Shares in Shire have suffered a blip after the UK drugmaker suggested that 2008 sales of Vyvanse, the follow-up to its attention deficit hyperactivity disorder drug Adderall XR will be at the lower-end of a previous forecast.

Nevertheless, the company has got off to a decent start to the year, and its first-quarter net income rose 14.1% to $128.6 million, while revenues climbed 32.9% to $702.2 million. Adderall XR (mixed amphetamine salts) rose 5% to $261.5 million, while Vyvanse (lisdexamfetamine dimesylate), launched in July last year, contributed $54.4 million to the coffers.

The latter was above the estimates of the investment community but analysts got worried by Shire’s statement that Vyvanse sales will at the lower end' of the $350-$400 million previously-stated range. The drug is vital to the firm’s fortunes seeing as Adderall XR will face generic competition in 2009.

Chief executive Matthew Emmens played down any fears that Vyvanse will not make that range and noted that the drug has just been approved in the USA for use by adult patients. It will be launched in that indication in the next few weeks and will provide a further boost to sales.

However, Merrill Lynch issued a research note saying it is surprised that “management has not waited to assess the impact for launch in the adult indication to reassess its guidance''. The broker added that “this apparent downshift in confidence following the strong management support for the product” on the release of full-year 2007 results will “exacerbate already-shaky investor nerves over future Vyvanse growth”.

As for Shire’s ADHD patch product Daytrana (methylphenidate), sales were up 71% to $20.3 million. Elaprase (idursulfase) for Hunter syndrome reached $71.5 million, up 169%, while turnover from Fosrenol (lanthanum carbonate) for high blood phosphate levels was up 59% to $36.2 million.

Replagal (agalsidase alfa), for the treatment of Fabry disease, contributed $42.5 million to the coffers, up 25%, while the ulcerative colitis therapy Pentasa (mesalamine) inched up 1% to $44.2 million. However the newer ulcerative colitis drug Lialda/Mezavant, launched in the USA in March last year, brought in $27.2 million and Shire said its market share stands at around 9.1%. Mezavant is now available in Canada, the UK, Germany and Ireland and will be rolled out in the rest of Europe through the year.