Shares of Cerus (CERS - Get Report) were down 5% to $2.85 in premarket trading on Tuesday. The Concord, Calif.-based company said Tuesday it was notified last week of a pending U.S. supply shortage of a platelet additive solution (PAS) made and sold by Fresenius Kabi. Due to the expected impact of the PAS supply disruption on INTERCEPT platelet production, Cerus adjusted its 2017 product revenue guidance.

"The pending shortage is due to an unanticipated delay in FDA approval of a plastic component used in the manufacture of the PAS container following discontinuation of the original component by Fresenius Kabi's supplier," Cerus said. "The shortage is expected to temporarily impact certain U.S. blood centers that utilize PAS to produce INTERCEPT platelets."

Cerus added that Fresenius Kabi "has stated that it is working with its suppliers and the FDA to resolve this delay and minimize any long-term disruption in supply."

Taking into account the expected impact of the PAS supply disruption on INTERCEPT platelet production, Cerus updated its 2017 product revenue guidance to the $38 million to $46 million range, versus prior guidance of $43 million to $48 million.

Meanwhile, shares of Alexion Pharmaceuticals (ALXN - Get Report) were down 4.3% to $110.50. The New Haven, Conn.-based firm on Tuesday announced changes to its leadership team, including its search for a new chief financial officer.

Alexion said CFO Dave Anderson will resign from the firm at the end of August and the company is on the hunt for a new CFO with the help of executive search firm Spencer Stuart.

Alexion head of research and development Martin Mackay will retire from the company at the end of the year and a search for a successor is underway with Spencer Stuart.

Other announcements on Tuesday include the appointment of Brian Goff as chief commercial officer effective June 1. Goff, an alum of firms such as Neurovance, Novartis and Johnson & Johnson, succeeds Carsten Thiel, who is moving on from Alexion to pursue new opportunities.

The company also said chief human resources officer Clare Carmichael is moving on from the company to pursue new opportunities effective June 1 and a search is underway for a replacement.

Tuesday's announcement comes after Alexion in March named Ludwig Hantson as its new CEO.

Other biotech movers include NantKwest (NK - Get Report) . Shares of the Culver City, Calif.-based firm were up 8.3% to $4.19.

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