A new analysis of the Phase 3 MycarinG study indicates that rozanolixizumab (Rystiggo; UCB Pharma) is effective and well-tolerated in older patients (≥65 years) with generalized myasthenia gravis (gMG). The findings, presented at the 2024 American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM) meeting, highlight the potential of rozanolixizumab in treating an often underrepresented population in gMG clinical trials.
The MycarinG study randomized 200 gMG patients to either placebo or rozanolixizumab (7mg/kg or 10mg/kg) administered weekly for six weeks. The primary endpoint was the change from baseline to day 43 in Myasthenia Activities of Daily Living (MG-ADL) scores. This post-hoc analysis further examined baseline characteristics and treatment-emergent adverse events (TEAEs) by age group.
Efficacy in Older Patients
The analysis revealed that rozanolixizumab demonstrated notable efficacy in older patients. Specifically, the mean change from baseline to day 43 in MG-ADL scores was -2.1 (SD, 4.0) for rozanolixizumab-treated patients aged at least 65 years, compared to 0.7 (SD, 2.8) for those on placebo. In younger patients (<65 years), the mean change was -3.7 (SD, 3.2) for rozanolixizumab and -1.1 (SD, 2.7) for placebo.
Safety and Tolerability
Regarding safety, TEAEs occurred in 72.7% of rozanolixizumab-treated older patients and 87.5% of placebo-treated older patients. In younger patients, TEAEs were reported in 85.0% and 60.8% of rozanolixizumab and placebo groups, respectively. The most common TEAE was headache, which was more prevalent in the younger subgroup (rozanolixizumab, n = 49; placebo, n = 11) compared to the older subgroup (rozanolixizumab, n = 6; placebo, n = 2).
Baseline Characteristics and Concomitant Medications
Baseline characteristics were generally similar between the age subgroups. A high percentage of patients (98.0% of those <65 years and 100% of those ≥65 years) used concomitant medications. Comorbidities, such as cardiac and vascular disorders, were more common in the older subgroup.
Broader Efficacy Across Subgroups
Previous subgroup analyses from the MycarinG study, presented at the 2023 American Academy of Neurology (AAN) Annual Meeting, indicated that rozanolixizumab is effective across a broad range of gMG patients, irrespective of prior therapy use and disease duration. These analyses considered the number of prior MG therapies, baseline disease severity, and disease duration.
Patients with at least one prior MG therapy showed least square mean (LSM) changes in MG-ADL of -3.2 and -3.3 in the rozanolixizumab 7 mg/kg and 10 mg/kg groups, respectively, compared to -1.0 in the placebo group. Similarly, those with at least two prior MG therapies had mean changes from baseline in MG-ADL of -2.5 and -3.0 in the rozanolixizumab groups, compared to -0.8 in the placebo group.
In patients with disease duration less than 4 years, LSM changes in MG-ADL at day 43 were -2.9 and -3.1 in the rozanolixizumab groups, compared to -0.6 in the placebo group. For those with longer disease duration, changes were -3.8 and -3.3 in the rozanolixizumab groups, compared to -0.7 in the placebo group.
These findings collectively support the use of rozanolixizumab as an effective treatment option for a diverse range of patients with gMG, including older adults and those with varying disease characteristics.
