Commercial-stage biotechnology company Krystal Biotech Inc (NASDAQ:KRYS) announced on Tuesday that the US Food and Drug Administration (FDA) has granted Fast Track designation for inhaled KB707 to treat solid tumours with pulmonary metastases that are relapsed or refractory to standard therapy.

KB707, a modified HSV-1 vector designed to deliver interleukin-12 and interleukin-2 genes to the tumour microenvironment, aims to promote immune-mediated tumour clearance.

In January 2024 the FDA cleared the Investigational New Drug (IND) application for Phase 1 clinical trial KYANITE-1, set to commence in the first half of 2024, targeting patients with locally advanced or metastatic solid tumours of the lung.

This is the second Fast Track for KB707, following the FDA's previous approval for intratumoral KB707 in melanoma treatment.