Cladribine and the risk of cancer in people with MS

No evidence for higher risk of cancer in patients with multiple sclerosis taking cladribine. Pakpoor J, Disanto G, Altmann DR, Pavitt S, Turner BP, Marta M, Juliusson G, Baker D, Chataway J, and Schmierer K. Neurol Neuroimmunol Neuroinflamm 2015;2:e158; doi: 10.1212/NXI.0000000000000158

You were asking for more official information, and now the wait is over as our study on the risk of cancer in people with MS taking Cladribine has been published.

Inspired by discussions at BartsMS, and executed with colleagues from Oxford, UCL, The London School of Hygiene and Tropical Medicine, Leeds and Lund (Sweden) Universities our analysis shows there is no evidence for an increased risk of cancer when Cladribine is being used as an induction treatment for people with MS.

Cladribine has been on the "BartsMS essential off-label DMT list" (see left upper corner) for quite some time, however having a license only for people with hairy cell leukaemia, but not MS, will always limit its use to exceptional treatment situations, certainly in countries with a high-cost system of health care and regulation.

We believe our work is a key step to put Cladribine back in the hunt for a license to treat MSers. Rather than falling in line with editorials around the globe that kept repeating the EMA's claim of an increased risk of cancer (the type of mud that really sticks!) we took the published evidence to task comparing the risk of cancer in the CLARITY and ORACLE MS phase III trials of Cladridine with your household brand of DMTs in MS.

We looked at the trials that underpinned the licencing of other current DMTs and found that what was unusual in the CLARITY trial was not the finding of three cancers in the Cladribine-treated group, but that there was 'no cancer' in the placebo arm.

Can we say there is no cancer risk with Cladribine? No, we cannot. However, the way to find this out is to monitor people taking the drug long term; a 2 year trial is too short to really get an answer. Obviously, this statement not only applies to Cladribine but all DMTs for MS.

This week has seen the announcement of the potential of B cell depletion in people with relapsing as well as progressive MS.  Rest assured this will be one of the biggest talking points at ECTRIMS next week.  In the wake of the Ocrelizumab success it is of interest to note a key effect of Cladribine is to deplete B cells whilst its effect on T cells is rather modest.  And unlike most other DMTs (including monoclonal antibodies), Cladribine penetrates into the CNS, the key immunological "battle ground" in people with MS.

CoI:  None relevant. This work was undertaken by BartsMS and received no specific funding. We are grateful to Barts Charity for supporting open access.