Home » Medical » Guardant and Janssen in Partnership for Companion DiagnosticMedicalGuardant and Janssen in Partnership for Companion Diagnostic Manny Johnson July 9, 2020 1 Views The Redwood City, CA-based company’s Guardant 360 CDx is at the center of the collaboration and will be used alongside Janssen’s amivantamab, an investigational biospecific antibody poised to treat non-small cell lung cancer.