Nusinersen has not been extensively studied in adults with SMA. 

Prospective, multicenter, longitudinal observational study of adults with SMA Type II/III initiating nusinersen. We report raw mean ± SD [N] changes from baseline over time and p-values of model-estimated means from an unadjusted repeated measures linear mixed model.

43 patients (20 female; 14 ambulatory; 3, 17, and 23 with 2, 3, and ≥4 SMN2 copies, respectively) with mean (SD) age 37.1 (11.9) years enrolled and completed baseline assessments.  Patients showed sustained improvement from baseline in the Revised Upper Limb Module (RULM) beginning 15 days after treatment initiation (1.4 ± 1.8 [29], p=0.0004) through months 6 and 14 (0.9 ± 2.0 [26]; 1.0 ± 2.4 [23]; p≤0.02) and in the self-assessment SMA-HI total score beginning 60 days after treatment initiation (-5.3 +/- 16.74 [38], p=0.03) through months 6 and 14 (-5.4 ± 17.3 [35]; -7.8 ± 17 [30]; p≤0.01).  Patient function was stable without mean change (p>0.05) from baseline through month 14 in the Revised Hammersmith Scale (RHS) (0.8 ± 4.1 [31]), Six-Minute Walk distance (11.9m± 57.8 [11]), % Predicted Forced Vital Capacity (0.1±8.6 [16]); and Maximum Inspiratory (-0.6 cm H₂0 ± 16.4 [15]) and Expiratory (11.1 cm H₂0 ± 41.2 [15]) Pressure.  At 14 months, more patients gained, as opposed to lost, ≥ 2 points on the RULM (9(39%) vs. 3(13%)/23) and ≥ 3 points on the RHS (8(26%) vs. 4(13%)/31). One serious adverse event (pancreatitis) was possibly related to treatment; all others were unlikely or not related to treatment.