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Papers of the Week

Papers: 25 Nov 2023 - 1 Dec 2023

2023 Nov 27

Clin Transl Sci


Safety, Pharmacokinetics, and Target Engagement of a Brain Penetrant RIPK1 Inhibitor, SAR443820 (DNL788), in Healthy Adult Participants.


Hincelin-Mery A, Nicolas X, Cantalloube C, Pomponio R, Lewanczyk P, Benamor M, Ofengeim D, Krupka E, Hsiao-Nakamoto J, Eastenson A, Atassi N


SAR443820 (DNL788) is a selective, orally bioavailable, brain penetrant inhibitor of receptor-interacting serine/threonine protein kinase 1 (RIPK1). This phase 1 first-in-human healthy participant study (NCT05795907) was comprised of three parts: randomized, double-blind, placebo-controlled single ascending dose (SAD; Part 1a); 14-day multiple ascending dose (MAD; Part 2) parts that evaluated safety, tolerability, pharmacokinetics (PK), and pharmacodynamics of SAR443820; and a separate open-label, single-dose Part 1b (PK-CSF) to assess SAR443820 levels in cerebrospinal fluid (CSF). SAR443820 was well-tolerated in healthy participants, and no treatment discontinuation related to an adverse event (AE) occurred. Most common AEs were dizziness and headache. No clinically meaningful changes were noted in laboratory values, vital signs, or electrocardiogram (ECG) parameters. SAR443820 had a favorable PK profile, with plasma half-lives (geometric mean) ranged between 5.7-8.0 h and 7.2-8.9 h after single and repeated doses, respectively. There were no major deviations from dose proportionality for maximum concentration and area under the curve across SAR443820 doses. Mean CSF-to-unbound plasma concentration ratio ranged from 0.8-1.3 over time (assessed up to 10 h postdose), indicating high brain penetrance. High levels of inhibition of activated RIPK1, as measured by decrease in pS166-RIPK1, were achieved in both SAD and MAD parts, with a maximum median inhibition from baseline close to 90% at predose (C ) after multiple dosing in MAD, reflecting a marked RIPK1 target engagement at peripheral level. These results support further development of SAR443820 in phase 2 trials in amyotrophic lateral sclerosis (NCT05237284) and multiple sclerosis (NCT05630547).