Dr Goyal on the Unique Mechanism and Selectivity of Lirafugratinib in FGFR2-Altered CCA

"When you have these irreversible inhibitors, they also are potentially able to have more durable and sustained inhibition through the receptor and that can help overcome resistance mutations."

Lipika Goyal, MD, an associate professor in the University Medical Line in the Division of Oncology of the Department of Medicine at Stanford University, as well as a member of the Stanford Cancer Institute, discussed why the mechanism of action of lirafugratinib (RLY-4008) is unique compared with that of other FGFR inhibitors in FGFR2-altered cholangiocarcinoma (CCA).

Goyal explained that lirafugratinib is distinct from existing FGFR inhibitors for 2 primary reasons: its exceptional selectivity and its irreversible binding. Although FDA-approved agents such as pemigatinib (Pemazyre), futibatinib (Lygtobi), or erdafitinib (Balversa), target multiple members of the FGFR family, lirafugratinib specifically targets FGFR2. This precision leads to higher potency at the intended receptor while significantly reducing adverse effects associated with inhibiting other family members, such as the hyperphosphatemia caused by FGFR1 inhibition.

The second defining characteristic is that lirafugratinib is an irreversible inhibitor that forms a covalent bond with the kinase, Goyal continued. Unlike reversible inhibitors such as pemigatinib, which bind and unbind dynamically, the inhibition provided by lirafugratinib persists even after circulating drug levels decrease, she explained. Goyal noted that this sustained activity is crucial for overcoming resistance mutations in the kinase domain that typically develop following treatment with earlier-generation inhibitors. Ultimately, the potent inhibition and covalent binding of lirafugratinib offer the potential for more durable responses and a delay in the emergence of resistance for patients with FGFR2-driven malignancies, Goyal concluded.

Of note, a new drug application for lirafugratinib as a second-line treatment option for patients with pretreated CCA harboring FGFR2 fusions or rearrangements was accepted by the FDA in January 2026 based on data from the phase 1/2 ReFocus trial (NCT04526106). The regulatory agency has assigned a Prescription Drug User Fee Act target action date of December 3, 2026.