Childhood Leukemia Drug Shows Promising Results

A drug already in use for adults could also help children affected with an aggressive subtype of leukemia.

AsianScientist (Jul. 23, 2015) – A recently-developed drug, already used safely in adult leukaemia clinical trials, holds great promise for some children with an aggressive form of cancer known as acute lymphoblastic leukaemia (ALL).

Each year, around 150 Australian children and almost as many adults are diagnosed with ALL, which is the most common childhood cancer. Around 15 percent will have an aggressive subtype of ALL (known as T-ALL) that is generally less responsive to therapy and more likely to relapse.

Under the Pediatric Preclinical Testing Program, a consortium funded by the US National Cancer Institute (NCI) to prioritize and fast track new drugs into clinical trials in children with aggressive cancers, researchers tested the drug PR-104 on children with ALL.

“During the ten years we’ve been funded under the NCI program, we’ve tested over 70 drugs and combinations, and PR-104 is one of the most exciting yet—with the potential to be fast-tracked into clinical trials for children,” said study author Professor Richard Lock.

“We were so encouraged by our first results with PR-104 that we undertook additional studies which showed the drug to be preferentially active against T-ALL, a subtype of ALL affecting white blood cells known as ‘T cells’.

“Around 15 percent of acute lymphoblastic leukaemia patients have T-ALL, while 85 percent have a disease that affects their ‘B cells’, another white blood cell type. PR-104 is much less effective against these B cell leukemias. We believe that PR-104 might be an effective drug for patients who have initially benefited from conventional treatment for T-ALL, but who have subsequently relapsed,” he said.

At first baffled by why T-ALL responded to PR-104, the researchers realized that it was only the T cell subtype expressed high levels of AKR1C3, an enzyme that activates PR-104. The research team is in the process of examining the molecular biology behind AKR1C3, and trying to understand why T-ALL cells express very high levels of the enzyme.

“If we can work out what activates this enzyme in T cells, we might find a way of activating it in B cells, making the B cell disease sensitive to the drug as well,” said Lock.

“Obviously it would be ideal if we could extend this drug’s reach to include all acute lymphoblastic leukaemia patients. In the meantime, we can envisage using PR-104 to target highly aggressive T-ALLs that express high levels of AKR1C3.”

The article can be found at: Manesh et al. (2015) AKR1C3 is a Biomarker of Sensitivity to PR-104 in Preclinical Models of T-Cell Acute Lymphoblastic Leukemia.

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Source: Children’s Cancer Institute; Photo: Quinn Dombrowski/Flickr/CC.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

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