Taking Zytiga with breakfast may allow a dose reduction (read: discount) of 75%
- Zytiga (abiraterone) is a drug used to treat some forms of metastatic prostate cancer.
- It is known that taking Zytiga with food can boost drug absorption by 5- to 10-fold.
- Taking advantage of this property, a study found that taking one Zytiga pill with breakfast was no worse than taking four on an empty stomach.
Zytiga is a drug used in combination with prednisone for patients with metastatic castration-resistant prostate cancer.
This drug is known to interact with food, particularly with fatty meals. Compared to when Zytiga was taken under fasting conditions, a 300-calorie, 7%-fat meal boosted the amount of drug in the blood by 5-fold; an 825-calorie, 57%-fat meal boosted it by 10-fold.
Can this effect be exploited to lower the number of pills patients have to take? After all, a 75% dose reduction means a 75% discount on the prescription. For a drug that may cost $8,000 a month, $6,000 a month in savings — $72,000 a year; is no small change.
To test this idea, a group of doctors in the US and Singapore devised a simple study.
Randomly assign 72 patients with metastatic castration-resistant prostate cancer to take full-dose Zytiga and prednisone on an empty stomach, or take it at 25% dose with a low-fat breakfast; then test their PSA after 3 months.
The result?
The authors concluded that “these data warrant consideration by prescribers and payors.”
Bottom line
- This study is a reminder to always think about drug interactions when getting a new prescription.
- Drug interactions aren’t always bad. Taking advantage of drug interactions with clinical evidence can lead to substantial benefits.
- While one study isn’t enough to start cutting the Zytiga dose down to size, this is a good start and patients should talk to their doctors about results of this study.
CI = Confidence interval; PSA = Prostate-specific antigen.
Source study: Szmulewitz RZ, et al. J Clin Oncol 2017;35(suppl 6S): abstract 176. A paid subscription may be required.
References: 1. Abiraterone Prescribing Information, 2016. 2. Szmulewitz RZ, et al. J Clin Oncol 2017;35(suppl 6S): abstract 176.
Photo adapted from original by Chris Potter, used under license.
