Efficacy and safety of mirikizumab (LY3074828) in the treatment of moderate-to-severe plaque psoriasis: results from a randomized phase II study.

BACKGROUND: Inhibiting interleukin (IL)-23 in patients with psoriasis has demonstrated high levels of skin clearance. OBJECTIVES: To investigate, in a phase II (AMAF; NCT02899988), multicentre, double-blind trial, the efficacy and safety of three doses of mirikizumab (LY3074828), a p19-directed IL-23 antibody, vs. placebo in patients with moderate-to-severe plaque psoriasis. METHODS: Adult patients were randomized 1 : 1 : 1 : 1 to receive placebo (n = 52), mirikizumab 30 mg (n = 51), mirikizumab 100 mg (n = 51) or mirikizumab 300 mg (n = 51) subcutaneously at weeks 0 and 8. The primary objective was to evaluate the superiority of mirikizumab over placebo in achieving a 90% improvement in the Psoriasis Area and Severity Index (PASI 90) response at week 16. Comparisons were done using logistic regression analysis with treatment, geographical region and previous biological therapy in the model. Missing data were imputed as nonresponses. RESULTS: Ninety-seven per cent of patients completed the first 16 weeks of the study. The primary end point was met for all mirikizumab dose groups vs. placebo, with PASI 90 response rates at week 16 of 0%, 29% (P = 0·009), 59% (P < 0·001) and 67% (P < 0·001) for patients receiving placebo, and mirikizumab 30 mg, 100 mg and 300 mg, respectively. There were two (1%) serious adverse events in mirikizumab-treated patients vs. one (2%) in a placebo-group patient. CONCLUSIONS: At week 16, 67% of patients treated with mirikizumab 300 mg at 8-week intervals achieved PASI 90. The percentage of patients reporting at least one treatment-emergent adverse event was similar among patients treated with placebo or mirikizumab.

A prospective phase III, randomized, double-blind, placebo-controlled study of brodalumab in patients with moderate-to-severe plaque psoriasis.

BACKGROUND: The interleukin-17 cytokine family plays a central role in psoriasis pathogenesis. OBJECTIVES: To evaluate the efficacy and safety of brodalumab, a human anti-interleukin-17 receptor antibody, in treating patients with moderate-to-severe plaque psoriasis. METHODS: In this phase III, double-blind, placebo-controlled study (NCT01708590; AMAGINE-1), adult patients in the U.S.A., Canada and Europe were randomized to brodalumab (140 or 210 mg) or placebo every 2 weeks (Q2W), with an additional dose at week 1, for a 12-week induction phase. At week 12, patients receiving brodalumab who achieved static Physician's Global Assessment 0 or 1 (sPGA success) were rerandomized to the placebo or induction dose. After week 16, patients with sPGA ≥ 3 were re-treated with the induction dose. After ≥ 12 weeks of retreatment, patients with sPGA 2 for ≥ 4 weeks or sPGA ≥ 3 were rescued with brodalumab 210 mg Q2W. At week 12, patients randomized to brodalumab with sPGA ≥ 2 or placebo received brodalumab 210 mg Q2W. Coprimary end points were the percentage of patients with ≥ 75% improvement in Psoriasis Area and Severity Index score (PASI 75) and sPGA success at week 12. RESULTS: There were 661 patients randomized: 220 placebo, 219 brodalumab 140 mg and 222 brodalumab 210 mg. At week 12, 60% (140 mg) and 83% (210 mg) vs. 3% (placebo) achieved PASI 75, and 54% (140 mg) and 76% (210 mg) vs. 1% (placebo) achieved sPGA success. The safety profile was considered acceptable. CONCLUSIONS: Brodalumab therapy resulted in significant clinical benefit and an acceptable safety profile in patients with moderate-to-severe plaque psoriasis.

A randomized, double-blind, placebo-controlled study to evaluate the addition of methotrexate to etanercept in patients with moderate to severe plaque psoriasis.

