Researchers examined the timing of lapatinib administration in patients with metastatic breast cancer to determine any impacts on adverse events associated with this treatment. Findings of the analysis were reported in the journal Cancer Medicine.

The researchers explained in their report that prandial status is a known factor affecting the bioavailability of lapatinib.

Outcomes for patients receiving lapatinib with different administration protocols were investigated in this unplanned, retrospective analysis of a phase 2 trial (Japan Breast Cancer Research Group Identifier: JBCRG-16 [Neo-LaTH]). Patients were stratified for this analysis based on timing of lapatinib administration: before breakfast (BB), between meals (BM), or at bedtime (AB). Multiple outcomes were assessed between patient groups.

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The BB group consisted of 15 patients, the BM group had 51 patients, and the AB group had 74 patients.

Compared with patients in the AB group, patients in the BB group had a lower rate of diarrhea (adjusted hazard ratio [aHR], 0.51; 95% CI, 0.27-0.89; P =.018). Overall, any-grade diarrhea was reported in 86.7% of patients in the BB group, 92.2% of the BM group, and 97.3% of the AB group. Rash also occurred at a lower rate in the BB group than in the AB group (aHR, 0.37; 95% CI, 0.17-0.70; P =.002). Pathological complete response was reported at similar rates between groups (P =.75).

The researchers noted that additional factors, such as concomitant medications taken at different times of day, may have influenced drug absorption and/or metabolism. However, they concluded that before-breakfast administration may be linked to lower risks of diarrhea or rash with this treatment compared with at-bedtime dosing.

Disclosures: Multiple authors declared affiliations with or received funding from the pharmaceutical industry. Please see the original article for a full list of disclosures.


Tsuda M, Ishiguro H, Toriguchi N, et al. Overnight fasting before lapatinib administration to breast cancer patients leads to reduced toxicity compared with nighttime dosing: a retrospective cohort study from a randomized clinical trial. Cancer Med. Published online October 23, 2020. doi:10.1002/cam4.3528

This article originally appeared on Oncology Nurse Advisor