Extended PBS Listing for Cemiplimab

Cemiplimab is now available on the Pharmaceutical Benefits Scheme (PBS) for the treatment of cutaneous squamous cell carcinoma (CSCC). The condition must be metastatic or locally advanced and be unsuitable for curative treatment via surgery or radiotherapy.

Cemiplimab is a monoclonal antibody that binds to the programmed cell death-1 (PD-1) receptor. This inhibitory immune checkpoint receptor interacts with ligands that may be expressed by tumour cells or cells within the tumour microenvironment. The binding of these ligands to the PD-1 receptor causes inhibition of T cell function, which tumours can use to evade the immune response. Therefore, cemiplimab enhances T cell-mediated antitumour responses.

The Therapeutic Goods Administration (TGA) granted provisional approval to cemiplimab for CSCC based on the objective response rate (ORR) and duration of response (DOR) from single-arm clinical trials. Further clinical data is required to confirm the benefit of cemiplimab in this setting.

The safety and efficacy of cemiplimab in CSCC were evaluated in Study 1540. Cemiplimab was given every two weeks to patients in Group 1 (metastatic CSCC) and Group 2 (locally advanced CSCC); and every three weeks to patients in Group 3 (metastatic disease). These groups showed substantial ORRs of 49.2%, 43.6%, and 41.1%, respectively. The DOR was at least six months for 93.1% of patients in Group 1 (follow-up was more limited in the other groups).

Cemiplimab can cause immune-related adverse effects, including pneumonitis, hepatitis, colitis, and hypothyroidism. Infusion-related reactions have been reported in 9.1% of cases. These reactions often present with nausea, pyrexia, vomiting, or rash. Mild or moderate infusion-related reactions can be managed with interruption or slowing of the infusion; severe or life-threatening reactions require permanent discontinuation.