GlaxoSmithKline has started a second late-stage trial of its cardiovascular drug darapladib, a treatment some analysts believe could be a blockbuster.

This particular Phase III trial, called Solid-Timi 52, will evaluate long-term treatment with darapladib, in adults with acute coronary syndrome. The plan is to enroll 11,500 patients from 40 countries and see how effective the drug is when added to standard of care (a statin, aspirin or blood pressure medication).

Specifically, the study will test whether darapladib, a new class of drug which inhibits the Lp-PLA 2 enzyme, affects the chances of having a heart attack or stroke when treatment is started within 30 days after an acute coronary syndrome. Patrick Vallance, senior vice president of drug discovery at GSK, noted that because cardiovascular disease “remains the world’s number one killer, new approaches to treatment are needed” and targeting and inhibiting the Lp-PLA2 enzyme may reduce the risk in patients with heart disease.

Darapladib, discovered by GSK but based on technology from partner Human Genome Sciences, is already being studied in a Phase III trial in over 15,000 patients suffering from chronic coronary artery disease, so the clinical programme will be “one of the largest-ever conducted to evaluate the efficacy and safety of any cardiovascular medication”, Dr Vallance noted.

If the drug gets to market, HGS would get 10% royalties on worldwide sales and it also has a 20% co-promotion option in North America and Europe.

GSK ends cancer deal with Cytokinetics
Meantime, GlaxoSmithKline has agreed to end a collaboration and licence agreement for an investigational oncology drug from Cytokinetics.

The pact will be terminated at the end of February, after which all rights to GSK-923295, an inhibitor of centromere-associated protein E, being developed to treat advanced, refractory solid tumours, will revert to Cytokinetics. However, GSK will remain responsible for all activities and costs associated with completing an ongoing Phase I trial.

Previously, Cytokinetics negotiated the return of all rights to two kinesin spindle protein inhibitors – SB-743921 and ispinesib – that were also initially developed in collaboration with GSK. The US firm will look to license out the three drugs, as it is pulling out of oncology research to focus on its “multiple programmes directed to the biology of muscle function”.