Autoimmune side effects during five years of Lemtrada (alemtuzumab) treatment were generally not serious and mainly affected the thyroid, according to an analysis of patients in three large, Phase 3 clinical trials of the therapy.
The data were presented at the Free Communications 1 session of the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) 2016 Congress held in London from Sept. 14 to 17.
The study, “Autoimmunity in patients treated With Alemtuzumab for relapsing-remitting multiple sclerosis: 5-Year follow-up of the CARE-MS studies,” was presented by Colin Dayan, a professor from the Cardiff University School of Medicine in the U.K.
The CARE-MS I (NCT00530348) and CARE-MS II (NCT00548405) trials compared Lemtrada to Rebif (interferon beta-1a) therapy in patients who either had not been treated with MS drugs before, or who had a poor response to previous treatment.
In a five-year extension study (NCT00930553), researchers followed patients in either treatment arm of the initial studies, and who received Lemtrada in cases of disease relapse.
Although treatment with Lemtrada most often gave rise to side effects in the form of reactions to the infusion, autoimmune side effects were also noted, and researchers decided to take a closer look at these particular side effects.
During the three trials, researchers routinely monitored autoimmune side effects, and every three months patients had thyroid function tests. Each month, researchers also took a complete blood count, with a closer look at platelet levels and symptoms that could indicate a loss of platelets.
Kidney function was monitored with monthly analyses of serum creatinine and a urine sample analysis.
Analyzing data from all three trials, involving 811 Lemtrada-treated patients from the first studies and 692 from the extension trial, showed that most autoimmune side effects were mild or moderate. Severe autoimmune side effects were noted 67 times. Importantly, no patients left the trials due to side effects.
Most commonly reported side effects involved the thyroid gland, and they peaked after three years of treatment, then declined during the fourth and fifth years of Lemtrada therapy. Serious adverse effects to the thyroid were rare.
In addition, depletion of platelets occurred 22 times, and two patients developed kidney disease.
“Autoimmune AEs [adverse events] over 5 years were generally mild or moderate in intensity in alemtuzumab-treated patients from the CARE-MS trials. No patients withdrew from the extension studies due to autoimmune AEs. Consistent with previous reports, most autoimmune AEs were thyroid-related events,” the team concluded.