Pertuzumab + Trastuzumab Promising in HER2+ Biliary Tract Cancers

Pertuzumab + Trastuzumab Promising in HER2+ Biliary Tract Cancers

NEW YORK (Reuters Health) – Dual anti-HER2 treatment with pertuzumab plus trastuzumab appears well tolerated and gives promising results in certain patients with HER2-positive advanced cancer of the biliary tract, according to an analysis of data from the MyPathway study.

“HER2/neu genetic alterations occur in 15% of gallbladder cancers and in 5 to 10% of cholangiocarcinomas,” Dr. Milind Javle of The University of Texas MD Anderson Cancer Center, in Houston, told Reuters Health by email. “These can be meaningfully targeted with trastuzumab plus pertuzumab. Another win for precision oncology in biliary-tract cancers!”

Dr. Javle and colleagues examined data on patients in one arm of MyPathway, an ongoing non-randomized, open-label, phase-2a, multiple basket study.

The evaluated the outcome in 39 patients who had received a median of two and as many as four previous lines of treatment for HER2-positive metastatic biliary-tract cancer and in whom no satisfactory alternative treatment options were available.

The patients were given intravenous pertuzumab in an 840 mg loading dose, then 420 mg every three weeks along with an 8 mg/kg loading dose of trastuzumab followed by 6 mg/kg every the weeks. Median follow-up was 8.1 months, the researchers report in The Lancet Oncology.

Based on Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1, nine patients achieved a partial response, giving an objective response rate of 23%. Disease control was achieved in 51% of patients, and the median progression-free survival was four months.

However, six patients had prolonged progression-free survival of more than one year. And, say the researchers, “Overall, these data compare favorably with outcomes reported for second-line chemotherapeutic regimens.”

Grade-3 to -4 treatment-emergent adverse events occurred in 18 patients (46%). These were most commonly increased alanine aminotransferase and aspartate aminotransferase. Ten patients (26%) had a serious treatment-emergent adverse event.

There were no cardiac, grade-4 to -5, or serious treatment-related adverse events and thus the researchers point out that the approach showed “good tolerability relative to traditional cytotoxic treatments.”

The team concludes that the data “support the consideration of pertuzumab plus trastuzumab as a treatment option in the second line and beyond, and are encouraging for the initiation of randomized, clinical trials to further explore the efficacy of this and other HER2-targeted regimens in this disease setting.”

The MyPathway study was funded by F Hoffmann-La Roche–Genentech. The company also funded the writing of the manuscript.

SOURCE: The Lancet Oncology, online July 30, 2021.

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