Impact of bariatric surgery on oral anticancer drugs: an analysis of real-world data.

PURPOSE: The number of patients with bariatric surgery who receive oral anticancer drugs is rising. Bariatric surgery may affect the absorption of oral anticancer drugs. Strikingly, no specific drug dosing recommendations are available. We aim to provide practical recommendations on the application of oral anticancer drugs in patients who underwent bariatric surgery. METHODS: Patients with any kind of bariatric surgery were extracted retrospectively in a comprehensive cancer center. In addition, a flowchart was proposed to assess the risk of inadequate exposure to oral anticancer drugs in patients who underwent bariatric surgery. Subsequently, the flowchart was evaluated retrospectively using routine Therapeutic drug monitoring (TDM) samples. RESULTS: In our analysis, 571 cancer patients (0.4% of 140.000 treated or referred patients) had previous bariatric surgery. Of these patients, 78 unique patients received 152 oral anticancer drugs equaling an overall number of 30 unique drugs. The 30 different prescribed oral anticancer drugs were categorized as low risk (13%), medium risk (67%), and high risk (20%) of underdosing. TDM plasma samples of 25 patients (82 samples) were available, of which 21 samples post-bariatric surgery (25%) were below the target value. CONCLUSIONS: The proposed flowchart can support optimizing the treatment with orally administered anticancer drugs in patients who underwent bariatric surgery. We recommend performing TDM in drugs that belong to BCS classes II, III, or IV. If more risk factors are present in BCS classes II or IV, a priori switches to other drugs may be advised. In specific cases, higher dosages can be provided from the start (e.g., tamoxifen).

The influence of body mass index on the tolerability and effectiveness of full-weight-based paclitaxel chemotherapy in women with early-stage breast cancer.

PURPOSE: To investigate the influence of body mass index (BMI) on the tolerability and effectiveness of full-weight-based paclitaxel chemotherapy in early breast cancer patients. METHODS: Early-stage breast cancer patients who received (neo)adjuvant weekly paclitaxel 80 mg/m2 chemotherapy were included in this retrospective study. Patients were divided into three groups based on their BMI: lean, overweight, and obese. Logistic regression was used to assess for association between BMI with administered relative dose intensity (RDI) < 85%. The occurrence of treatment modifications and the pathological response on neoadjuvant chemotherapy were compared between BMI categories. RESULTS: Four hundred (400) patients were included in this study; 200 (50%) lean, 125 (31%) overweight, and 75 (19%) obese patients. The adjusted odds ratio to receive RDI < 85% for BMI was 1.02 (p value, .263). Treatment modifications occurred in 115 (58%), 82 (66%), and 52 (69%) patients in the respective BMI categories (p value = .132). Peripheral neuropathy was observed in 79 (40%), 58 (46%), and 41 (55%) patients in the lean, overweight, and obese group (p value = .069), whereas hematologic toxicity was observed in 31 (16%), 10 (8%), and 4 (5%) patients (p value = .025). Pathological complete response was observed in 22 (17%), 11 (14%), and 6 (13%) patients in the respective BMI categories (p value = .799). CONCLUSION: BMI did not significantly influence the tolerability and effectiveness of full-weight-based paclitaxel chemotherapy. Therefore, the results of this study align with current guideline recommendations of using full-weight-based paclitaxel chemotherapy in obese patients.

Representativeness of Phase III Trial for Osimertinib in Pretreated Advanced EGFR-Mutated Non-small-cell Lung Cancer Patients and Treatment Outcomes in Clinical Practice.

BACKGROUND: Overall survival (OS) data of osimertinib in pretreated non-small-cell lung cancer (NSCLC) in real-world practice is limited, and treatment benefits for patients not represented in the pivotal trials (ineligible) are unclear. OBJECTIVE: To determine the representativeness of the AURA3 trial for NSCLC patients treated with osimertinib in a real-world setting and to determine outcomes of patients who were represented in the AURA3 trial (eligible) and those who were ineligible. METHODS: Advanced NSCLC patients receiving post first-line osimertinib were included in this retrospective study and were divided into two groups based on eligibility criteria of the AURA3 trial. Progression-free survival (PFS) and OS were estimated using the Kaplan-Meier method. Cox models were used to estimate the association of eligibility criteria with OS. RESULTS: 328 patients were included; 126 (38%) patients were eligible and 202 (62%) patients were ineligible. The most common ineligibility reasons were the number of earlier treatment lines and an Eastern Cooperative Oncology Group performance status (ECOG PS) > 1. PFS of eligible and ineligible patients was not statistically different (8.0 vs. 5.8 months, p = 0.062). Eligible patients had a longer OS (24.0 vs. 15.4 months, p = 0.001) compared to ineligible patients. ECOG PS was the best predictor for OS. An ECOG PS of 1 was already associated with poorer survival compared to an ECOG PS of 0 (hazard ratio 1.54; p = 0.016). CONCLUSION: The majority of the study population was not represented in the AURA3 trial. Survival outcomes of eligible patients are in concordance with the AURA3 trial, while OS of ineligible patients was significantly shorter compared to eligible patients.

A Review of CYP3A Drug-Drug Interaction Studies: Practical Guidelines for Patients Using Targeted Oral Anticancer Drugs.

Many oral anticancer drugs are metabolized by CYP3A. Clinical drug-drug interaction (DDI) studies often only examine the effect of strong CYP3A inhibitors and inducers. The effect of moderate or weak inhibitors or inducers can be examined using physiologically based pharmacokinetic simulations, but data from these simulations are not always available early after approval of a drug. In this review we provide recommendations for clinical practice on how to deal with DDIs of oral anticancer drugs if only data from strong CYP3A inhibitors or inducers is available. These recommendations were based on reviewed data of oral anticancer drugs primarily metabolized by CYP3A and approved for the treatment of solid tumors from January 1st, 2013 to December 31st, 2015. In addition, three drugs that were registered before the new EMA guideline was issued (i.e., everolimus, imatinib, and sunitinib), were reviewed. DDIs are often complex, but if no data is available from moderate CYP3A inhibitors/inducers, a change in exposure of 50% compared with strong inhibitors/inducers can be assumed. No a priori dose adaptations are indicated for weak inhibitors/inducers, because their interacting effect is small. In case pharmacologically active metabolites are involved, the metabolic pathway, the ratio of the parent to the metabolites, and the potency of the metabolites should be taken into account.