Regulatory Decision Summary for Imfinzi

This supplement to a new drug submission (SNDS) was filed to obtain market authorization for Imfinzi for the treatment of patients with limited-stage small cell lung cancer (LS-SCLC) whose disease had not progressed following chemoradiation therapy.

After evaluation of the submitted data package, Health Canada authorized Imfinzi for the following indication:

Imfinzi, as monotherapy, is indicated for the treatment of adult patients with limited-stage small cell lung cancer (LS-SCLC) whose disease has not progressed following platinum-based chemoradiation therapy (CRT).

This submission was filed under the Priority Review Policy.

The submission was classified as a Project Orbis Type B submission and Health Canada collaborated with the United States Food and Drug Administration (FDA), Australia’s Therapeutic Goods Administration (TGA), Singapore’s Health Science Authority (HSA), Switzerland’s Swiss Agency for Therapeutic Products (Swissmedic [i.e. SMC]), United Kingdom’s Medicines and Healthcare products Regulatory Agency (MHRA), Brazil’s National Health Surveillance Agency (ANVISA) and Israel’s Ministry of Health (IMOH) for the review.

The recommendation for market authorization of Imfinzi was based on the results of a pivotal phase 3, randomized, double-blind, placebo-controlled, multicenter study in adult patients with histologically or cytologically confirmed LS-SCLC whose disease had not progressed following concurrent platinum-based chemoradiation therapy. Patients were randomized 1:1:1 to receive Imfinzi monotherapy, Imfinzi in combination with another agent, or placebo. The evaluation of efficacy relied on comparison between the Imfinzi monotherapy arm and the placebo arm.

The major efficacy outcome measures were overall survival (OS) and progression-free survival (PFS). At the first interim analysis (IA1), a statistically significant improvement in OS was observed for Imfinzi compared to placebo with a hazard ratio (HR) (95% confidence interval [CI]) of 0.73 [0.57, 0.93]). The median OS was 55.9 months (95% CI: 37.3, not reached) for the Imfinzi arm and 33.4 months (95% CI: 25.5, 39.9) for the placebo arm, representing an estimated 22.5-month improvement in median OS with Imfinzi. At IA1, treatment with Imfinzi also resulted in a statistically significant improvement in PFS compared to placebo (HR = 0.76 [95% CI: 0.61, 0.95]). Median PFS was 16.6 months (95% CI: 10.2, 28.2) in the Imfinzi arm and 9.2 months (95% CI: 7.4, 12.9) in the placebo arm.

The safety of Imfinzi in patients with LS-SCLC was generally consistent with its established safety profile. Immune-mediated adverse reactions were observed; however, these adverse reactions can be managed in most cases and the Imfinzi Product Monograph adequately captures these and other risks of treatment and includes strategies for the management of immune-mediated adverse reactions.

Overall, Imfinzi was shown to be an effective treatment option for a patient population for whom the standard of care has remained largely unchanged for decades. When administered at the authorized dosage, Imfinzi is expected to provide a clinical benefit with a manageable safety profile. The risks associated with Imfinzi can be effectively managed in the post-market setting.

A Risk Management Plan (RMP) for Imfinzi was reviewed by Health Canada and considered acceptable.

The benefit/risk profile of Imfinzi is considered favourable for the authorized indication. Therefore, a Notice of Compliance (NOC) was recommended.

For further details about Imfinzi, please refer to the Product Monograph, approved by Health Canada and available through the Drug Product Database.