Despite the rise of targeted therapies, traditional chemotherapy remains a critical component of cancer treatment, particularly for aggressive or resistant tumors.
Among these, anthracyclines are some of the most widely used and are listed by the World Health Organization as essential medicines. These drugs work by interfering with topoisomerase II, an enzyme that helps unwind DNA during replication and transcription. By preventing the DNA strands from being properly separated and repaired, anthracyclines induce DNA breaks that ultimately kill rapidly dividing cancer cells.
However, the effectiveness of anthracyclines is often limited by toxicity and drug resistance. Their toxic effects are multifaceted, with cardiotoxicity being the most well-documented and clinically significant. In addition to the heart, anthracyclines can also damage the liver, kidneys, and central nervous system, which restricts how aggressively they can be used in patients.
Drug resistance presents an even greater challenge. Most cancer-related deaths occur not from the primary tumor itself, but from tumor progression and treatment resistance. Multidrug resistance (MDR) can arise through multiple mechanisms, including genetic heterogeneity, adaptive signaling changes, enhanced DNA damage repair, and altered drug metabolism. Once resistance develops, conventional anthracyclines often lose their therapeutic efficacy.
Researchers have long suggested that patients with aggressive cancers might benefit from more potent chemotherapy capable of overwhelming tumor defenses and reducing the chance of relapse. But simply increasing the dose of existing drugs is rarely an option as anthracyclines are already limited by severe side effects, and pushing the dose higher can quickly become life-threatening.
Now, in a development that could reshape cancer treatment, researchers from the Medical University of Vienna, the HUN-REN Research Centre for Natural Sciences, and Eötvös Loránd University have engineered a highly potent derivative of daunorubicin called 2-pyrrolino-daunorubicin (PyDau). In laboratory tests, PyDau was up to 1,000 times more cytotoxic than standard anthracyclines.
However, this meant it was too toxic to administer directly. Instead, the team encapsulated it in pegylated lipid nanoparticles, or liposomes, creating LiPyDau. The liposomes act as protective carriers, allowing the drug to circulate safely, accumulate in tumors, and release its payload directly inside cancer cells. Published in Molecular Cancer, preclinical trials using LiPyDau have shown dramatic results, eliminating tumors that have resisted standard treatments.
The future of cancer treatment
LiPyDau combines a chemically enhanced cytotoxic agent with targeted delivery. Encapsulating the drug in pegylated liposomes protects healthy tissue, prolongs circulation time, and concentrates the drug in tumors, significantly reducing side effects such as cardiotoxicity and myelosuppression. The pegylated liposomes also evade the body’s clearance systems and exploit the enhanced permeability and retention effect, which naturally directs them into tumors.
This targeted delivery not only minimizes systemic exposure but also helps LiPyDau overcome drug resistance. Gergely Szakács, oncologist and group leader at the Medical University of Vienna, told DDN, “LiPyDau likely bypasses resistance mechanisms through its favorable pharmacokinetics and tumor targeting. The liposomal carrier allows higher plasma exposure and increased tumoral drug load, which helps overcome efflux pumps or other cellular mechanisms that usually reduce drug efficacy. By delivering PyDau directly into tumor cells in a protected form, the liposome helps the drug maintain its cytotoxic activity even in multidrug-resistant tumors.”
In preclinical studies, LiPyDau demonstrated remarkable efficacy across multiple cancer models. A single dose almost completely halted tumor growth in a melanoma model. In lung cancer, the treatment was effective in both a standard mouse model and a patient-derived xenograft model containing human tumor cells that were resistant to standard therapies.
Aggressive breast cancer models showed similarly striking results. LiPyDau treatment led to near-complete tumor regression, and in hereditary, hard-to-treat forms of breast cancer, tumors were permanently eliminated. The drug also proved effective against MDR tumors, which typically respond poorly to existing chemotherapy.
“This demonstrates a major scientific advance by combining a novel cytotoxic agent with a delivery system that enhances both safety and efficacy,” said Szakács. “While mouse models do not fully recapitulate the human condition, these preclinical models are still valuable in selecting promising candidates for further studies.”
Redefining chemotherapy
LiPyDau represents a modern approach for using traditional chemotherapies limited by toxicity and treatment resistance.
If LiPyDau proves safe and effective in clinical trials, it has the potential to redefine what is possible in chemotherapy and offer new hope for patients facing cancers that were once considered untreatable.
Szakács explained, “Patients with aggressive, multidrug-resistant tumors or cancers that are difficult to treat with conventional anthracyclines due to toxicity would benefit most from this drug. This includes melanoma, lung cancer, and breast cancer, as well as other tumor types where high efficacy and reduced systemic toxicity are essential.”
