This discovery may explain that the low incidence of many cancers (with the exception of melanoma) in patients with Parkinson's disease could lead the way to carbidopa being repurposed as an anticancer medication.
"Carbidopa is an FDA-approved drug for treating Parkinson's disease. Hence, clinical trials can be conducted right away to evaluate its efficacy in humans as an anticancer drug," said lead study author Dr Yangzom Bhutia from Texas Tech University's health sciences center in the USA.
Parkinson's disease is a degenerative neurological disorder that mostly influences a person's movement and motor skills, with symptoms including shaking, rigidity and difficulty in walking.
Many studies show that patients with Parkinson's disease have a lower rate of most cancers compared with the general population. As most patients in these studies were treated with a combination of L-DOPA and carbidopa, it is possible that one or both of these drugs could exhibit anti-cancer properties and contribute to the lower incidence of cancer observed in these patients.
Bhutia explained that Carbidopa is never used by itself as a drug for any disease.
The recent data showed that carbidopa by itself possesses the anticancer effect.
The researchers as well as collaborators from Japan and India, tested the effects of carbidopa on a human pancreatic cancer cell line and also in mouse models of pancreatic cancer.
The researchers believe that carbidopa is likely to have wide ranging anticancer effects, but chose to focus on pancreatic cancer for this study because of the low survival rate and limited treatment options for this form of the disease.
Given the fact that it is an FDA-approved drug, re-purposing the same drug for cancer treatment would be tremendously cost- and time-saving.
While this study was not carried out in humans, the dose of carbidopa given to the mice that stopped tumour growth was equivalent to a dose in humans of less than 400 mg/day, which is within the dose range considered to be safe for patients.
The research appears in the Biochemical Journal. (ANI)