This target is clinically validated, so you can't assume this is a case of "drug works but target isn't clinically relevant."
Also, P&G is dropping a drug to a validated target in late preclinical. It's unlikely that they could have made a tangible determination of whether or not the drug has the efficacy to compete with denosumab at this point. That suggests to me that there was a show stopper of some sort. Immunogenicity or the possibility that the drug is too rapidly cleared are possibilities that come to mind.