Why
More stage IV neuroblastoma patients relapse than don’t relapse. And although Peter has responded well to this point and the scans look clear, there can be neuroblastoma cells that aren’t detected by the scans. Antibody treatment is a way to eliminate those cells and prevent relapse.
What
The antibody molecules, called 3F8’s, are made mostly from mouse. The 3F8’s attach to neuroblastoma cells and can destroy them. They administer “rounds” of antibody treatments until the patient reaches HAMA response. HAMA occurs when the patient’s body recognizes the foreign molecules in their body and develops an antibody against the 3F8 antibody. Ideally this happens after four or more rounds and then the treatment is stopped.
When
They like to start this treatment prior to day +90 after transplant, because the body is still weak and doesn’t recognize the antibody as quickly, elapsing multiple rounds of treatment before HAMA. But Peter is already past day +100, so there is a chance that his body will reach HAMA quickly after only a round or two of treatment. That doesn’t necessarily mean that the treatment won’t have benefits, but obviously you want to get four rounds completed for maximum effectiveness.
The exact schedule is being determined at this point. Along with this treatment, he will need to be tested at Sloan-Kettering every three months for the next two years.