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. 2023 Sep 1;12(9):5.
doi: 10.1167/tvst.12.9.5.

Ocular Pharmacology and Toxicology of TRPV1 Antagonist SAF312 (Libvatrep)

Muneto Mogi  1 , Anisha E Mendonza  1 , James Chastain  1 , John T Demirs  1 , Quintus G Medley  1 , Qin Zhang  1 , Julien P N Papillon  1 , Junzheng Yang  1 , Yan Gao  1 , YongYao Xu  1 , Kalliopi Stasi  1
Affiliations

Ocular Pharmacology and Toxicology of TRPV1 Antagonist SAF312 (Libvatrep)

Muneto Mogi et al. Transl Vis Sci Technol. .

Abstract

Purpose: To evaluate the pharmacology and toxicology of SAF312, a transient receptor potential vanilloid 1 (TRPV1) antagonist.

Methods: TRPV1 expression in human ocular tissues was evaluated with immunohistochemistry. Inhibition of calcium influx in Chinese hamster ovary (CHO) cells expressing human TRPV1 (hTRPV1) and selectivity of SAF312 were assessed by a fluorescent imaging plate reader assay. Ocular tissue and plasma pharmacokinetics (PK) were assessed following a single topical ocular dose of SAF312 (0.5%, 1.0%, 1.5%, 2.5%) in rabbits. Safety and tolerability of SAF312 were evaluated in rabbits and dogs. Effects of SAF312 on corneal wound healing after photorefractive keratectomy (PRK) surgery were assessed in rabbits.

Results: TRPV1 expression was noted in human cornea and conjunctiva. SAF312 inhibited calcium influx in CHO-hTRPV1 cells induced by pH 5.5 (2-[N-morpholino] ethanesulfonic acid), N-arachidonoylethanolamine, capsaicin, and N-arachidonoyl dopamine, with IC50 values of 5, 10, 12, and 27 nM, respectively, and inhibition appeared noncompetitive. SAF312 demonstrated high selectivity for TRPV1 (>149-fold) over other TRP channels. PK analysis showed highest concentrations of SAF312 in cornea and conjunctiva. SAF312 was found to be safe and well tolerated in rabbits and dogs up to the highest feasible concentration of 2.5%. No delay in wound healing after PRK was observed.

Conclusions: SAF312 is a potent, selective, and noncompetitive antagonist of hTRPV1 with an acceptable preclinical safety profile for use in future clinical trials.

Translational relevance: SAF312, which was safe and well tolerated without causing delay in wound healing after PRK in rabbits, may be a potential therapeutic agent for ocular surface pain.

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Conflict of interest statement

Disclosure: M. Mogi, Novartis Institutes for BioMedical Research (E); A.E. Mendonza, Novartis Institutes for BioMedical Research (E); J. Chastain, Novartis Institutes for BioMedical Research (E); J.T. Demirs, Novartis Institutes for BioMedical Research (E); Q.G. Medley, Novartis Institutes for BioMedical Research (E), The Janssen Pharmaceutical Companies of Johnson & Johnson (E); Q. Zhang, Novartis Institutes for BioMedical Research (E); J.P.N. Papillon, Novartis Institutes for BioMedical Research (E); J. Yang, Novartis Institutes for BioMedical Research (E); Y. Gao, Novartis Institutes for BioMedical Research (E); Y.Y. Xu, Novartis Institutes for BioMedical Research (E); K. Stasi, Novartis Institutes for BioMedical Research (E), Adverum Biotechnologies (E)

Figures

Figure 1.
Figure 1.
TRPV1 was expressed in the human cornea and conjunctiva. (A) TRPV1 expression (red) colocalized with nerve marker β-III tubulin (green) in human cornea, including nerves deep in the corneal stroma (40×). (B) Higher magnification of immunofluorescent detection of TRPV1 expression in conjunctival epithelium and some nerves located in conjunctival connective tissue (20×). Cell nuclei were stained with DAPI and appear blue. DAPI, 4′,6-diamidino-2-phenylindole; H&E, hematoxylin and eosin.
Figure 2.
Figure 2.
SAF312 inhibited (A) NADA-stimulated and (B) capsaicin-stimulated human TRPV1 receptor in a selective and noncompetitive manner. FLIPR, fluorescent imaging plate reader; NADA, N-arachidonoyl dopamine; SD, standard deviation; TRPV1, transient receptor potential cation channel subfamily V member 1.
Figure 3.
Figure 3.
The mean concentration of a single bilateral topical ocular administration of SAF312 0.5% was >30× higher than the IC50 of SAF312 against NADA and capsaicin in both (A) cornea and (B) conjunctiva through 12 hours. N = 2 rabbits and 4 eyes per time point.
Figure 4.
Figure 4.
Topical ocular bilateral administration of SAF312 did not delay corneal wound healing after PRK surgery in rabbits, with or without the concurrent use of a bandage contact lens (CL). *Reference treatments.
See this image and copyright information in PMC

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