Barts-MS rose-tinted-odometer: ★★★★★★★
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How good is cladribine as an immune reconstitution therapy?
The CLASSIC-MS study was our attempt to get back all the pwMS who had participated in the original phase 3 programme, from 15 years ago. The following poster is from my late-breaking poster at ECTRIMS and describes what has happened to the subjects from the CLARITY and CLARITY extension study and does not include subjects with clinically isolated syndrome from the ORACLE study.
As you can see the subgroup of subjects from CLASSIC-MS is similar to the overall population of subjects in the original trial. Therefore we think these results are representative of the overall population.
The median time to follow-up in the CLASSIC-MS study was 10.9 years (range 9.3, 14.9).
The remarkable observation is how few study subjects progressed (to be presented later in more detail) with less than 1 in 5 needing a walking aid to manage 100m.
56% of cladribine treated subjects did not require a follow-on DMT compared to only 27% of subjects that were not treated with cladribine. These results indicate that the duration of action of cladribine may be much longer than we realise and is beginning to mirror what we see in clinical practice with this particular agent.
Given this data and the other attributes of cladribine, it is going to be a serious contender for the go-to DMT at the bottom of the therapeutic pyramid on which to build an induction-maintenance strategy and combination therapies.
Oral cladribine has several favourable attributes for managing MS, particularly during the COVID-19 pandemic:
- High-efficacy DMT allowing flipping of the pyramid
- Good COVID-19 outcomes
- Oral therapy, therefore reduced hospital contacts
- No cell lysis syndrome or infusion-type reactions
- No pre-dosing with steroids
- Innate immunity intact
- Only moderate reduction in T-cell counts
- Less impact on CD8+ compared to CD4+ T-cells
- Antiviral immunity relatively intact
- Vaccine immunity intact
- Low monitoring requirements
- Small risk of lymphocyte count being less than 500/mm3
- CNS penetration targeting CNS resident B and T cells
- Post-dosing immune reconstitution
- Good seroconversion post-COVID-19 vaccination
- Cost-effective; providing value to the NHS
Giovannoni et al. Long-term efficacy for patients receiving cladribine tablets in CLARITY/CLARITY extension: Primary results from 9–15 years of follow-up in the CLASSIC-MS study. ECTRIMS 2021, P975.
Introduction: CLASSIC-MS (NCT03961204) was an exploratory, ambispective Phase IV study designed to evaluate the long-term efficacy of cladribine tablets (CladT) in the real-world setting, for patients with relapsing multiple sclerosis (RMS) who were previously enrolled to Phase III (parent) trials.Objectives: To report primary results for CLASSIC-MS in terms of long-term mobility and disability beyond the treatment courses that patients received in the parent trials, with the aim of informing future treatment approaches.
Methods: This analysis represents patients in CLASSIC-MS who participated in the Phase III CLARITY trial whether or not they participated in CLARITY Extension, and who had received ≥1 course of CladT or placebo. The primary objective of CLASSIC-MS was the evaluation of long-term mobility (no wheelchair use/bedridden; i.e. EDSS <7 in the 3 months prior to first visit in CLASSIC-MS). The main secondary objective was long-term disability status (no requirement for an ambulatory device; i.e. EDSS <6 any time since last parent study dose [LPSD]). Analyses are descriptive and shown in relation to exposed/never exposed to CladT in CLARITY.
Results: The CLASSIC-MS population who previously participated in CLARITY/CLARITY Extension comprised 435 patients with RMS (67.8% female; mean±SD EDSS score, 3.87±2.07 at CLASSIC-MS baseline), with a median time since LPSD of 10.9 (range 9.3–14.9) years and a median disease duration of 20.7 (range 13.9–46.5) years at CLASSIC-MS baseline. A total of 90.6% (n=394) were exposed to CladT during CLARITY/CLARITY Extension, including 160 patients who received the approved cumulative dose of 3.5 mg/kg over 2 years; the remaining 9.4% (n=41) were never exposed. The proportion of patients not using a wheelchair/bedridden in the 3 months prior to CLASSIC-MS (i.e. EDSS <7) was 90.0% of the CladT exposed cohort and 77.8% of the never exposed cohort. Regarding long-term disability status, the proportion of patients with no requirement for an ambulatory device (i.e. EDSS <6) was 81.2% of the CladT exposed and 75.6% of the never exposed cohorts, respectively.
Conclusions: Baseline patient characteristics suggest that patients enrolled in CLASSIC-MS were a representative sample of all patients included in the original parent studies. Reported findings for CLASSIC-MS, with a median of 10.9 years’ follow-up after CLARITY/CLARITY Extension, suggests sustained efficacy of CladT in terms of long-term mobility and disability status.
Disclaimer: Please note that I am the PI on the oral cladribine programme including the CLASSIC-MS study and have been involved with the development of oral cladribine as a DMT for MS since 2002. I was a member of the original advisory panel that Serono put in place when they decided to in-license the oral formulation for development. Therefore you need to interpret what I say about cladribine and oral cladribine very carefully. In short, I am likely to be very biased.
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General Disclaimer: Please note that the opinions expressed here are those of Professor Giovannoni and do not necessarily reflect the positions of the Barts and The London School of Medicine and Dentistry nor Barts Health NHS Trust and are not meant to be interpreted as personal clinical advice.