medwireNews: Adding atezolizumab to carboplatin plus etoposide does not lead to substantially more adverse events (AEs) than placebo and does not adversely affect health-related quality of life (HRQoL) in patients with extensive-stage small-cell lung cancer (ES-SCLC), IMpower133 trial data show.
As previously reported by medwireNews, the addition of first-line atezolizumab 1200 mg to carboplatin and etoposide in the phase 1/3 IMpower133 study resulted in a significant 30% lower risk for death and a significant 23% lower risk for disease progression or death in patients with ES-SCLC.
In the current study, Aaron Mansfield (Mayo Clinic, Rochester, Minnesota, USA) and colleagues set out to assess the benefit–risk profile of this regimen among 394 patients from the induction phase and 318 from the maintenance phase of the original trial.
Overall, patients were exposed to carboplatin and etoposide for a median of 2.2 months in each arm and received a median seven doses of atezolizumab and six of placebo.
Mansfield and co-authors report in the Annals of Oncology that the safety profile of the atezolizumab-containing regimen was similar to that of the placebo-containing one.
In the induction phase of the study, 98% of patients receiving atezolizumab experienced at least one AE of any grade, 63% experienced a grade 3 or 4 AE, 29% experienced a serious AE, and 7% discontinued treatment. In the placebo arm the rates were 94%, 58%, 27%, and 2%, respectively.
In the maintenance phase, the overall AE rates were 82% versus 72%, with grade 3 or 4 AEs occurring in 28% versus 23%, serious AEs in 15% versus 12%, and treatment discontinuation occurring in 5% versus 1%, respectively.
Immune-related AEs were more common with atezolizumab than with placebo, particularly rash and hypothyroidism, but other immune-related AEs occurred at a similar rate between the two arms, the researchers note.
Mansfield and team also assessed HRQoL among the subset of patients (83–89% depending on the group) who completed the EORTC Quality of Life Questionnaire – Core 30 and the supplemental lung cancer module at baseline.
They found that both function and HRQoL improved among the patients following treatment initiation regardless of the regimen, but the improvements were greater and persisted for longer among those receiving atezolizumab.
In addition, there were comparable between-group changes from baseline to week 54 in treatment-related symptoms, such as diarrhea, dysphagia, sore mouth, peripheral neuropathy, nausea/vomiting, and insomnia.
Mansfield et al conclude that their data “demonstrate the positive benefit–risk profile of first-line atezolizumab plus [carboplatin and etoposide] in ES-SCLC and further support this regimen as a new standard of care in this setting.”
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