Taihu oncology drug for bile duct cancer is now agreed by the Food and Drug Administration, providing a new treatment option for patients with advanced disease. The regulatory decision makes Taihu the third approved product for such cancers driven by a specific genetic signature, but the drug company maintains that its cancer treatment has an advantage over those competing products.
The approval of Taiho’s drug, futibatinib, covers adults with intrahepatic cholangiocarcinoma, a rare cancer of the bile ducts in the liver. Several genetic variants can drive the development of this cancer. The approval announced late Friday covers one of them: a gene fusion or other rearrangement of fibroblast growth factor receptor 2 (FGFR2), a protein involved in cell division and maturation. Futibatinib is a small molecule designed to block this protein. Taiho will market its new property under the name “Lytgobi”.
Bile duct cancer is rare, resulting in an estimated 8,000 cases diagnosed in the United States annually, according to the American Cancer Society. This number includes both intrahepatic cancer, which is found inside the liver, as well as extrahepatic cancer diagnosed outside the organ. About 20% of patients diagnosed with bile duct cancer have the intrahepatic form of the disease. When this cancer develops or spreads after first-line treatments, patients have few drug options available.
The FDA’s decision on Lytgobi was based on the results of a phase II, open-label, single-arm clinical trial involving 103 patients. These patients had advanced bile duct cancer characterized by an FGFR2 gene signature confirmed by genetic sequencing. The main objectives of the study were to measure total response and response duration. The results showed that treatment with a once-daily pill resulted in an overall response rate of 42%. The median duration of response was 9.7 months. The most common adverse reactions observed in the study included nail toxicity, muscle pain, constipation and diarrhea.
Taiho has been studied in patients whose cancers developed after receiving standard treatment, which included other FGRF2 inhibitors. Other FGRF2-blocking drugs that have already hit the market for bile duct cancer are from Incyte and QED Therapeutics. I miss Pemazyre was the firstwhich gained express approval in 2020. Sales of this drug were $68.5 million in 2021, according to Incyte financial reports.
Last year, the FDA Trusltiq approved From QED, a subsidiary of BridgeBio Pharma. In March, BridgeBio announced that it did modified Its partnership with Switzerland-based Helsinn Group granted that company an exclusive license to market Trusseltiq in the United States and develop the drug globally, with the exception of China, Hong Kong and Macau. Under the initial partnership concluded in 2021, the partners agreed to engage in commercialization of the United States along with co-development of the molecule globally.
Taeho’s notes Incyte and QED are so-called reversible ATP inhibitors. Such drugs do not form a covalent bond with their targets. By contrast, Taihu says her drug forms a covalent bond with FGFR2. This stronger association can improve the drug’s selectivity, as well as its efficacy and duration of action.
With the caveat that Lytgobi’s clinical trial has not compared it head-to-head with the drugs Incyte and QED, results for Taiho show higher measures of overall survival and response time. In clinical trial results supporting approval of Incyte, the overall response rate was 36%; The median duration of response was 9.1 months. For QED, the overall response was 23% and the median duration of response was 5 months.
Lytgobi’s regulatory decision is fast-track approval, which means that Taiho will need to generate more clinical data to confirm the drug’s safety and efficacy. Taiho Oncology of Princeton, NJ, is part of Taiho Pharmaceutical, which discovered the small molecule and continues to develop the drug for potential applications in other types of tumors. Ongoing mid-phase clinical trials of the drug include tests in breast cancer, stomach cancer, and medullary lymphoma, as well as bladder and lung cancers. Taiho Pharmaceutical is itself a subsidiary of Tokyo-based Otsuka Holdings, a holding company whose business includes Otsuka Pharmaceutical.
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