THUR 192 Yearly lymphopenia rates in cladribine tablets-treated rms patients

BackgroundCladribine tablets 3.5 mg/kg (CT3.5) demonstrated efficacy in RMS patients in CLARITY/CLARITY-Extension. Lymphopenia was common (CT3.5: mechanism of action).ObjectiveEvaluate whether lymphopenia persists following treatment/re-treatment with CT3.5 in CLARITY/CLARITY- Extension.MethodsLymphopenia by grade for patients randomised to CT3.5 throughout CLARITY/CLARITY-Extension (7 mg/kg cumulative 4 year dose; n=186) are reported. Patients with Grade 0 (G0) lymphopenia (≥1.0 × 109 cells/L) before the first course of CT and G0/1 (≥0.8 × 109 cells/L) before subsequent treatment in Years 2 (Y2), 3 and 4 were analysed.Results176 patients were G0 at the start of CLARITY (167 were G0/1; CLARITY-Extension). G3 lymphopenia was observed in 1% patients (Week-13, Y1), and in 7%, 11% and 12% patients at Week-12 in Y2, 3 and 4. In each year, G3 lymphopenia was observed in 1%, 4%, 4% and 4% patients (Week-24), in 1%, 2%, 2% and 2% patients (Week-36), and in 1% patients (Week-48) in Y2 only. G3 lymphopenia was reported in ConclusionsIn patients meeting treatment/re-treatment guidelines, no G4 lymphopenia occurred at the end of any treatment year; G3 lymphopenia was uncommon. Lymphocyte-based re-treatment criteria minimised the incidence of severe, sustained lymphopenia during 4 years’ treatment with CT.Disclaimerhttp://medpub-poster.merckgroup.com/ABN2018DISC_Year1-4.pdf