Oncology nurses awareness of drug interactions

Drug-drug interactions in subjects enrolled in SWOG trials of oral chemotherapy

BACKGROUND

Patients with cancer are at increased risk of drug-drug interactions (DDI), which can increase treatment toxicity or decrease efficacy. It is especially important to thoroughly screen DDI in oncology clinical trial subjects to ensure trial subject safety and data accuracy. This study determined the prevalence of potential DDI involving oral anti-cancer trial agents in subjects enrolled in two SWOG clinical trials.

METHODS

Completed SWOG clinical trials of commercially available agents with possible DDI that had complete concomitant medication information available at enrollment were included. Screening for DDI was conducted through three methods: protocol-guided screening, Lexicomp® screening, and pharmacist determination of clinical relevance. Descriptive statistics were calculated.

RESULTS

SWOG trials S0711 (dasatinib, n = 83) and S0528 (everolimus/lapatinib, n = 84) were included. Subjects received an average of 6.6 medications (standard deviation = 4.9, range 0-29) at enrollment. Based on the clinical trial protocols, at enrollment 18.6% (31/167) of subjects had a DDI and 12.0% (20/167) had a DDI that violated a protocol exclusion criterion. According to Lexicomp®, 28.7% of subjects (48/167) had a DDI classified as moderate or worse, whereas pharmacist review indicated that 7.2% of subjects (12/167) had a clinically relevant interaction. The majority of clinically relevant DDI identified were due to the coadministration of acid suppression therapies with dasatinib (83.3%, 10/12).

CONCLUSIONS

The high DDI prevalence in subjects enrolled on SWOG clinical trials, including a high prevalence that violate trial exclusion criteria, support the need for improved processes for DDI screening to ensure trial subject safety and trial data accuracy.

Drug interaction screening in SWOG clinical trials

PURPOSE

The frequency and process for drug interaction (DI) screening at sites enrolling patients into SWOG clinical trials were studied.

METHODS

Survey invitations were e-mailed to 180 SWOG head clinical research associates to determine the frequency of and personnel involved in DI assessment in subjects who were screened for and enrolled in clinical trials at their sites. Descriptive statistics were performed to evaluate the data.

RESULTS

A total of 83 surveys recorded a response to at least 1 question, yielding an overall response rate of 46.1%. At least 72 completed surveys were submitted, for a completion rate of 40.0%. The majority of sites (51%) reported that DI screening only occurred during eligibility assessment when a DI was included in the protocol exclusion criteria. The pharmacist was "always" involved in DI screening during eligibility assessment at 17% of sites. Clinical research coordinators (56%) and research nurses (45%) were the predominant personnel who performed DI screening to assess eligibility for trial enrollment. A subset of sites (3-6%) reported not having access to a pharmacist. Fewer than 10% of sites reported that they "always" use drug information services, websites, resources, or literature searches, though many tools were used "often" or "sometimes" by more than 20% of sites.

CONCLUSION

A survey revealed that DI screening was not being systematically conducted within SWOG clinical trials. When DI screening did occur, it was primarily conducted by clinical research coordinators or study nurses. Pharmacist-led DI screening was not the current practice within SWOG sites surveyed and was precluded by a lack of pharmacists' availability or involvement.

Prevalence of drug-drug interactions in oncology patients enrolled on National Clinical Trials Network oncology clinical trials

Background

Drug-drug interactions (DDIs) in subjects enrolling in clinical trials can impact not only safety of the patient but also study drug outcomes and data validity. This makes it critical to adequately screen and manage DDIs. The study objective was to determine the prevalence of DDIs involving study medications in subjects enrolling in National Clinical Trials Network (NCTN) clinical trials at a single institution. DDIs were evaluated based on study protocol recommendations for concomitant medication use (i.e. exclude, avoid or use caution), screening via DDI tool, and pharmacist review.

Methods

Subjects enrolled in NCTN trials of commercially available agents between January 2013 and August 2017 were included if a complete medication list was available. Complete medication lists were collected from the date of enrollment or the next available date then screened utilizing protocol guidance and the DDI screening tool, Lexicomp® Drug Interactions (Wolters Kluwer, Hudson, OH). Interactions were reviewed for clinical relevance: defined as a DDI that would require a medication change to ensure study agent safety and efficacy at enrollment.

Results

One hundred and twenty-eight subjects enrolled in 35 clinical trials were included. Protocol guidance detected 15 unique DDI pairs that should be avoided or used with caution in 10.2% (13/128) of subjects. The majority of these subjects did not have a clinically relevant DDI (69.2%, 9/13) based on pharmacist review. Lexicomp® detected moderate to major DDIs in 24.2% (31/128) of subjects, with 9.4% (12/128) having a clinically relevant DDI.

Conclusions

This study confirms a high prevalence of DDIs present in subjects enrolling in oncology clinical trials. Further efforts should be made to improve methods to detect and manage DDIs in patients enrolling on clinical trials to ensure patient safety and trial data validity.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-5076-0) contains supplementary material, which is available to authorized users.