Citing illness, Mountain View, Calif.-based VIVUS (VVUS) CEO Anthony P. Zook announced Tuesday that he will resign from his posts as both chief executive officer and company director, effective today. Replacing him as CEO and board director will be new hire Seth H.Z. Fischer, a former exec at Johnson & Johnson.

Wishing Zook well on his departure, company Chairman Michael Astrue said: "VIVUS is keeping Tony in its thoughts and we wish him a rapid recovery. We are grateful for his contributions and his willingness to work with Seth through mid-September 2013 to assist with the transition."

Astrue further welcomed Fischer to the company and reiterated the goals the board will ask him to pursue: "(1) expand use of Qsymia through targeted patient and physician education; (2) find the right partner for Qsymia; (3) quickly create a pathway for approval in Europe; and (4) eliminate expenses that are not essential to expanding use of Qsymia."

Probably VIVUS's signature product, Qsymia is the company's new weight-loss drug. It went on the market one year ago.

VIVUS shares shrugged off news of the management change, rising 3% in Tuesday trading to close at $12.90.