Guselkumab: Expanded Indications

Two new indications have been added to the product information of guselkumab. Guselkumab is now indicated for the treatment of ulcerative colitis and Crohn’s disease, in addition to the original indications of plaque psoriasis and psoriatic arthritis.

Guselkumab is a monoclonal antibody that is selective for interleukin-23, a key cytokine involved in inflammatory and autoimmune diseases. Interleukin-23 drives intestinal inflammation by activating T helper 17 (Th17) cells, which release pro-inflammatory cytokines, and by directly stimulating other immune cells. Elevated levels of interleukin-23 have been observed in the colon tissue of patients with inflammatory bowel disease.

The QUASAR induction and remission studies evaluated guselkumab in patients with moderately to severely active ulcerative colitis:

• Induction study – clinical remission at 12 weeks was achieved in 23% of patients receiving IV guselkumab vs 8% with placebo
• Maintenance study – clinical remission at week 44 was 50% (200 mg SC every 4 weeks) and 45% (100 mg SC every 8 weeks), compared to 19% with placebo.

The GALAXI-3 study assessed the efficacy of guselkumab in patients with Crohn’s disease. There were two active treatment groups which both received guselkumab 200mg IV every four weeks for induction. For maintenance, the high-dose group continued on 200mg SC every four weeks, and the low-dose group received 100mg SC every eight weeks. The composite endpoint of clinical response at week 12 and clinical remission at week 48 was achieved in 48% of the high dose group and 47% of the low dose group, compared to 13% of the placebo group. The safety outcomes were favourable and consistent with its use in other approved indications.

Note: guselkumab is not currently subsidised on the Pharmaceutical Benefits Scheme (PBS) for ulcerative colitis or Crohn’s disease.