Exploring the impact of endocrine therapy brand switching in patients with breast cancer (SWITCH)

Research Question Do patients that switch brands of medicines experience a greater adverse-event burden?

Background Women with breast cancer who do not adhere to adjuvant endocrine therapy (AET) have an increased risk of mortality, recurrence, and reduced quality-adjusted life-years. AET is offered to approximately 70% of women with invasive breast cancer (~38500 UK women per year).

Low adherence has been linked with switching brands of AET and women believe that their concerns around this are unheard.

Higher adverse-event (AE) burden for certain brands of medicines can be attributed to two reasons. 1) Psychological: women may be aware of the change and experience greater AEs 2) Different drugs have different ingredients(excipients) that can enhance the effects of the active drug. To date no study has evaluated the impact of switches in drugs especially as they are all low-cost treatments.

Aims and Objectives To answer our research question, we have developed the following objectives Examine occurrence of brand changes in women receiving AET and investigate associations between brand changes, frequency of AE reporting and adherence (WS1,WS3) Gain in-depth understanding of women s experiences of brand changes in AET (WS1) Explore healthcare professional prescribing behaviors and understand their views on brand changes (WS2) Co-develop recommendations with key stakeholders and prepare pathway to impact.

Methods Using routinely collected primary care data, we will investigate patterns in prescribing over a 5-year treatment period and monitor when patients do not pick up their prescriptions, have changes in brands and stop early.

We will investigate the changes that occurred in this timeframe regionally and the different ingredients of the brands used.

We will follow 500 women from around the country who have been prescribed AET, monitoring their experiences with the treatment and prescribed brands over 9 months. This will be complemented with interviews with patients and healthcare professionals.

We will bring all our findings together to plan more work to help make sure women are supported around side effects and brand changes in endocrine therapy. Timelines for delivery Ethical approvals and data requests will be made pre-award. Months 1-3 – Ethical approvals, site set up.

Months 4-6 – Data acquisition (primary care), commence patient recruitment, conduct focus groups, patient interviews.

Months 7-9 – Review of different brands of drugs, primary care data analysis, continue recruitment and interviews, further focus groups. Months 9-12 – Reporting of primary care analysis & dissemination; continued recruitment and interviews. Months 13-15 – continued interviews, cease recruitment.

Month 16-18 – Longitudinal analysis Month 19-21 Analysis. Month 22-24 Planning and conduction of dissemination. Final reporting and planning future research.

Anticipated Impact and dissemination We have dedicated time to dissemination to maximise impact beyond traditional scientific outputs. We are cognisant that simply communicating via traditional academic channels will not have the desired impact.

Dissemination includes developing patient facing media guided by our patient representative and holding a national collaborative event to share findings and building on our existing connections to communicate our findings with patients/members of the public/ healthcare professionals and commissioners.