Activating FGFR3 alterations are implicated in a significant proportion of muscle-invasive bladder cancer and metastatic urothelial carcinoma (mUC), affecting 15-20% of cases, and are even more prevalent in non-muscle invasive bladder cancers (up to 80%). Furthermore, germline mutations in FGFR3 are linked to various skeletal dysplasias, including achondroplasia, the most common form of dwarfism, frequently caused by a G380R mutation in FGFR3. The pan-FGFR inhibitor erdafitinib has been approved for mUC with FGFR3 alterations, but its use is limited by off-target toxicities and the emergence of on-target gatekeeper resistance mutations. To address these limitations, TYRA-300 (22) was developed using a structure-based design approach as a potent and selective FGFR3 inhibitor.
Development of TYRA-300
TYRA-300 is designed to selectively inhibit FGFR3, thereby avoiding the toxicities associated with inhibiting FGFR1, FGFR2, and FGFR4. The design also aims to circumvent FGFR3 gatekeeper mutations, which often lead to resistance to other FGFR inhibitors.
Clinical Development
TYRA-300 is currently being evaluated in a Phase 1 clinical trial involving patients with urothelial cancers and solid tumors. Plans are underway to initiate Phase 2 studies focusing on urothelial cancers and achondroplasia. The trials will assess the safety and efficacy of TYRA-300 in these patient populations. The oral availability of TYRA-300 offers a convenient administration route, potentially improving patient compliance and quality of life.
