The Phase II clinical trial of KF-0210, an EP4 antagonist independently developed by Keythera Pharmaceuticals, for the treatment of knee osteoarthritis has officially commenced. On October 12, 2025, the first participant has successfully received the initial dose.

KF-0210 is a highly selective EP4 receptor antagonist that exerts anti-inflammatory and analgesic effects by targeting and blocking the PGE₂-EP4 signaling pathway, without inhibiting the synthesis of PGE₂ and PGI₂. It is expected to significantly reduce the risk of gastrointestinal and cardiovascular adverse effects associated with traditional nonsteroidal anti-inflammatory drugs (NSAIDs), particularly COX-2 selective inhibitors. Preclinical studies have demonstrated that KF-0210 not only exhibits excellent anti-inflammatory and analgesic efficacy but also shows potential in promoting articular cartilage repair, indicating characteristics of a disease-modifying osteoarthritis drug (DMOAD). Phase I clinical studies have also revealed favorable safety and tolerability profiles.

Currently, no EP4 antagonists have been approved globally for the treatment of osteoarthritis. Keythera Pharmaceuticals possesses the global development and commercialization rights for KF-0210 and is committed to advancing its international clinical development and collaboration landscape.

Osteoarthritis is the most common degenerative joint disease, characterized primarily by the damage, fibrosis, rupture of articular cartilage, and and degradation of joint function, with progressive involvement of the synovium, ligaments, and bone tissue.Clinical symptoms include joint pain, stiffness, swelling, and restricted movement, making it one of the leading causes of disability in middle-aged and elderly individuals.

According to data from the Global Burden of Disease (GBD) study published in The Lancet in 2023, the number of people globally affected by osteoarthritis reached approximately 595 million by 2020, accounting for about 7.6% of the global population. In China, the total number of individuals with osteoarthritis was around 153 million in 2021, with over 11.6 million new cases reported annually, showing a consistent upward trend.

According to the Chinese Guidelines for the Diagnosis and Treatment of Osteoarthritis (2024 Edition), the treatment strategies for OA include basic treatment, pharmacotherapy, reparative surgery, and reconstructive surgery. Pharmacotherapy serves as the core approach for pain control, with oral NSAIDs (including non-selective and COX2 selective inhibitors) recommended for patients with moderate-to-severe or persistent pain. However, attention must be paid to their gastrointestinal and cardiovascular safety. It is noteworthy that while existing medications can alleviate symptoms, they generally lack efficacy in promoting cartilage repair.