In addition to the discontinuation of pembrolizumab 50mg vials, Merck Sharp & Dohme have advised of some upcoming changes to the Pharmaceutical Benefits Scheme (PBS) listing for the 100mg/4mL vials. These changes affect the dosing of pembrolizumab in the treatment of unresectable Stage III or Stage IV malignant melanoma.

From 1st August 2019, the PBS dosing criteria for this indication will be:

  • Initial treatment – up to six doses administered every three weeks with each maximum dose fixed at 200mg; and
  • Continuing treatment – maximum dose administered every three weeks fixed at 200mg.

These dosing criteria will replace the current maximum dose of 2mg/kg (up to 240mg). Pembrolizumab was first registered in Australia for the treatment of melanoma. Clinical studies used to support the initial application used weight-based doses of 2mg/kg and 10mg/kg. Later studies demonstrated equal efficacy of the higher and lower weight-based doses, leading to the introduction of a fixed 200mg dose for other indications.

The product information should be referred to for further dosing information and the PBS website for current PBS criteria. The PBS listing for the 50mg presentation of pembrolizumab will be deleted on 1st September 2019.


  1. Chatterjee M, Turner DC, Felip E, Lena H, Cappuzzo F, Horn L, et al. Systematic evaluation of pembrolizumab dosing in patients with advanced non-small-cell lung cancer. Ann Oncol. 2016; 27(7): 1291-8.
  2. Keytruda® (pembrolizumab) Australian approved product information. Macquarie Park: Merck Sharp & Dohme. Approved July 2019.

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