New research shows that many patients taking oral cancer drugs that target key enzymes in tumor cells are also taking other drugs that may inhibit the cancer treatment’s full benefits or increase the risk of side effects.
Researchers studied 9 oral kinase inhibitors, which included the medications imatinib and erlotinib, and found that 23% to 74% of patients taking these oral oncology medications were also taking a drug that had the potential to reduce the effectiveness of the cancer treatment or increase its toxicity. Medications that may cause drug-drug interactions include calcium channel blockers, proton pump inhibitors, steroids, and certain antibiotics and antifungal agents.
“Oral cancer drugs represent a huge advancement in oncology treatment, but make no mistake these are powerful drugs. These high costs medications can have severe side effects and need to be actively monitored for proper use and adherence,” said Dr Milayna Subar, national practice leader at the Medco Oncology Therapeutic Resource Center. “What’s as important is knowing what other medications the patient is on. The fact that about one quarter to 75% of patients on these oral drugs may not be getting the full benefit of their treatment or may in fact be putting their health at further risk because of another medication they are taking is concerning.”
In addition to imatinib and erlotinib, researchers studied dasatinib, everolimus, lapatinib, nilotinib, pazopanib, sorafenib, and sunitinib. Scientists reviewed the pharmacy claims of approximately 11,600 patients taking 1 of the 9 kinase inhibitors and evaluated the number of patients taking at least 1 other drug that had the potential to cause a drug interaction with their cancer treatment.
Of the 4617 patients receiving imatinib in the study, 43% were prescribed a drug that may diminish the cancer drug’s efficacy, and 68% of patients received a drug that may raise the level of toxicity of the treatment. The efficacy of other drugs were found to be potentially impaired between 23% and 57% of the time. Moreover, from 24% to 74% of patients were using medications that could increase the toxicity of the other cancer drugs studied.
The emergence of these oral cancer drugs in the past decade has also brought about high costs. In some cases, a year of treatment exceeds $100,000. In 2010, specialty drugs for cancer treatment, which include many of the medications in the study, saw spending growth increases of 21%.
“By taking a holistic approach to caring for cancer patients and being diligent that they are managing their treatment regimen properly and getting the full benefit of the medications they are on, we can drive down both waste and cost, while helping to improve the health outcomes of the patient,” said Subar.
Source: Medco.