Wyeth has posted a solid set of financials for the first quarter especially given the sales decline suffered by its antiulcerant blockbuster Protonix as generic competition kicks in.

Net income declined 4.6% to $1.20 billion, or $0.89 per share, which included $81.0 million in charges related to “productivity initiatives”. Group sales were up 6% to $5.71 billion and pharmaceutical revenues contributed $4.76 billion (+6%) to the total.

The most impressive performances came from the pneumococcal disease vaccine Prevnar, which grew 14% to $706 million, and the arthritis therapy Enbrel (etanercept), which jumped 36% to $606 million (excluding the USA and Canada, where it is sold by Amgen). Wyeth’s best-seller continues to be the antidepressant Effexor (venlafaxine), which rose 15% to $1.02 million, maintaining its place as “the number one global antidepressant in sales”.

The firm’s Premarin (conjugated oestrogens) range of hormone replacement therapies rose 15% to $276 million, a healthy leap given the concerns (and court cases) which have suggested that the drugs can increase the risk of breast cancer and stroke.

On the negative side, sales of Protonix (pantoprazole) sank 66% to $159 million as a result of ‘at risk’ generic launches in the USA by Teva and Sun Pharmaceutical Industries. The New Jersey-based firm launched its own copy of Protonix in January but those sales “have not, and cannot, offset the substantial harm caused by the launch of infringing generics”.

Wyeth said that its Protonix compound patent is strong and it will “continue to vigorously pursue its litigation” against Teva, Sun and others infringing generics, as well as seek to recover lost profits.

Future growth at Wyeth will depend a lot on how successful the firm is at switching patients to newly-approved Pristiq (desvenlafaxine) from Effexor which will go off-patent in 2010. To add the switch, the company said during a conference call that it will price Pristiq at a 20% discount to the older antidepressant.

Wyeth has suffered a number of pipeline setbacks of late, most recently ending development of a hepatitis C drug, HCV-796, that was in mid-stage trials, and Barbara Ryan, an analyst at Deutsche Bank, issued a note saying that “we have long believed that the new drug pipeline at Wyeth is unattractive, and certainly insufficient to offset the loss of patents” on key drugs.