QLT Inc. reported Monday that global sales of the eye drug Visudyne, its main source of revenue, dropped by 13.7 per cent to $106.8 million US in the first quarter from the same period last year.

The announcement comes three days before the Vancouver-based company is scheduled to release its first-quarter financial results.

The sales figures were provided by QLT's partner Novartis AG, which markets and distributes Visudyne. QLT manufactures and supplies the drug, which is used to treat age-related macular degeneration.

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QLT (TSX:QLT) has said it expects Visudyne sales in 2006 to be between $370 million and $400 million.

The company and Novartis share equally the net revenues from sales of the drug after manufacturing and marketing costs are deducted.

QLT shares have been under pressure since last July, when a U.S.-based company announced good test results for a rival anti-blindness drug called Lucentis.

• FROM JULY 19, 2005: QLT stock tumbles

QLT reported a loss of $325.4 million US last year after taking a huge charge related to its acquisition of Atrix Laboratories Inc. in 2004.

• FROM FEB. 22, 2006: QLT posts big loss on acquisition charge

It also lost $185.7 million US in 2004 on revenue of $186.1 million.

Shares of QLT slipped 16 cents to $9.21 on the TSX.