Therapeutic Focus

Vitamin D Insufficiency

Vitamin D hormone production declines markedly if the pro-hormone, 25-hydroxyvitamin D, is in short supply, a condition often described by terms such as “vitamin D insufficiency”. Therefore, measurement of 25-hydroxyvitamin D levels in blood has become the accepted method among healthcare professionals to monitor vitamin D status.

Vitamin D insufficiency is nearly ubiquitous in the chronic kidney disease (CKD) population.  Recent studies have documented that the great majority of CKD patients have low blood levels of 25-hydroxyvitamin D, suggesting that the onset of CKD is a significant risk factor for vitamin D insufficiency and that the prevalence of vitamin D insufficiency increases as CKD progresses.  In addition, recent studies have linked vitamin D insufficiency to progression of CKD and increased morbidity and mortality in hemodialysis patients.

U.S. Market Opportunity

Vitamin D insufficiency has been shown to exacerbate the development of secondary hyperparathyroidism (SHPT) and related bone diseases (e.g., renal osteodystrophy). Published sources indicate that approximately 70% of Stage 3, 80% of Stage 4, and 90% of Stage 5 patients suffer from vitamin D insufficiency. There are approximately 12 million Stage 3 and 4 CKD patients, and over 500,000 Stage 5 patients in the U.S.

Parallel advances in the understanding of vitamin D insufficiency and its complications have resulted in a global initiative known as Kidney Disease: Improving Global Outcomes (KDIGO). The guidelines from KDIGO advocate the treatment of vitamin D insufficiency in CKD patients with SHPT.

Currently in the U.S., there are only two options available for the prevention and treatment of vitamin D insufficiency: over-the-counter (OTC) dietary supplements which typically contain 400 to 5,000 IU per unit dose of either vitamin D₂ or D₃, and prescription oral products containing 50,000 IU per unit dose of vitamin D₂. Recent studies have shown that both options have limited efficacy in restoring adequate vitamin D pro-hormone level, especially in patients who are overweight.