Cabozantinib: cabometyx versus cometriq. Are they interchangeable?

Abstract

Cabozantinib is an oral multi-tyrosine kinase inhibitor that targets vascular endothelial growth factor (VEGFR), mesenchymal epithelial transition factor (MET) and AXL. Cabozantinib is used for treating different types of cancer. It is available in the market in two different dosage forms with two different trade names. Cabometyx (cabozantinib) is available as 20mg, 40mg and 60mg film coated tablets and is approved by FDA for the management of renal cell carcinoma and hepatocellular carcinoma. However, cometriq (cabozantinib) is available as 20mg and 80mg capsules and is approved by FDA for treatment of thyroid cancer. Availability of two dosage forms for cabozantinib with different trade names for different indications is considered as potential for confusion and prescribing error. Implementation of good prescribing practice is essential in this case. Successive governments have promoted the prescribing of drugs by generic rather than the trade name. Some drugs should not be prescribed generically for different reasons, for example when dosage forms of the products are not pharmaceutically equivalent. Cabozantinib is an example for this scenario. Cabometyx and cometriq are not bioequivalent. In conclusion, each institution should have a generic prescribing policy. This policy must include drugs that cannot be prescribed generically. Based on posology, cabometyx and cometriq should not be used interchangeably but in case a patient must switch from cabozantinib capsules to cabozantinib tablets, the patient should continue with cabometyx using a dose not exceeding 60mg or to continue with the current cometriq dose whichever is lower. Do NOT substitute cabometyx tablets with cometriq capsules