How it works
Delivering chemotherapy effectively into solid tumours by traditional routes, such as intravenously, is particularly challenging when treating brain and pancreatic cancers because of protective barriers that surround the tumours. Recognising this, Professor Chris McConville has developed a drug delivery system, ChemoSeed, capable of improving chemotherapy’s clinical performance by delivering it directly into cancer tissues.
Each ChemoSeed consists of a cylinder made from a biocompatible and biodegradable polymer, such as PLGA (polylactic-co-glycolic acid copolymer), that contains a chemotherapeutic drug. They can be multilayered, allowing for up to 4 drugs to be delivered at once, with different release rates and dosing enabling personalised treatment.
ChemoSeed can be implanted directly into a solid tumour or, during surgery to remove part or all of a solid tumour (known as ‘resection’ or ‘debulking’), into the margin of apparently normal tissue that is left after its removal. This bypasses barriers that can reduce a drug’s efficacy, such as the blood–brain barrier or the stroma that surrounds pancreatic tumours. The drug slowly diffuses out of each ChemoSeed and directly into the surrounding cancer tissue, enabling the continuous delivery of therapeutic levels of drugs to all residual tissue in the tumour margin. This means that the drugs are available exactly where they are needed, making them more effective and reducing the risk of side effects, and thereby improving the quality of patients’ lives.
Development pathway for brain tumour treatment
Preclinical
Following early studies, the incorporation of 30% irinotecan into ChemoSeed (a process known as ‘drug loading’) was determined to be a safe and potentially effective dose. This was confirmed when 30% irinotecan-loaded ChemoSeed implants were evaluated using a sample of an extremely aggressive and invasive tumour from a patient with glioblastoma, which was grown in a mouse model and compared with intravenous delivery of irinotecan and the current standard of care treatment for glioblastoma (75 mg/kg of temozolomide). The results were compelling. All mice in the irinotecan and temozolomide groups had died by day 43 and 125, respectively. In contrast, mice treated with 30% irinotecan-ChemoSeed had a highly significant survival rate of 80% at day 148, and when the surviving mice were euthanised there were no signs of the tumour being present.
Phase I clinical study
The results of the first-in-human Phase I clinical trial indicated the safety and feasibility of administering irinotecan via drug-loaded beads into the resection cavity after surgery in patients with recurrent glioblastoma. The median overall survival was 30.5 months and the 2-year survival rate was 56%, double that of survivors at 2 years when compared with the current standard of care for patients after their initial diagnosis of glioblastoma.
Scheduled to enter phase II clinical trial at the beginning of 2026 clinical trials for brain tumours, ChemoSeed can be developed to treat any solid tumour