Conference Coverage
In clinical trials, fingolimod and dimethyl fumarate reduced patients’ annualized relapse rate by more than 50%, compared with placebo. The 14-mg dose of teriflunomide reduced relapses by 32%. The oral medications had a robust effect on MRI activity. They also reduced 12-week disability progression, compared with placebo (32% reduction with fingolimod, 30% with teriflunomide, and 38% with dimethyl fumarate).
Natalizumab, an IV therapy that targets VLA-4 antigen on immune cells, reduced patients’ annualized relapse rate by 68% and had a robust effect on MRI activity, compared with placebo, in a phase III trial. Treatment reduced 12-week disability progression by 42%. Alemtuzumab, another IV treatment, depletes mature B and T cells, and infusions are needed only once per year. Initial treatment is 12 mg/day for five consecutive days. The following year, patients receive the same dosing for three days. Afterwards, many clinicians monitor patients and do not treat patients further unless they observe relapses or MRI activity, Dr. Newsome said. In two phase III trials, treatment with alemtuzumab reduced relapses by about 50% and had a robust effect on MRI activity, compared with treatment with interferon beta-1a given three times per week. In addition, alemtuzumab significantly reduced disability progression in one of the phase III trials, Dr. Newsome said.
Daclizumab is a fully humanized monoclonal antibody that targets CD25 on T cells. The FDA approved the therapy, an injection administered by the patient monthly, on May 27. In a phase III trial, daclizumab reduced patients’ annualized relapse rate by 45%, compared with interferon beta-1a given once per week. It also reduced disability progression at six months by 27% and had a robust effect on MRI activity (65% reduction in new gadolinium-enhancing lesions), compared with interferon beta-1a.
The Importance of Laboratory Monitoring
“The higher the potency and efficacy of the drugs, the greater the risk” of adverse events, Dr. Newsome said. Laboratory monitoring is critical. “With all of the therapies that we have available today, with the exception maybe of glatiramer acetate, you need to check labs routinely,” he said. Complete blood counts with differential to monitor patients’ absolute lymphocyte counts and liver function tests “are the bare minimum” needed to monitor patients on most of these drugs, he said.
Certain therapies require additional safety monitoring. For example, patients treated with alemtuzumab require monthly blood work and urine tests. Patients must undergo cardiac monitoring when initiating treatment with fingolimod. With natalizumab, the serum JCV antibody test reliably stratifies patients’ risk of PML over time. Individual MS drugs are associated with a range of minor and major adverse events. Certain therapies may unmask or reactivate infections, cause secondary autoimmunity, or increase the risk of rare opportunistic infections.
The Future
Ocrelizumab, a fully humanized monoclonal antibody that targets CD20+ B cells, is a potential future therapy that is delivered as an infusion every six months. In two relapsing-remitting MS phase III trials, ocrelizumab reduced patients’ annualized relapse rate by close to 50%, compared with interferon beta-1a given three times per week. It also reduced disability progression by around 40% and had a robust effect on MRI activity (> 90% reduction in new gadolinium-enhancing lesions), compared with interferon beta-1a. Ocrelizumab was also found to reduce disability progression at three and six months (24% and 25%, respectively) and reduce worsening in walking speed in patients by 29% in primary progressive MS, compared with placebo.
Investigators also are evaluating strategies for remyelination. Despite the increasing number of available agents, more therapies are needed. “We need more medications and more interventions that impact neurodegeneration and have the potential to repair damage,” Dr. Newsome said.
—Jake Remaly