Imagine a world where one of the most aggressive forms of breast cancer could be tackled with a new, powerful treatment strategy. That’s exactly what a groundbreaking preclinical study led by the Vall d’Hebron Institute of Oncology (VHIO) suggests. The research reveals that Omomyc, a pioneering MYC inhibitor, significantly enhances the effectiveness of PARP inhibitors, offering a glimmer of hope for patients with drug-resistant triple-negative breast cancer (TNBC). But here's where it gets even more intriguing: this combination doesn’t just work—it synergizes, creating a therapeutic effect greater than the sum of its parts.
Published in Cell Reports (https://www.cell.com/cell-reports/fulltext/S2211-1247(25)01376-2), the study highlights Omomyc’s unique ability to induce DNA damage in cancer cells while simultaneously working alongside poly (ADP-ribose) polymerase inhibitors (PARPi). This dual action is a game-changer, especially for TNBC patients who often face limited treatment options and frequent resistance to PARPi therapies. And this is the part most people miss: MYC, a transcription factor long considered one of oncology’s most elusive targets, plays a complex role in both DNA damage and repair—a duality that Omomyc cleverly exploits.
MYC is essential for regulating orderly cell division, but when deregulated (as seen in up to 70% of human cancers), it drives uncontrolled growth, metastasis, and treatment resistance. For decades, targeting MYC has been a Holy Grail in cancer research, yet its complexity has made it notoriously difficult to inhibit. Enter Omomyc, the first and only direct MYC inhibitor to complete a phase I clinical trial. Developed by Laura Soucek, Director of VHIO’s Models of Cancer Therapies Group, and her team, this mini-protein (also known as OMO-103) has already shown a manageable safety profile and early signs of anti-tumor activity in advanced solid tumors. Now, it’s being tested in phase Ib and II trials for metastatic pancreatic cancer and advanced osteosarcoma, respectively.
But what makes MYC so controversial? Its role in DNA repair is a double-edged sword. As Fabio Giuntini, the study’s first author, explains, “MYC promotes genomic instability through replication stress, but it also enhances certain DNA repair mechanisms. This delicate balance allows cancer cells to thrive under high genomic stress without dying.” Omomyc disrupts this balance, tipping the scales in favor of DNA damage and making cancer cells more vulnerable to PARPi.
In TNBC, which accounts for 15-20% of breast cancer cases and is notoriously aggressive, PARPi are often used in patients with BRCA1/2 mutations. However, resistance frequently develops, leaving patients with few alternatives. Using PARPi-resistant cell lines and patient-derived xenograft models, the researchers found that Omomyc not only increased DNA damage within cancer cells but also decreased the expression of DNA repair genes. When combined with PARPi, the results were striking: a synergistic anti-tumor response, increased apoptosis, and superior disease control compared to either treatment alone.
Here’s the bold part: the study also uncovered that PARPi-resistant tumors had significantly higher MYC activity, and Omomyc successfully overcame this resistance. Even more fascinating, MYC-related gene expression in pre-treatment tumor samples could predict which patients were more likely to respond to PARPi therapy. This opens the door to personalized medicine, where treatment could be tailored based on MYC activity.
So, is Omomyc the key to resensitizing resistant tumors? Laura Soucek believes so. “Our findings position Omomyc as a novel DNA-damaging agent capable of cooperating with PARPi to re-sensitize TNBC to targeted therapy,” she says. But here’s the question for you: Could this combination therapy revolutionize how we treat not just TNBC, but other MYC-driven cancers as well? Share your thoughts in the comments—let’s spark a discussion!
