CD4, and CD8 lymphocyte counts) of lifitegrast were evaluated in a subset of 43 to 47 patients
before and after twice daily dosing with the proposed commercial lifitegrast ophthalmic solution
(5% w/v). At approximately 180 days and/or 360 days of repeated topical ocular dosing with
lifitegrast 5%, 9 (~20%) of the patients included in the substudy had detectable (≥ 0.5 ng/mL)
predose lifitegrast concentrations in the plasma. Of these 9 patients, 2 had predose concentrations
that exceeded the EC50 (2.5 ng/mL) needed to inhibit T-cell adhesion in vitro, and an additional
patient had treatment-emergent potentially clinically important (as per the sponsor) abnormalities
in CD8 lymphocyte counts. The applicant stated that none of these 3 patients experienced
systemic infections or immunosuppressive complications during the 12-month treatment period.
Overall, these findings suggest that topical ocular (1 drop twice daily) administration of the
proposed commercial lifitegrast 5% ophthalmic solution did not produce clinically significant
lifitegrast exposures and inhibition of lymphocyte function in these dry eye disease patients.