Carolyn DaSilva

Odanacatib, a cathepsin-K inhibitor for osteoporosis: A two-year study in postmenopausal women with low bone density

Cathepsin K, a cysteine protease expressed in osteoclasts, degrades type 1 collagen. Odanacatib selectively and reversibly inhibited cathepsin K and rapidly decreased bone resorption in preclinical and phase I studies. A 1‐year dose‐finding trial with a 1‐year extension on the same treatment assignment was performed in postmenopausal women with low bone mineral density (BMD) to evaluate the safety and efficacy of weekly doses of placebo or 3, 10, 25, or 50 mg of odanacatib on BMD and biomarkers of skeletal remodeling. Women with BMD T‐scores of −2.0 or less but not less than −3.5 at the lumbar spine or femoral sites were randomly assigned to receive placebo or one of four doses of odanacatib; all received vitamin D with calcium supplementation as needed. The primary endpoint was percentage change from baseline lumbar spine BMD. Other endpoints included percentage change in BMD at hip and forearm sites, as well as changes in biomarkers of skeletal remodeling. Twenty‐four months of treatment produced progressive dose‐related increases in BMD. With the 50‐mg dose of odanacatib, lumbar spine and total‐hip BMD increased 5.5% and 3.2%, respectively, whereas BMD at these sites was essentially unchanged with placebo (−0.2% and −0.9%). Biochemical markers of bone turnover exhibited dose‐related changes. The safety and tolerability of odanacatib generally were similar to those of placebo, with no dose‐related trends in any adverse experiences. In summary, 2 years of weekly odanacatib treatment was generally well‐tolerated and increased lumbar spine and total‐hip BMD in a dose‐related manner in postmenopausal women with low BMD.

Odanacatib in the treatment of postmenopausal women with low bone mineral density: Three-year continued therapy and resolution of effect

The selective cathepsin K inhibitor odanacatib (ODN) progressively increased bone mineral density (BMD) and decreased bone‐resorption markers during 2 years of treatment in postmenopausal women with low BMD. A 1‐year extension study further assessed ODN efficacy and safety and the effects of discontinuing therapy. In the base study, postmenopausal women with BMD T‐scores between −2.0 and −3.5 at the lumbar spine or femur received placebo or ODN 3, 10, 25, or 50 mg weekly. After 2 years, patients (n = 189) were rerandomized to ODN 50 mg weekly or placebo for an additional year. Endpoints included BMD at the lumbar spine (primary), total hip, and hip subregions; levels of bone turnover markers; and safety assessments. Continued treatment with 50 mg of ODN for 3 years produced significant increases from baseline and from year 2 in BMD at the spine (7.9% and 2.3%) and total hip (5.8% and 2.4%). Urine cross‐linked N‐telopeptide of type I collagen (NTx) remained suppressed at year 3 (−50.5%), but bone‐specific alkaline phosphatase (BSAP) was relatively unchanged from baseline. Treatment discontinuation resulted in bone loss at all sites, but BMD remained at or above baseline. After ODN discontinuation at month 24, bone turnover markers increased transiently above baseline, but this increase largely resolved by month 36. There were similar overall adverse‐event rates in both treatment groups. It is concluded that 3 years of ODN treatment resulted in progressive increases in BMD and was generally well tolerated. Bone‐resorption markers remained suppressed, whereas bone‐formation markers returned to near baseline. ODN effects were reversible: bone resorption increased transiently and BMD decreased following treatment discontinuation.

Odanacatib in the treatment of postmenopausal women with low bone mineral density: five years of continued therapy in a phase 2 study.

