Lemtrada’s maker, Sanofi-Genzyme, said the study covered the two-year CARE-MS II Phase 3 clinical trial (NCT00548405) and a long-term extension (NCT00930553) trial of people with relapsing-remitting MS.
In addition to demonstrating Lemtrada’s effectiveness, the study showed that it was safe, researchers said.
Their article, “Alemtuzumab CARE-MS II 5-year follow-up, Efficacy and safety findings,” was published in the journal Neurology.
The Phase 3 trial participants had had an active disease, with at least two relapses in the two years before the study and an inadequate response to earlier treatment. The trial compared Lemtrada’s effectiveness with that of Rebif (interferon beta-1a).
The Lemtrada group received 12-mg doses for five consecutive days at the start of the study and three consecutive days a year later.
Ninety-three percent of the 435 patients who completed the trial enrolled in the extension, which followed patients for another three years.
Remarkably, 60 percent of patients required no additional treatment after the two years of the Phase 3 study.
Among the 376 patients who required more treatment, 30 percent had one additional Lemtrada course, 10.4 percent had two, and 1.6 percent had three. A small proportion of patients also received other disease-modifying treatments.
The most common reason for additional treatment was relapse. Nevertheless, Lemtrada reduced annualized relapse rates to only 0.18 of patients by the fifth year. In addition, during the five years, 75 percent of patients experienced no worsening of their disability over six-month cycles. And 49 percent of patients’ disability improved.
Researchers also tracked patients’ scores on the NEDA — or No Evidence of Disease Activity — index. The composite measure takes into account relapses, disease activity detected in MRI scans, and disability progression. In year five, 58 percent of patients achieved NEDA, slightly more than the 53 percent in year three.
Another important finding was that patients’ loss of brain tissue slowed in the first two years, and dropped further during the extension.
Researchers also noted that adverse events dropped during the extension trial. Ninety-six percent were mild or moderate, and no patient left the study because of side effects.
The rate of infusion-associated reactions was lower in the extension study than in the Phase 3 study. Patients who did have a reaction most often experienced headache, fever, or rash.
Infections did not become more common with accumulating Lemtrada doses and, again, were less common in the extension trial. Patients most often developed colds or urinary tract infections.
Autoimmune reactions against the thyroid gland were relatively common, however. Thirty-eight percent of patients developed them over the five years. Most were moderate in severity.
Four patients developed various types of cancers.
Researchers also examined Lemtrada in the CARE-MS I clinical trial and its extension trial. They reported long-term outcomes and safety findings similar to those in the latest study.
Overall, the newest results demonstrated that Lemtrada slowed disease progression over five years in relapsing-remitting MS patients who failed to respond to previous therapy.