Key Takeaways:

• Oral diphenhydramine and dexamethasone IV (D-IV) and oral cetirizine and oral dexamethasone (C-PO) are premedication regimens for patients with multiple sclerosis (MS) who are treated with Ocrevus (ocrelizumab).
• C-PO was preferred by a majority of patients (75%), as infusion was associated with less drowsiness and fewer treatment-related side effects than D-IV.
• Oral premedication is a potential alternative treatment that could improve a patient’s overall therapy experience by easing infusion-related reactions (IRRs).

During the National Infusion Center Association (NICA) 2026 Annual Conference, Marissa Shackleton, Executive Director of The Elliot Lewis Center, presented her team’s research, “Tolerability of Oral Cetirizine and Oral Dexamethasone vs. Oral Diphenhydramine and IV Dexamethasone.”

This study was conducted by The Elliot Lewis Center’s Dragonfly Research cohort, led by Joshua Katz, MD, and Andrew Bouley, MD, who worked closely with research coordinators Isabelle Messina and Paola Castro Mendoza.

Research Goal and Methods

The study compared 2 premedication regimens: D-IV against C-PO in patients with MS who were treated with Ocrevus (ocrelizumab). Participants included 50 patients with MS receiving ocrelizumab and premedication D-IV without a history of IRRs. Rates of drowsiness and treatment-related symptoms during and after infusion were observed.

In the first cycle, patients received D-IV premedication and completed 2 surveys, 1 immediately following infusion and another 24 hours after infusion. In the second cycle, patients received C-PO premedication and completed the same surveys.

D-IV vs C-PO

The surveys showed that 75% of patients preferred C-PO premedication. Firstly, this regimen was associated with fewer rates of sedation than D-IV. Only 11% of patients with C-PO had to be sedated during or after infusion, while 28% of patients with D-IV required sedation.

C-PO had fewer reports of drowsiness than D-IV. During infusion, only 35% of patients experienced drowsiness with C-PO, which is significantly lower than the 77% who reported drowsiness with D-IV.

Additionally, C-PO had fewer reports of treatment-related side effects. During infusion, 67% of patients reported side effects with C-PO while 89% reported treatment-related symptoms with D-IV.

Only 1 patient required rescue diphenhydramine with C-PO, and no patients needed their infusions slowed or interrupted.

Implications for Managed Care

The use of oral premedication for patients with MS receiving ocrelizumab could improve care by decreasing IRRs and shortening overall treatment time.

With less severe reactions to infusion and fewer treatment-related side effects, oral premedication is a promising alternative treatment for patients with MS.

Reference

Messina I, Castro Mendoza P, Fearey M, et al. Tolerability of oral cetirizine and oral dexamethasone vs. oral diphenhydramine and IV dexamethasone. Poster presented at: National Infusion Center Association (NICA) 2026 Annual Conference; July 9-10, 2026; Las Vegas, NV.