Odanacatib (ODN) is a selective inhibitor of the collagenase cathepsin K that is highly expressed by osteoclasts. In this 2‐year, phase 2, dose‐ranging trial, postmenopausal women with bone mineral density (BMD) T‐scores −2.0 to −3.5 at spine or hip were randomized to weekly placebo or ODN 3, 10, 25, or 50 mg plus vitamin D3 and calcium. Prespecified trial‐extensions continued through 5 years. In year 3, all women were re‐randomized to ODN 50 mg or placebo. For years 4 and 5, women who received placebo or ODN 3 mg in years 1 and 2 and placebo in year 3 received ODN 50 mg; others continued year 3 treatments. Endpoints included lumbar spine (primary), hip, 1/3 radius, and total body BMD; markers of bone metabolism; and safety. Women in the year 4 to 5 extension receiving placebo (n = 41) or ODN 50 mg (n = 100) had similar baseline characteristics. For women who received ODN (10–50 mg) for 5 years, spine and hip BMD increased over time. With ODN 50 mg continually for 5 years (n = 13), mean lumbar spine BMD percent change from baseline (95% confidence interval [CI]) was 11.9% (7.2% to 16.5%) versus −0.4% (−3.1% to 2.3%) for women who were switched from ODN 50 mg to placebo after 2 years (n = 14). In pooled results of women receiving continuous ODN (10–50 mg, n = 26–29), year 5 geometric mean percent changes from baseline in bone resorption markers cross‐linked N‐telopeptide of type I collagen (NTX)/creatinine and cross‐linked C‐telopeptide (CTX) were approximately −55%, but near baseline for bone formation markers bone‐specific alkaline phosphatase (BSAP) and amino‐terminal propeptide of type I procollagen (P1NP). In women switched from ODN 10 to 50 mg to placebo after 2 years (n = 25), bone turnover markers were near baseline. In summary, women receiving combinations of ODN (10–50 mg) for 5 years had gains in spine and hip BMD and showed larger reductions in bone resorption than bone formation markers. Discontinuation of ODN resulted in reversal of treatment effects. Treatment with ODN for up to 5 years was generally well‐tolerated.

Effects of odanacatib on BMD and safety in the treatment of osteoporosis in postmenopausal women previously treated with alendronate: a randomized placebo-controlled trial.

CONTEXT Odanacatib (ODN) is a selective cathepsin K inhibitor being developed to treat osteoporosis. OBJECTIVE The effects of ODN were evaluated on bone mineral density (BMD), biochemical markers of bone turnover, and safety in patients previously treated with alendronate. DESIGN This was a randomized, double-blind, placebo-controlled, 24-month study. SETTING The study was conducted at private or institutional practices. PARTICIPANTS Postmenopausal women (n = 243) ≥ 60 years of age with low BMD at the total hip, femoral neck, or trochanter (T-score ≤-2.5 but >-3.5 without prior fracture or ≤-1.5 but >-3.5 with prior fracture) on alendronate for ≥ 3 years. INTERVENTION The intervention included ODN 50 mg or placebo weekly. MAIN OUTCOME MEASURES The primary end point was percentage change from baseline of femoral neck BMD at month 24. BMD was assessed by dual-energy x-ray absorptiometry at baseline and 6, 12, and 24 months. Biochemical markers of bone turnover (serum C-telopeptides of type 1 collagen, urinary N-telopeptides of type 1 collagen, serum bone specific alkaline phosphatase, and serum N-terminal propeptide of type 1 collagen) were measured at baseline and 3, 6, 12, 18, and 24 months. RESULTS In the ODN group, BMD changes from baseline at the femoral neck, trochanter, total hip, and lumbar spine at 24 months (1.7%, 1.8%, 0.8%, and 2.3%, respectively) were significantly different from the placebo group. ODN significantly decreased urinary N-telopeptides of type 1 collagen to creatinine ratio and significantly increased serum N-terminal propeptide of type 1 collagen compared with placebo. Serum C-telopeptides of type 1 collagen was unexpectedly increased with ODN treatment. The safety profile appeared similar between groups. CONCLUSIONS ODN provided incremental BMD gains in osteoporotic women after alendronate treatment.

A tacrolimus-related immunosuppressant with reduced toxicity

BACKGROUND Tacrolimus (FK506) has potent immunosuppressive properties reflecting its ability to block the transcription of lymphokine genes in activated T cells through formation of a complex with FK506 binding protein-12, which inhibits the phosphatase activity of calcineurin. The clinical usefulness of tacrolimus is limited, however, by severe adverse effects, including neurotoxicity and nephrotoxicity. Although this toxicity, like immunosuppression, appears mechanistically related to the calcineurin inhibitory action of the drug, a large chemistry effort has been devoted to search for tacrolimus analogs with reduced toxicity but preserved immunosuppressive activity that might have enhanced therapeutic utility. METHODS Here, we report on the identification of such an analog, which was synthetically derived from ascomycin (ASC), the C21 ethyl analog of tacrolimus, by introducing an indole group at the C32 position. The profile of biological activity of indolyl-ASC was characterized in rodent models of immunosuppression and toxicity. RESULTS Indolyl-ASC was found to exhibit an immunosuppressive potency equivalent to that of tacrolimus in T-cell activation in vitro and in murine transplant models, even though indolyl-ASC bound about 10 times less to intracellular FK506 binding protein-12 than tacrolimus or ASC. Further evaluation of indolyl-ASC revealed that it is threefold less potent than tacrolimus in inducing hypothermia, a response that may reflect neurotoxicity, and in causing gastrointestinal transit alterations in mice. Moreover, indolyl-ASC was at least twofold less nephrotoxic than tacrolimus upon 3-week oral treatment in rats. CONCLUSIONS Altogether, these data indicate a modest but definite improvement in the therapeutic index for indolyl-ASC compared with tacrolimus in rodent models.

