Adherence to Imatinib in GIST Patients Still Subpar

Despite the high efficacy of imatinib to treat patients with gastrointestinal stromal tumors (GIST), a recent article review of multiple GIST studies reveals that a large number of patients still achieve suboptimal adherence levels.

Routine assessments of adherence to imatinib may be necessary to ensure patients on tyrosine kinase therapies get the best treatment possible, according to a recent article published in Cancer Treatment Reviews. Without the proper level of compliance, patients are more likely to encounter further problems, such as tumor progression, poor clinical outcomes, and higher-than-average health care costs.

Lead authors Jean-Yves Blay and Piotr Rutkowski examined numerous studies on adherence to imatinib in patients with unresectable and/or metastatic GIST. Although the potential for adverse events is one of the most highly cited reasons for nonadherence, the authors found that economic factors also influence abandonment rate. Through a review of studies analyzing pharmacy claims data, they observed that high cost sharing, increased prescription activity, lower income, and Medicare coverage were all associated with suboptimal adherence rates.

In a separate study, the authors observed that even a good clinical response to imatinib and a general feeling of well-being after treatment initiation may affect adherence and give patients “the impression that stringent adherence to therapy is no longer necessary.”

In addition, Blay and Rutkowski pointed out in a separate study of 173 GIST patients that nearly half of these patients admitted missing or skipping doses of imatinib. In yet another study, both patients and physicians were found to overestimate adherence; there were large discrepancies between actual and perceived adherence rates to GIST therapies.

The authors concluded that GIST patients could achieve better health outcomes through the use of a patient-centered team approach and “technology-supported” clinical systems. “Self-management and adherence programs for patients, effective management of imatinib-related adverse events and the use of blood level testing are powerful tools that could increase the uptake of health-promoting behaviors, maximize adherence, and achieve optimal clinical outcomes in patients with GIST,” the authors wrote.