Elan (NYSE:ELN) has been on quite a roll lately. On Tuesday, the Irish drug developer announced that British medical authorities were reversing their previous decision to exclude its multiple sclerosis drug, Tysabri, from public reimbursement.

Previously, Britain's National Institute for Health and Clinical Excellence had denied reimbursement of Tysabri due to its high cost and its efficacy and safety relative to other multiple sclerosis treatments. Unlike some other health-care agencies throughout the world, British national medical authorities take into account a drug's cost-effectiveness when determining whether to approve its reimbursement.

Getting Tysabri approved for reimbursement means that the drug will be available on a much wider basis to the British citizens who rely on publicly provided health care.

Since I grew cold on Elan's valuation, its shares have been up 50% since the beginning of 2007 after the company announced that it was moving forward with development of its lead Alzheimer's drug, which is in development in collaboration with Wyeth (NYSE:WYE).

The reversal of fortunes for Tysabri in a large market like Britain is undoubtedly a positive event for Elan and warrants a higher valuation for the company, but with a market cap over $10 billion, shares of Elan look priced for more than perfection to me.

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Fool contributor Brian Lawler does not own shares of any company mentioned in this article. The Fool has a disclosure policy.