Unique Features of the Molecule

image01 Potential osteogenic property and shows accelerated fracture repairing. New bone formation at the fracture site is increased by ~40% in rats.

image01 Increases callus formation at only 1 mg/kg dose and restores trabecular microarchitecture at fractured site in normal female and osteopenic rats

image01 It leads to accelerated fracture repair by BMP-2/Smad signaling pathway.

image01 Compound found safe in single dose toxicity studies in rodents and in 10 days DRF studies.

image01 Essential Safety Pharmacology study as per schedule Y is completed and no mortality/adverse effect was observed.

Background & Scientific Basis of the Project

Osteoporosis and related bone metabolic diseases have emerged as leading health care issues worldwide. The overall weakening of bone that results in osteoporosis is caused by a shift in the equilibrium of bone remodeling in which bone formation by osteoblasts is overtaken by the resorption of old bone by osteoclasts. India has the largest population in world suffering from osteoporosis. One out of three female and one out of eight male are suffering from osteoporosis which predisposes to greater fracture risks. In addition, the accidental fracture rates in India are one of the highest in world. Despite the biologically optimized nature of the repair process, patients still require several months before a fracture achieves complete return to mechanical stability. Consequently, there is significant interest in treatments that could enhance the rate of repair providing for a more rapid return to an active lifestyle and work. The identification of a compound that could effectively enhance repair under these less than optimal conditions would be of significant social and economic benefit.

Highlights of results

Medicarpin, a natural pterocarpan, was identified as the most potent osteogenic agent. Subsequently new synthetic derivatives based on Medicarpin scaffold were synthesized. Out of these, a synthetic pterocarpan, CDRI-S007-1500 was taken up for further studies based on the preliminary studies which revealed enhanced osteoblastogenesis and chondrogenesis by CDRI-S007-1500 (CSIR-CDRI PCT Pub. No. WO/2010/052734. We identified S007-1500 (M.W. 294) to be the most potent among the other members of the series. S007-1500 required estrogen receptor (ER) function for its osteogenic action. S007-1500 stimulated several osteogenic bone morphogenetic proteins (BMPs), including BMP-2, 6 &-7. Pharmacological blockade of ER signalling abrogated the stimulatory effect of S007-1500 on BMP secretion from osteoblasts. Presence of endogenous BMP inhibitor, noggin also abrogated differentiation induction of osteoblasts by S007-1500. S007-1500 also stimulated BMP-2&-7 synthesis in human mesenchymal stem cells and this action exhibited ER dependence. Despite requiring ER function for its osteogenic effect, S007-1500 has no uterine estrogenicity/anti-estrogenicity. In vivo, S007-1500 stimulated new bone formation and bone biomechanical strength in growing female rats at a minimum oral dose of 1.0 mg/kg dose. S007-1500 also increased cortical microarchitectural parameters in the growing rats that further confirmed its favourable effect on bone strength. In OVx rats (with established osteopenia), S007-1500 at 10.0 mg/kg oral dose increased mineral apposition rate (MAR) and bone formation rate (BFR) over sham + vehicle, OVx + vehicle and OVx + PTH groups. qCT measurements demonstrates that S007-1500 treatment to OVx rats also improved cortical thickness over OVx + vehicle group. Although, S007-1500 stimulated BMP synthesis by osteoblasts, it has no effect on the BMP-2 mRNA levels of aorta and cardiac valves of rats treated with this compound, suggesting absence of off-target effect. S007-1500 at 1.0 mg/kg oral dose also accelerated fracture healing in normal adult as well as in OVx (osteopenic) rats. S007-1500 accelerated fracture repairing by stimulating BMP-2/Smad signaling pathway. Single-dose toxicity studies and 10 days DRF studies suggest that S007-1500 is well tolerated. Together, pharmacological data suggest that S007-1500 possesses potential osteogenic property and shows accelerated fracture repairing by significantly increasing the callus formation at the fracture site in the test models i.e. normal adult females and osteopenic OVx rats at 1.0 mg/kg dose and also restoration of trabecular microarchitecture as determined by microCT. These data suggest that S007-1500 has therapeutic potential as rapid fracture repairing agent and possesses several beneficial effects on improving bone health in the management of osteoporosis and bone related disorders.

