KEY TAKEAWAYS
- This study assessed carboplatin/cisplatin plus etoposide with ATZ in patients with untreated ES-SCLC beyond progression.
- The exploratory analysis showed that continuing ATZ after PD has a favorable risk-benefit profile, supporting its use in pts with good clinical status at PD time.
Prior findings from the IMfirst study, a phase IIIB trial conducted in Spain, validated the safety and efficacy of combining atezolizumab (ATZ) with chemotherapy for treating newly-diagnosed extensive-stage small cell lung cancer (ES-SCLC). While the standard treatment involves platinum-etoposide and anti-PD-L1 inhibitors, options after disease progression (PD) are limited in efficacy and come with high toxicity. While continuing ATZ beyond PD has shown promise in NSCLC patients (pts) with good clinical performance, its role in ES-SCLC remains uncertain. To explore this, IMfirst permitted pts to stay on ATZ even after confirmed PD.
The study allowed pts to continue ATZ if they met specific criteria following radiographic PD as per RECIST v1.1. These criteria included observed clinical benefits, stable ECOG status not worsened by PD, no unmanageable tumor growth at critical sites, and informed consent to delay other treatments. Patients were closely monitored, and ATZ was ceased in cases of severe toxicity or further clinical or radiographic deterioration.
The study included 155 pts with a median follow-up of 28.4 months as of December 22, 2022. Of the 118 pts who experienced disease progression (PD), 34.7% did not pursue further treatment (No-Tx), 26.3% continued with atezolizumab treatment beyond progression (ATZ-TBP), and 39.0% opted for alternative treatments (Other-Tx). Those on ATZ-TBP underwent a median of 3 additional ATZ cycles post-PD, and 32.3% received other treatments after a second PD event.
Median overall survival (mOS) since the start of treatment was 14.3 months for ATZ-TBP pts, compared to 12.6 months for Other-Tx and 7.3 months for No-Tx. After PD, mOS was 7.2 months for ATZ-TBP, 6.1 months for Other-Tx, and 1.7 months for No-Tx pts. The median progression-free survival (mPFS) for ATZ-TBP was 6.5 months pre-PD and 2.2 months post-PD. Notably, 22.6% of ATZ-TBP pts had a post-PD PFS longer than the study’s median PFS of 6.3 months. Serious adverse events related to ATZ were observed in 6.5% of ATZ-TBP pts before PD and none after PD.
The study showed that ATZ-TBP has a positive benefit-risk profile, indicating that continued ATZ treatment may be viable for pts who maintain good clinical status upon reaching PD.
Source: https://cattendee.abstractsonline.com/meeting/10925/presentation/2399
Clinical Trial: https://www.clinicaltrialsregister.eu/ctr-search/search?query=2019-002784-10
García-Campelo, R., Dómine Gómez, M., de Castro, J., Vega, A.M., Aix, S.P., Arriola, E., Carcereny, E., Tarruella, M.M., Vence, G.H., González, E.E., Pradera, J.F., Ortega Granados, A.L., Morales, M.G., Sureda, B.M., Vilà, L., Cordellat, A.B., Fajardo, C.A., Crama, L., Lerones, N., Cobo Dols, M. Treatment Beyond Progression with Atezolizumab in Extensive-Stage SCLC: Exploratory Analysis from the IMfirst Study.
