Control Toxicity Through Controlled Exposure
Paclitaxel is widely used to treat breast, non-small cell lung (NSCLC), ovarian and digestive tract cancers. Despite being a potentially life-saving drug, it is also quite toxic. As demonstrated below, most patients treated with paclitaxel suffer seriously debilitating side effects, especially neutropenia, which is characterized by an abnormally low number of neutrophils, making patients susceptible to bacterial infections that can be life threatening.1
Multiple studies have demonstrated high interpatient variability of paclitaxel plasma drug exposure with BSA-based dosing.2-3 Patients receiving BSA-based paclitaxel can show greater than a 10-fold variability in clearance rates. High paclitaxel exposure has been shown to be a good predictor of severe neutropenia.2
Higher paclitaxel exposure has also been shown to lead to higher grades and incidence of peripheral neuropathy (PNP).4 This is damage to nerves of the peripheral nervous system and symptoms may include muscle weakness, numbness or burning pain, cramps, spasms, loss of balance or coordination often experienced in the arms and legs.
The incidence of severe side effects can be reduced by controlling systemic paclitaxel levels. MyPaclitaxel enables oncologists to identify paclitaxel-treated patients who are at high risk of severe toxicity by measuring their systemic drug exposure. Armed with this information, physicians can reduce their patients’ dose of paclitaxel or prophylactically administer granulocyte colony-stimulating factor (GCSF) to prevent the onset of serious toxic side effects.
Clinical implementation of paclitaxel dose management with MyPaclitaxel is simple. One blood sample is drawn 24 hours after the end of paclitaxel infusion. Upon analysis by a clinical laboratory, an individualized report is generated and returned to your doctor in time to make therapeutic adjustments for the next cycle of treatment. The critical pharmacokinetic parameter for paclitaxel is Time Above Concentration Threshold (Tc), the time that a given concentration of drug is maintained in the bloodstream. The MyPaclitaxel test result, together with the professional clinical experience and medical knowledge of your doctor, will be the basis for the decision on dose adjustment. Monitoring patients’ systemic paclitaxel levels helps control toxicity throughout the course of treatment, preventing premature treatment discontinuation.
1. TAXOL® package insert.
2. Joerger, M., et al., Clin Cancer Res, 13(21):6410-6418, 2007.
3. Gianni, L, et al., J Clin Onc, 13(1):180-190, 1995.
4. Mielke, S, et al., Clin Cancer Res, 11(13):4843-4850, 2005.