Treating the ineligible: Disease modification in people with multiple sclerosis beyond NHS England commissioning...

Whilst there is a broad selection of drugs licensed as disease modifying treatments (DMTs) for people with relapsing multiple sclerosis (pwRMS), access to DMTs remains restricted, particularly for people with progressive MS (pwPMS). Cladribine has shown efficacy at all stages of MS. Following withdrawal from the market of oral cladribine in 2011, partly due to issues associated with lymphopenia, and following a thorough risk assessment, we started using subcutaneously injected cladribine (Litak^®) to treat both pwRMS and pwPMS. Here, we report on the real life safety and tolerability of this treatment option.

Cladribine was offered to (i) pwRMS as a choice despite fulfilling NHS England (NHSE) criteria for licensed DMTs, and (ii) pwRMS and pwPMS not eligible for NHSE approved DMTs. To avoid lymphocyte depletion lower than 0.5 × 10⁹/l (WHO grade 2) cladribine was administered using a personalised dosing scheme (30-40 mg in week 1; and another 0-30 mg in week 5 pending total lymphocyte count at week 4). Anti-viral prophylaxis was given from day 1 for 60 days. Patients approaching week 48 were given a second treatment cycle. Data collection included side effects, relapses, change in disability and MRI indices.

Seventy-one pwMS (40 female, 31 male; 36 RMS, 35 PMS,) received at least one treatment cycle. Mean age for starting cladribine was 44 years (range 22-72 years), median EDSS was 5 (range 1-8.5). Maximum follow-up was 28 months. 35/71 pwMS were followed up for at least 20 weeks. These patients had a median EDSS of 5.0 (range 1.0-7.5) at baseline and 5.5 (range 1.0-8.0) after a mean follow-up of 11 months (range 5-28). Cladribine was well tolerated with very few treatment-related adverse events observed. Personalised dosing led to grade 1-2 lymphopenia in 50% of cases. A single patient developed transient grade 3 lymphopenia. No cases of varicella or other infections were observed. Four/17 people with relapsing MS, experienced a total of six relapses during a mean follow-up of 13 months (range 5-28 months). In people with PMS (n = 18) median EDSS was 5.5 (2.0-7.5) at baseline and 6.0 (2.5-7.5) after a median of 10 months (range 5-18). In pwPMS MRI showed that 25% had active scans at baseline, and 0% at follow-up.

Personalised dosing of cladribine avoided severe lymphopenia in all but one patients and was very well tolerated across a large spectrum of disease severity. Our data suggests cladribine may offer benefit people with relapsing and progressive MS alike. The personalised protocol used appears safe, however warrants controlled studies to more definitively assess efficacy and safety, particularly in groups of pwMS who are not eligible for licensed DMT including oral cladribine (Mavenclad^®).