Answer
They reduce important pemetrexed toxicities, particularly severe effects on blood cells and the gastrointestinal system. They are protective supportive treatment rather than treatment for vitamin deficiency.
Sources for this answer
- Pemetrexed 25 mg/ml concentrate for solution for infusion — Current selected SmPCemc · Summary of Product Characteristics
General medicine information. Follow the instructions for your own medicine and speak to a pharmacist or clinician about your individual circumstances.