This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Unknown
[{'content': 'Fusion inhibitor is- \nSelect and explain. \nA. Enfuvirtide, B. Ritonavir, C. Efavirenz, D. Didanosine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. is \'a\' i.e., Enfuvirtide New drugs in HIV infection o Etravirine is recently approved NNRTI. This is the second generation NNRTI and is effective against HIV resistant to first generation NNRTI (Efavirenz, Delavirdine. Nevirapine). Fusion inhibitors (Entry inhibitors) o Enfuvirtide binds to Gp41 subunit of HIV envelop protein and inhibits the fusion of viral and host cell membrane. o Maraviroc is a CCR5 Co-receptor antagonist and is only active against "CCR - 5 - tropic virus" which tends to predominate early in infection. Integrase inhibitors o Raltegravir and Elvitegravir act by inhibiting enzyme integrase.', 'role': 'assistant'}]