Rates of infection or serious infection with satralizumab in the overall treatment period were not higher than those on placebo in the double-blind period and did not increase over time.
Data from the double-blind (DB) and open-label extension (OLE) periods of the SAkura Star and Sky studies showed that satralizumab (Enspryng; Genentech), a drug that received FDA approval in 2020, has a favorable safety profile that was sustained with long-term treatment in patients with neuromyelitis optica spectrum disorder (NMOSD).
Lead author Benjamin Greenberg, MD, pediatric neurologist, University of Texas Southwestern Medical Center, presented these findings at the 2021 Annual Meeting of the Consortium of Multiple Sclerosis Centers (CMSC), October 25-28. Investigators comprised data on adverse events (AEs), reported as events per 100 patient years (PY), in individuals from SAkuraSky (NCT02028884) and SAkuraStar (NCT02073279). The satralizumab treatment period (OST), which consisted of those who received at least 1 dose in the DB and/or OLE periods, included 75 patients from SAkuraSky and 91 patients from SAkuraStar.
Median treatment exposure was 205 (range, 4-311) weeks in SAkuraSky and 157 (range, 5-265) weeks in SAkuraStar during the OST period. Across this period, rates of AEs and serious AEs (SAEs) were comparable to that observed in the DB. Rates of AEs were 389.6/100 PY (95% CI, 365.9-414.4) and 403.0/100 PY (95% CI, 379.4-427.6), respectively, in the SAkuraSky and SAkuraStar studies. SAEs were also similar between the groups, with a rate of 11.2/100 PY (95% CI, 7.5-16.1) in SAkuraSky and 12.2/100 PY (95% CI, 8.4-17.1) in SAkuraStar.
Rates of infection with satralizumab in the OST period were not higher than with placebo in the DB period and did not increase over time in either study. Overall, the rates were 130.5 AE/100 PY (95% CI, 8.4-17.1) in SAkuraStar and 89.7 AE/100 PY (95% CI, 78.8-101.7) in SAkuraSky. Similarly, these results remained true for serious infections as well (SAkuraSky: 3.5 SAE/100 PY [95% CI, 1.6-6.6]; SAkuraStar: 3.0 SAE/100 PY [95% CI, 1.3-5.8]).
Overall, no deaths nor anaphylactic reactions to satralizumab were reported in either study. Investigators noted that exposure length to satralizumab in the OST period was not associated with more severe laboratory abnormalities.
In August 2020, data from the SAkura studies helped the drug gain FDA approval to treat patients with NMOSD who are anti-aquaporin-4 (APQ4-IgG) antibody positive.2 It joined Alexion’s eculizumab (Soliris) and Horizon Therapeutics’ inebiluzumab (Uplizna) as the only treatments currently approved for these patients.
The clinical trials combined included more than 170 patients who were randomly assigned to received satralizumab 120 mg or placebo. In SAkuraStar, 30% of patients treated with satralizumab monotherapy experienced relapse compared with 50% of those who received placebo (HR 0.45; 95% CI, 0.23—0.89; P =.018). Among those who were AQP4-IgG antibody positive, a 74% reduction in relapse risk was observed. In the overall satralizumab-treated population, 76.1% and 72.1% were relapse-free at 48 and 96 weeks, respectively, compared with 61.9% and 51.2% with placebo. Data from the AQP4-IgG seropositive subgroup showed that 82.9% and 76.5% were relapse-free at 48 and 96 weeks compared with 55.4% and 41.1% with placebo, respectively.3
In SAkuraSky, the overall population saw a 62% reduction in the risk of relapse (HR 0.38, 95% CI, 0.16-0.88; P =.0184), while the group of AQP4-IgG seropositive patients experienced a 79% reduction in relapse risk (HR 0.21, 95% CI, 0.06-0.75; P =.0086).5 Results showed 88.9% and 77.6% of patients in the total population were relapse-free at 48 and 96 weeks, respectively, compared with 66% and 58.7% of patients in the placebo group. Among AQP4-IgG seropositive patients, 91.5% treated with satralizumab were relapse-free at 48 and 96 weeks compared with 59.9% and 53.3% of patients in the placebo group.
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