Hard to Treat Diseases Inc. engages in the research, development, purchase, sale, and marketing of biological vaccines in China. It offers various vaccines, such as hepatitis A, hepatitis B, varicella, poliomyelitis, influenza virus, DTaP combined, meningococcal, and MMR combined vaccines. The company also provides other biological products, including refined tetanus antitoxin and cerebroprotein hydrolysate for injection. In addition, it offers API and injection products comprising meropenem for injection and Imipenem/Cilastatin sodium for injection.HTDS is a holdco of a China based Shenzhen Mellow Hope Pharm Industrial Co., Ltd.