Pfizer has been barred from presenting clinical findings on its new cholesterol drug torcetrapib at the American Heart Association’s annual meeting, after it was judged to have broken an embargo on publicising the findings.

Pfizer issued a press release on October 31 that gave an account of the findings of a study of torcetrapib in combination with its blockbuster cholesterol-lowerer Lipitor (atorvastatin), noting that the combination hiked protective HDL cholesterol by 10%-15% more than atorvastatin alone, and cut harmful LDL cholesterol by 55% to 60% compared to monotherapy.

That amounted to breaking the embargo, the AHA ruled on Friday. It had already pulled the abstract of the study from its website in protest at Pfizer’s move while internal discussions were ongoing on the issue.

Pfizer said it regretted the development, but had apologised to the AHA and would present the data at a later meeting.

The early release of the data also raised concerns about a possible side effect of the drug, namely that of raising blood pressure. Torcetrapib was associated with a 3-4 millimetre increase in systolic blood pressure, roughly 1mmHg more than had been seen in earlier studies, prompting analysts to express concern that regulators might ask for evidence that the increase does not worsen outcomes in patients, delaying the drug's approval.

For its part, Pfizer stressed that the Phase III trial programme for torcetrapib is incomplete and the early results cover less than 25% of all the patients in the studies.