NCT05773092

A Phase 2 Study of Osimertinib and S-1 in Treatment Resistant EGFR Mutant NSCLC

A Phase 2 Study of Osimertinib and S-1 in Treatment Resistant EGFR Mutant NSCLC (SOS-1 Study)

• Status: Active Not Recruiting
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 30 (actual)
• Sponsor: National Cancer Centre, Singapore · Academic / Other
• Sex: All
• Age: 21 Years – 99 Years
• Healthy volunteers: Not accepted

Summary

The objective of this study is to determine best overall response rate (BOR) based on radiological assessment per RECIST v1.1 to combination of S-1 and Osimertinib in treatment-resistant EGFR mutant lung cancer.

Detailed description

A lead-in phase of 6 patients will be initiated prior to the formal phase II study. The planned sample size is 27 patients (lead-in and phase II). The primary objective of the study is to demonstrate that S-1 fixed dose 40 mg BD is safe and effective in EGFR metastatic lung cancer resistant to Osimertinib in terms of best overall response (BOR). The secondary objective of this study will be to further analyse the Disease Control Rate at stipulated timepoints (6,12 and 24 months), Progression-free survival, Overall Survival, and also the Toxicity by CTCAE 5.0.

Conditions

• NSCLC

Interventions

Type	Name	Description
DRUG	Oral S-1 + Oral Osimertinib	S-1 (40mg) will be given orally twice a day (daily) from Day 1 to 14 (21 day cycle), and Osimertinib (80mg) will be given orally daily continuously.

Timeline

• Start date: 2023-08-01
• Primary completion: 2026-03-31
• Completion: 2028-03-31
• First posted: 2023-03-17
• Last updated: 2025-09-03

Locations

1 site across 1 country: Singapore