Real-World Evidence of Atezolizumab Efficacy as Part of First-Line Treatment for Extensive-Stage SCLC in Bulgaria.

Simple Summary: Small cell lung cancer accounts for a relatively small share of lung cancer cases, yet is highly lethal, without notable advances in treatment approaches over the past three decades. The recent introduction of immunotherapy as part of the initial chemotherapy regimens has contributed...

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Published in:Cancers Vol. 18; no. 7; pp. 1129 - 1143
Main Authors: Manova, Manoela, Ivanova, Boryana, Krasteva, Rositsa, Conev, Nikolay, Zlatanova, Tanya, Arabadjiev, Jeliazko, Chilingirova, Natalia, Petrova, Mila, Dudov, Assen, Robev, Bozhil, Minchev, Velko, Tonev, Ivan, Koynov, Krassimir, Penchev, Daniel, Georgiev, Todor, Rangelov, Antoan, Savova, Alexandra
Format: research tables/charts Journal Article
Published: MDPI Apr2026
Online Access:View this record in EBSCOhost
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      dt: Apr2026
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      pub: MDPI
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        atl: Real-World Evidence of Atezolizumab Efficacy as Part of First-Line Treatment for Extensive-Stage SCLC in Bulgaria.
      aug:
        au:
          Manova, Manoela
          Ivanova, Boryana
          Krasteva, Rositsa
          Conev, Nikolay
          Zlatanova, Tanya
          Arabadjiev, Jeliazko
          Chilingirova, Natalia
          Petrova, Mila
          Dudov, Assen
          Robev, Bozhil
          Minchev, Velko
          Tonev, Ivan
          Koynov, Krassimir
          Penchev, Daniel
          Georgiev, Todor
          Rangelov, Antoan
          Savova, Alexandra
        affil: Department of Organization and Economy of Pharmacy, Faculty of Pharmacy, Medical University, 1000 Sofia, Bulgaria
      sug:
        subj:
          Drug Efficacy
          Neoplasm Staging
          Carcinoma, Small Cell Drug Therapy
          Antibodies, Monoclonal Therapeutic Use
          Chemotherapy, Cancer
          Antineoplastic Agents, Combined Therapeutic Use
          Etoposide Therapeutic Use
          Carboplatin Therapeutic Use
          Human
          Retrospective Design
          Record Review
          Hospitals Bulgaria
          Bulgaria
          Cancer Patients
          Progression-Free Survival
          Funding Source
          Machine Learning Algorithms
          Kaplan-Meier Estimator
          Confidence Intervals
          Log-Rank Test
          Descriptive Statistics
          Immunohistochemistry
          Middle Age
          Aged
          Adult
          Aged, 80 and Over
          Male
          Female
          Middle Aged: 45-64 years
          Aged: 65+ years
          Adult: 19-44 years
          Aged, 80 & over
          Male
          Female
      ab: Simple Summary: Small cell lung cancer accounts for a relatively small share of lung cancer cases, yet is highly lethal, without notable advances in treatment approaches over the past three decades. The recent introduction of immunotherapy as part of the initial chemotherapy regimens has contributed to improving survival, bringing a renewed hope for better patient outcomes. With the approval of atezolizumab for clinical use, however, it is essential to accumulate evidence on its efficacy and safety in real clinical practice. In the present study, we provide real-world evidence from Bulgarian patients receiving atezolizumab as part of their initial treatment for small cell lung cancer. The current data corroborate the notion that this newly introduced regimen delays disease progression to an extent comparable to that reported in the clinical trial that led to atezolizumab approval for small cell lung cancer. Background/Objectives: Small cell lung cancer (SCLC) is a highly metastatic and lethal malignancy. Doublet chemotherapy consisting of a platinum compound and etoposide had remained the standard first-line regimen for decades, particularly for the majority of patients, who are diagnosed with extensive-stage disease. Over the past 5 years, results from the IMpower133 trial led to the approval of anti-PD-L1 agent atezolizumab as part of the first-line regimen for extensive-stage SCLC. The accumulation of real-world evidence on atezolizumab efficacy in this context is essential for corroborating trial results and further improving patient outcomes. Herein, we present real-world evidence from a Bulgarian cohort receiving atezolizumab as part of first-line extensive-stage SCLC treatment, comparing these data to the results of IMpower133. Methods: Data were extracted from the electronic health records of patients receiving atezolizumab plus chemotherapy as first-line treatment for extensive-stage SCLC in the period between 1 January 2022 and 31 December 2024. Analysis was conducted via the Danny Platform, an analytic platform for the integration of real-world evidence using embedded machine learning and LLM algorithms. Patients matching IMpower133 inclusion criteria were included in a group for comparison with trial results. Results: A total of 302 patients were included in the analysis. The real-world progression-free survival (PFS) in our study surpassed that in IMpower133 (7.6 versus 5.2 months), in addition to higher PFS rates beyond six months. A lower Objective Response Rate (ORR) (38.7% versus 65.4%) was noted in our real-world cohort, which we attribute to real-world documentation practices. Conclusions: Real-world evidence regarding PFS and treatment response generally align with the efficacy of adding atezolizumab to first-line extensive-stage SCLC treatment reported in the IMpower133 trial, while reflecting differences that may arise in routine clinical practice.
      pubtype: Academic Journal
      doctype:
        research
        tables/charts
        Journal Article
      ougenre: Article
    language: English
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