ESMO Asia Congress 2022

Abstract 391P

Background

ROS1 as a driver mutation is observed in approximately 1-2% of all non-small cell lung cancer (NSCLC). We report the demographics, treatment pattern and outcomes of these patients treated at our institute.

Methods

It is a retrospective analysis of ROS1-positive NSCLC patients registered between January 2015 to December 2021 for baseline characteristics, therapies received and clinical outcomes i.e. overall survival (OS) and progression free survival (PFS).

Results

Of total 2414 patients tested for ROS1, 78 had ROS1 positivity by Fluorescent in situ hybridization (FISH) (3.23%). Of these 78, baseline characteristics were available for 70 patients. Median age at presentation was 52 years, 39(39/70, 55.7%) were males, most (51, 72.86%) were non-smokers and 10 patients (10/70, 13.3%) had ECOG PS >2 at presentation. Most common site of metastasis was lung (49 , 70%) while central nervous system involvement was noticed in 13 (18.57%).Total 67 patients receiving cancer directed therapy and having treatment details were considered for survival analysis. The 1stline therapies included - ROS1 tyrosine kinase inhibitors (TKIs) in 38, chemotherapy in 20, epidermal growth factor receptor (EGFR) TK in 8 and chemotherapy-bevacizumab in 1 only.ROS1 TKI was availed to 20 patients through assistance programme. The overall response rate and disease control rate with ROS1 tyrosine kinase inhibitors were 76.32% and 89.47% respectively. The median OS and PFS for entire cohort were 37.9(95% CI 20.6-NA) months and 13(95% CI 9.92-26.1)months respectively while the same for patients on ROS1 TKI were 48.59(95% CI 37.85-NA) and 27.07(95% CI 13.0-50.8)months respectively. Poor ECOG PS (PS >2) at presentation was the only independent prognostic factor for both OS and PFS. Table: 391P

Clinical outcomes comparision of ROS1 tyrosine kinase inhibitor vs chemotherapy

Cohort (n=)	Median follow up (95% CI) in months	Median PFS(95% CI) in months	3 years PFS/5 years PFS	Median OS(95% CI) in months	3 years OS/5 years OS
ROS1 TKI in 1st line (n=38)	27.4 (95% CI 13.0-50.8)	27.07(95% CI 24.28-NA)	41.8%/23.9%	48.59 (95% CI 37.85-NA)	71.8%/46.6%
Chemotherapy (n=20)	14.5 (95% CI 12.1-NA)	6.87 (95% CI 5.55-14.5)	10.53%/5.26%	10.9 (95% CI 7.16-NA)	36.7%/36.7%

Conclusions

In India, access to the ROS1 TKI is currently limited. The use of ROS1 TKI improves the outcomes though statistically not significant. To further improve outcomes, future trials should pay special attention to patients with poor PS and find a way for increased access to TKI.