This article investigates the synergistic anticancer effects of combining fenbendazole and diisopropylamine dichloroacetate (DADA) in a mouse model using human lung cancer cells. The experiment demonstrates that administering these two compounds together significantly reduces tumor volume and promotes tumor regression without causing adverse side effects on vital organ functions, such as the liver and kidneys. By evaluating tumor growth, survival duration, and safety profiles over a sixty-day period, the findings highlight a promising, well-tolerated combination therapy. Ultimately, the authors conclude that this repurposed drug combination offers a safe and effective therapeutic strategy for non-small cell lung cancer, warranting further clinical validation in human studies.
Fenbendazole (FZ), a veterinary benzimidazole antiparasitic agent, demonstrates multi-targeted anticancer activity by destabilizing microtubules, inducing apoptosis, arresting the cell cycle, and altering tumor energy metabolism. Intestinal absorption constraints and potential hepatotoxicity have historically limited FZ monotherapy, but combination strategies—most notably pairing FZ with metabolic regulators like diisopropylamine dichloroacetate (DADA)—significantly enhance its in vivo antitumor efficacy.
1. Primary Molecular Mechanisms & Cellular Targets
Microtubule Disruption & Tubulin Binding: FZ binds tubulin subunits, inhibiting microtubule polymerization and dynamics similarly to conventional antimitotic agents.
G2/M Cell Cycle Arrest: FZ induces G2/M phase cell cycle arrest across multiple cell lines—including hepatocellular carcinoma (H4IIE), colorectal cancer (SNU-C5), cervical cancer (HeLa), and non-small cell lung cancer (A549)—by downregulating Cyclin A and Cyclin E expression.
Apoptotic Cascade Activation: FZ elevates reactive oxygen species (ROS) levels and triggers mitochondrial apoptosis by downregulating anti-apoptotic Bcl-2, upregulating pro-apoptotic BAX, and inducing the cleavage/activation of caspase-3, caspase-7, and PARP.
Metabolic & Signaling Interference: FZ disrupts cancer cell proliferation and energy/glucose metabolism via the MEK3/6–p38–MAPK signaling pathway.
2. In Vivo Efficacy & Metabolic Synergy (A549 Lung Cancer Model)
Intestinal Absorption & Monotherapy Limits: Because the intestine limits absorption, systemic concentrations of FZ and its metabolites remain relatively low after oral dosing. Consequently, oral FZ monotherapy (40 mg/kg) achieves modest complete tumor regression rates (11.1%) in mouse xenografts.
Synergistic Enhancement with DADA: Combining oral FZ (40 mg/kg) with DADA (100 mg/kg)—a pyruvate dehydrogenase kinase (PDK) inhibitor and vitamin B15 derivative—produces potent synergistic antitumor effects in immunodeficient BALB/c nude mice bearing A549 non-small cell lung cancer (NSCLC) xenografts.
Tumor Regression & Extended Survival: The FZ + DADA (40:100 mg/kg) combination increases complete tumor regression to 50% (5 out of 10 mice achieving complete tumor loss, compared to 0% in untreated controls and 11.1% in monotherapy groups). The regimen significantly decreases overall tumor volume, accelerates tumor regression, and markedly extends average survival duration.
3. Safety, Hepatoprotection & Toxicity Profile
Mitigating Drug-Induced Liver Injury: High-dose or prolonged FZ self-administration has been associated with transient drug-induced liver injury. Co-administering DADA serves a dual role by providing hepatoprotective benefits, maintaining normal serum transaminase levels (ALT and AST), and preserving liver lobular histology during long-term treatment.
Systemic Tolerability: In preclinical trials, the 60-day oral FZ + DADA combination demonstrated high safety with no adverse impact on body weight, blood glucose or lactate concentrations, hematopoietic parameters (red blood cell count, white blood cell count, hemoglobin), or renal function (serum urea and creatinine).
FZ DADA Cancer Therapy
Non-small cell lung cancer (NSCLC) accounts for approximately 85% of all lung cancer cases and remains a leading cause of global cancer mortality. Despite therapeutic advancements in surgery, chemotherapy, radiotherapy, targeted therapy, and immunotherapy, 5-year overall survival remains around 20%. Consequently, drug repurposing strategies—such as combining the veterinary antiparasitic fenbendazole (FZ) with the metabolic and hepatoprotective agent diisopropylamine dichloroacetate (DADA)—have emerged as novel combination therapies for NSCLC.
1. Molecular & Cellular Rationale
Fenbendazole (FZ): A benzimidazole tubulin-binding agent that disrupts microtubule dynamics, arrests the cell cycle in the G2/M phase, and induces reactive oxygen species (ROS) in cancer cells. However, oral FZ self-administration is limited by poor intestinal absorption and potential drug-induced liver injury.
