The European Union’s highest court issued a mixed ruling in which the drugmaker was cited for possibly violating trade rules by preventing Greek wholesalers from reselling its meds in more profitable countries, according to reports.

The European Court of Justice in Luxembourg decided that Glaxo and other big drugmakers can’t refuse “ordinary orders by wholesalers” to prevent parallel trade. The court referred the case back to Greece to determine whether the wholesalers’ orders in this case were “out of the ordinary,” The Financial Times reports.

Greek drugmakers sued Glaxo as part of an eight-year dispute over its refusal to supply them with three drugs in Greece and limit the stock they could export to higher-priced countries, Bloomberg News notes. The cases went to the EU court after a Greek tribunal asked it how far dominant companies can go in blocking the parallel drug trade.

The court “has confirmed that companies must be able to take reasonable and proportionate steps to protect their own commercial interests, even if they hold a dominant position and such steps must be assessed in the light of the ordinary requirements of the markets,” Glaxo wrote in a e- mailed statement to Bloomberg.

Drugmakers have been fighting the practice by which wholesalers buy meds at state-regulated prices in countries such as Greece and then sell them in more expensive markets such as the UK. This case helps to clarify the rights of drugmakers to control supply to parallel traders. Glaxo and its rivals claim the practice costs them more than $5.7 billion in annual sales.

“The ruling makes it clear that efforts by manufacturers to stamp out their competitors by abusing their dominant position are illegal,” Richard Freudenberg, president of the European Association of Euro-Pharmaceutical Companies, which supports parallel trade, said in an e-mailed statement. “Patients and sick funds in Europe can continue to count on the benefits provided by parallel distribution of medicines.”

Competition rules shouldn’t be used “to export the health choices of one member state to another,” Arthur Higgins, president of the European Federation of Pharmaceutical Industries and Associations, which represents 43 drugmakers, wrote in an e-mail to Bloomberg. They “should protect consumers and patients rather than parallel traders.”

In 2000, Glaxo stopped supplying the Greek traders with the epilepsy drug Lamictal, migraine medication Imigran and the Serevent asthma treatment. Glaxo instead distributed the drugs directly to Greek hospitals and pharmacies. Later, Glaxo’s Greek unit limited the quantities supplied to the traders to just enough to meet national demand.

The volume of the wholesalers’ orders were “preposterous” and “exorbitant,” lawyers for Glaxo told the court at a hearing in January. The parallel drug trade, which is supported by the European Commission, takes away hundreds of millions in euros from the pharmaceutical industry, the lawyers said.

Glaxo’s argument that the parallel exports which it seeks to limit are of only minimal benefit to the final consumers” can’t be justified, the court decided.

In Europe, where drug prices are regulated on a state-by-state basis, big drugmakers such as Glaxo can’t be prevented from refusing to meet wholesalers orders, the court ruled. Still, drugmakers must “take steps that are reasonable and in proportion to the need to protect its own commercial interest.”

While a dominant drugmaker can’t cease to honor “ordinary orders” by an existing customer, it is allowed to “counter in a reasonable and proportionate way the threat to its own commercial interests,” the court ruled.