For a number of reasons it is generally accepted that the current range of drugs used to treat MS are unsatisfactory. Issues include the potentially severe side-effects associated with Tysabri to the relatively limited effectiveness of the ABCR (Avonex, Betaferon, Copaxone, Rebif) therapies. The high cost of therapy and the fact they all require either injection or infusion only serves to fuel the feelings of dissatisfaction.
Pharmaceutical companies have long been mindful of these issues and research continues apace into improving existing treatments and developing alternatives. For instance, it is well known that daily or weekly injections of the ABCR drugs often leads to poor compliance and/or the discontinuation of therapy. Companies have recognised this and invested heavily towards making the administration of these drugs as ‘comfortable’ as possible by developing improved formulations of these drugs and/or new injection devices. It is worth pointing out that (for reasons similar to those preventing the development of oral insulin) it is not possible to develop oral versions of the ABCR drugs or Tysabri.
However, there are a number of alternative drugs in development that could be administered orally. Indeed a range of potential oral treatments for MS are currently progressing through the different stages of clinical development around the world. So what are these therapies and when are they likely to be available in the UK? A few of the key compounds include:
– currently in phase III clinical trials for RRMS. If successful it is likely to be the first oral therapy launched for MS and potentially available in the UK in 2011. It is believed to be at least as effective as the ABCR therapies in terms of reduction of relapse rate with the clear benefit of oral dosing. Potential drawbacks include concerns over its side effect profile, particularly when administered over a longer period of time as in MS.
Until there is greater clarity over the drugs side effect profile we remain unsure where it might fit into therapy. Our current view is that physicians are unlikely to use it as a first line agent in RRMS (replacing the ABCR therapies) however it may find a valuable role as the drug of choice in patients who have had to discontinue ABCR therapy.
– currently in phase III clinical trials for RRMS. If successful it is likely to be one of the first oral therapies launched for MS, also potentially available in the UK in 2011. It is believed to be significantly more effective than the ACBR therapies in terms of reduction in relapse rate, but not as effective as Tysabri. Often heralded as the next big breakthrough for MS, the drug’s image has been tarnished recently after clinical trial data highlighted a number of fairly significant drug-related side effects. Discontinuation rates were also relatively high in this trial suggesting a number of patients struggled to tolerate the drug. The potential need for extensive patient monitoring when the drug is first prescribed compounds the issues further.
As such we believe it is highly likely that doctors will reserve treatment with this drug for those patients who struggle to tolerate, or are poorly controlled, on ABCR therapies. This is presently where Tysabri is used, however, as an oral drug, fingolimod offers patients a more acceptable and convenient alternative to Tysabri. (In the event that cladribine is also available we believe that it will be used before fingolimod in patients with less severe forms of the disease).
– currently in phase III clinical trials for RRMS. BG-12 is slightly behind cladribine and fingolimod in terms of the clinical development process – if successful it is likely to be available in the UK in 2014 at the earliest. Like these drugs it is also given orally, however it is believed to have a better long-term safety and side effect profile meaning that doctors should be far more comfortable prescribing it to patients. With efficacy believed to be similar to the current ABCR therapies in terms of reduction of relapse rate, BG-12 is a potentially promising first line drug for MS patients.
Of all the drugs in development we believe that BG-12 has the greatest potential to replace the ABCR therapies as the first line treatment choice for newly diagnosed patients who want an oral drug. It is also likely to be used in those patients who struggle to tolerate, or are poorly controlled, on ABCR therapies. It is unlikely that physicians will switch those patients who are well managed on the current ABCR therapies.
This article has focused on a number of oral drugs in the latter stages of clinical development for MS. In our view these represent those drugs most likely to make it onto the market in the next 3 – 5 years although we would caution that drug development is fraught with risks and we cannot guarantee that any of these drugs will ever be launched. However, as is the case with the pharmaceutical industry, there are many more drugs progressing through the different phases of clinical development. While further oral drugs are in development there are also a number of promising drugs being studied that require either injection or infusion. However, unlike the current range of therapies, these would only be dosed every 6-months or even annually – a potentially interesting development. These will be discussed in more detail in subsequent issues.
In summary, it is clear that both physicians and patients are relatively unhappy with the current range of MS therapies. In an effort to address these issues the pharmaceutical companies have funded large research and development programmes into developing safer and more effective therapies to treat it, some of which are discussed above. While none of the new drugs likely to be launched during the next 5 years promises to cure the disease, they do offer the potential to significantly improve the quality of lives of those patients living with the disease.
Action MS would ask any patient interested in these drugs to contact Action MS, their GP or neurologist for further information.
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