A plain language summary of the results from the phase 2b HERIZON-BTC-01 study of zanidatamab in participants with HER2-amplified biliary tract cancer.

WHAT IS THIS SUMMARY ABOUT?: Researchers wanted to study whether the research drug zanidatamab could help people with a type of cancer called biliary tract cancer. In some people, biliary tract cancer cells make extra copies of a gene called HER2 (also called ERBB2). This is known as being HER2-amplified. Zanidatamab is an antibody designed to destroy cancer cells that have higher-than-normal HER2 protein or gene levels. Zanidatamab is currently under research and is not yet approved for any diseases. Participants in this phase 2b clinical study had tumors that were HER2-amplified and at the advanced or metastatic stage. Participants also had cancer which had become worse after previous chemotherapy or had side effects that were too bad to continue chemotherapy. They also had to meet other requirements to be enrolled. Researchers measured the amount of HER2 protein in the tumor samples of the participants who were enrolled. There were 80 participants with tumors that were both HER2 amplified and had higher-than-normal HER2 protein amounts (considered to be 'HER2-positive'). There were 7 participants with tumors that were HER2-amplified, but had little-to-no levels of the HER2 protein (considered to be 'HER2-low'). All participants in the study were treated with zanidatamab and no other cancer treatments once every 2 weeks. WHAT ARE THE KEY TAKEAWAYS?: In the HER2-positive group, 33 of 80 (41%) participants had their tumors shrink by 30% or more of their original size. In half of these participants, their tumors did not grow for 13 months or longer. No participant in the HER2-low group had their tumors shrink by 30% or more. In total, 63 of 87 participants (72%) had at least one side effect believed to be related to zanidatamab treatment. Most side effects were mild or moderate in severity. No participant died from complications related to zanidatamab. Diarrhea was one of the more common side effects and was experienced by 32 of 87 participants (37%). Side effects related to receiving zanidatamab through the vein, such as chills, fever, or high blood pressure, were experienced by 29 of 87 participants (33%). WHAT ARE THE CONCLUSIONS REPORTED BY THE RESEARCHERS?: The results of this study support the potential for zanidatamab as a new therapy for people with HER2-positive biliary tract cancer after they had already received chemotherapy. More research is occurring to support these results.Clinical Trial Registration: NCT04466891 (HERIZON-BTC-01 study).

The HERIZON-BTC-01 study revealed zanidatamab as a potentially effective treatment for HER2-positive biliary tract cancer after standard chemotherapy fails. Read more in the lay summary by @hardingjjmd, @DrShubhamPant, and coauthors. #BiliaryTractCancer #HER2 #zanidatamab.

Zanidatamab for HER2-amplified, unresectable, locally advanced or metastatic biliary tract cancer (HERIZON-BTC-01): a multicentre, single-arm, phase 2b study.

BACKGROUND: HER2 is overexpressed or amplified in a subset of biliary tract cancer. Zanidatamab, a bispecific antibody targeting two distinct HER2 epitopes, exhibited tolerability and preliminary anti-tumour activity in HER2-expressing or HER2 (also known as ERBB2)-amplified treatment-refractory biliary tract cancer. METHODS: HERIZON-BTC-01 is a global, multicentre, single-arm, phase 2b trial of zanidatamab in patients with HER2-amplified, unresectable, locally advanced, or metastatic biliary tract cancer with disease progression on previous gemcitabine-based therapy, recruited at 32 clinical trial sites in nine countries in North America, South America, Asia, and Europe. Eligible patients were aged 18 years or older with HER2-amplified biliary tract cancer confirmed by in-situ hybridisation per central testing, at least one measurable target lesion per Response Evaluation Criteria in Solid Tumours (version 1.1), and an Eastern Cooperative Oncology Group performance status of 0 or 1. Patients were assigned into cohorts based on HER2 immunohistochemistry (IHC) score: cohort 1 (IHC 2+ or 3+; HER2-positive) and cohort 2 (IHC 0 or 1+). Patients received zanidatamab 20 mg/kg intravenously every 2 weeks. The primary endpoint was confirmed objective response rate in cohort 1 as assessed by independent central review. Anti-tumour activity and safety were assessed in all participants who received any dose of zanidatamab. This trial is registered with ClinicalTrials.gov, NCT04466891, is ongoing, and is closed to recruitment. FINDINGS: Between Sept 15, 2020, and March 16, 2022, 87 patients were enrolled in HERIZON-BTC-01: 80 in cohort 1 (45 [56%] were female and 35 [44%] were male; 52 [65%] were Asian; median age was 64 years [IQR 58-70]) and seven in cohort 2 (five [71%] were male and two [29%] were female; five [71%] were Asian; median age was 62 years [IQR 58-77]). At the time of the data cutoff (Oct 10, 2022), 18 (21%) patients (17 in cohort 1 and one in cohort 2) were continuing to receive zanidatamab; 69 (79%) discontinued treatment (radiographic progression in 64 [74%] patients). The median duration of follow-up was 12·4 months (IQR 9·4-17·2). Confirmed objective responses by independent central review were observed in 33 patients in cohort 1 (41·3% [95% CI 30·4-52·8]). 16 (18%) patients had grade 3 treatment-related adverse events; the most common were diarrhoea (four [5%] patients) and decreased ejection fraction (three [3%] patients). There were no grade 4 treatment-related adverse events and no treatment-related deaths. INTERPRETATION: Zanidatamab demonstrated meaningful clinical benefit with a manageable safety profile in patients with treatment-refractory, HER2-positive biliary tract cancer. These results support the potential of zanidatamab as a future treatment option in HER2-positive biliary tract cancer. FUNDING: Zymeworks, Jazz, and BeiGene.

Functional characterization of uveal melanoma oncogenes.

Uveal melanoma (UM) is a currently untreatable form of melanoma with a 50% mortality rate. Characterization of the essential signaling pathways driving this cancer is critical to develop target therapies. Activating mutations in the Gαq signaling pathway at the level of GNAQ, GNA11, or rarely CYSLTR2 or PLCß4 are considered alterations driving proliferation in UM and several other neoplastic disorders. Here, we systematically examined the oncogenic signaling output of various mutations recurrently identified in human tumors. We demonstrate that CYSLTR2 → GNAQ/11 → PLCß act in a linear signaling cascade that, via protein kinase C (PKC), activates in parallel the MAP-kinase and FAK/Yes-associated protein pathways. Using genetic ablation and pharmacological inhibition, we show that the PKC/RasGRP3/MAPK signaling branch is the essential component that drives the proliferation of UM. Only inhibition of the MAPK branch but not the FAK branch synergizes with inhibition of the proximal cascade, providing a blueprint for combination therapy. All oncogenic signaling could be extinguished by the novel GNAQ/11 inhibitor YM-254890, in all UM cells with driver mutation in the Gαq subunit or the upstream receptor. Our findings highlight the GNAQ/11 → PLCß â†’ PKC → MAPK pathway as the central signaling axis to be suppressed pharmacologically to treat for neoplastic disorders with Gαq pathway mutations.