To describe the absolute lymphocyte counts (ALC) at the time of first infection in patients with relapsing multiple sclerosis (RMS) who received ozanimod 0.92 mg/d in phase 3 parent trials (SUNBEAM?NCT02294058; RADIANCE?NCT02047734) and an open-label extension (OLE) trial (DAYBREAK?NCT02576717).

Ozanimod is a sphingosine 1-phosphate (S1P) receptor 1 and 5 modulator for treatment of adults with relapsing multiple sclerosis (RMS). S1P receptor modulators decrease ALC by reducing lymphocyte egress from secondary lymphoid organs.

Patients in the parent/OLE trials with ALC measured 92 days before or after their first infection were divided into  ALC groups: ≥lower limit of normal (LLN) (group 1), 0.8×10⁹/L?<LLN (group 2), 0.5?<0.8×10⁹/L (group 3), 0.2?<0.5×10⁹/L (group 4), and <0.2×10⁹/L (group 5). The incidence of total infections, serious infections, and opportunistic infections was assessed by group in the parent trials and the OLE trial.

During the parent trials, 762 patients had a postbaseline ALC assessment. At the time of first infection, 3.9%, 3.5%, 15.4%, 13.0%, and 0.3% of patients had ALC in groups 1-5, respectively. At the time of first serious infection, 0.1%, 0.1%, 0.4%, 0.3%, and 0% had ALC in groups 1-5, and at first opportunistic infection, 0.4%, 0.1%, 0.7%, 0.5%, and 0% had ALC in groups 1-5, respectively.

During the OLE trial, 2251 patients had a postbaseline ALC assessment. At the time of first infection, 7.4%, 5.9%, 21.5%, 20.7%, and 1.0% of patients had ALC in groups 1-5, respectively. At first serious infection, 0.1%, 0.3%, 1.1%, 1.2%, and 0.04% had ALC in groups 1-5, and at first opportunistic infection, 0.7%, 0.3%, 1.4%, 2.6%, and 0.1% had ALC in groups 1-5, respectively.

At the time of first infection, most patients had ALC between 0.2×10⁹/L and 0.8×10⁹/L; few had ALC <0.2×10⁹/L. There was no association between infections and lymphopenia degree in patients receiving ozanimod.