Assessing response to neoadjuvant docetaxel and trastuzumab in Nigerian women with HER2-positive breast cancer (ARETTA).

TPS622 Background: Breast cancer rates are increasing in Nigeria and across sub-Sahara Africa without the necessary infrastructure to manage the disease. Adequate clinical trial resources are needed to address the growing need for high quality, patient centered cancer care on the Continent. The ARETTA clinical trial was initiated by the Nigerian Breast Cancer Study Team in partnership with the University of Chicago Comprehensive Cancer Center. To build local capacity for biomarker informed clinical trials and translational research. Clinical investigators receive extensive training and local facilities at four University-based Cancer Centers in Southwest Nigeria were upgraded. The study is a pragmatic single-arm, phase II clinical trial to determine the safety and efficacy of neoadjuvant taxotere and trastuzumab in women with HER2-positive breast cancer. The study sought to 1) determine the pathological complete response (pCR) rate of patients with early stage breast cancer to neoadjuvant docetaxel and subcutaneous trastusumab 2) assess the feasibility of conducting oncology clinical trials using upgraded facilities and trained personnel and 3) determine accrual rate of participants. Methods: The study is currently open to accrual. Inclusion criteria include treatment naïve women aged 18 years to 70 years with Her-2 positive breast cancer stages II-IIIC (AJCC). Eligible participants receive four cycles of docetaxel 75mg/m2 and trastuzumab every 3 weeks. Those with incomplete clinical response by breast ultrasound volume measurements receive 3 additional cycles of chemotherapy; cyclophosphamide 600mg/m2, epirubicin 90mg/m2 and 5-fluorouracil 600mg/m2 every 3 weeks before re-evaluation for surgery. All participants receive a fixed dose of sub-cutaneous Herceptin (600mg) every 3 weeks (total of 18 doses). The primary endpoint is pCR rate. Secondary objectives are to evaluate invasive disease-free survival (iDFS), the pattern of response and mechanisms of resistance to treatment based on genomic markers, the pharmacokinetics of Herceptin SC, quality of life, and adverse event rates, including cardiac toxicity. Planned enrollment is 47 evaluable patients, which will provide 90% power to test the null hypothesis that the pCR rate is 20% versus a 40% alternative (one-sided alpha=0.05). More protocol details can be found at ClinicalTRial.gov NCT03879577 and JCO Glob Oncol2020 doi: 10.1200/GO.20.00043. Progress: Accrual commenced on 3rd April 2020 and is 75% completed. To date, monitoring, regulatory, as well as Data Safety and Monitoring Board progress evaluation did not identify any logistical or safety issues such as underdeveloped infrastructure, unacceptable rate of non-compliance with study protocol, poor informed consent procedure or serious adverse events to warrant stopping the trial. Clinical trial information: NCT03879577.