Design and synthesis of selective sphingosine-1-phosphate receptor 1 agonists with increased phosphorylation rates

FTY720 and IMMH002, prodrugs for sphingosine-1-phosphate receptor 1 (S1P₁) agonists, show inadequate and inconsistent levels of phosphorylation in humans compared to that in rats. In this study, FTY720 or IMMH002 analogues (21–24) were designed and synthesized with modified head pieces to improve the biotransformation of the prodrugs to the active phosphorylated forms. Target compounds were synthesized via a convergent route using the key and optically pure building block 9, which was first synthesized via asymmetrically catalyzed amination. The phosphorylation rates of these analogues in rat or human blood were compared. The new methyl-substituted analogue compound 21 showed higher phosphorylation rates in both rats and humans than the parent compound, whereas compound 23 showed improvements in rats, but not in humans. In pharmacokinetics studies of rats, compounds 21 and 23 both had higher levels of phosphorylation than FTY720 and IMMH002. Thus, our study not only yielded new compounds with therapeutic potential, but also showed species differences between rats and humans in response to the structural modifications, which might be useful for predicting the biotransformation behavior and efficacy of this class of prodrugs in the clinic.

A novel S1P1 modulator IMMH002 ameliorates psoriasis in multiple animal models

Psoriasis is characterized by abnormal proliferation of keratinocytes, as well as infiltration of immune cells into the dermis and epidermis, causing itchy, scaly and erythematous plaques of skin. The understanding of this chronic inflammatory skin disease remains unclear and all available treatments have their limitations currently. Here, we showed that IMMH002, a novel orally active S1P₁ modulator, desensitized peripheral pathogenic lymphocytes to egress signal from secondary lymphoid organs and thymus. Using different psoriasis animal models, we demonstrated that IMMH002 could significantly relieve skin damage as revealed by PASI score and pathological injure evaluation. Mechanistically, IMMH002 regulated CD3⁺ T lymphocytes re-distribution by inducing lymphocytes’ homing, thus decreased T lymphocytes allocation in the peripheral blood and skin but increased in the thymus. Our results suggest that the novel S1P₁ agonist, IMMH002, exert extraordinary capacity to rapidly modulate T lymphocytes distribution, representing a promising drug candidate for psoriasis treatment.

CYP2J2 is the major enzyme in human liver microsomes responsible for hydroxylation of SYL-927, a novel and selective sphingosine 1-phosphate receptor 1 (S1P1 ) agonist

SYL-927, a novel and selective S1P₁ agonist, is transferred to its active phosphate for the regulation of lymphocyte recirculation. This in vitro metabolism study is to elucidate the P450-mediated oxidation pathway of SYL-927 in human liver microsomes (HLMs). The results demonstrated that the ω-1 hydroxylated metabolite SYL-927-M was formed after incubation of SYL-927 with HLMs. Recombinant human CYP1A1 and CYP2J2 can efficiently catalyse SYL-927-M formation, followed by markedly less substrate conversion with CYP1A2, CYP2C19 and CYP2D6. Inhibition studies with chemical inhibitors and antibodies suggested that arachidonic acid, the substrate of CYP2J2, and CYP2J2-specific antibody effectively inhibited the formation of SYL-927-M in HLMs whereas no significant inhibition was observed with the inhibitors for CYP1A1, CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP2E1 and CYP3A4, demonstrating that CYP2J2 was primarily responsible for the formation of SYL-927-M.

(7-Benzyloxy-2,3-dihydro-1H-pyrrolo[1,2-a]indol-1-yl)acetic Acids as S1P1 Functional Antagonists

S1P1 is a validated target for treatment of autoimmune disease, and functional antagonists with superior safety and pharmacokinetic properties are being sought as second generation therapeutics. We describe the discovery and optimization of (7-benzyloxy-2,3-dihydro-1H-pyrrolo[1,2-a]indol-1-yl)acetic acids as potent, centrally available, direct acting S1P1 functional antagonists, with favorable pharmacokinetic and safety properties.

Discovery of BAF312 (Siponimod), a Potent and Selective S1P Receptor Modulator

A novel series of alkoxyimino derivatives as S1P1 agonists were discovered through de novo design using FTY720 as the chemical starting point. Extensive structure-activity relationship studies led to the discovery of (E)-1-(4-(1-(((4-cyclohexyl-3-(trifluoromethyl)benzyl)oxy)imino)ethyl)-2-ethylbenzyl)azetidine-3-carboxylic acid (32, BAF312, Siponimod), which has recently completed phase 2 clinical trials in patients with relapsing-remitting multiple sclerosis.