How long does it take for Serputinib/Serpatinib (Ruitu) to take effect?

Selpercatinib is a highly selective RET inhibitor, mainly used for non-small cell lung cancer (NSCLC), thyroid cancer and other tumor types carrying RET fusion or RET mutation. Due to its clear target and clear mechanism of action, many patients will pay attention to a core question before starting treatment: how long will it take to take Septinib to take effect. Judging from overseas clinical practice experience, seputinib is generally considered a targeted drug with a relatively fast onset of action, but the definition of "effectiveness" needs to be understood from multiple dimensions.

Different from traditional chemotherapy, Seputinib does not rapidly kill tumor cells through cytotoxicity, but by continuously inhibiting the RET signaling pathway, gradually blocking the growth and spread of tumor cells. Some patients may experience improvement at the symptom level at an early stage after taking the drug, such as relief of dyspnea, pain relief, or improvement in physical status, which often indicates that the biological activity of the tumor is being suppressed. However, at the imaging level, it usually still takes a period of continuous and standardized treatment to more clearly judge the changing trend of tumor load.

Easy evaluation of the efficacy of seputinib should be avoided. Even if no significant reduction is seen in the short-term review, as long as the lesions are stable and no new progression appears, the treatment can still be considered to be working. For targeting RET-driven tumors, sustained suppression often has more long-term significance than short-term drastic changes.

In addition, individual differences among patients will also affect the onset of effect. For example, patients with larger tumor burdens and more previous treatments may take longer to observe clear changes; while tumor types that are more dependent on RET tend to have more obvious responses. Overall, the "effectiveness" of seputinib is more reflected in the gradual establishment of disease control rather than instantaneous changes, which is also one of the important characteristics of targeted therapy.

Reference:https://en.wikipedia.org/wiki/Selpercatinib