Related Experiment Video
Updated: Sep 21, 2026
Evaluating the Effectiveness of Cancer Drug Sensitization In Vitro and In Vivo
Published on: February 6, 2015
Toxicity and efficacy of benzamide riboside in cancer chemotherapy models
Hiremagalur N Jayaram1, Joel A Yalowitz, Francisco Arguello
1Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS4053, Indianapolis, Indiana 46202-5122, USA. hjayaram@iupui.edu
Abstract:
Benzamide riboside (BR), a synthetic C-nucleoside, acts as a strong growth inhibitor of cancer cells in vitro and in vivo. BR, like TR and related nucleoside prodrugs, act by anabolism to NAD analogs. These analogs selectively inhibit IMPDH, leading to depletion of cellular GTP, growth cessation, and cell differentiation. To date only preclinical studies have been carried out. However, in tiazofurin (TR), a related drug, phase I/II clinical trials have been conducted in patients with acute leukemia and shown to be a very promising agent with a response rate of 85% in 26 patients in one of the trials. Tiazofurin is now undergoing phase III clinical trials as a result. Dose limiting toxicity of tiazofurin was headache, somnolence and nausea with no myelosuppression noted. By contrast, BR showed skeletal muscle toxicity, hepatotoxicity and myelosuppression in preclinical data. Skeletal muscle toxicity was noted in the paraspinal muscles and may represent dose-limiting toxicity. Since BR does exhibit myelosuppression, the most common chemotherapy-related side effect in humans, careful judgment is warranted should BR be included in multidrug regimens, although BR's potent cytotoxicity to tumor cells in preclinical models still makes it a promising drug.
Insights
Benzamide riboside (BR) inhibits cancer cell growth by depleting GTP. While promising, BR shows preclinical toxicities like muscle and liver damage, unlike tiazofurin.
Area of Science:
- Biochemistry
- Pharmacology
- Oncology
Background:
- Benzamide riboside (BR) is a synthetic C-nucleoside with potent anticancer properties.
- BR functions similarly to tiazofurin (TR) by forming NAD analogs that inhibit IMPDH.
- This inhibition leads to GTP depletion, cell growth arrest, and differentiation.
Purpose of the Study:
- To review the preclinical efficacy and toxicity of Benzamide riboside (BR) as a cancer therapeutic.
- To compare BR's profile with tiazofurin (TR), a related nucleoside prodrug that has undergone clinical trials.
Main Methods:
- Review of preclinical studies on Benzamide riboside (BR) in cancer models.
- Analysis of clinical trial data for tiazofurin (TR) in acute leukemia patients.
Main Results:
- BR demonstrates significant in vitro and in vivo cancer cell growth inhibition.
- Tiazofurin (TR) showed an 85% response rate in Phase I/II trials for acute leukemia with manageable toxicities (headache, somnolence, nausea).
- Preclinical data indicate BR exhibits skeletal muscle toxicity, hepatotoxicity, and myelosuppression, potentially dose-limiting.
Conclusions:
- Benzamide riboside (BR) is a potent anticancer agent, but its preclinical toxicity profile requires careful consideration for clinical development.
- Myelosuppression observed in BR preclinical studies warrants caution when considering combination therapies.
- Despite toxicities, BR's potent cytotoxicity suggests continued investigation may be warranted.
Related Concept Videos
02:49Cancer Therapies
However, cancer treatments can pose several challenges, as therapies used to kill cancer cells are generally also toxic to normal cells. Moreover, cancer cells mutate rapidly and can develop resistance to chemical agents or radiation therapy. Besides, all types of cancer cells may not respond to the same therapy. Some cancer cells respond to one...
01:10Drugs that Destabilize Microtubules
01:11Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase