Cultural factors related to adherence to imatinib in CML: a Mexican perspective

The advent of imatinib as a therapeutic option of chronic myeloid leukemia (CML) has transformed this previously highly resistant disease into one that is susceptible to management with oral drugs that now offer high long-term survival rates. However, achieving an adequate adherence to treatment regimes is of critical importance. The characteristics of treatment compliance in Mexican patients have not been determined.

We evaluated 38 CML patients, members of the Glivec(®) International Patient Assistance Program (GIPAP). A bimonthly simplified medication adherence questionnaire was applied and the adherence rate was calculated by direct tablet counting.

Two groups, one of local patients and another of out-of-town patients, were studied using an 85% adherence rate as a cut-off. The overall adherence rate was 85.9%. Fifteen patients were considered non-adherent (39.5%). The group of out-of-town patients presented a higher adherence rate of 92.8% in contrast with 76.3% in the local population (P = 0.021). The probability of achieving a complete cytogenetic response at some point of evolution after 8 years of follow-up was 93% in the adherent group vs. 58% in the group with an adherence rate <85% (P = 0.008). In patients with imatinib failure, the adherence rate was 75.8% compared to 95.5% (P = 0.008) in the optimal response group.

In Mexican patients with CML, non-adherence to treatment is a cause of the failure to achieve remission or the subsequent loss of a complete cytogenetic and major molecular response.