The findings – published in the journal Pharmaceuticals – show that a candidate drug called 212Pb-TCMC-trastuzum – which combines a tumour targeting antibody attached to a radioactive lead marker – has remained within specifications for 10 of the 11 criteria tested for a period five years.
Only one criterion – protein concentration – fell outside specification, varying by 0.01mg/mL after 48 months.
Also results from ion-exchange chromatography testing and a competitive radioimmunoassay suggested the drug may be changing, although both measurements are still within specified limits.
The authors concluded that - while the protein concentration results merit further study - the conjugated molecule have remained stable and functional since being manufacturered by Areva Med and Dallas-based ligand contractor Macrocyclics.
The authors wrote that: “The immunoconjugate, the TCMC-trastuzumab, has proven to be a robust construct.”
They added that: “Considering the resources financial, time and personnel required to translate a radioimmunoconjugate from the bench to bedside through to treating patients, these results are certainly encouraging.”
The drug also performed well in the trial, which was a Phase I study of the safety, distribution, pharmacokinetics, immunogenicity and tumor response in patients with human epidermal growth factor receptor type 2 (HER-2)–expressing breast cancer.
According to preliminary results patients with carcinomatosis experienced minimal agent-related toxicity after five doses of 212Pb-TCMC-trastuzumab.
Areva Med – which is a subsidiary of French nuclear and renewable energy firm Areva – acquired Macrocyclics in 2011.