Diisopropylamine Dichloroacetate (DADA / Vitamin B15): A pyruvate dehydrogenase kinase (PDK) inhibitor that suppresses tumor glycolysis while functioning as a potent hepatoprotective agent.
Synergistic Apoptotic Cascades: In A549 NSCLC cells, the FZ–DADA combination induces ROS production, arrests the cell cycle by inhibiting Cyclin A and Cyclin E, and triggers mitochondrial apoptosis via Bcl-2 downregulation, BAX upregulation, and activation of caspase-3, caspase-7, and PARP.
2. In Vivo Efficacy in A549 Xenograft Models
Complete Tumor Regression: In immunodeficient BALB/c nude mice transplanted with human A549 NSCLC cells, daily oral co-administration of 100 mg/kg DADA + 40 mg/kg FZ achieved a 50% complete tumor regression rate (5 out of 10 mice exhibiting complete tumor loss) by Day 60. In comparison, FZ monotherapy achieved an 11.1% regression rate, while DADA monotherapy, cisplatin, and untreated controls yielded 0% complete regression.
Tumor Volume & Survival Extension: The 40:100 mg/kg FZ–DADA combination produced significant reductions in tumor volume starting from Day 14 and markedly extended cumulative survival compared to untreated controls.
3. Safety Profile & Hepatoprotection
Preserved Liver & Kidney Function: Combining FZ (40 mg/kg) with DADA (100 mg/kg) over 60 days produced no significant hepatocellular damage or elevated liver transaminases (ALT and AST). Renal function markers (serum urea and creatinine) and tissue histology remained within normal limits.
Systemic Tolerability: The combination regimen exerted no adverse effects on overall body weight, blood glucose or lactate levels, or hematological parameters (RBC, hemoglobin, and WBC counts).
Dual Role of DADA: By mitigating potential FZ-induced liver toxicity while enhancing metabolic tumor suppression, DADA provides a favorable safety and tolerability profile for long-term NSCLC treatment.
Comparing the Fenbendazole + Diisopropylamine Dichloroacetate (FZ–DADA) oral combination regimen to traditional cisplatin chemotherapy highlights fundamental differences in systemic toxicity, organ preservation, and preclinical antitumor outcomes:
FZ-DADA vs Cisplatin
1. Systemic Toxicity & Organ Safety
Cisplatin Adverse Effects: In clinical settings, intravenous cisplatin is associated with severe, dose-limiting systemic toxicities—most notably nephrotoxicity, severe bone marrow suppression, and heightened infection risk—which can severely impair patient quality of life and shorten overall survival.
Hematological Preservation: Unlike cisplatin, which frequently causes myelosuppression, 60 days of FZ–DADA combination therapy caused no significant changes in red blood cell counts, hemoglobin concentrations, or white blood cell counts compared to healthy or untreated control animals.
Renal & Hepatic Protection: Serum urea and creatinine levels, along with kidney histological sections, confirmed no renal damage or impairment across FZ–DADA treatment groups. Furthermore, because DADA is hepatoprotective, the combination prevented FZ-induced liver injury, maintaining normal liver histology and serum transaminase levels (ALT and AST).
Metabolic & Physiological Tolerability: Animals receiving FZ–DADA maintained stable body weight, normal blood glucose and lactate concentrations, active physical movement, and healthy gastrointestinal function throughout the 60-day study.
2. Comparative Antitumor Efficacy
Tumor Regression Rates: In immunodeficient BALB/c nude mice bearing A549 NSCLC xenografts, daily oral co-administration of 100 mg/kg DADA + 40 mg/kg FZ achieved a 50% complete tumor regression rate (5 out of 10 mice achieving complete tumor loss) by Day 60. By contrast, the positive control group receiving daily peritumoral cisplatin injections (5 mg/kg) achieved 0% complete tumor regression.
Survival Extension: Both the FZ–DADA combination and cisplatin significantly extended survival compared with untreated tumor controls (mortality began by Day 21). However, FZ–DADA achieved 100% survival through Day 60 while delivering superior tumor clearance without cumulative toxicity.
3. Translational & Quality-of-Life Implications
Because FZ–DADA is orally bioavailable and exhibits low systemic toxicity, researchers note it presents a promising translational candidate for long-term NSCLC management—particularly for patients with compromised liver function or those unable to tolerate the severe organ toxicities of conventional platinum-based chemotherapy.
Nguyen, T. Q., Phan, U. T. T., Can, M. V., Nguyen, D. H., Han, B., & Hoang, B. X. (2025). Synergistic anti-tumor effect of fenbendazole and diisopropylamine dichloroacetate in immunodeficient BALB/c nude mice transplanted with A549 lung cancer cells. Translational Lung Cancer Research, 14(7), 2509–2521.