Real-world Australian data on the use of cladribine in MS supports a rapid and durable disease modifying effect.
The study comprised 90 patients, most on a Patient Familiarisation Program when cladribine was available during 2010-2011, with follow-up data from the MSBase registry.
Most patients (78%) had relapsing-remitting MS (RRMS) as opposed to secondary progressive MS (SPMS).
Due to the non-availability of cladribine in 2011, patients only received treatment in one year (cumulative dose 1.75 mg/kg) rather than two (3.5 mg/kg).
The study found about 80% of patients with adequate post-cladribine follow-up (n=66) were free from EDSS progression, driven by the patients with RRMS.
And 65% of patients were free from relapses two years after treatment.
Most patients (69%) received other disease modifying treatments, in particular fingolimod or dimethyl fumarate, following cladribine and were able to switch without relapse.
The investigators said disability trajectories suggested an overall increasing EDSS prior to treatment with cladribine.
“We observed that this trajectory was altered during the 2 years following treatment in RMS patients – a particularly notable finding given that this is a cohort of more disabled, older and extensively pre-treated RMS patients than patients in the clinical trials of cladribine tablets in MS.”
They said other evidence, including that from the CLARITY Extension study, demonstrates that the efficacy of cladribine tablets appeared to occur rapidly after administration of the first course and can be long lasting.
“The quantitative, and perhaps qualitative, changes in key immune cells thought to be important in MS that persist for long after administration of cladribine tablets and long after the recovery of total lymphocyte counts combined with the sustained reduction of clinical activity seem to be an important feature of treatment with cladribine tablets,” they said.
Co-author Associate Professor Suzanne Hodgkinson, from the Ingham Institute for Applied Medical Research, told the limbic some patients did exceptionally well on cladribine.
“Not everybody improves but some people definitely improve. People that we wouldn’t have necessarily thought could improve. It’s quite an interesting drug.”
“There is no other drug quite like cladribine that is available for MS. There are some other new drugs e.g. anti-CD20 medications and we are now testing tyrosine kinase inhibitors as well.”
She said cladribine’s relative safety and the fact that it crosses the blood-brain barrier were some of the differences compared to monoclonal antibodies.
“It has not been supplanted. The reason it came back was it is a very good drug and fills a useful niche.”
Cladribine became available on the PBS in January 2019, was also approved by the FDA in the same year and has recently been approved in New Zealand.