NEW YORK – RemeGen said on Wednesday that the US Food and Drug Administration has accepted its investigational new drug application for the antibody drug conjugate disitamab vedotin, allowing for the start of Phase II clinical trials in HER2-positive patients with metastatic or unresectable urothelial cancer.
The drug has already been studied in HER2-positive urothelial cancer patients in China, and RemeGen presented data from a Phase II study at the 2019 American Society of Clinical Oncology meeting. In that 43-patient Phase II trial, pretreated HER2-positive metastatic urothelial cancer patients on disitamab vedotin had an overall response rate of 60.5 percent.
The median progression-free survival for the overall study population was not reached by the date of data collection in January 2019, but the median progression-free survival was 7.8 months for the nine patients who started the drug before June 2018.
The study further explored response rates in patient subgroups. For 17 patients who were HER2 FISH-positive or IHC3-positive, the overall response rate was 70.6 percent. In the 37 patients who had visceral metastasis, the ORR was 64.9 percent, and in 20 patients who had liver metastasis, the ORR was 70 percent. In patients who were treated with more than two lines of therapy before starting disitamab vedotin, the response rate was 64.3 percent. In those who had received immunotherapy previously, the response rate was 75 percent.
The drug also appeared to be well tolerated, with most adverse effects falling into either grade 1 or 2.
There have been no new treatment options for HER2-positive metastatic urothelial cancer in the past 20 years. RemeGen estimated that 81,400 new cases of urothelial cancer will be diagnosed in the US in 2020.