Enrollment Increase Likely to Delay Trial Completions and Launch Up to One Year

The latest news from the battle of the PCSK9 inhibitors is that according to clinicaltrials.gov Pfizer has increased enrollment by approximately 40% in its SPIRE-1 (NCT01975376) and SPIRE-2 (NCT01975389) cardiovascular outcomes trials (CVOTs). The changes were made on the website on October 29, 2014, with SPIRE-1 increasing from 12,000 to 17,000 patients, and SPIRE-2 from 6,300 to 9,000. Presumably as a consequence of this increased enrollment, the estimated completion dates have now been shifted back by almost one year to March 2018 and June 2018 for SPIRE-1 and SPIRE-2, respectively. The question now is: what has driven the need for increasing the study populations. A desire to match the trial size of competitors. A lack of treatment effect?

Previously, Pfizer appeared well-positioned to capitalize on any delays to approval of Sanofi/Regeneron's alirocumab and Amgen's evolocumab. Their LDL-lowering trial data was months behind their rivals, but they were expected to be first in terms of demonstrating CV outcomes benefit, with their CVOTs  expected to complete approximately six months before their rivals.  Unless, the CVOTs for its competitors are also delayed, any market traction that Pfizer was hoping to gain from bococizumab being the first PCSK9 inhibit to have CVOT data appears to have been lost. However, Amgen's recent patent infringement lawsuit of Sanofi and Regeneron could yet blow the PCSK9 inhibitor race wide open.

In-depth analysis of dyslipidemia, with accompanying epidemiology-driven sales forecast models, are presented in Decision Resources Group's Dyslipidemia Pharmacor (due to publish November 17, 2014).

Tim Blackstock, M.B. Ch.B., M.Phil., is a Business Insights Analyst and Conor Walsh, M.Sc., Ph.D., is a Senior Director in the Cardiovascular, Metabolic and Renal Disorders team at Decision Resources Group.

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