SemBioSys Genetics Inc. said Wednesday that MannKind Corp. purchased an option to license rights to its plant-based genetically engineered human insulin for potential use in MannKind’s inhaler.

Calgary-based SemBioSys will receive $2.5 million for the option, which includes the purchase by Valencia-based MannKind of 2.4 million units of SemBioSys shares upon closing at a price per unit of 83 cents each. The option period ends on March 31, 2009.

MannKind plans to soon apply to the U.S. Food and Drug Administration for permission to market its Afresa inhaler as way to quickly regulate diabetic insulin levels at mealtimes.

“We believe MannKind’s Afresa program has the potential to transform the treatment of diabetes, and that our cost-effective production system would provide them with significant cost benefits over existing production methods,” said SemBioSys Chief Executive Andrew Baum in a statement.

MannKind shares closed up 2 cents, or less than 1 percent, to $3.57 on the Nasdaq.