OnDose® Study Demonstrates Need for Improved Dosing Approach for Colorectal Cancer Patients
Posted by Adrienne Choma on Fri, Jun 10, 2011 @ 04:00 PM
I recently wrote about the shortcomings of Body Surface Area (BSA) based dosing of chemotherapy drugs. A study just published in Clinical Colorectal Cancer has reaffirmed that BSA dosing of 5-fluorouracil for colorectal cancer patients receiving FOLFOX treatment regimens is suboptimal in ensuring that patients are administered the right dose for treatment efficacy.
This study analyzed the 5-FU plasma concentrations of 357 patients who were dosed based upon BSA. Over 50% of these patients received too little drug to reach the plasma target range and another 28% were above the target range. Only 21% of patients were found to have drug plasma levels within the target range with BSA dosing. Prior studies have shown that patients whose plasma drug levels are within target range realize better treatment outcomes and suffer lower toxic side effects associated with chemotherapy drugs.
Why is there such wide variation in drug plasma concentrations among patients? BSA dosing is based solely upon body mass and does not take into account the many factors that impact drug metabolism, including age, gender, disease state, drug-drug interactions, genotype and organ function.
Sixty-two of the patients in the study had their 5-FU doses personalized during the course of treatment to reach the drug plasma target range. Of these 62, only 5% were within target range at the beginning of the study and over 50% were outliers. After four rounds of adjusted dosing, 37% were within target and only 14.5% were outliers.
OnDose®, the simple blood test that enables oncologists to determine whether their patients are being over- or under-dosed is being offered in the United States by Myriad Genetics.
Adrienne Choma, Vice President, Marketing & Sales