A new study finds that adding a specific human antibody to the medication might restore its cancer-killing capabilities.
Rituximab, which is sometimes sold under the brand name Rituxan, is used to treat certain autoimmune diseases and some types of cancer.
Rituximab is not a chemotherapy drug, but rather a monoclonal antibody therapy that can be used either alone or alongside chemotherapy. This type of intervention uses antibodies, which bind to specific cells or proteins, thereby stimulating the patient’s immune system to attack them.
Specifically, rituximab is an antibody against a protein called CD20, which occurs most commonly on the surface of immune B cells. Rituximab is useful in treating non-Hodgkin lymphoma and chronic lymphocytic leukaemia; in these conditions, the cancer primarily affects the immune cells.
The team was led by senior author Dr Edward F Patz, Jr, the James and Alice Chen Professor of Radiology at Duke. In earlier studies, Dr Patz and his colleagues identified some patients who had antibodies to CFH, and who therefore had a natural ability to fight cancer.
By producing this antibody, they were able to shut off CFH, effectively removing the cancer cell’s security system and leaving it open to the immune system or drugs such as rituximab.
Dr Patz set out to understand whether the antibody to CFH could make rituximab effective in patients who were naturally resistant to it.
To begin, the researchers tested the leukemic cells of 11 patients in order to ascertain whether or not they were resistant to rituximab. Ten out of the 11 participants’ tumour cells were unresponsive to the drug.
As Dr Patz explains, “This is a combination approach, and it appears to strip away the immune protection of cancer cells. Patients who had been rituximab resistant became rituximab sensitive.”
The team already has a phase 1 clinical trial planned in order to put the antibody through its paces. This future research will measure how it works on advanced solid tumours, including breast, colon, and lung cancers.
The more advanced our understanding of cancer becomes, the more complexities we find in the disease. This makes pushing for new treatments is an increasingly convoluted task.
As the authors conclude in their paper, “It is becoming increasingly clear that tumours use multiple mechanisms to evade the immune system and are often resistant to monotherapy. A better understanding of resistance mechanisms will help optimise cancer therapy.”
If the results of the current study are replicated in the phase 1 trial, the new CFH antibody treatment could further improve the efficacy of an already successful cancer treatment.
