Dr Gunashree Nagaraju1, Dr Annie Reynolds
1HBDHB, HASTINGS, NEW ZEALAND
Background
Newer cancer treatments which include targeted therapy and immunotherapy agents are being increasingly recognised to cause kidney injury.
Kadcyla (Trastuzumab emtansine) is a HER2-targeted antibody-drug conjugate. In current practise Kadcycla is used in the treatment of Her 2 positive breast cancer (both early and metastatic stages). Renal adverse effects are not commonly noted side effects of this drug. We describe a case of nephrotic syndrome related to Kadcycla use.
Case – 37 year old European woman with metastatic breast cancer was referred to renal clinic with anasarca and nephrotic range proteinuria. She was treated with neoadjuvant chemotherapy and mastectomy after initial diagnosis in 2017 and palliative chemotherapy. In 2020 she developed confusion and diagnosed with brain metastasis. There was no other significant medical comorbidities. Baseline renal function and albumin prior to initiation of Kadcycla was normal. In March 2021 she commenced 3 weekly Kadcycla and 3 monthly Zoledronic acid infusion (briefly paused Kadcycla while receiving radiotherapy in August).
On initial review in renal clinic in November 2021 she reported weight gain of 30 kilograms since starting treatment. She was noted to have developed adrenal insufficiency and diabetes. She had 12 gm proteinuria, serum albumin 22 g/dl and eGFR 90ml/min. Further investigations for causes of nephrotic syndrome. Kidney biopsy showed normal light microscopy and foot process effacement on electron microscopy indicating minimal change disease. Kadcyla and Zoledronic acid were discontinued. An expectant approach was taken and proteinuria and anasarca improved with cessation.
Conclusion – The trend of proteinuria and hypoalbuminemia coincided with timing of Kadcyla infusion. Hence we conclude Kadcycla is the likely cause for nephrotic syndrome. There are case reports of nephrotic syndrome related to Kadcycla.
Biography:
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