Bayer HealthCare has hit a stumbling block in the sales campaign for its new drug Eylea (aflibercept), or VEGF Trap-Eye, recommended for treatment of age-related wet macula degeneration (AMD). The German Institute for Quality and Efficiency in Health Care (IQWiG), a healthcare cost watchdog, said it could not assess whether the drug was more effective than a rival product.

Developed in partnership with Regeneron Pharmaceuticals, Eylea is one of the most promising drugs to emerge from the German chemicals and pharmaceuticals group's pipeline in recent years. It has been projected by Bayer to return peak sales of more than €1 billion. Regeneron holds exclusive rights in the U.S.  Eylea was approved in the U.S. in late 2011. Japan, Australia and Europe followed in 2012.

IQWiG compared trial data on Eylea and the Novartis preparation for treatment of macular edema, Lucentis. However, the institute said it was not able to draw conclusions for cost effectiveness because, in the trial, neither drug was being administered in the way specified by regulators when it was approved by German health authorities.

When approving the drug for U.S. consumption, the Food and Drug Administration (FDA) said Eylea and Lucentis performed equally well in clinical trials. Treatment with Lucentis can cost as much as $2,000 per once-a-month dose. Eylea was priced at $1,850 per dose at its U.S. launch.

Germany's medical cost-benefit agency, Gemeinsame Bundesausschus (G-BA), is due to publish an assessment of Eylea's cost-effectiveness within the next three months, and will take into account IQWiG's opinions as a guide for reimbursement by the country public health insurance companies.

Bayer said it planned to respond to IQWiG's statement within three weeks.