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THUR 178 Infections during grade 3/4 lymphopenia with cladribine tablets
  1. Stuart Cook1,
  2. Thomas Leist2,
  3. Giancarlo Comi3,
  4. Xavier Montalban4,5,
  5. Elke Sylvester6,
  6. Christine Hicking6,
  7. Fernando Dangond7
  1. 1Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, NJ, USA
  2. 2Jefferson University, Comprehensive MS Center, PA, USA
  3. 3Università Vita-Salute San Raffaele, Ospedale San Raffaele, Milan, Italy
  4. 4St Michael’s Hospital, University of Toronto, Toronto, ON, Canada
  5. 5Vall d’Hebron University Hospital, Vall d’Hebron, Barcelona, Spain
  6. 6Merck KGaA, Darmstadt, Germany
  7. 7EMD Serono Research and Development Institute, Inc., a business of Merck KGaA, Darmstadt Germany


Background In CLARITY, cladribine tablets 3.5 mg/kg (CT3.5) demonstrated efficacy in relapsing MS patients. The most common AE was lymphopenia, reflecting cladribine’s mode of action. Integrated safety analysis showed infection incidence was not higher in patients receiving CT3.5 vs placebo, bar a small increase of herpes zoster (HZV).

Objective Post-hoc analysis examined infectious AEs occurring concurrently with Grade 3/4 lymphopenia (G3/4) in CT3.5 treated patients.

Methods The AE profile for CT3.5 during the periods of G3/4 was analysed. Adjusted-AE incidences per 100 patient years (Adj-AE/100PY) were calculated in a cohort of patients receiving CT3.5 monotherapy in clinical trials.

Results Data are presented as Adj-AE/100PY: G3/4 vs without G3/4. Adj-AE/100PY for any infections/infestations was 57.53 vs 24.50. Infections were similar between periods. ≥50% cases with G3/4 were easily-treatable upper- respiratory-tract infections (nasopharyngitis: 13.48 vs 5.24; upper-respiratory-tract infection: 9.67 vs 3.41; pharyngitis: 4.51 vs 0.73). HZV occurred in 4 patients with G3/4 (4.50 vs 0.73); cases were dermatomal and mild-to- moderate in severity. Single occurrences were reported for most infectious AEs. Opportunistic infections were single occurrences, not severe, serious or difficult-to-treat.

Conclusions G3/4 increased frequency of infections but did not affect the type of infectious AEs in CT3.5 treated patients. HZV profile was uncomplicated, consistent with findings of previous analyses.


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