Risdiplam

Risdiplam (CAS No.: 1825352-65-5) is an orally administered small-molecule drug used to treat spinal muscular atrophy (SMA). Its primary mechanism of action is to increase full-length SMN protein expression by modifying SMN2 gene pre-mRNA splicing, thereby raising functional SMN protein levels in both central and peripheral tissues. Clinical studies show that Risdiplam can improve or stabilize motor function in patients with various types of SMA. In infant-onset SMA patients, results from the FIREFISH trial showed that treated infants achieved motor milestones not observed in the natural course of the disease, and 85% of infants survived without the need for permanent ventilatory support. In later-onset SMA patients, the SUNFISH trial showed a modest but significant improvement in motor function after 12 months of treatment, with the effect sustained for more than 24 months. Risdiplam is generally well tolerated; common adverse reactions include fever, diarrhea, rash, and upper respiratory tract infection, with fewer serious adverse events. Due to its oral administration, it avoids the risks associated with intrathecal injection, but systemic exposure requires ongoing safety monitoring. Nonclinical animal studies indicate that Risdiplam may affect reproductive function; therefore, appropriate counseling is needed for patients with reproductive potential. In cellular and animal models, Risdiplam improves motor neuron function by upregulating SMN protein expression, thereby enhancing motor ability. The doses or concentrations used in experiments typically depend on the experimental design and research objectives. Overall, Risdiplam provides an effective and convenient treatment option for SMA patients.