"Alemtuzumab's putative mode of action is via depleting your immune system and allowing it to recover spontaneously. Alemtuzumab kills or bursts open white blood cells, or leukocytes, by binding to a specific protein CD52 on the surface of the cell. When alemtuzumab binds to the cells it attracts a large number of other proteins, called complement, to the surface of the cells and these proteins pierce a hole in the cell causing it to burst. Complement is the family of proteins the immune system uses to kill damaged or cancerous cells and invading organisms. When the white cells burst they release their contents into the bloodstream; some of these substances are proteins that mediate the effects of inflammation on the body, which is why alemtuzumab causes an infusion reaction with a raised temperature, chills, rigors and a skin rash in most treated patients. To dampen down the infusion reactions we pretreat patients who are about to receive alemtuzumab with steroids, paracetamol and anti-histamines."
"Alemtuzumab is given as short courses on a yearly basis; daily for 5 days in the first year and then daily for 3 days in the second and subsequent years. Subsequent courses are only given if your MS has been shown to reactivate, i.e. you have relapses or develop new or enhancing lesions on MRI. The majority of MSers (two-thirds) only require 2 courses to go into long-term remission. A minority of MSers will require 3, 4 or very rarely 5 courses of alemtuzumab. Please note that reactivation of your MS after alemtuzumab does not mean that you have failed to respond to alemtuzumab it simply means you need another course, this is different to maintenance therapies (give continuously) were disease reactivation is an indication of non or suboptimal response."
"After each course the white cells recover by dividing or proliferating. When the immune system recovers there have been questions about whether or not it is competent to fight infections, cancers and whether or not it can remember the vaccines you have had in the past. A small study has shown that when the immune system recovers post-alemtuzumab it is competent and does remember the vaccinations you have had in the past. Another observation that tells us the immune system post-alemtuzumab is competent, or nearly competent, is the lack of so called opportunistic infections in alemtuzumab-treated MSers."
"There is one major caveat; when the white blood cell counts post-alemtuzumab are very low, or have not yet fully recovered MSers are at risk of herpes virus reactivation. Unfortunately, the lady below had herpes zoster. Once infected with herpes viruses they persist in the body in a dormant state and can reactivate when the immune system is stressed or compromised. To prevent this from occurring we prescribe prophylactic anti-viral drugs for about 6 weeks to prevent herpes virus reactivation. Despite doing this there is an approximately 1 in 50 chance of developing shingles after alemtuzumab treatment. In the clinical trials the majority of shingles cases were mild or moderate. It is also reassuring to know that shingles can be treated with anti-viral drugs."
"Whether or not MSers treated with alemtuzumab are at increased risk of developing secondary cancers is at present unknown. There have been too few MSers treated with alemtuzumab, and the ones who have been treated have been followed for too short a time, to answer this question. Therefore the increased cancer risk is a theoretical risk at present. In my opinion the cancer risk is low as we have not seen many of the so called indicator cancers, i.e. those cancers associated with drugs that target the immune system, in any of the MSers treated with alemtuzumab in the phase 3 trials. But on balance it is too early to make any judgement on this."
"The one risk from being treated with alemtuzumab is the development of secondary antibody-mediated autoimmune diseases that occur months to years after the last course of alemtuzumab. Autoimmune thyroid disease is the commonest disease and occurs in ~30% of treated MSers. The second most common is immune mediated thrombocytopenia, or ITP, that occurs in 2-3% of treated subjects. In ITP the immune system destroys the platelets or cells that help stop bleeding. A much more rare disease is so called Goodpasture's disease when the immune system makes antibodies that can damage the kidney. This last two diseases can be serious, but if detected early and treated most people make a good recovery. These autoimmune complications of alemtuzumab are why MSers who have been treated with the drug need to be monitored with monthly blood and urine tests for at least 4 years after the last course of treatment. Therefore if you are eligible for alemtuzumab and you want to be treated with this drug you are going to have to be adherent to the monitoring programme. If not and MSers die, or have near-death experiences, from these treatable complications the regulatory authorities may restrict alemtuzumab's use in the future. This would be unfair on those MSers who may wish to be treated with the drug in the future."
"The real advantage of alemtuzumab is the fact that it is an induction therapy; i.e. you get treated with the drug and you don't have to have it continuously. This has advantages for MSers who can't tolerate daily injection or oral therapies. Another advantage is the long-term remission that the majority of MSers go into after a two courses. Woman wanting to fall pregnant and start a family will find this attribute of the drug very appealing. What has been played down is that a large number of MSers who have disabilities find that they improve spontaneously after alemtuzumab. I don't think this is because alemtuzumab is a neurorestorative drug, but it simply reflects that when you suppress and stop inflammation in the brain and spinal cord you allow spontaneous recovery to occur. This is why I don't believe we need drugs to promote remyelination in MS; remyelination will occur spontaneously if we suppress inflammation with sufficiently effective therapies early in the disease course; a similar observation occurs with natalizumab or Tysabri. An important point regarding the spontaneous improvement post-alemtuzumab is the observation that it is more likely to occur early in the course of the disease, before the demyelinated axons die and there is sufficient reserve capacity to allow recovery. You can't remyelinate an axon that is not there; and this is why alemtuzumab has not be as effective in MSers in with secondary progressive MS."