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Zytiga

Active Substance: abiraterone acetate
Common Name: abiraterone
ATC Code: L02BX03
Marketing Authorisation Holder: Janssen-Cilag International N.V.
Active Substance: abiraterone acetate
Status: Authorised
Authorisation Date: 2011-09-05
Therapeutic Area: Prostatic Neoplasms
Pharmacotherapeutic Group: Endocrine therapy

Therapeutic Indication

Treatment of metastatic castration-resistant prostate cancer in adult men who are asymptomatic or mildly symptomatic after failure of androgen-deprivation therapy in whom chemotherapy is not yet clinically indicated.

Treatment of metastatic castration-resistant prostate cancer in adult men whose disease has progressed on or after a docetaxel‑based chemotherapy regimen.

What is Zytiga?

Zytiga is a medicine that contains the active substance abiraterone acetate. It is available as tablets (250 mg).

What is Zytiga used for?

Zytiga is used to treat cancer of the prostate (a gland of the male reproductive system) in adult men when the cancer is metastatic (has spread to other parts of the body). It is used in the following cases:

  • when medical castration (stopping the production of male hormones in the body using medicines) with a treatment called androgen-deprivation therapy has not worked or no longer works in men who have either no symptoms or only mild symptoms of the disease, and who do not yet need chemotherapy (anticancer medicines);
  • when medical or surgical castration and chemotherapy containing docetaxel have not worked or no longer work.

Zytiga is used together with the medicines prednisone or prednisolone.

The medicine can only be obtained with a prescription.

How is Zytiga used?

Zytiga tablets are swallowed whole with water at least two hours after eating and at least one hour before further food. The recommended dose is four tablets taken once a day. Blood levels of liver enzymes should be checked before starting treatment and regularly thereafter. If patients develop liver problems, treatment should be interrupted. Treatment may be resumed at a reduced dose if liver function returns to normal, but should be stopped if liver problems continue. If patients develop severe side effects, treatment may have to be interrupted until symptoms have improved or resolved.

Androgen-deprivation therapy with a medicine called a ‘luteinising-hormone-releasing-hormone (LHRH) analogue’ should be continued in patients who are not surgically castrated.

How does Zytiga work?

The active substance in Zytiga, abiraterone acetate, is changed in the body to abiraterone which stops the body from producing testosterone, a male hormone. Abiraterone does this by blocking an enzyme called CYP17 found in the testes and elsewhere in the body. Because the cancer needs a supply of testosterone to survive and grow, by reducing the production of testosterone, abiraterone acetate may slow the growth of the prostate cancer.

How has Zytiga been studied?

Zytiga was compared with placebo (a dummy treatment) in two main studies. The first study involved 1,195 men with metastatic prostate cancer whose disease had got worse despite surgical or medical castration treatment and chemotherapy with docetaxel. The main measure of effectiveness was overall survival (how long the patients lived).

The second study involved 1,088 men with metastatic prostate cancer who had either no or only mild symptoms of the disease and for whom castration treatment had not worked or no longer work. The main measure of effectiveness was how long the patients lived without their disease getting worse.

In both studies, patients were treated with prednisone or prednisolone together with either Zytiga or placebo.

What benefit has Zytiga shown during the studies?

In the first study, patients treated with Zytiga lived for just under 15 months from the start of treatment, while patients given placebo lived for just under 11 months. In the second study, patients treated with Zytiga lived for an average of around 16 months without their disease getting worse, compared with around eight months in patients taking placebo.

What is the risk associated with Zytiga?

The most common side effects with Zytiga (seen in more than 1 patient in 10) were urinary-tract infection, hypokalaemia (low blood potassium levels), hypertension (high blood pressure) and peripheral oedema (swelling of the limbs due to fluid retention). Other important side effects include cardiac disorders (heart problems), hepatotoxicity (liver problems) and fractures. For the full list of all side effects reported with Zytiga, see the package leaflet.

Zytiga must not be used in people who are hypersensitive (allergic) to the active substance or any of the other ingredients. It must also not be used in patients with severely reduced liver function. It is not for use in women and must not be given to women who are or who may be pregnant.

Why has Zytiga been approved?

The CHMP noted that Zytiga in combination with prednisone or prednisolone improved survival compared with placebo in patients whose disease had got worse despite castration treatment and chemotherapy with docetaxel. The Committee noted that there were very few alternative treatments for those patients. The Committee also considered the fact that Zytiga is given by mouth to be a further advantage. In patients where medical castration has not worked and who have no or only mild symptoms, Zytiga is of benefit when chemotherapy is not yet required. In terms of safety, Zytiga is well tolerated and its risks are considered manageable. Therefore, the CHMP concluded that the benefits of Zytiga were greater than its risks, and recommended it be granted marketing authorisation.

Other information about Zytiga

The European Commission granted a marketing authorisation valid throughout the European Union for Zytiga on 5 September 2011.

For more information about treatment with Zytiga, read the package leaflet (also part of the EPAR) or contact your doctor or pharmacist.

Source: European Medicines Agency

Disclaimer: Every effort has been made to ensure that the information provided here is accurate, up-to-date and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. This information has been compiled for use by healthcare practitioners and consumers in the United States. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate that the drug or combination is safe, effective or appropriate for any given patient. If you have questions about the substances you are taking, check with your doctor, nurse or pharmacist.

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