RT Journal Article SR Electronic T1 Short term relapse risk after switching from natalizumab to ocrelizumab or cladribine – an international cohort study (1712) JF Neurology JO Neurology FD Lippincott Williams & Wilkins SP 1712 VO 96 IS 15 Supplement A1 Johanna Treffts A1 Yan Van Kesteren A1 Sandra Thiel A1 Alexander Stahmann A1 Melinda Magyari A1 Achim Berthele A1 Katrin Giglhuber A1 Stefan Bittner A1 Erik Ellwardt A1 Klemens Angstwurm A1 Björn Tackenberg A1 Jan Jurs A1 Andrea Viehover A1 Luisa Klotz A1 Lena Theis A1 Ralf Gold A1 David Ellenberger A1 Kerstin Hellwig YR 2021 UL http://n.neurology.org/content/96/15_Supplement/1712.abstract AB Objective: To assess short term relapse and disability risk after switching from natalizumab (NTZ) to ocrelizumab (OCR) or cladribine (CLAD) in patients with relapsing-remitting multiple sclerosis (RRMS)Background: The relapse risk after stopping NTZ varies between 9 and 80% and seems to be lower after switching to second line drugs as fingolimod. Information on disease activity after switching to newer drugs as OCR/CLAD is scarce.Design/Methods: Patients were recruited from several academic centers (AC) throughout Germany and two national registries (Denmark (DMSR)/Germany (GMSR)). We included 223 adults with RRMS who stopped NTZ (treated ≥3 months) and switched to OCR/CLAD 6 months after the last infusion with at least 6 months follow up on OCR/CLAD (exposure).The frequency of relapses was assessed in different phases after FTY was discontinued.Results: 196 patients (DMSR: N=61, GMSR: N=79, AC: N=56) switched from NTZ to OCR, 27 patients (DMSR: N=17, GMSR: N=8, AC: N=2) from NTZ to CLAD.In the treatment free switching interval regardless of following switch treatment 11/4.93% patients had ≥1 relapse in 42.23 patient years (py) (DMSR: N=1/1.28% in 12.85 py, GMSR: N=5/5.75% in 17.47 py, AC: N=5/8.62% in 12.01 py).During the first six months after OCR/CLAD start 20/8.97% had ≥1 relapse regardless of following switch treatment.Stratified by drug type 16/8.16% of the OCR switchers had ≥1 relapse (DMSR: N=2/3.28%, GMSR: N=6/7.59%, AC: N=8/14.29%) and 4/14.81% of the CLAD switchers (DMSR: N=1/5.88%, GMSR: N=2/25%, AC: N=1/50%).Conclusions: The overall relapse risk during the treatment free switching interval was low in our cohort but varied by data source.Disclosure: Ms. Treffts has nothing to disclose. Mr. Van Kesteren has nothing to disclose. Ms. Thiel has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Bayer Healthcare . Alexander Stahmann has received personal compensation for serving as an employee of MS Forschungs- und Projektentwicklungs-gGmbH. Dr. Magyari has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Roche. Dr. Magyari has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Merck. Dr. Magyari has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Abbvie. Dr. Magyari has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Alexion. Dr. Magyari has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Biogen. Dr. Magyari has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Merck. Dr. Magyari has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Novartis. Dr. Magyari has received personal compensation in the range of $10,000-$49,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Sanofi. The institution of Dr. Magyari has received research support from The Danish MS Society. The institution of Dr. Magyari has received research support from Biogen. The institution of Dr. Magyari has received research support from Novartis. The institution of Dr. Magyari has received research support from Roche. The institution of Dr. Magyari has received research support from Merck. The institution of Dr. Magyari has received research support from Sanofi. Achim Berthele, MD has nothing to disclose. Katrin Giglhuber has nothing to disclose. Stefan Bittner has received personal compensation in the range of $500-$4,999 for serving as a Honoria with Biogen Idec. Stefan Bittner has received personal compensation in the range of $500-$4,999 for serving as a Honoria with Merck Serono. Stefan Bittner has received personal compensation in the range of $500-$4,999 for serving as a Honoria with Novartis. Stefan Bittner has received personal compensation in the range of $500-$4,999 for serving as a Honoria with Roche. Stefan Bittner has received personal compensation in the range of $500-$4,999 for serving as a Honoria with Sanofi. Erik Ellwardt has nothing to disclose. Klemens Angstwurm, MD has nothing to disclose. Dr. Tackenberg has received personal compensation for serving as an employee of F. Hoffmann-La Roche AG. Dr. Tackenberg has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Roche. Dr. Tackenberg has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Merck Serono. Dr. Tackenberg has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Biogen. Dr. Tackenberg has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Novartis. Dr. Tackenberg has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for GILEAD. Dr. Tackenberg has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Alexion. Dr. Tackenberg has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Celgene. Dr. Tackenberg has received personal compensation in the range of $10,000-$49,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Roche. Dr. Tackenberg has received personal compensation in the range of $50,000-$99,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Merck. Dr. Tackenberg has received personal compensation in the range of $10,000-$49,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Biogen. Dr. Tackenberg has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Celgene. Dr. Tackenberg has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Alexion. Dr. Tackenberg has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for Roche. Dr. Tackenberg has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for Merck Serono. Dr. Tackenberg has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for Biogen. Dr. Tackenberg has received personal compensation in the range of $10,000-$49,999 for serving on a Speakers Bureau for Novartis. Dr. Tackenberg has received stock or an ownership interest from F. Hoffmann-La Roche AG. The institution of Dr. Tackenberg has received research support from Biogen. The institution of Dr. Tackenberg has received research support from Novartis. The institution of Dr. Tackenberg has received research support from Roche. Mr. Jurs has nothing to disclose. Andrea Viehover has nothing to disclose. Dr. Klotz has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Bayer. Dr. Klotz has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Biogen. Dr. Klotz has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Genzyme. Dr. Klotz has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Grifols. Dr. Klotz has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Merck Serono. Dr. Klotz has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Novartis. Dr. Klotz has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Santhera. Dr. Klotz has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Teva. Dr. Klotz has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Roche. Dr. Klotz has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Novartis. Dr. Klotz has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Alexion. Dr. Klotz has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Merck. Dr. Klotz has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Sanofi. Dr. Klotz has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Janssen Cilag. The institution of Dr. Klotz has received research support from Immunic AG. The institution of Dr. Klotz has received research support from Merck. The institution of Dr. Klotz has received research support from Novartis. Lena Theis has nothing to disclose. Dr. Gold has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Biogen . Dr. Gold has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Novartis. Dr. Gold has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Roche. Dr. Gold has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Genzyme. Dr. Gold has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Bayer Vital. Dr. Gold has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Eisai Pharamaceuticals. Dr. Gold has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Biogen. Dr. Gold has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Roche. Dr. Gold has received personal compensation in the range of $10,000-$49,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for SAGE Publishers. Dr. Gold has received personal compensation in the range of $500-$4,999 for serving as an Expert Witness for Novartis. Dr. Gold has received personal compensation in the range of $500-$4,999 for serving as an Expert Witness for Biogen. The institution of Dr. Gold has received research support from Novartis. The institution of Dr. Gold has received research support from Biogen. David Ellenberger has nothing to disclose. Kerstin Hellwig has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Teva . Kerstin Hellwig has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Biogen . Kerstin Hellwig has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for INC research . Kerstin Hellwig has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Novartis . Kerstin Hellwig has received personal compensation in the range of $5,000-$9,999 for serving on a Speakers Bureau for Merck . Kerstin Hellwig has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Biogen . Kerstin Hellwig has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Bayer .