American Academy of Neurology 61st annual meeting
Open Door - August 2009 pages 4-5
The American Academy of Neurology (AAN) meeting, held this year in Seattle in May, is a showcase for the latest developments in scientific research. There were more than 380 presentations concerned with multiple sclerosis alone, covering all areas of research, from basic laboratory studies aimed at understanding the mechanisms of MS, through to announcements of clinical trial results for experimental treatments and new data for existing therapies.
Some of the highlights included:
- New oral treatments for relapsing remitting MS
- Fingolimod (FTY720)
- Other new, experimental treatments
- Alemtuzumab (Campath)
- New data for existing treatments
- Natalizumab (Tysabri)
- Interferon beta 1a (Avonex)
- Combination therapy
New oral treatments for relapsing remitting MS
The race is on to be the first tablet treatment for relapsing remitting MS, so clinical trial data for two experimental, oral treatments, cladribine and fingolimod, were eagerly anticipated. Both are currently in phase III trials and manufacturers plan to submit these drugs for licensing in 2009. In the UK, NICE (the National Institute for Health and Clinical Excellence) has already announced that it will be including fingolimod and cladribine in its next round of appraisals.
- In an extension of a phase II study, people continued to take fingolimod, including those previously on placebo. Relapse rates remained low with up to 70% remaining relapse-free after four years.
- TRANSFORMS is a one year phase III study involving 1,292 participants comparing two doses of fingolimod with interferon beta 1a (Avonex). 80 to 83% of the fingolimod groups remained relapse-free compared with 69% of those on interferon beta 1a. These data support results previously announced in a company press release in December 2008 showing that the relapse rate at one year was 52% lower in people taking fingolimod compared to those taking interferon beta 1a.
Cladribine is currently licensed in an injectable form to treat types of leukaemia. The manufacturers have developed a tablet formulation for the treatment of MS.
Results were presented for the two year phase III study, CLARITY, which involved more than 1,300 people with relapsing remitting MS. In this study, two different dosing routines were compared to placebo: cladribine was taken once daily for five consecutive days, either twice a year for the two years (low dose) or four times in the first year and twice in the second year (high dose).
Those in the low dose group experienced a 58% reduction in annual relapse rate compared to placebo, while those in the high dose group experienced a 55% reduction. Other clinical measures showed similar results.
Although these drugs are showing promising results, there are safety issues associated with both treatments which will need further clarification.
Other new, experimental treatments
Alemtuzumab is currently licensed to treat a type of leukaemia. It is given by intravenous infusion and is in phase III clinical trials for relapsing remitting MS.
Researchers announced further analysis of data from the phase II CAMS223 study which compared interferon beta 1a (Rebif) with two dose levels of alemtuzumab in early, active relapsing remitting MS. Sustained reduction in disability, defined as a decrease in EDSS (a clinical measure of disability) of one point or more for more than six months, was twice as likely in those taking alemtuzumab as those taking interferon beta 1a. The researchers suggest that alemtuzumab may halt progression of disability and potentially reverse pre-existing neurological impairment, but further study is needed to confirm this.
New data for existing treatments
Natalizumab is licensed to treat highly active relapsing remitting MS. Several presentations provided further data on natalizumab. These included:
- Sophisticated MRI techniques provided evidence that natalizumab treatment may promote remyelination.
- Further analysis of data from a clinical trial which compared natalizumab with placebo investigated reductions in EDSS scores, suggesting reduced disability. Natalizumab significantly increased the probability of a one point EDSS reduction over two years by 69% compared to placebo.
- Progressive multifocal leucoencephalopathy (PML) is a rare but potentially fatal side effect of natalizumab treatment. In a presentation of postmarketing surveillance data for natalizumab, the manufacturer, Biogen Idec, provided evidence that the risk of PML is lower than previously thought and the infection less severe. Following clinical trials, the risk of developing PML had been calculated as 10 in 10,000 but data from general use suggest a risk closer to 1.2 in 10,000.
- Oral herpes virus eruptions were three times more likely in people who were taking natalizumab than in those on no therapy.
Since the meeting a number of further cases of PML have been reported.
Mitoxantrone is a chemotherapy drug used to treat aggressive forms of relapsing remitting MS. Previous studies have shown that people with MS treated with the drug have an increased risk of developing leukaemia. Those studies showed that acute leukaemia occurred in up to 0.25% of people with MS taking mitoxantrone. A retrospective study of 2,854 Italian people with MS found that leukaemia occurred in 0.74%, three times higher than previously thought.
Interferon beta 1a (Avonex)
Neurologists continue to debate whether to start disease modifying treatments immediately after the first symptoms of MS or to delay treatment until confirmed diagnosis. A ten year follow up showed that people treated immediately after their first episode of MS symptoms had a significantly smaller chance of experiencing a second attack compared with those for whom treatment was delayed.
Methylprednisolone is a steroid, typically used in treating MS relapses. A study combined methylprednisolone, given in pulses every four weeks, with interferon beta 1a. Those who received both drugs had 38 percent fewer relapses over the three year study, compared to those who received interferon beta 1a alone. There was a high drop out rate on the study - in the group receiving methylprednisolone because of side effects, and in the placebo group because of lack of effect. The researchers acknowledged that these results need to be confirmed in larger studies.
This clinical trial has recently been published in the Lancet Neurology.
Soelberg Sorensen P, et al.
NORdic trial of oral methylprednisolone as add-on therapy to Interferon beta-1a for treatment of relapsing-remitting multiple sclerosis (NORMIMS study): a randomised, placebo-controlled trial.
Lancet Neurology 2009;8(6):519-529.
MS Trust information
The MS Trust has factsheets on several of the drugs mentioned at the AAN meeting.
- Alemtuzumab (Campath)
- More on natalizumab (Tysabri) - A to Z of MS
- Disease modifying drug therapy (book)
- More on research
Information in the A to Z of MS