Vitamin D receptor agonist - elocalcitol
Calcitriol, the active metabolite of vitamin D3, is known to be involved in the regulation of bone metabolism, and also in calcium and phosphorus homeostatis. However, it also targets the vitamin D receptor that is present in a variety of other tissues and involved in the regulation of numerous processes, such as cell proliferation, differentiation and apoptosis, plus functions within the immune system.
Calcitriol, the active metabolite of vitamin D3, is known to be involved in the regulation of bone metabolism, and also in calcium and phosphorus homeostatis. However, it also targets the vitamin D receptor that is present in a variety of other tissues and involved in the regulation of numerous processes, such as cell proliferation, differentiation and apoptosis, plus functions within the immune system.
As a result, calcitriol and derivatives have been used therapeutically in several indications, including cancer, benign prostatic hyperplasia, osteoporosis and chronic inflammatory conditions such as psoriasis.
However, it causes side-effects such as hypercalcaemia, so an analogue with a better profile would be extremely useful. One such compound is elocalcitol, being developed by Italian company BioXell under licence from Roche, which is being looked at for several indications.1
One of these is osteoporosis. A total of 101 postmenopausal women with osteoporosis were given each day 1.2g calcium and 400 IU of vitamin D, along with 150µg oral elocalcitol or placebo.2 Those given the drug had a significant increase in bone mass density, and bone formation and resorption decreased.
It is also being looked at to treat BPH. A double blind, parallel group Phase IIa trial was carried out in 119 men aged 50 or over who had BPH.3 They were given 150µg elocalcitol once a day or placebo for 12 weeks. Those given the drug had a mean reduction in prostate volume of 2.9%, compared with a 4.3% increase in the control group.