SkyePharma said the European Commission had given it the go-ahead to start marketing its asthma medicine, flutiform, across the continent.
The firm said the European Commission's decision was binding and 21 member states were now required to grant national marketing authorisations or approvals consistent with the decision.
The news pushed shares up 28% in trading on Tuesday.
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SkyePharma said it was looking launch the product across Europe in the second half of this year, having been developing it since 2004.
The company anticipates the marketing authorisations will be granted shortly, typically between one and three months.
In other countries negotiations would be required with national pricing and reimbursement authorities before the product could be made commercially available, it said.
"To get a product of this complexity through to approval has been an immense achievement by SkyePharma and our partner Mundipharma," said Chief Executive Peter Grant.
"It is also a strong endorsement of the group's capabilities in developing innovative and complex respiratory products and good news that a new treatment option will be available for many patients suffering from asthma across Europe," he added.
