Resistance to antiemetic treatment with 5-hydroxytryptamine 3 receptor antagonists is a problem, with 20-30% of patients showing unsatisfactory responses. Efflux transport by P-glycoprotein, encoded by the ATP-binding cassette ABCB1 gene in the blood-brain barrier, has been the suggested resistance mechanism. We evaluated the association between the antiemetic efficacy of granisetron plus dexamethasone and ABCB1 polymorphisms 3435C>T and 2677G>T/A. Sixty-four breast cancer patients treated with doxorubicin plus cyclophosphamide were evaluated for their responses to antiemetic therapy. Genotyping of patient DNA samples for ABCB1 single nucleotide polymorphisms was performed; the genotypes were then investigated for their association with the efficacy of prophylactic antiemetics. The acute phase complete response rate was 83% in GG subjects (n = 12), and 69% (n = 35) and 41% (n = 17) in heterozygous and homozygous carriers of the 2677T/A allele, respectively (p = 0.047). The ABCB1 2677 TT genotype group showed significantly lower rates of complete control of acute emesis than the group with GG genotypes (p = 0.045). No significant association with complete response was found for 3435C>T (p = 0.190). ABCB1 polymorphisms may influence the extent of acute emesis control in granisetron-treated patients, making the ABCB1 genotype a predictor of prophylactic antiemetic response.

This study presents a simple, accurate, and selective bioanalytical method of bevacizumab detection from plasma samples based on aptamer affinity purification–high-temperature reversed-phased liquid chromatography (HT-RPLC) with fluorescence detection. Bevacizumab in plasma samples was purified using magnetic beads immobilized with an anti-idiotype DNA aptamer for bevacizumab. The purified bevacizumab was separated with HT-RPLC and detected with its native fluorescence. Using aptamer affinity beads, bevacizumab was selectively purified and detected as a single peak in the chromatogram. HT-RPLC achieved good separation for bevacizumab with a sharp peak within 10 min. The calibration curves of the two monoclonal antibodies ranged from 1 to 50 μg/mL and showed good correlation coefficients (r² > 0.999). The limit of detection (LOD) and lower limit of quantification (LLOQ) values for bevacizumab were 0.15 and 0.51 μg/mL, respectively. The proposed method was successfully applied to the bioanalysis of the plasma samples obtained from the patients with lung cancer and may be extended to plan optimal therapeutic programs and for the evaluation of biological equivalencies in the development of biosimilars.