Shire has posted a strong set of figures for the first quarter which reveal that net income shot up 66.0% to $213.5 million on the back of strong sales of the firm’s attention-deficit hyperactivity disorder drugs.

Revenues rose 16.5% to $817.8 million, driven again by the ADHD blockbuster Adderall XR (mixed amphetamine salts), sales of which climbed 13.5% to $295.8 million, helped by price increases. However this is likely to be the last quarter that the drug enjoys such growth as Teva started shipping its generic version of Adderall XR earlier this month, so Shire acknowledged that its own sales “will decrease significantly”.

However the follow-up to Adderall XR, Vyvanse (lisdexamfetamine dimesylate), had a storming quarter and contributed $116.6 million, up 114%. US prescriptions of Vyvanse increased 102% over the first quarter in 2008.

As for Shire’s ADHD patch product Daytrana (methylphenidate), sales fell 2% to $19.9 million, while revenues from Elaprase (idursulfase) for Hunter syndrome reached $82.8 million, up 16%. Turnover from Fosrenol (lanthanum carbonate) for high blood phosphate levels was up 10% to $39.8 million.

Replagal (agalsidase alfa), for the treatment of Fabry disease, contributed $40.2 million to the coffers, down 5%, hit by the impact of currency exchange, while the ulcerative colitis therapy Pentasa (mesalamine) rose 16% to $51.2 million. The firm’s newer ulcerative colitis drug Lialda/Mezavant brought in $49.4 million, an increase of 82%, while Firazyr (icatibant), for acute attacks of hereditary angioedema, which Shire gained when it bought Germany’s Jerini, had revenues of $500,000.

Chief executive Angus Russell said the solid quarter reflected “the continuing development of our business and effective cost control”. He added that "we are putting the right level of resources behind our products”, as evidenced by the recently announced co-promotion agreement for Vyvanse in the USA with GlaxoSmithKline.

As for pipeline, Mr Russell said that in the second half of the year, a launch is planned for a new ADHD drug Intuniv (guanfacine) “and the completion of several Phase II and Phase III studies”. He added that “we also have the flexibility to take advantage of opportunities for further expansion of our business” and dismissed as illogical the suggestion by certain analysts that Shire should consider divesting its portfolio of ADHD treatments.

Mr Russell concluded by reiterating Shire’s full-year earnings forecast of $3.00-$3.40 per share and said that sales will grow in the mid-teens range between 2009 and 2015.