Hypothemycin inhibits the proliferative response and modulates the production of cytokines during T cell activation.

Hypothemycin, a resorcylic acid lactone antibiotic, was identified as active in a screen for inhibitors of T cell activation. It was found to inhibit the proliferation of mouse and human T cells stimulated with anti-CD3 mAb + PMA and of human PBMC stimulated with anti-CD3 mAb alone. This inhibition was partially reversed by exogenous IL-2 indicating that it is not due to non-specific toxicity. Hypothemycin potently suppressed the production of IL-2 (IC50: 9 nM) but affected IL-2-induced proliferation to a lesser extent (IC50: 194 nM). Hypothemycin also inhibited IL-6, IL-10, IFN-gamma and TNF-alpha production. By contrast, it markedly enhanced the production of IL-4, IL-5 and IL-13. These effects were seen both at the mRNA and protein secretion levels. Analysis of the effect of hypothemycin on CD69 induction suggested that it disrupts calcineurin-independent rather than calcineurin-dependent signaling. Furthermore, hypothemycin was able to inhibit the phosphorylation of ERK1/2 induced by PMA treatment of T cells. Therefore, hypothemycin represents an inhibitor of T cell activation with a novel mode of action and unique modulatory activity on cytokine production.

OP0247 Effects of Odanacatib on BMD and Safety in the Treatment of Osteoporosis in Postmenopausal Women Previously Treated with Alendronate– a Randomized Placebo-Controlled Trial

Background Odanacatib (ODN) is an orally-active cathepsin K inhibitor being developed for the treatment of postmenopausal osteoporosis. Objectives This study evaluated the effects of ODN 50mg once weekly on BMD, bone turnover markers and safety in patients previously treated with alendronate (ALN). Methods This was a randomized, double-blind, placebo-controlled, 24-month study. The primary endpoint was % change from baseline at month 24 of femoral neck (FN) BMD. Postmenopausal women (n=243) ≥60 years of age with low BMD T-score at the total hip, FN or trochanter but no history of hip fracture and who have taken ALN for ≥3years were randomized to receive ODN or placebo. Patients received vitamin D3 and calcium supplementation. BMD was assessed by DXA at baseline, 6, 12 and 24 months. Biochemical markers of bone turnover (sCTx, uNTx, sBSAP and sP1NP) were measured at baseline and 3, 6, 12, 18 and 24 months. Results In the ODN group, BMD changes from baseline at 24 months were significantly increased from placebo at the femoral neck, trochanter, total hip and lumbar spine (1.7%, 1.8%, 0.8%, and 2.3%, respectively). In the placebo group, BMD at the femoral neck, trochanter and total hip declined significantly from baseline by month 24 (-0.9%, -1.4%, and -1.9% respectively). ODN significantly decreased bone resorption marker, u-NTx/Cr, and significantly increased bone formation markers, s-P1NP and s-BSAP, vs. placebo. The increase observed for the bone resorption marker s-CTx with ODN treatment was unexpected. Adverse events were comparable between the 2 treatments arms. The overall safety profile appeared similar between ODN and placebo. Image/graph Conclusions In this study ODN provided incremental BMD gains in osteoporotic women following ALN treatment. Biomarker results suggest that ODN decreases bone resorption while preserving bone formation. Disclosure of Interest S. Palacios Grant/research support from: Merck Sharp & Dohme Corp., S. Bonnick Grant/research support from: Merck Sharp & Dohme Corp., T. De Villiers Speakers bureau: Merck Sharp & Dohme Corp., R. Chapurlat Grant/research support from: Merck Sharp & Dohme Corp., Consultant for: Merck Sharp & Dohme Corp., A. Odio: None Declared, B. Scott Employee of: Merck Sharp & Dohme Corp., C. Le Bailly De Tilleghem Employee of: Merck Sharp & Dohme Corp., C. DaSilva Employee of: Merck Sharp & Dohme Corp., A. Leung Employee of: Merck Sharp & Dohme Corp., D. Gurner Employee of: Merck Sharp & Dohme Corp.