A Study to Evaluate the Efficacy of Osimertinib With Early Intervention SRS Treatment Compared to the Continuation of Osimertinib Alone, in Patients With EGFR Mutated NSCLC and Asymptomatic Brain Metastases

Inclusion Criteria

• •1. Newly diagnosed metastatic NSCLC, not amenable to curative surgery or curative radiotherapy.
• •2. Documented EGFR mutation (at any time since the initial diagnosis of NSCLC) known to be sensitive to Osimertinib - These include exon 19 del; L858R (exon 21); G719X (exon 18); L861G (exon 21); S768I (exon 20) and T790M (exon 20) NOTE: Mutation analysis is to be done as per local practice.
• •3. An MRI showing brain metastases. At randomization, number of brain lesions is under 20. Patients with over 20 brain lesions at randomization MRI will be suitable for whole brain radiation, and will not be randomized.
• •4. Brain metastases are asymptomatic or with minor symptoms (ECOG≤2) at study randomization.
• •5. ECOG performance status ≤2 and a minimum life expectancy of at least 6 months
• •6. Must be eligible and receive Osimertinib as their anti EGFR TKI at time of randomization.
• •7. Must be eligible for SRS treatment at time of randomization.
• •8. Provided written informed consent.
• •9. Be male or female and at least 18 years of age on the day of signing informed consent.
• •10. Female patients:
• •1. Willing to use adequate contraceptive measures until 6 weeks after the final dose of study treatment
• •2. Not breast feeding
• •3. Have a negative pregnancy test prior to the start of dosing if of childbearing potential or have evidence of non-childbearing potential by fulfilling one of the following criteria at screening:
• •4. Post-menopausal, defined as aged more than 50 years and amenorrheic for at least 12 months following cessation of all exogenous hormonal treatments ii. Women under 50 years old would be considered postmenopausal if they have been amenorrheic for 12 months or more following cessation of exogenous hormonal treatments and with Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH) levels in the post-menopausal range for the institution iii. Documentation of irreversible surgical sterilization by hysterectomy, bilateral oophorectomy or bilateral salpingectomy but not tubal ligation
• •11. Male patients who are willing to use barrier contraception (i.e. condoms) until 4 months after the final dose of study treatment.