BACKGROUND: Etanercept plus methotrexate combination therapy has not been adequately investigated in psoriasis. OBJECTIVES: To evaluate etanercept plus methotrexate vs. etanercept monotherapy in patients with moderate to severe plaque psoriasis who had not failed prior methotrexate or tumour necrosis factor-inhibitor therapy. METHODS: Patients received etanercept 50 mg twice weekly for 12 weeks followed by 50 mg once weekly for 12 weeks and were randomized 1 : 1 to receive methotrexate (7·5-15 mg weekly) or placebo. The primary endpoint was the proportion of patients achieving ≥75% improvement in Psoriasis Area and Severity Index (PASI 75) at week 24. RESULTS: In total, 239 patients were enrolled in each arm. PASI 75 was significantly higher at week 24 for the combination therapy group compared with the monotherapy group (77·3% vs. 60·3%; P < 0·0001). Other PASI improvement scores at week 12 [PASI 75, 70·2% vs. 54·3% (P = 0·01); PASI 50, 92·4% vs. 83·8% (P = 0·01); and PASI 90, 34·0% vs. 23·1% (P = 0·03)] showed similar results as did week 24 PASI 50 (91·6% vs. 84·6%; P = 0·01) and PASI 90 (53·8% vs. 34·2%; P = 0·01). Significantly more patients receiving combination therapy than monotherapy had static Physician's Global Assessment of clear/almost clear at week 12 (65·5% vs. 47·0%; P = 0·01) and week 24 (71·8% vs. 54·3%; P = 0·01). Adverse events (AEs) were reported in 74·9% and 59·8% of combination therapy and monotherapy groups, respectively; three serious AEs were reported in each arm. CONCLUSIONS: Combination therapy with etanercept plus methotrexate had acceptable tolerability and increased efficacy compared with etanercept monotherapy in patients with moderate to severe psoriasis.

Mammary epithelial cell-cycle progression via the alpha(2)beta(1) integrin: unique and synergistic roles of the alpha(2) cytoplasmic domain.

The alpha(2)beta(1) integrin supports cell-cycle progression of mammary epithelial cells adherent to type I collagen matrices. Integrin collagen receptors containing the alpha(2) cytoplasmic domain stimulated expression of cyclin E and cyclin-dependent kinase (cdk)2, resulting in cyclin E/cdk2 activation in the absence of growth factors other than insulin. Integrin collagen receptors in which the alpha(2) cytoplasmic domain was replaced by the alpha(1) cytoplasmic domain or an alpha(2) subunit cytoplasmic domain truncated after the GFFKR sequence failed to stimulate cyclin E/cdk2 activation or entry into S phase in the absence of growth factors. Although overexpression of cyclins D or E or cdk2 in cells expressing the integrin collagen receptor with the alpha(1)-integrin cytoplasmic domain did not restore G(1) progression when mammary epithelial cells adhered to type I collagen, co-expression of cyclin E and cdk2 did rescue the ability of the transfectants to enter S phase. Activation of cyclin E/cdk2 complex by mammary epithelial cells required synergy between adhesion mediated by an integrin collagen receptor containing the alpha(2)-integrin subunit cytoplasmic domain and the insulin receptor.

Specific residues within the alpha 2 integrin subunit cytoplasmic domain regulate migration and cell cycle progression via distinct MAPK pathways.

The alpha(2) integrin subunit cytoplasmic domain is necessary for epidermal growth factor (EGF)-stimulated chemotactic migration and insulin-dependent entry into S-phase of mammary epithelial cells adherent to type I collagen. Truncation mutants revealed that the seven amino acids, KYEKMTK, in addition to the GFFKR motif were sufficient for these functions. Mutation of tyrosine 1134 to alanine inhibited the ability of the cells to phosphorylate p38 MAPK and to migrate in response to EGF but had only a modest effect on the ability of the cells to induce sustained phosphorylation of the ERK MAPK, to up-regulate cyclin E and cdk2 expression, and to enter S-phase when adherent to type I collagen. Conversely, mutation of the lysine 1136 inhibited the ability of the cells to increase cyclin E and cdk2 expression, to maintain long term phosphorylation of the ERK MAPK, and to enter S-phase but had no effect on the ability of the cells to phosphorylate the p38 MAPK or to migrate on type I collagen in response to EGF. Methionine 1137 was essential for both migration and entry into S-phase. Thus, distinctly different structural elements of the alpha(2) integrin cytoplasmic domain are required to engage the signaling pathways leading to cell migration or cell cycle progression.

alpha 2 integrin subunit cytoplasmic domain-dependent cellular migration requires p38 MAPK.

