I am 59, Will Osimertinib affect my kidney function?

Question

Hi doctor,

I am a 59-year-old man recently diagnosed with stage IIIB non-small cell lung cancer. My oncologist recommended comprehensive cancer genome testing, and the results showed an EGFR exon 19 deletion mutation. I have been advised to start Osimertinib. However, I also have a history of chronic kidney disease (CKD stage 3a), with my latest eGFR at 52 mL/min/1.73m² and serum creatinine at 1.6 mg/dL. I am concerned about how targeted therapy might affect my kidney function. I have also been feeling more fatigued lately, with hemoglobin at 10.4 g/dL and mild lower limb swelling. I take Amlodipine 5 mg and Losartan 25 mg daily for hypertension. Will the EGFR inhibitor worsen my renal function? Do I need a dose adjustment due to CKD? Also, should I repeat the genome testing if the treatment fails or stops working? I am trying to weigh my options before starting therapy.

Please advise.

Answer 1

Hi,

Welcome to icliniq.com

So starting Osimertinib for your estimated glomerular filtration rate(EGFR) exon 19 mutation is a well-supported and effective approach for stage IIIB non-small cell lung cancer, particularly because this targeted therapy has shown strong benefits in controlling disease and improving survival.

Fortunately, Osimertinib is generally well tolerated in patients with mild to moderate chronic kidney disease(CKD), including stage 3a, like yours. It does not typically require dose adjustment unless kidney function is severely impaired, and current data do not suggest that it directly worsens renal function in most patients.

However, since your kidney function is already compromised, it is important to monitor renal markers like serum creatinine and eGFR regularly after starting therapy, especially if new symptoms such as increased swelling or worsening fatigue develop.

The anemia and mild edema you are experiencing could be partly due to CKD, but cancer-related fatigue and possible early effects of disease progression may also contribute. Your antihypertensive medications, particularly losartan, are kidney-protective but may need review if your blood pressure or kidney function becomes unstable. Regarding genome testing, if Osimertinib stops working or your cancer progresses, it is recommended to repeat molecular testing, often through a liquid biopsy or tissue re-biopsy, to check for resistance mutations like T790M or other actionable changes that could guide second-line treatment.

Overall, Osimertinib remains a strong and appropriate first step, and with careful monitoring, it can be used safely alongside your existing kidney condition.

I hope this answers your query.

Thank you.