Tislelizumab (previously BGB-A317) is an immune checkpoint inhibitor that researchers are currently investigating both as a monotherapy and as part of combination therapy to treat a wide array of solid tumors and blood-borne cancers. BeiGene, based in Beijing, is developing the treatment.

How does tislelizumab work?

Tislelizumab is an antibody that binds to PD-1, a receptor protein found on the surface of immune cells called T-cells. When PD-1 binds to its ligand PD-L1, the T-cells are inactive and do not mount an immune response. Cancer cells can produce PD-L1 and inactivate T-cells, evading the immune response.

By binding to PD-1, tislelizumab blocks the receptor from recognizing PD-L1. Researchers hope that this way, the T-cells will be active and able to kill cancer cells.

Tislelizumab, which is administered intravenously (into the bloodstream), differs from the existing anti-PD-1 antibodies because of its high affinity and superior target specificity, according to BeiGene.

Tislelizumab in clinical trials

Researchers are testing tislelizumab in Phase 2 and Phase 3 clinical trials in solid tumors and blood cancers. They are also testing it in global Phase 3 trials in a number of cancers, including non-small cell lung cancer, hepatocellular carcinoma (HCC or liver cancer), and esophageal squamous cell carcinoma (ESCC).

A multicenter, open-label, Phase 1a/1b clinical trial (NCT02407990) is investigating the safety, tolerability, pharmacokinetics (movement in the body), and efficacy of tislelizumab in 450 patients with advanced tumors.

Patients tolerated tislelizumab well, according to initial data announced in 2016. The treatment also showed anti-tumor activity in a number of advanced solid tumors. Preliminary Phase 1 data, released in June 2017, revealed that tislelizumab produced anti-tumor activity in patients diagnosed with advanced HCC. The data that researchers presented was from 40 patients with HCC. The estimated completion date of the study is August 2020.

A single-arm, multicenter Phase 2 clinical trial (NCT03209973) is investigating the efficacy of tislelizumab in people with Hodgkin’s lymphoma that returned or did not respond to other treatments. The primary goal of the study is patients’ overall response rate. A secondary outcome measure is the progression-free survival rate of patients up to two years after the first dose of tislelizumab to the date of disease progression or death. The study, conducted China, is estimated to be completed in June 2020.

Researchers are also evaluating the efficacy of tislelizumab in combination with other treatments to explore its potential in cancer patients.

For example, a Phase 1 study (NCT02660034) is investigating the safety, pharmacokinetics, and anti-tumor activity of tislelizumab in combination with pamiparib in people with advanced solid tumors. Pamiparib is a compound that has demonstrated effectiveness in inhibiting tumor cell growth. Conducted in the U.S, Australia, France, New Zealand, Spain, and the United Kingdom, the study is expected be completed in September 2020.

An open-label, multi-center Phase 2 trial (NCT03469557) in China is assessing the effects of tislelizumab in combination with standard chemotherapy in people with gastric/gastroesophageal junction adenocarcinoma or ESCC who have not received any previous treatments. Preliminary data from this study showed that seven patients from both groups showed a partial response to treatment. Researchers expect to complete this study in June 2020.

Another Phase 1 study (NCT02795182), taking place in Australia and China, is evaluating tislelizumab plus zanubrutinib to assess the safety and preliminary efficacy of the combination therapy in people with B-cell lymphoid malignancies, such as many non-Hodgkin’s lymphomas. Zanubrutinib is a potent and highly selective small molecule that has the ability to kill malignant B-cells. The study was expected to conclude in May 2020.

 

Last updated: June 8, 2020

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