A Study to Investigate Nicotinic Acid on VEGFR Inhibitor-Associated Hand-Foot Skin Reactions

Inclusion Criteria: * Written informed consent obtained prior to performing any protocol-related procedures, including blood serum collecting * HFSR grade 2 or higher after treatment with VEGFR inhibitors (such as sorafenib, regorafenib, anlotinib, and apatinib), according to NCI CTCAE V5.0 - PPE * Age from 18 to 75 years. * Life expectancy of at least 3 months at Day 1 Exclusion Criteria: * History of allergy to B vitamins * Major surgery or severe traumatic injury, fracture within 4 weeks prior to first dose of nicotinic acid or ulceration and any factors that significantly affect oral drug absorption, such as inability to swallow, chronic diarrhea, and intestinal obstruction * Patient who takes isoniazid in combination with sorafenib and other VEGFR inhibitors. * History of psychiatric drugs substance abuse and fails to quit it or has amental disorder * Pregnant or nursing women, fertile patient who is unwilling or unable to use effective contraception