After successful completion of phase III clinical trials, participants can often enter what is known as extension studies. These studies allow additional data to be gathered over a longer period of time, helping to determine how long the treatment effects last and as well as building a more in-depth safety profile.

Recently, two scientific publications have reported the interim results from two extension studies looking at the efficacy and safety of Alemtuzumab – available here and here.
Alemtuzumab, commonly known as Lemtrada, is an antibody which recognises a protein called CD52 found on the surface of certain immune cells in the body. Alemtuzumab treatment removes these cells, which are thought to include those that cause the relapses of MS. Alemtuzumab is given as an intravenous infusion for five days, then again for three days 12 months later.

These two latest publications are based on extension studies which follow on from the CARE-MS I and CARE-MS II clinical trials, which both lasted two years.

The CARE-MS I trial compared Alemtuzumab to interferon in 563 people with relapsing-remitting MS who have not previously received treatment. Of those, 386 received Alemtuzumab and they had fewer relapses which had a slight, but not significant, decrease in accumulation of disabilities compared to those on interferon.

The CARE-MS II trial looked at 628 people with relapsing-remitting MS, who had previously been treated with interferon or glatiramer acetate. Of the 628, 436 patients received Alemtuzumab, and they also had fewer relapses and a decreased accumulation of disabilities compared to those on interferon.

The vast majority (94%) of patients enrolled in these clinical trials entered into the three-year extension studies. Most of these patients did not need an additional round of treatment, but of those that required additional treatments around 1.5% of patients required retreating each year for five years, and 2.3% in CARE-MS 1 extension study and 7.6% in CARE-MS 2 extension study ended up receiving some other disease-modifying therapy.

Both extension studies showed ongoing protective effects of Alemtuzumab. The annualised relapse rate remained similar to the original studies, with 79%-89% of patients being relapse free each year for the five years. In both studies, over half the participants had a stable or reduced disability over the five years. Additionally, the results have showed that 53-68% of people had NEDA (no evidence of disease activity), with around 70% of patients showing no new MRI lesion each year over the length of the studies. These results suggest that Alemtuzumab can decrease relapse rates, stop worsening of disabilities and reduce the formation new lesions. It also slowed brain volume loss, which is common as we get older but is accelerated in people with MS.

Like any medication, there are potential side effects. Common side effects include infusion-associated reactions, such as headaches, fever, nausea, and the appearance of a rash. There is also a chance of other additional autoimmune conditions arising and an elevated risk of infection. These are serious side effects, but with proper monitoring, they appear to be mainly treatable. Most of these side efforts seem to decline over the five-year timeframe.

The longer period of these studies have shown that there is a sustained response to this medication even up to 5 years in the absence of continuous treatment. They also show that Alemtuzumab is a high efficacy therapy, impacting on relapses, disability progression and brain volume loss.

Everybody’s MS is different, therefore it is important that any treatment decisions should be made carefully in consultation with your neurologist, taking into consideration the potential benefits and the possible side effects.

With thanks to MS Research Australia – the lead provider of research summaries on our website.