In a radiation-proof room at the Erasmus Medical Center in Rotterdam, Emar Thomasa sits behind shielded glass as he carefully measures and mixes lutetium octreotate, an intravenous treatment for certain types of cancer.

The Dutch hospital has been offering it to patients for more than a decade at 16,000 euros ($18,000) for one course of treatments. Drug firm Novartis, which in 2018 acquired rights to sell it in Europe, is asking more than five times that for its proprietary version, Lutathera.

Thomasa is part of a protest against high drug prices launched by an unlikely group of rebels: Dutch pharmacies.

Three – Erasmus, Amsterdam’s University Medical Center (UMC) and the Transvaal Pharmacy in The Hague – have vowed to bypass drug company products and make treatments for a handful of rare diseases themselves, exercising their right to “compound” medicines.

The dispute is part of a growing global backlash against high drug prices, from the United States and Canada to Japan, and campaigners said it was being closely watched by health experts elsewhere.

Compounding is the ancient practice of preparing medicines for individual patients. Pharmacists are trained to compound, though nowadays most medicines are made by industrial producers.

UMC received a 5-million-euro grant last month to expand its compounding program. It plans to use the money to set up a center to swap know-how with pharmacies at home and abroad.

The worldwide push against high drug prices has seen the Trump administration in the United States declare bringing down prescription prices a top priority.

The Dutch pharmacies, whose production is on a small scale, acknowledge they may face legal challenges from the drug industry. However, such a case could set a precedent for other European countries.

Pharmacies retain the right under European and American law to prepare medicines for individual patients. Common examples including making lower dosage versions for children or liquid versions for people with difficulty swallowing.

However, in the United States, for-profit compounding pharmacies have tested the limits of what they are allowed to do in recent years, including mixing medicines in large quantities. In some cases, that has prompted legal conflicts with drugmakers.

Official scrutiny of the practice increased after the 2012 deaths in Massachusetts, which led to U.S. lawmakers requiring bulk compounding facilities to register with the Food and Drug Administration (FDA) and meet quality and labeling standards – still not as stringent as full FDA drug approval.

The first two drugs targeted by Dutch pharmacies are Novartis’s Lutathera and a drug called CDCA, registered in Europe by Leadiant.

Novartis boss Narasimhan said he was worried by developments in the Netherlands. “The Netherlands’ characterization that the local medicine that is made in the hospitals is the same as what we’ve done from a regulatory, full-development standpoint, particularly given (the Dutch) will house the European Medicines Agency, I think is troubling,” he told Reuters in an interview.