KAI-4169 is a novel pharmaceutical agent for the treatment of secondary hyperparathyroidism (SHPT), which is a frequent complication of chronic kidney disease (CKD). KAI-4169 has the potential to be best in class with superior efficacy and tolerability than other currently marketed therapies for SHPT. KAI-4169 is in IND-enabling studies with human clinical trials anticipated in 2010.

SHPT develops early in CKD and worsens as renal function declines and progresses to end-stage renal disease (ESRD). SHPT, which affects approximately 90% of patients with ESRD, is associated with bone disease (high-turnover renal osteodystrophy) and cardiovascular disease and can lead to significant morbidity. Several factors contribute to the development of SHPT. Mineral metabolism disturbances (hypocalcemia and hyperphosphatemia) and impaired vitamin D synthesis are crucial determinants of excess parathyroid hormone (PTH) secretion in patients with renal failure. Increased PTH levels, in turn, mobilize bone calcium, maintaining serum calcium levels at the expense of bone mineralization.

SHPT represents a significant unmet medical need. There are roughly 350,000 and 8 million patients in the U.S. with ESRD and CKD, respectively, representing an estimated $3 billion market opportunity.

Phase 1 clinical studies with a first generation compound demonstrated a dose-dependent reduction in the secretion of PTH and provided proof of principle for this class of compounds. KAI-4169 is an optimized second generation compound with superior pharmaceutical properties.