Brief Report: Updated Data From IMscin001 Part 2, a Randomized Phase III Study of Subcutaneous Versus Intravenous Atezolizumab in Patients With Locally Advanced or Metastatic NSCLC

Introduction

Subcutaneous atezolizumab is approved for the treatment of various solid tumors. Previous results from the IMscin001 study (NCT03735121) revealed that the pharmacokinetics, efficacy, immunogenicity, and safety of subcutaneous and intravenous atezolizumab were consistent (data cutoff: April 26, 2022). We present updated data from this trial (data cutoff: January 16, 2023).

Methods

Eligible patients aged above or equal to 18 years with locally advanced or metastatic NSCLC were randomized (2:1) to receive atezolizumab subcutaneously (1875 mg, n = 247) or intravenously (1200 mg, n = 124) every 3 weeks. Here, we present updated efficacy (overall survival [OS]; progression-free survival; objective response rate; duration of response), safety, and immunogenicity end points, alongside patient-reported outcomes and health care practitioner (HCP) perspectives.

Results

In this updated analysis, the median survival follow-up was 9.5 months. Median subcutaneous injection time was 7.1 minutes, with an average subcutaneous injection time of 4 to 8 minutes in most patients (75.7%). OS data were mature: median OS was similar between treatment arms, at 10.7 and 10.1 months in the subcutaneous and intravenous arms, respectively (hazard ratio: 0.88; 95% confidence interval: 0.67–1.16). Other efficacy end points, as well as immunogenicity, patient-reported outcomes, and safety, were similar between arms. Most HCPs found subcutaneous administration convenient (79.5%), easy to administer (89.7%), and were satisfied with the treatment (84.6%); 75.0% of HCPs agreed that administering atezolizumab subcutaneously compared with intravenously could save time.

Conclusions

In this analysis, mature OS data were similar between treatments. The updated efficacy and safety profile of subcutaneous atezolizumab is consistent with previous findings and equivalent to intravenous atezolizumab.