ono-5334 and Osteoporosis

Cathepsin K is the protease that is primarily responsible for the degradation of bone matrix by osteoclasts. Inhibitors of cathepsin K are in development for treatment of osteoporosis. Currently available antiresorptive drugs interfere with osteoclast function. They inhibit both bone resorption and formation, due to the coupling between these processes. Cathepsin K inhibitors, conversely, target the resorption process itself and may not interfere with osteoclast stimulation of bone formation. In fact, when cathepsin K is absent or inhibited in mice, rabbits, or monkeys, bone formation is maintained or increased. In humans, inhibition of cathepsin K is associated with sustained reductions in bone resorption markers but with smaller and transient reductions in bone formation markers. The usefulness of cathepsin K inhibitors in osteoporosis is now being examined in phase 2 and phase 3 clinical trials of postmenopausal osteoporotic women.

Topics: Alkaline Phosphatase; Animals; Biphenyl Compounds; Bone Density; Bone Remodeling; Bone Resorption; Cathepsin K; Humans; Osteoporosis; Osteoporosis, Postmenopausal; Thiazolidines

A sustained-release tablet (SRT) of ONO-5334 was compared to the immediate-release tablet (IRT) dose, which demonstrated effects on bone mineral density (BMD) comparable to those of therapy with alendronate. The single-dose phase was a randomized, partial single-blind, crossover study where 50-, 100-, and 300-mg SRTs and 300-mg IRTs were administered to nine post-menopausal women. The multiple-dose phase was a randomized, double-blind, placebo-controlled, parallel-group study where 100- and 300-mg SRTs, or placebo were administered to 24 women. After a single administration of a 300-mg SRT, mean C max was 3.3-fold lower, mean AUCinf was 0.83-fold lower and mean C 24h was 5.4-fold higher compared to the 300-mg IRT. Repeated SRT dosing did not significantly affect PK, although C 24h increased slightly. After a single ONO-5334 dose, serum CTX-I was suppressed by ~50 % within 1 h, reaching maximum suppression 6 h post-dose. Greater suppression was maintained longer by the 300-mg SRT vs. the 300-mg IRT. Second morning void and cumulative urine CTX-I showed clear dose-response effects at/over 24 h for SRT, with maximum suppression occurring at/over 24 h (except 50- and 300-mg cumulative urine). Repeated dosing suggested greater suppression of urine CTX-I. Compared with the IRT, the SRT showed reduced C max, greater C 24h, and slightly reduced AUCinf dose for dose. The SRT showed clear dose-response suppression on bone resorption and greater efficacy dose for dose vs. the IRT.

Topics: Aged; Alendronate; Area Under Curve; Bone and Bones; Bone Density; Bone Resorption; Cathepsin K; Collagen Type I; Cross-Over Studies; Delayed-Action Preparations; Female; Humans; Middle Aged; Osteoporosis; Postmenopause; Single-Blind Method; Thiazolidines

The purpose of the study was clarify the effect of the cathepsin K inhibitor ONO-5334 on bone resortion markers using sustained release (SR) formulations with different pharmacokinetic (PK) patterns, and identify the optimal SR formulation. The PK profiles and pharmacodynamic effect on bone resorption markers of 4 SR candidates formulations were evaluated in healthy postmenopausal women within a randomized, 2-part, open-label crossover study. In Part A, subject received a single dose of each formulation orally in the fed state. In Part B, two selected formulations were evaluated in the fasted state. From the results from Part A, C(max) was reduced and plasma concentrations of ONO-5334 were sustained with all SR formulations compared with an immediate release tablet. In pharmacodynamics, the level of C-terminal telopeptide of type I collagen (CTX) in serum and urine were inhibited with SR tablets rather than with granules. C max and area under the concentration-time curve from time 0 to the last measurable time point (AUC(0-t)) of SR tablets were higher than those of granules. From Part B, C max in the fasted condition was lower than that in the fed condition with two SR tablets. In contrast, C(24 h) in the fasted condition was slightly higher than that in the fed condition, but AUC(0-t) was similar. The inhibitory effect on CTX in serum and urine may depend on the PK pattern of ONO-5334. The SR tablets was well tolerated in postmenopausal women and has the optimal SR profiles on pharmacodynamics effect on bone resortion markers and PK profile. These results suggest that SR tablets of ONO-5334 are an excellent drug candidate for osteoporosis.

Topics: Aged; Aged, 80 and over; Cathepsin K; Cross-Over Studies; Female; Humans; Middle Aged; Osteoporosis; Thiazolidines

This study compared the effects of ONO-5334, a cathepsin K inhibitor, with those of alendronate on bone mass and strength in ovariectomized rats. Ovariectomy resulted in significant elevation in urinary deoxypyridinoline and plasma C-terminal cross-linking telopeptide of type I collagen (CTX) 8 weeks after surgery. Peripheral quantitative computed tomography analysis showed that total, trabecular, and cortical bone mineral content (BMC) decreased in the proximal tibia, which was paralleled with a significant decline in bone strength. Treatment with ONO-5334 (0.12, 0.6, 3 or 15 mg/kg) once daily for 8 weeks dose-dependently restored the decrease in total BMC and bone mineral density (BMD) in the proximal tibia and suppressed urinary deoxypyridinoline and plasma CTX levels. Alendronate (1 mg/kg, once daily) also fully restored these bone mass parameters. Separate analysis of trabecular and cortical bones, however, showed that ONO-5334 only partially restored trabecular BMD and BMC at 15 mg/kg, whereas alendronate fully restored these parameters. On the other hand, ONO-5334 increased both cortical BMD and BMC with an effect more potent than that of alendronate. Bone geometric analysis indicated that ONO-5334 at 15 mg/kg decreased endosteal circumference without affecting periosteal circumference, resulting in marked increase in cortical thickness. Interestingly, the effects of ONO-5334 on bone strength parameters were more prominent than those of alendronate, although the two test compounds had a similar effect on total BMC. Taken together, our results indicate that ONO-5334 has pharmacological characteristics different from those of alendronate and may offer a unique therapy for patients with osteoporosis.

Topics: Alendronate; Animals; Bone Density; Bone Density Conservation Agents; Cathepsin K; Female; Osteoporosis; Ovariectomy; Rats; Thiazolidines; Tibia