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The safety, tolerability, pharmacokinetics, and pharmacodynamics of PF-06700841 were assessed in a randomized, double-blind, placebo-controlled, single- and multiple-dose escalation, parallel-group study in healthy subjects and patients with plaque psoriasis. The single ascending dose (1, 3, 10, 30, 100, or 200 mg) and multiple ascending dose (MAD; PF-06700841; up to 175 mg once daily or 50 mg twice daily for 10 days) periods included 54 healthy participants. In addition, 30 patients with psoriasis received PF-06700841 30 or 100 mg or placebo once daily for 28 days. Single PF-06700841 doses were rapidly absorbed, with peak plasma concentrations ≤ 1 hour, proportional exposure up to 100 mg, and mean half-life 3.8-7.5 hours. On day 10 of MAD, plasma concentrations peaked at ≤1.5 hours postdose (10-175 mg once daily). Elimination half-life was 4.9-10.7 hours; steady state was reached by day 8. In psoriasis patients on day 28, peak plasma concentrations occurred at 1-2 hours. Biomarkers IP-10 and high-sensitivity C-reactive protein were reduced and returned to near baseline levels after dosing. Maximal mean percent change from baseline in the Psoriasis Area and Severity Index scores for PF-06700841 30 mg once daily and 100 mg once daily were -67.92% and -96.31%, respectively, in week 4. All adverse events were mild/moderate. PF-06700841 was safe and well tolerated up to 200 mg once daily in healthy subjects and 100 mg once daily in patients with psoriasis, suggesting potential therapeutic utility in plaque psoriasis and other inflammatory diseases.

BACKGROUND AND PURPOSE: Slowly expanding/evolving lesions measured by conventional T1-weighted/T2-weighted brain MR imaging may contribute to progressive disability accumulation in MS. We evaluated the longitudinal change in myelin and axonal tissue integrity in white matter slowly expanding/evolving lesions by means of the magnetization transfer ratio and DTI radial diffusivity.MATERIALS AND METHODS: Slowly expanding/evolving lesions were detected within the Study to Assess the Efficacy, Safety, Tolerability, and Pharmacokinetics of BIIB033 in Participants With Relapsing Forms of Multiple Sclerosis When Used Concurrently With Avonex (SYNERGY) Phase 2 clinical trial dataset (NCT01864148), comprising patients with relapsing-remitting and secondaryprogressive MS (n ¼ 299) with T1-weighted/T2-weighted MR imaging at all trial time points (baseline to week 72). RESULTS:Compared with non-slowly expanding/evolving lesions (areas not classified as slowly expanding/evolving lesion) of baseline nonenhancing T2 lesions, slowly expanding/evolving lesions had a lower normalized magnetization transfer ratio and greater DTI radial diffusivity, both in patients with relapsing-remitting MS (n ¼ 242) and secondary-progressive MS (n ¼ 57, P , .001 for all). Although the changes with time in both the normalized magnetization transfer ratio and DTI radial diffusivity between slowly expanding/evolving lesions and non-slowly expanding/evolving lesions were positively correlated (P , .001), a decrease in the normalized magnetization transfer ratio and a greater increase in DTI radial diffusivity were observed in slowly expanding/evolving lesions versus non-slowly expanding/evolving lesions from baseline to week 72 in relapsing-remitting MS and secondary-progressive MS (P , .001 for all).CONCLUSIONS: Patterns of longitudinal change in the normalized magnetization transfer ratio and DTI radial diffusivity in slowly expanding/evolving lesions were consistent with progressive demyelination and tissue loss, as seen in smoldering white matter MS plaques.ABBREVIATIONS: MT ¼ magnetization transfer; MTR ¼ magnetization transfer ratio; nMTR ¼ normalized MTR; nT1 ¼ normalized T1; RD ¼ radial diffusivity; RRMS ¼ relapsing-remitting multiple sclerosis; SEL ¼ slowly expanding/evolving lesion; SPMS ¼ secondary-progressive multiple sclerosis C hronic active lesions, or smoldering plaques, are a neuropathologic hallmark of chronic inflammation in MS 1 and are not found in neuromyelitis optica spectrum disorders 2 or chronic cerebrovascular diseases. 3 Pathologically, chronic active lesions are typified by a "rim" of activated microglia and/or macrophages that may contain iron; they have altered morphology, sparse T-and B-cells at the core, and a slow rate of ongoing demyelination and axonal loss. 1,[4][5][6][7] Susceptibility-based MR imaging methods have identified a hypointense paramagnetic rim that may reflect activity associated with iron accumulation and other MS-related pathology in the periphery of those chronic active white matter MS lesions. 4,...

