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What: Despite winning FDA approval of its kidney disease drug Rayaldee last month, shares in Opko Health (OPK -1.60%) declined 11.3% in June according to S&P Global Market Intelligence.

So what: Rayaldee treats secondary hyperparathyroidism in chronic kidney disease patients that is caused by vitamin D insufficiency. An estimated 9 million CKD patients suffer from vitamin D deficiency and that suggests that Opko Health's market opportunity for Rayaldee is big.

Despite the number of patients that develop vitamin D insufficiency, investors are taking a cautious view to Rayaldee's approval. Pessimism may stem from worry that Opko Health will struggle to win reimbursement with insurers or that its sales force will have a tough time convincing doctors to prescribe Rayaldee instead of the vitamin D supplements that are commonly used today.

While pessimism may be warranted, Rayaldee delivered solid efficacy in clinical trials and that may make it easier to win over skeptics. In trials, 80% of Rayaldee patients had their vitamin D insufficiency corrected, while only 7% of people receiving placebo saw their vitamin D insufficiency resolved. 

Now what: Opko Health's CEO is Phillip Frost, a healthcare billionaire who is legendary for his M&A savvy. Frost sold Ivax Labs to Teva Pharmaceutical for $7.4 billion in 2005 and prior to taking over the reins at Opko Health full-time, he served as Teva Pharmaceutical's chairman.

Over the years, Frost has aggressively acquired companies that he believes will transform Opko Health into a top tier healthcare company. His deals include landing the rights to Varubi, a chemotherapy-induced nausea and vomiting drug it later licensed to Tesaro, the acquisition of Cytochroma to land Rayaldee, and the purchase of Prolor Biotech, which landed Opko Health hGH-CTP, a long-lasting human growth hormone.

Varubi won FDA approval late last year and phase 3 data for hGH-CTP is on deck later this year. If hGH-CTP's trial is a success, Opko Health could have three drugs on the market by the end of 2017. 

Frost is also positioning Opko Health as a major player in diagnostics and testing. Opko Health already markets the 4Kscore test for prostate cancer and last year, it bought Bio-Reference Labs, a large, specialty lab company with sales approaching $1 billion annually.

Overall, it's anyone's guess if Varubi, Rayaldee, or hGH-CTP will be commercial successes, so some caution is warranted. However, I'm not betting against Frost. Frost is so confident in Opko Health that he's the company's biggest shareholder, and he spent $20 million buying shares last month as its shares fell. Given Frost's track-record, investors might want to follow in his footsteps.