Taking Zytiga At A Lower Dose With Food

Since abiraterone acetate (Zytiga) was approved for men with metastatic prostate cancer, it is well known that taking the drug with food in your stomach as opposed to having an empty stomach enhances the amount of drug that becomes active.  Given the very high cost of Zytiga, many men have been tempted to take fewer pills along with a meal.  

We have always tried to discourage this practice.  We understand the logic and the temptation, but we felt that this put men at risk since there was no way to control how much drug will become active if there was food in your stomach. 

In response to this question and in light of the very high cost of Zytiga there was a recent small trial designed to test the hypothesis that it is possible to safely use lower doses of Zytiga along with a low-fat meal.  

The results of a randomized Phase II clinical trial was published in the Journal of Clinical Oncology by Szmulewitz et al.  This was a small, pilot study, enrolling only 72 men with progressive, castration-resistant prostate cancer (CRPC).

The men were randomized to one or other of two groups:

  • Treatment with low-dose abiraterone acetate (250 mg/day) with a low-fat meal
  • Treatment with a standard dose of abiraterone acetate (1,000 mg/day) while fasting

As required on the Zytiga label all the men also received prednisone (5 mg twice daily).

The trial found that:

  • At 12 weeks of follow-up, the PSA response was
    • 58 percent in the low dose + food arm
    • 50 percent in the standard dose arm
  • At 12 weeks of follow-up, it was also found that the average (mean) log changes in PSA levels were
    • –1.59 in the low dose + food arm
    • –1.19 in the standard dose arm

At 12 weeks the non-inferiority of the low dose + food was established compared to the standard dosing.  

The trial also showed that the average (median) progression-free survival (PFS) of the men was the same, approximately nine months in each of the two groups.  It also showed that the androgen levels in both groups decreased similarly, the goal of hormone therapy.

The research group concluded that using low dose Zytiga along with a low-fat meal is non-inferior to the standard high dose treatment protocol on an empty stomach.

This is just a small, early study that needs to be replicated and have a more extended follow-up period before we can say that it should change the standard of care.  These follow-up studies need to be done quickly given the high cost of Zytiga.

If you decide not to wait for the follow-up studies, which Cancer ABCs does not recommend, we do urge that you speak with your doctor to make sure that they approve.  We also suggest that you have a consult with a nutritionist to have them help design an appropriate low-fat meal.  

Joel T. Nowak, MA, MSW wrote this Post.  Joel is the CEO/Executive Director of Cancer ABCs.  He is a Cancer Thriver diagnosed with five primary cancers - Thyroid, Metastatic Prostate, Renal, Melanoma, and the rare cancer Appendiceal cancer.