Bill Mathews, founder and contributing editor to The Cheap Investor, selected Achillian Pharmaceuticals (ACHN) as a more speculative idea for 2019. The stock has risen 69%. Here's his latest update on this biotech firm.

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Achillion Pharmaceuticals has been a great investment. It is a clinical-stage biopharmaceutical company focused on advancing its oral small molecule complement inhibitors into late-stage development and commercialization.

Research has shown that an overactive complement system plays a critical role in multiple disease conditions including the therapeutic areas of nephrology, hematology, ophthalmology and neurology.

The company is initially focusing its drug development activities on complement-mediated diseases where there are no approved therapies or where existing therapies are inadequate for patients.

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I continue to like Achillion because they have several products in FDA Trials. Their pipeline includes four products in late stage II and two products in stage I. They have a huge amount of cash $254 million.

Currently, 133 institutions own 80% of the float and the top nine institutions purchased 13.5 million more shares than they sold for the quarter ended March 30. Even though I think the stock has the potential of going higher, investors should protect their profits with stop loses.

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