Memantine and its analogs: Potential applications in cancer therapy.

Drug repurposing refers to the process of using an existing drug or drug candidate for a new treatment or medical condition for which it was not indicated before. The process of "drug repurposing" usually involves an FDA-approved entity which has undergone clinical development and have a with well-established safety and toxicity profile in patients. Several convergent studies show that repurposed drugs may present a promising strategy for the management and therapy of several human cancers. Memantine is used to combat dementia in moderate-to-severe Alzheimer's disease (AD) patients. Several convergent studies show that memantine (and its analogs) may have applications in multiple disease conditions associated with human cancers. Memantine and its related compounds have shown promise as neuroprotective agents, anti-fatigue agents and pain-relieving agents to alleviate the toxic side effects of radiation therapy and chemotherapy. Recent publications have revealed that memantine displays anti-cancer activity by exerting direct growth-suppressive activity on the primary tumor as modulating the genomic/cellular landscape of the tumor microenvironment. Currently, clinical trials are in progress, which aim to evaluate the potential applications of memantine in cancer treatment. The adamantane scaffold in memantine has proved to be a versatile tool for the discovery of synthetic memantine analogs with robust anti-cancer activity. The discovery of second-generation memantine analogs may have wider applications in combating cancer recurrence and addressing clinical challenges in the treatment of drug-resistant and metastatic cancers.