NEW YORK – Guardant Health said Tuesday that the Japanese Ministry of Health, Labor, and Welfare has approved its Guardant360 CDx liquid biopsy test as a companion diagnostic to select patients with unresectable advanced or recurrent, HER2-mutant non-small cell lung cancer who are eligible for treatment with Daiichi Sankyo's antibody drug conjugate Enhertu (trastuzumab deruxtecan).
According to Guardant, HER2 mutations drive between 2 percent and 4 percent of non-squamous NSCLC. The new approval in Japan follows a nod from the US Food and Drug Administration for the same indication in August 2022.
"Oncologists in Japan now have the first blood-based companion diagnostic to determine if their patients are eligible to receive the first HER2-directed therapy approved to treat this specific condition," Guardant Health co-CEO and Chairman Helmy Eltoukhy said in a statement.
Japan's MHLW initially approved the Guardant360 CDx for comprehensive genomic profiling in patients with advanced solid tumors in March 2022 with added CDx indications for identifying patients with microsatellite instability-high solid tumors who may benefit from Keytruda (pembrolizumab) or Opdivo (nivolumab), and patients with metastatic NSCLC who may benefit from treatment with Lumakras (sotorasib). The test received national reimbursement approval in Japan in July of this year.
The approval comes after Guardant's stock took a sharp dive on Friday, falling 11 percent to close at $35.01 on the Nasdaq, as the company said it had halted its COBRA clinical trial, designed to validate the firm's minimal residual disease assay called Guardant Reveal.
JP Morgan's Rachel Vatnsdal wrote in a note to investors that the market reaction was "overblown given the multitude of additional studies [Guardant] has underway that use a next-generation version of the Reveal assay."
In Tuesday morning trade, Guardant's stock was up about 4 percent at $36.50.