Center for Drug Evaluation and Research growing crisis around HIV testing and treatment and an inter-agency dispute between officials from the former Bureau of Drugs and officials from the former Bureau of Biologics over whether to approve Genentech's Activase (tissue plasminogen activator) led to the split. In its original form, CDER was composed of six offices: Management, Compliance, Drug Standards, Drug Evaluation I, Drug Evaluation II, Epidemiology and Biostatistics, and Research Resources. The Division of Antiviral Products was added in 1989 under Drug Evaluation II due to the large amount of drugs proposed for treating AIDS. The Office of Generic Drugs was also formed. In 2002,
Small molecule drug conjugate linker systems and drug payloads and generate SMDCs for different diseases. The most advanced SMDC is vintafolide, a derivative of the anti-mitotic chemotherapy drug vinblastine which is chemically linked to folic acid. SMDCs are currently being developed by Endocyte for treating cancer, inflammatory diseases and kidney disease, as well as a companion imaging agent that is created by replacing the potent drug with an imaging agent. Small molecule drug conjugate Small molecule drug conjugates or SMDCs are built with three modules: a targeting ligand, a linker and a drug payload. The targeting ligands consist of low molecular weight, high-affinity ligands