Abstract 1536P
Background
Lurbinectedin recently received approval from Health Canada based on a single-arm Phase II trial (B-005) demonstrating a positive response to lurbinectedin in patients with relapsed SCLC who were previously treated with platinum-based chemotherapy. We assessed the efficacy of lurbinectedin in the trial population compared to the current SoC in a real-world Canadian SCA.
Methods
Patients diagnosed with SCLC between 2004-2019 in Alberta, Canada were identified using cancer registry data. Relevant eligibility criteria from the lurbinectedin trial were applied to patients who received platinum-based chemotherapy and initiated a subsequent line of systemic therapy. Overall survival (OS) was examined from initiation of post-platinum therapy. KM estimates were generated for the SCA and standardized to the chemotherapy-free interval (CTFI) and stage distribution of the trial. The CTFI-adjusted hazard ratio (HR) comparing lurbinectedin to the SoC was estimated using a Cox proportional hazards model.
Results
577 patients with SCLC were diagnosed and initiated post-platinum therapy, of which 174 (30%) were included in the SCA (Table). In the SCA, the unadjusted median OS was 6.7 months (95% CI: 6.0 - 7.7) and the CTFI and stage-standardized median OS was 6.1 months (5.4 - 7.7) compared to 9.3 months (6.3 - 11.8) in the lurbinectedin trial. The CTFI-adjusted HR comparing lurbinectedin to the SoC was 0.61 (0.45 - 0.82; p = 0.001; unadjusted HR: 0.72, 0.54 - 0.97; p = 0.028). In a quantitative bias analysis, the estimated HR was similar when adjusting for both CTFI and stage (HR: 0.59, 0.44 - 0.79). For patients with CTFI ≥90 days, the HR was 0.49 (0.33 - 0.73; p<0.001). Table: 1536P
Baseline characteristics of SCLC patients in the SCA compared to the trial
| Variable | SCA | Trial | ASD |
| n | 174 | 105 | - |
| Male (%) | 85 (48.9) | 63 (60.0) | 0.22 |
| Age at start of Post-Platinum Tx (mean (SD)) | 65.1 (8.8) | 60.0 (2.3) | 0.77 |
| ECOG 0-1 (vs 2) (%) | 146 (85.4) | 97 (92.4) | 0.22 |
| Extensive Stage at Diagnosis (%) | 100 (57.5) | 73 (69.5) | 0.25 |
| 3+ Metastatic Sites at Baseline (%) | 41 (23.7) | 79 (75.2) | 1.20 |
| Bulky Disease (%) | 51 (30.0) | 34 (32.4) | 0.05 |
| PCI (%) | 106 (60.9) | 61 (58.1) | 0.06 |
| CTFI ≥90 Days (%) | 145 (83.3) | 60 (57.1) | 0.60 |
| Post-Platinum Regimen (%) | |||
| Carbo/Cis + Etoposide | 126 (72.4) | - | - |
| Other | 18 (10.3) | - | - |
| CAV | 17 (9.8) | - | - |
| Etoposide | 13 (7.5) | - | - |
Conclusions
These findings suggest potential benefit with initiation of lurbinectedin compared to the SoC in the post-platinum SCLC setting.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Jazz Pharmaceuticals.
Disclosure
D. Dawe, A. Pabani: Financial Interests, Personal, Other, Honoraria: Jazz Pharmaceuticals. C. Baratta: Financial Interests, Personal, Full or part-time Employment: Jazz Pharmaceuticals. All other authors have declared no conflicts of interest.