The IL-23/T helper type 17 cell axis is a target for psoriasis. The TYK2/Janus kinase 1 inhibitor PF-06700841 will directly suppress TYK2-dependent IL-12 and IL-23 signaling and Janus kinase 1edependent signaling in cells expressing these signaling molecules, including T cells and keratinocytes. This clinical study sought to define the inflammatory gene and cellular pathways through which PF-06700841 improves the clinical manifestations of psoriasis. Patients (n ¼ 30) with moderate-to-severe psoriasis were randomized to once-daily 30 mg (n ¼ 14) or 100 mg (n ¼ 7) PF-06700841 or placebo (n ¼ 9) for 28 days. Biopsies were taken from nonlesional and lesional skin at baseline and weeks 2 and 4. Changes in the psoriasis transcriptome and genes induced by IL-17 in keratinocytes were evaluated with microarray profiling and reverse transcriptaseePCR. Reductions in IL-17A, IL-17F, and IL-12B mRNA were observed as early as 2 weeks and approximately 70% normalization of lesional gene expression after 4 weeks. Immunohistochemistry showed significant decreases in markers of keratinocyte activation, epidermal thickness, KRT16 and Ki-67 expression, and immune cell infiltrates CD3 þ /CD8 þ (T cells) and CD11c (dendritic cells) after 2 weeks of treatment, corresponding with improvement in histologic score. PF-06700841 improves clinical symptoms of chronic plaque psoriasis by inhibition of proinflammatory cytokines that require TYK2 and Janus kinase 1 for signal transduction.

Objectives Bruton's tyrosine kinase (BTK) plays a non‐redundant signaling role downstream of the B‐cell receptor (BCR) in B cells and the receptors for the Fc region of immunoglobulins (FcR) in myeloid cells. Here, we characterise BIIB091, a novel, potent, selective and reversible small‐molecule inhibitor of BTK. Methods BIIB091 was evaluated in vitro and in vivo in preclinical models and in phase 1 clinical trial. Results In vitro, BIIB091 potently inhibited BTK‐dependent proximal signaling and distal functional responses in both B cells and myeloid cells with IC 50 s ranging from 3 to 106 n m , including antigen presentation to T cells, a key mechanism of action thought to be underlying the efficacy of B cell‐targeted therapeutics in multiple sclerosis. BIIB091 effectively sequestered tyrosine 551 in the kinase pocket by forming long‐lived complexes with BTK with t 1/2 of more than 40 min, thereby preventing its phosphorylation by upstream kinases. As a key differentiating feature of BIIB091, this property explains the very potent whole blood IC 50 s of 87 and 106 n m observed with stimulated B cells and myeloid cells, respectively. In vivo , BIIB091 blocked B‐cell activation, antibody production and germinal center differentiation. In phase 1 healthy volunteer trial, BIIB091 inhibited naïve and unswitched memory B‐cell activation, with an in vivo IC 50 of 55 n m and without significant impact on lymphoid or myeloid cell survival after 14 days of dosing. Conclusion Pharmacodynamic results obtained in preclinical and early clinical settings support the advancement of BIIB091 in phase 2 clinical trials.