# Development of experimental cancer drug RK-251 in India > Live situation record from CLSTR: https://clstr.news/situations/development-of-experimental-cancer-drug-rk-251-in-india > Updated: 2026-08-24T11:41:12.000Z. Sources: 8. Developments: 2. Researchers in India, led by the Institute of Advanced Study in Science and Technology (IASST) and the Indian Institute of Technology (IIT) Guwahati, have developed an experimental “smart” cancer drug candidate named RK-251. The drug is designed as a site-activated prodrug that remains largely inactive until it encounters high levels of reactive oxygen species (ROS), which are commonly found in tumor environments. Upon activation by ROS, RK-251 releases NBDHEX, a compound that interferes with proteins essential for cancer cell survival and treatment resistance. In preclinical laboratory studies, the drug has shown promising activity against aggressive triple-negative breast cancer cells. Testing in zebrafish embryos indicated no obvious signs of toxicity and lower toxicity in healthy cells. While these results are encouraging, RK-251 remains in the preclinical stage and requires further studies to establish safety, effective dosage, and efficacy in humans before clinical trials can begin. ## Timeline ### 2026-08-24: Indian scientists develop smart cancer drug RK-251 Indian scientists have developed RK-251, a preclinical ‘smart’ drug that activates inside cancer cells using high reactive oxygen species levels to release anticancer compounds while sparing healthy tissue. 6 sources. https://clstr.news/cluster/indian-scientists-develop-smart-cancer-drug-rk-251 ### 2026-08-21: Indian researchers develop experimental “smart” cancer drug RK-251 Indian researchers have developed RK-251, an experimental “smart” cancer drug that activates inside tumors to release anticancer compounds, potentially reducing the side effects of traditional chemotherapy. 2 sources. https://clstr.news/cluster/indian-researchers-develop-experimental-smart-cancer-drug-rk-251 --- Cite as: Development of experimental cancer drug RK-251 in India. CLSTR, https://clstr.news/situations/development-of-experimental-cancer-drug-rk-251-in-india