KEI Submission to WHO Essential Medicines List – Enzalutamide / Abiraterone Acetate

The WHO Essential Medicines List is a major WHO tool used to expand access to medicines.  In 2017, the WHO issued the 20th Essential Medicines List (EML) which was the 40th anniversary of the list.  The WHO is currently in the process of making selections for it 22nd EML.  Interested parties file applications for treatments that they believe should be included on the EML. For more information on the list and the selection process, please visit:

KEI has previously filed applications for trastuzumab, trastuzumab emtansine (T-DM1), and enzalutamide. Trastuzumab was added to the 19th EML in 2015, while enzalutamide and T-DM1 were not included in the 20th EML (the cycle to which they were submitted).

This year, KEI submitted an application for enzalutamide and abiraterone acetate, both important treatments for prostate cancer. The summary of the application follows below.

Summary statement of the proposal for inclusion

Enzalutamide (sold by Astellas trade name Xtandi, sold by Glenmark trade name Glenza) is indicated to treat metastatic castration-resistant prostate cancer (CRPC) and is a second generation competitive androgen receptor inhibitor. While there are other treatments used to treat CRPC, enzalutamide is far less invasive as it is administered via daily oral tablets, and has a low pill burden compared to the one other oral tablet CRPC treatment (abiraterone acetate).

The first registration was by Astellas, for Xtandi. The patent protection for Xtandi varies from country to country. At least one generic supplier, Glenmark, has entered the market.

With recent clinical trials reporting better prostate cancer control when enzalutamide is used in chemotherapy naive CRPC cases or in combination with other agents, it is expected that this drug will soon be prescribed to an even wider subset of patients. The listing of enzalutamide is being sought for the core Essential medicines List.

Abiraterone acetate (sold by Johnson and Johnson under the trade name Zytiga), is an antiandrogen medication which is used in the treatment of prostate cancer. It is specifically indicated for use in conjunction with castration and prednisone for the treatment of metastatic castration-resistant prostate cancer (mCRPC) and in the treatment of metastatic high-risk castration-sensitive prostate cancer (mCSPC).

The US patent 8,822,438, which covered Zytiga, was invalidated in October 2018.1 There several generic suppliers of abiraterone acetate.

Both drugs offer significant medical benefits for target populations, although for some patients, one will better tolerated with few adverse effects than the other.