Rhenium-based complexes and in vivo testing: A brief history

The success of metal‐based anticancer therapeutics in the treatment of cancer is best exemplified by cisplatin. Currently used in 32 / 78 cancer regimens, the use for metal‐based therapeutics has a clear role in cancer therapy. Despite this, metal‐based therapeutics are not without drawbacks, with issues such as toxic side effects and the development of resistance mechanisms. This has led to investigations of other metal‐based therapeutics such as auranofin, a gold‐based drug candidate as well as ruthenium‐based candidates, NAMI‐A, NKP‐1339 and TLD‐1433. All are undergoing current clinical trials. Another class of complexes under study are rhenium‐based; such complexes have undergone extensive in vitro testing but only seven have displayed antitumor in vivo activity which is a necessary step before entering clinical trials. This present review will document, chronologically, the rhenium‐based drug candidates that have undergone in vivo testing and the outlook for such complexes