A first-in-human clinical trial of DEP-SN38, a novel dendrimer nanoparticle formulation of the topoisomerase I inhibitor SN38, has demonstrated promising anticancer activity with an improved safety profile compared to conventional irinotecan therapy. The results, published in the Journal of Clinical Oncology, represent a significant advancement in nanotechnology-based cancer treatment delivery.
Clinical Trial Results Show Encouraging Activity
The multicenter study enrolled 114 patients with advanced solid tumors, including those with platinum-resistant ovarian cancer, colorectal cancer, pancreatic cancer, and breast cancer. Patients were heavily pretreated, having received a median of 4 prior therapy lines before entering the trial.
At the recommended phase 2 dose of 12.5mg/m2, DEP-SN38 demonstrated encouraging anticancer activity across multiple tumor types. Notably, the treatment showed lower rates of severe gastrointestinal toxicity and eliminated the cholinergic toxicity typically associated with irinotecan, the conventional formulation of SN38's prodrug.
"This first-in-human study demonstrates promising activity in heavily pretreated patients with ovarian, colorectal, pancreatic & breast cancers," said Dr. Jia (Jenny) Liu, Translational Lead of Early Phase Drug Development at The Kinghorn Cancer Centre, who served as a principal investigator on the study.
Enhanced Drug Delivery Through Dendrimer Technology
The DEP-SN38 formulation utilizes poly-lysine dendrimer nanotechnology to improve the delivery of SN38, a potent topoisomerase I inhibitor. This approach leverages the enhanced permeability and retention (EPR) effect in tumor microenvironments, allowing for more targeted drug delivery to cancer cells while reducing systemic toxicity.
Dr. Liu noted that the findings suggest "alternative technologies can also improve the cytotoxic delivery of payloads like SN38, using poly-lysine dendrimer nanotechnology," positioning this approach as a potential alternative to antibody-drug conjugate (ADC) platforms for payload delivery.
Patient Quality of Life Improvements
Beyond the clinical efficacy measures, the study revealed meaningful quality of life improvements for participants. Many patients experienced signals of prolonged benefit and were able to return to work and everyday activities while receiving treatment, a significant achievement given their heavily pretreated status.
Innovative Trial Conduct During Pandemic
The Kinghorn Cancer Centre, serving as the only enrolling site in Australia, led enrollment of more than 20 patients despite post-COVID pandemic challenges. The site successfully implemented innovative trial conduct methods including remote consenting, telehealth-facilitated assessments, and local 5-FU disconnection procedures.
The NSW Early Clinical Trials Alliance (NECTA) facilitated patient-centric cross-referrals, contributing to successful enrollment. These decentralized elements have since been incorporated into other trials and formally studied as part of ongoing research into optimized clinical trial conduct.
Broader Implications for Oncology Drug Development
The successful development of DEP-SN38 suggests that dendrimer technologies may have broader applicability in oncology drug development. The platform's ability to deliver cytotoxic payloads with enhanced efficacy through EPR effects in tumor microenvironments could potentially be applied to other therapeutic agents.
The study was conducted across multiple sites with collaboration between The Kinghorn Cancer Centre, The Christie NHS Foundation Trust, and other institutions, with Starpharma developing the innovative dendrimer platform technology.
