PHERGain II Trial Launched to Examine Chemotherapy-Free Treatment for Patients With HER2+ Breast Cancer


The PHERGain II trial will investigate the treatment of patients with early HER2-positive breast cancer using a chemotherapy-free treatment approach of trastuzumab plus pertuzumab.

A clinical trial to support the use of a chemotherapy-free therapeutic approach has been launched and will aim to demonstrate that this approach is as effective as the current standard of care in certain patients with HER2-positive early breast cancer, according to a news release from MEDSIR.1

The current standard of care to treat patients with this disease typically involves the use of more toxic treatments, motivating the initiation of the PHERGain II trial.

“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,” Antonio Llombart-Cussac, MD, PhD, principal investigator of the study and head of the Medical Oncology Service at the Arnau de Vilanova Hospital, said in a press release.

The PHERGain II trial is designed to administer preoperative treatment with trastuzumab (Herceptin) and pertuzumab (Perjeta) to patients with HER2-positive early breast cancer without chemotherapy.

MRI scans of tumors before and after treatment will be used to determine if a pathological response can be assessed with noninvasive tumor imaging.

After surgery, patients will be re-examined to define their response to the trastuzumab and pertuzumab treatment. The team of investigators will then determine if the patient will continue receiving this therapy or receive T-DM1 (ado-trastuzumab amtansine; Kadcyle), with chemotherapy being reserved only for patients whose prognosis got worse after preoperative treatment.

The cohort of patients will consist of 393 patients from 70 health centers in Spain, France, Germany, the United Kingdom, and Italy.

A 3-year follow-up will continue after the results of the data to determine how its efficacy compares with chemotherapy in patients with this disease.

The study’s goal is to maintain clinical effectiveness while reducing the use of chemotherapy to improve patient quality of life. These goals are in alignment with the top priorities of cancer research organizations, such as the American Society of Clinical Oncology (ASCO).

“Although this new therapeutic approach will not allow all patients to dispense with chemotherapy, it opens the door for us to design new ways to reduce the toxicity of antitumor therapies based on the response of the tumor to preoperative treatment,” Llombart said.

The PHERGain I trial (NCT03161353) presented virtually at the recent ASCO Annual Meeting detailed positive results when investigating other chemotherapy-free approaches for patients with HER2-positive early breast cancer. A significant number of the patients included in this trial experienced a complete pathological response to the preoperative chemotherapy-free treatment option.2

Even for patients with a good prognosis, chemotherapy is still the standard treatment option to prevent tumor recurrence after surgery. Eliminating the need for chemotherapy while maintaining clinical efficacy will lead to better quality of life for patients with this disease.


1. A study of a new therapeutic strategy to avoid chemotherapy in patients with early HER-2+ breast cancer. News release. MEDSIR. Published February 3, 2021. Accessed February 17, 2021.

2. Cortes J, Gebhart G, Ruiz Borrego M, et al. Chemotherapy (CT) de-escalation using an FDG-PET/CT (F-PET) and pathological response-adapted strategy in HER2[+] early breast cancer (EBC): PHERGain Trial. J Clin Oncol. 2020;38(suppl 15):503. doi:10.1200/JCO.2020.38.15_suppl.503

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