Disease modifying therapy for adult patients with SMA still raises certain questions regarding its effectiveness, given the long-term chronic process with often significant neurological deficits at the time of initiation of therapy. This paper presents three clinical cases of adult sitter patients with SMA type 2, who began risdiplam therapy 16.5—41 years after the disease onset. All patients have been receiving therapy since 2020, at the time of observation for 2.5—3 years. All patients showed subjective and objective (using specialized scales) improvement during long-term therapy with risdiplam. In addition to an increase in muscle strength, mainly in the proximal and distal parts of the arms, several non-motor effects were also noted (including improved swallowing and breathing), which cannot be recorded using scales. No adverse events were recorded during therapy.