Lenvatinib+Letrozole Versus Fulvestrant in Metastatic ER+/HER2- Breast Cancer, Post Progression on Al + CDK4/6 Inhibitor

"Patient will receive letrozole 2.5mg daily plus lenvatinib 14mg daily until disease progression/unacceptable toxicity.~Patient review, safety evaluations, thyroid function monitoring and urine dipstick will be done. Toxicities will be graded using NCI CTCAE toxicity grading vs 4.0. Patient should be discontinued if drug cannot be resumed within 28 days due to toxicities.~Drugs should be withheld when subject has imminent risk to develop hypertensive crisis/has significant risk factors for severe complications of uncontrolled hypertension. Drugs can be resumed once patient received same hypertensive medications for at least 48 hours and the BP is controlled.~Lenvatinib should be withheld for at least 1 week prior to elective surgery, at least 2 weeks after major surgery, until adequate wound healing.~For risk of ONJ, oral dental examination and preventive dentistry should be considered prior to lenvatinib intake.~There is no dose modifications for letrozole."

Patients will be treated with Fulvestrant 500mg injections that are administered into the muscles (intramuscularly). This is injected at 2-weekly interval for the first 3 doses, followed by 4-weekly interval dosing.