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Spotlight: PHERGain-2 HER2+ early breast cancer trial

Updated: Nov 29, 2021

Human epidermal growth factor receptor 2 (HER2) is a protein that promotes the growth of cancer cells. Around 20% of all breast cancers are HER2+, meaning they have cancer cells that have extra copies of the gene that makes this HER2 protein. HER2+ breast cancer is considered one of the more aggressive forms.

In the United States and Europe, most case of HER2+ breast cancer are detected early and can be completely resected with surgery. In addition, systemic therapy with chemotherapy (paclitaxel) and trastuzumab is administered either before or after surgery. Around 34% of breast cancer patients will have curative or palliative chemotherapy. Recently, there has been a focus on utilizing HER2 targeting drug without any chemotherapy component in order to improve quality of life of the patient.

In hopes of finding a treatment that no longer relies on the use of chemotherapy, MEDSIR developed the PHERGain trial(NCT03161353).This trial provided evidence that the PET-CT imaging test was able to identify around 40% of patients with localized HER2-positive early breast cancer who might not require chemotherapy. Additionally, patients that did not receive chemotherapy had a better toxicity profile and improved impact on quality of life compared with patients who received chemotherapy. These astonishing results were presented at ASCO 2020 and published in The Lancet.

The results of the PHERGain trial paved the way for PHERGain-2 which will assess the viability of the chemotherapy free alternative PHESGO™ - a combination of trastuzumab and pertuzumab – for the treatment of HER2+ early breast cancer. The primary outcome measures of the study will be 3-year recurrence-free survival and global health status decline. The study will enroll 393 patients with early breast cancer that are characterized as a small tumor (5-25mm), strongly positive for HER2, and has not spread to the lymph nodes.

A secondary aim of the study is to explore the ability of using MRI to predict a pathological complete response (pCR) which will help assess the rate of BCS (Breast Conserving Surgery) and potentially explore whether there could be a second de-escalation approach with opportunity to omit surgery in patients with good response by MRI. Specifically, MRI scanning will be completed before and after treatment to correlate between the final MRI results and breast conserving surgery (BCS), pCR, and RCB at surgery.

Given the side effects and the impact of chemotherapy on the quality of life of patients with early breast cancer, it is advisable to find a new therapeutic strategy that allows dispense with traditional systemic chemotherapy in those patients who can achieve a similar response with a less toxic treatment,explained Dr. Antonio Llombart, Head of the Medical Oncology Service at the Arnau de Vilanova Hospital (Valencia, Spain) and principal investigator of the study.

The PHERGain-2 trial will recruit patients in 70 planned health centers in Spain, Italy, Germany, Hungary, Bulgaria and Poland. Contact us to learn more and if you have a brilliant idea on a clinical trial that you would like to develop, tell us, we can make it happen!


Cancer Research UK,, Accessed November 2021.



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