This is why Chloroquine has become part of many clinical trials, in combination with chemotherapy and other form of cancer treatments. The results are promising: “The results are very encouraging — striking, even says senior author Ravi Amaravadi, MD, an assistant professor of Medicine at Penn’s Abramson Cancer Center. Temsirolimus by itself has little effect in this patient population. Tumors laugh at it, with response percentages of just zero to 5 percent. But by combining it with hydroxychloroquine, we found that 14 out of 21 patients had stable disease after treatment, including five out of six melanoma patients.”

Its anticancer properties are relevant for most cancers. Therefore, this drug can be part of an anti-cancer drug cocktail and I would consider it as an addition next to chemo and/or radiation treatment. However, whenever considering to add to a chemo treatment just perform a short google check of the specific chemo and Chloroquine combo to make sure there is no study indicating antagonism.

Update April 22nd 2018: Another anti-malaria drug called Amodiaquine, seems to be even more effective than Chloroquine/ Hydroxychloroquine https://www.nature.com/articles/cddis2017416

Update August 1st 2019: Due to it’s antithrombotic, vascular protective, immunomodulatory, improved glucose tolerance, lipidlowering and anti-infectious activity, Hydroxychloroquine will be used in French hospitals to possibly induce prevention of recurrent miscarriage (Ref.).

Update March 12th, 2020: Hydroxychloroquine has been shown to be effective against Coronavirus.