guidance principles for human long-term safety trials released by the National Medical Products Administration on July 3, 2025, the company initiated the human long-term safety trial for KT-939.
This long-term safety trial is an open-label, single-arm, single-center study designed to evaluate the potential for adverse skin reactions from long-term topical use of cosmetics containing KT-939 ingredient, primarily focusing on the safety of continuous 48-week topical application of 0.2% KT-939 on the skin. The trial received approval from the Ethics Committee of Shanghai Skin Disease Hospital in mid-August this year, with Professor Tan Yimei, Director of the Cosmetics Research Center at Shanghai Skin Disease Hospital, serving as the principal investigator.
The primary endpoints of the trial include all adverse events reported by study subjects that may be related to the use of the test substance, as well as all adverse events observed by the research institution occurring on the skin during the use of the test substance. As of the announcement date, KT-939 has completed multiple safety and toxicology evaluation trials as well as a 28-day consecutive topical human efficacy trial. Trial results indicate that KT-939 demonstrates good performance in both efficacy and safety.
Based on previous comparisons of KT-939 with common whitening ingredients such as Thiamidol and phenylethyl resorcinol (377) in terms of efficacy and safety, the company is actively advancing preparation for KT-939's registration application, planning to formally submit the registration application to China's drug regulatory authority in the third quarter of next year.
Thiamidol, a tyrosinase inhibitor with the same mechanism for melanin production, was approved for registration by China's National Medical Products Administration in November 2024, becoming the first and currently only whitening agent cosmetic new ingredient approved for registration since the implementation of the "Cosmetics Supervision and Administration Regulation" in 2021, and the second whitening agent cosmetic ingredient approved for registration domestically after 377, marking a 12-year gap.
KT-939 is expected to become China's first independently developed and approved whitening agent cosmetic new ingredient, achieving a "zero breakthrough" in complete independent intellectual property rights in this field for China, providing new options for the spot-removing and whitening cosmetics market in China and globally.
Furthermore, according to China's cosmetic management regulations, cosmetic products with whitening effects must obtain special cosmetic registration certificates before market launch. At the same time, the state encourages simultaneous registration applications for functional cosmetic products and innovative ingredients. Based on these policy orientations, the company is officially launching nationwide investment promotion business starting today, actively seeking strategic cooperation with whitening cosmetic brand enterprises to jointly advance product development and market positioning.