Extended PFS Achieved With [vic-]Trastuzumab Duocarmazine in HER2-Positive Breast Cancer

Jan Schellens, MD, PhD

Treatment with [vic-]trastuzumab duocarmazine (SYD985) demonstrated a statistically significant improvement in progression-free survival (PFS) compared with physician’s choice of treatment in patients with pretreated HER2-positive unresectable locally advanced or metastatic breast cancer, meeting the primary end point of the phase 3 TULIP study, according to a press release from Byondis B.V.

The study also showed encouraging preliminary overall survival results, the company reported. The full study results will be presented during an upcoming scientific conference and the company plans to submit a biologic license application to the FDA before the close of the year.

"There is considerable unmet medical need in patients with HER2-positive metastatic breast cancer and [vic-]trastuzumab duocarmazine represents a promising potential clinical advance," said chief medical officer of Byondis, Jan Schellens, MD, PhD. "We are excited by the topline results of TULIP and indebted to all patients who participated in the clinical studies."

TULIP is a recently completed multicenter, open-label, randomized clinical trial (NCT03262935) of [vic-]trastuzumab duocarmazine administered intravenously every 3 weeks versus physician’s choice of either lapatinib (Tykerb) with capecitabine, trastuzumab (Herceptin), plus capecitabine, trastuzumab plus vinorelbine, or trastuzumab plus eribulin. Other secondary end points explored in the study included objective response rate, investigator-assessed PFS, and patient-reported outcomes.

Regarding the trial’s competition, Marco Timmers, PhD, the chief executive officer of Byondis stated, “A large trial involving breast cancer patients with advanced disease is difficult in the best of times, but it is especially challenging during a global pandemic. The completion of TULIP is a testament to the dedication of all involved, especially the patients, their families, and participating clinical sites."

Patients included in the TULIP study were those with histologically confirmed, unresectable locally advanced or metastatic breast cancer who had either progressed during or after at least 2 HER2-targeting treatment regimens for locally advanced or metastatic disease or who had progressed after receiving (ado-)trastuzumab emtansine (Kadcyla). All patients included in the study had HER2-positive disease, an ECOG performance status of 2 or lower, an estimated life expectancy of more than 12 months, and adequate organ function and blood cell count. The study’s protocol allowed for patients with either measurable or non-measurable disease per RECIST 1.1.

Individuals excluded from the clinical trial were those who had a history of infusion-related reactions and/or hypersensitivity to trastuzumab or (ado-)trastuzumab emtansine, as well as those with a history of keratitis. In addition, patients who presented with severe, uncontrolled systemic disease, a left ventricular ejection fraction of <50%, a cardiac troponin value of the upper limit of normal, history of clinically significant cardiovascular disease, untreated brain metastases, and history of diopathic pulmonary fibrosis, organizing pneumonia (e.g., bronchiolitis obliterans), drug-induced pneumonitis, or idiopathic pneumonitis, or evidence of active pneumonitis were all excluded from the study.

_Reference:

_{Byondis announces positive topline results of pivotal phase III TULIP® study in patients with HER2-positive unresectable locally advanced or metastatic breast cancer. News release. Byondis BVS. June 8, 2021. Accessed June 10, 2021. https://prn.to/3pGZdFz}