Taking one-fourth the standard dose of abiraterone acetate (Zytiga, Janssen Biotech), a widely used drug for prostate cancer, with a low-fat breakfast can be as effective––at a quarter of the cost––as taking the standard dose as recommended (on an empty stomach), according to a study from the University of Chicago Medical Center.
The finding has significant financial implications, the researchers say. Abiraterone retails for more than $9,000 per month. Even patients with blue-ribbon health insurance can have co-pays ranging from $1,000 to $3,000 per month.
Patients taking abiraterone typically remain on the medication for 12 to 18 months. Since 2011, according to the manufacturer’s website, more than 100,000 patients in the United States have filled prescriptions for the product. If each of those 100,000 patients had taken the drug for 12 months and, theoretically, had paid the list price out of pocket but took the lower dose with food, the 75% cost reduction could have saved them more than $6 billion, according to the investigators.
Seventy-two patients ages 52 to 89 years (median age: 74 years) with advanced prostate cancer participated in the study, which was conducted in the United States and Singapore. The patients’ disease had progressed despite standard initial hormonal therapy. They were randomly assigned to receive the standard dose of abiraterone on an empty stomach or a lower dose with breakfast. The study’s primary objective was to compare the change in blood levels of prostate-specific antigen (PSA), a measure of disease burden and progression.
Despite a 75% difference in dose, there was no difference in abiraterone activity, as measured by variations in PSA levels between the two groups. The times to disease progression also were nearly identical (approximately 14 months) for both arms.
Patients who took abiraterone with food appeared to have an additional benefit. They were less likely to complain about stomach discomfort than were those who took the drug as recommended. The label for abiraterone recommends fasting for two hours before and one hour after swallowing the medication. Taking the drug with breakfast is therefore easier for patients, according to the researchers.
Patients with early-stage prostate cancer are usually treated initially with drugs that disrupt the production of male hormones, such as testosterone, which promotes tumor growth. This can slow or halt progression of the disease. Over time, however, cancer cells adapt. They develop the ability to grow and metastasize without relying on hormones, a stage known as castration-resistant prostate cancer. Historically, those patients were treated with chemotherapy, which can have significant adverse effects.
Abiraterone, approved for the treatment of patients with metastatic prostate cancer in 2011, added a new layer to the sequence. It “sits between hormone therapy and chemotherapy,” explained study director Russell Szmulewitz, MD. “It delays disease progression, improves survival, and delays deterioration of quality of life.” When the drug’s effects diminish, clinicians shift to a similar, competing product or move on to chemotherapy.
“This was a relatively small study, too small to show with confidence that the lower dose is as effective,” Szmulewitz conceded. “It gives us preliminary but far from definitive evidence. Physicians should use their discretion, based on patient needs.”
The study indicated that patients with concerns about costs could, with careful guidance and regular follow-up from their physicians, consider the smaller dose of abiraterone taken with a low-fat breakfast. This would enable them to spread the cost of one month’s supply of pills over four months––a per-patient savings of up to $7,500 each month.
The American Cancer Society estimates that 161,360 men will be diagnosed with prostate cancer in 2017 and that 26,730 men will die from the disease.
Source: Medical Xpress; February 13, 2017.