The alpha(2) integrin subunit cytoplasmic domain uniquely supported epidermal growth factor (EGF)-stimulated migration on type I collagen. p38 MAP kinase- and phosphatidylinositol 3-kinase-specific inhibitors, but not a MEK-specific inhibitor, eliminated EGF-stimulated and unstimulated alpha(2)-cytoplasmic domain-dependent migration. Following adhesion to collagenous matrices, cells expressing the full-length alpha(2) integrin subunit, but not cells expressing a chimeric alpha(2) integrin subunit in which the alpha(2)-cytoplasmic domain was replaced by the cytoplasmic domain of the alpha(1)-subunit, exhibited sustained and robust phosphorylation of p38 MAP kinase. Expression of dominant negative p38 MAP kinase inhibited alpha(2)-cytoplasmic domain-dependent, EGF-stimulated migration as well as unstimulated migration on collagen. Expression of constitutively active Rac1(Val-12) augmented p38 MAP kinase activation and alpha(2)-cytoplasmic domain-dependent migration. It also rescued the ability of cells expressing the alpha(1)-cytoplasmic domain to activate p38 MAPK and to migrate. These results suggest that the alpha(2) integrin cytoplasmic domain uniquely stimulates the p38 MAP kinase pathway that is required for unstimulated and EGF-stimulated migration on type I collagen.

Inactivation of Escherichia coli-expressed rabbit cytochrome P-450 2C enzymes by 17 beta-substituted steroids.

The specific inactivation of rabbit cytochromes P-450 2C by 17 beta-substituted steroids has been investigated by using purified, Escherichia coli-expressed enzymes. The expressed P-450s provided a means to characterize accurately the effects of 21,21-dichloroprogesterone, 21,21-dichloropregnenolone, 21-chloro-21-fluoropregnenolone, pregn-5,20-diene-3 beta-ol and pregn-4,20-diene-3-one on progesterone hydroxylation by P-450 2C5, 2C4, 2C3 and 2C3v. Previous studies using rabbit liver microsomes had suggested that 21-chloro-21-fluoropregnenolone is a selective inactivator of 2C5, a progesterone 21-hydroxylase. Studies of the expressed P-450 2C forms showed little selectivity of 21,21-dichloroprogesterone, pregn-5,20-diene-3 beta-ol or pregn-4,20-diene-3-one, whereas 21,21-dichloropregnenolone and 21-chloro-21-fluoropregnenolone preferentially inactivate 2C5. The data indicate the importance of progesterone 21-hydroxylase activity in facilitating selective mechanism-based inactivation of 2C subfamily P-450s by 21,21-dihalogenated steroids. Studies of the inactivation of P-450 2C16, a progesterone 16 alpha-hydroxylase, by the three dihalogenated steroids yielded results consistent with previous findings of 16 alpha-hydroxylase inactivation in rabbit liver microsomes from the inbred B/J strain. Additionally, two mutants, 2C3v:V113A and 2C3v:V113A, T364N were created which confer progesterone 21-hydroxylation on 2C3v. The single mutant, a 6 beta- and 21-hydroxylase, is inactivated rapidly by all three of the 21,21-dihalogenated steroids, whereas the double mutant, a 16 alpha- and 21-hydroxylase, is preferentially inactivated by 21,21-dichloroprogesterone.(ABSTRACT TRUNCATED AT 250 WORDS)

Structural determinants of cytochrome P450 2B1 specificity: evidence for five substrate recognition sites.

Twelve site-directed mutants of rat cytochrome P450 2B1 distributed over seven positions and four putative substrate recognition sites (SRS) were constructed and expressed in COS cells. Function was examined using androstenedione and testosterone as substrates. Substitutions at positions 303, 360, and 473 did not markedly affect the regio- or stereoselectivity of androgen metabolism, whereas mutants in positions 206 (SRS-2), 302 (SRS-4), and 363 and 367 (SRS-5) exhibited markedly different steroid metabolite profiles compared with parental P450 2B1. In particular, the Phe-206-->Leu substitution conferred androgen 6 alpha- and testosterone 7 alpha-hydroxylase activities, and the Thr-302-->Ser substitution suppressed androgen 16 beta-hydroxylation in favor of androstenedione 16 alpha- and testosterone 15 alpha-hydroxylation. Replacement of Val-363 or Val-367 with Ala conferred androgen 15 alpha-hydroxylase and 6 beta-hydroxylase activities, respectively, and suppressed susceptibility to mechanism-based inactivation by the P450 2B1-selective chloramphenicol analog N-(2-p-nitrophenethyl)chlorofluoroacetamide. The Val-367-->Ala mutant was also resistant to chloramphenicol itself. The Leu mutant at position 363 exhibited increased specificity for androstenedione and testosterone 16 beta-hydroxylation, whereas the Leu mutant at position 367 exhibited decreased stereospecificity. Most interestingly, the size of key residues identified plays a critical role in governing steroid hydroxylation from the alpha-face or beta-face and hydroxylation on the D-ring or the B-ring.(ABSTRACT TRUNCATED AT 250 WORDS)