Constitutional Court to Hear Enzutrix Patent Dispute

Eurolab asks the court to rule it did not infringe a University of California patent on the prostate cancer drug enzalutamide.

Updated on Nov. 8, 2026 in Cancer

Constitutional Court to Hear Enzutrix Patent Dispute

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Should generic drugs be allowed on the market while patent disputes are still pending?

The Constitutional Court will hear a patent dispute this month over Enzutrix, a generic prostate cancer drug distributed by Dis-Chem. The University of California and Astellas Pharma Inc. accuse Eurolab and Dis-Chem of infringing the patent on enzalutamide, the active ingredient in Xtandi.

Why it matters

The case concerns whether patients in South Africa can access a cheaper generic version of a costly cancer treatment while the patent was in force. The Supreme Court of Appeal found patients using the cheaper drug would face an immediate and serious impact, shaping the balance between patent rights and access to medicines.

Xtandi costs nearly R361,000 ($21,700) a year compared with R299,407 ($18,000) for Enzutrix, a difference of about R60,000 ($3,600) per patient. The outcome of the Constitutional Court case on infringement has yet to be determined.

The players

Eurolab

Eurolab is the Johannesburg-based company that registered and sells the generic prostate cancer drug Enzutrix in South Africa.

Dis-Chem

Dis-Chem is a South African pharmacy chain with about 330 stores and annual revenue of roughly R40 billion, which distributes Enzutrix.

Astellas Pharma Inc.

Astellas Pharma Inc. is the Japanese pharmaceutical company that sells Xtandi, the enzalutamide-based prostate cancer treatment.

The Regents of the University of California

The Regents of the University of California hold the patent on enzalutamide and are pursuing damages over the alleged infringement.

The details

The University of California and Astellas asked Eurolab not to launch the drug for the life of the patent, and Eurolab refused and challenged the patent at the Commissioner of Patents. The Commissioner revoked the patent, but the Supreme Court of Appeal overturned that decision on 17 March and upheld it, and refused to stop Eurolab and Dis-Chem selling Enzutrix during litigation. The patent expired on 29 March, and Eurolab now plans to ask the Constitutional Court to rule that it did not infringe.

January 2023: Eurolab registered Enzutrix with the South African Health Products Regulatory Authority.
17 March: The Supreme Court of Appeal overturned the patent revocation and upheld the patent.
29 March: The Xtandi patent expired.
November 2026: The Constitutional Court is scheduled to hear the case this month.

Roadmap

The dispute sits within a wider contest over generic versions of high-cost cancer medicines in South Africa, where patent rights and patient access are weighed case by case. The Supreme Court of Appeal's finding that patients would face immediate and serious harm without the generic has set the terms the Constitutional Court will now consider.

Patients who need enzalutamide may face a choice between the costly Xtandi and the lower-priced Enzutrix, depending on how the court rules on infringement. The outcome will affect the price and availability of the generic version for those being treated for prostate cancer.

The takeaway

The case shows how patent expiry and court rulings can determine whether patients can afford a cancer drug. Readers following treatment costs should watch the Constitutional Court's ruling in November 2026.

What happens next

The Constitutional Court is scheduled to hear the case in November 2026, when it will consider Eurolab's request for a ruling that it did not infringe the patent.