The drug candidate ZB131 for cholangiocarcinoma may be effective as a monotherapy to treat the disease, according to new data from preclinical studies. It may also increase the antitumor effect of the standard-of-care chemotherapy drug gemcitabine when used as a combination therapy.

“ZB131 has shown strong antitumor activity in vitro and in mouse models. Additionally, it has demonstrated an excellent safety profile with no toxicities identified in [good laboratory practice]-enabling toxicology studies in non-human primates,” said Kimberly Kelly, PhD, chief executive officer of ZielBio, in a press release.

During the preclinical studies, ZB131 administered as a monotherapy to mice inoculated with human cholangiocarcinoma significantly suppressed tumor growth in most animals and led to complete regression in 17% of them. When administered in combination with gemcitabine, ZB131 showed an increased tumor response compared to gemcitabine alone.

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Cholangiocarcinoma tumors highly express cancer-specific plectin, a protumorigenic protein exclusively expressed on the surface of cancer cells.

Read more about the prognosis of cholangiocarcinoma

ZB131 is a first-in-class humanized monoclonal antibody that has high affinity and specificity for cancer-specific plectin. It is currently in phase 1 clinical trial to evaluate its safety, tolerability, and preliminary efficacy in patients with solid tumors with high cancer-specific plectin expression.

The results of the preclinical studies will be presented at the American Association for Cancer Research Annual Meeting 2022 on April 12th in New Orleans, Louisiana by Lindsey Brinton, PhD, the head of discovery at ZielBio.

The prognosis of cholangiocarcinoma is still poor with an overall 5-year survival rate of less than 10% and only a few approved standard therapies available. New and more efficient treatments are therefore urgently needed to treat this disease that is responsible for about 15% of all primary liver tumors and the second most common primary malignancy of the liver.


ZielBio to present new data demonstrating preclinical efficacy of ZB131 in cholangiocarcinoma at AACR Annual Meeting 2022. News release. ZielBio; April 12, 2022.