Leivers is leaving the company "to pursue other opportunities". A GSK spokeswoman added that she wanted "to take time out to decide what to do".
She will be replaced by Chris Harley-Martin, GSK Nutritional Healthcare's vice-president for business development and strategy, who takes on the new role of vice-president for marketing and innovation from May 10. He was formerly responsible for new-product development.
Leivers joined GSK last November from McCain where she oversaw the brand's £15m repositioning campaign through TBWA\London. Before joining McCain, she held senior posts at Coca-Cola and PepsiCo Foods.
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