image01 S007-1500 does not increases BMP-2 expression in heart valve (bicuspid and tricuspid) and common aortic arch suggestive of absence of any off-target effects.

image01 S007-1500 increases the alkaline phospatase activity and nascent calcium deposition in primary calvarial osteoblast cells.

image01 S007-1500 increases the mineralization from bone marrow derived osteoblast cells.

image01 S007-1500 increases mRNA levels of osteogenic genes in osteoblasts.

image01 S007-1500 enhances osteoblastogenesis via ER/BMP2 pathway.

image01 Increased BMP-2- and -7 expression in human marrow stromal cells.

image01S007-1500 improves cortical microarchitecture in growing rats.

image01 S007-1500 promotes osteoid formation in ovariectomized rats.

image01 S007-1500 improves cortical microarchitecture in OVx rats.

image01 S007-1500 has no uterine estrogenicity.

image01S007-1500 enhances chondrocyte mineralization.

image01 Accelerated fracture repairing by S007-1500 in a BMP-2/Smad dependent manner.

Comparative superiority over the marketed drugs

Current therapeutic approaches in India for the management of Osteoporosis and bone related disorders include calcium, vitamin D, hormone replacement therapy, raloxifene, alendronate and risedronate out of which bisphosphonates (alendronate) constitute the mainstay of treatment in India. All of these treatments attempt to reduce fracture risk primarily by reducing the rate of bone resorption and remodeling and in some cases, leading to minimal increases in bone mass. The reduction of bone loss alone, however, does not routinely lead the restoration of normal bone mass or strength and only leads to modest reductions in fracture risk. PTH has been shown to significantly increase bone mineral density and reduce fracture risk but is associated with other side effects (Matthew et al 2011). Recombinant human BMP2 (INFUSE® Bone Graft) has also been approved for open tibial fractures by FDA. However, the use of BMP2 is hampered by numerous clinical complications which include postoperative inflammation, cyst-like bone formation and life-threatening cervical swelling. Food and Drug Administration (FDA) has in fact issued a warning that in anterior cervical spine surgery, use of BMP/INFUSE posed the risks of dysphagia, hematoma and swelling. Consequently, there is an urgent need to discover safe and economical orally active agents that promote bone repairing and regeneration. Currently, no orally active rapid fracture repairing agent is available nationally and internationally. Our Studies have led to identification of osteogenic activity in molecules like medicarpin (Tyagi et al 2010; Bhargavan et al 2012). Subsequently, several synthetic analogues of Medicarpin have been designed. Of these, CDRI-S007-1500 has been found to have bone regeneration potential as assessed by its effect on chondrogenesis and fracture callus formation.

Current Status of Developmental Studies

Pharmacokinetic evaluations
The plasma concentration versus time profile of S007-1500 was subjected to non-compartmental analysis by WinNonLin 5.1. The mean oral bioavailability of S007-1500 in female SD rats was found to be 5.13% (20 mg/Kg). The maximum plasma concentration was reached at 1 hour. The mean oral bioavailability of S007-1500 in male SD rats was found to be 22.04% (at 10mg/kg) and 16.49 % (at 20 mg/kg). The maximum plasma concentration reached, Cmax, was 213.25±92.80 ng/mL and was reached after 30 min in both the cases.

Single dose toxicity studies in rodents
Single Dose Toxicity Study in Rat by oral route and by intramuscular route (Doses: 3,6,12 and 25 mg/kg bw); Single Dose Toxicity Study in Mice by oral route (Doses: 25, 50 and 100 mg/ kg bw). No mortality was observed in treated or control group. Compound is safe at the doses used in the above studies.

Intellectual Property Right Protection (IPR) / Patent Status

image01 Indian Patent App No. 2511DEL2008, Filed on 06 Nov 2008.

image01 Chinese Patent App No. 200980152325.9, Filed on 23 Jun 2011.

image01 European Patent App No. 09787590.0, Filed on 05 May 2011.

image01 Japanese Patent App No. 2011-535212, Filed on 06 May 2011; Granted: JP 535212 dt 03.03.2015).

image01 • Korean Patent App No. 10-2011-7012523, Filed on 31 May 2011.

image01 • US Patent App No. 13/127913, Filed on 05 May 2011 Granted: US-8686028 dated 01-04-2014.

image01 • PCT Patent App No. PCT/IN2009/000285, Filed on 14 May 2009.