FDA approves novel kidney disease drug

After initially rejecting calcifediol (Rayaldee, Opko Health) for chronic kidney disease earlier this year because of manufacturing concerns, FDA approved the drug 4 months ahead of its new timeline.

Rayaldee extended release capsules is the first drug to receive FDA approval for the treatment of secondary hyperparathyroidism (SHPT) in adults with stage 3 or 4 chronic kidney disease (CKD) and serum total 25-hydroxyvitamin D levels less than 30 ng./mL. Rayaldee is a patented extended-release product containing 30 mcg. of a prohormone called calcifediol (25-hydroxyvitamin D₃).

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The drug will be available in the second half of this year.

"Rayaldee fills a large void in the current treatment options for SHPT in predialysis patients," commented Charles W. Bishop, CEO of OPKO's Renal Division. "The current standard of care is high-dose vitamin D supplementation, an approach for treating SHPT that is neither FDA-approved nor demonstrated to be safe and effective in this population. SHPT is a progressive disease that becomes increasingly debilitating and difficult to treat, necessitating timely and effective treatment."

FDA’s approval was based two, 26-week placebo-controlled, double-blind phase 3 trials which demonstrated that a larger proportion of stage 3 or 4 CKD patients with SHPT and vitamin D insufficiency achieved greater than 30% reductions in plasma intact parathyroid hormone (iPTH) when treated with Rayaldee than with placebo.

In addition, Vitamin D insufficiency was corrected in more than 80% of the patients receiving Rayaldee, compared with less than 7% of subjects receiving placebo. No differences in Rayaldee’s efficacy or safety were observed between patients with stage 3 CKD or stage 4 CKD.

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Potential side effects of Rayaldee include hypercalcemia (elevated serum calcium), which can also lead to digitalis toxicity, and adynamic bone disease with subsequent increased risk of fractures if intact PTH levels are suppressed by Rayaldee to abnormally low levels. Severe hypercalcemia may require emergency attention.

Digitalis toxicity can be potentiated by hypercalcemia of any cause. Excessive administration of Rayaldee can cause hypercalciuria, hypercalcemia, hyperphosphatemia or oversuppression of intact PTH. Common symptoms of vitamin D over-dosage may include constipation, decreased appetite, dehydration, fatigue, irritability, muscle weakness, or vomiting. Patients concomitantly taking cytochrome P450 inhibitors, thiazides, cholestyramine, phenobarbital or other anticonvulsants may require dose adjustments and more frequent monitoring.

The most common adverse reactions in clinical trials were anemia, nasopharyngitis, increased blood creatinine, dyspnea, cough, congestive heart failure and constipation.

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