Early results from two phase II trials of patients with chronic lymphocytic leukaemia (CLL) treated with MabThera (rituximab) have revealed promising results.
The study outcomes were presented at the 49th Annual Meeting of the American Society of Hematology (ASH) in Atlanta.
The first trial, conducted by the UK CLL study group, focused on patients with relapsed CLL.
This demonstrated a higher overall response rate for patients treated with MabThera in combination with chemotherapy than with chemotherapy alone: 70% vs.57%. In addition more patients also achieved minimal residual disease negativity (22% vs. 9%) – a measure of quality of response to therapy.
In the second trial, 92% of treatment naïve patients achieved a response to MabThera in combination with chemotherapy.
The study, which is run by the Spanish Group for CLL (GELLC), is also investigating the impact of MabThera maintenance therapy (MabThera every three months for up to two years) in patients that respond to the induction therapy. Further results from the second part of the study are expected in 2008.
“The potential benefit of adding MabThera to chemotherapy seen in these two trials is extremely encouraging,” said Professor Peter Hillmen, from the department of Haematology, Leeds General Infirmary, Leeds.
“They indicate that MabThera may have an integral part in improving outcomes for patients with CLL.”
Chronic Lymphocytic Leukaemia (CLL) is the most common type of leukaemia in adults, accounting for approximately 35% of all leukaemias in the UK. Incidence of CLL in the UK is over 2,400 and is nearly twice as common in men as in women.
It mainly affects the elderly with 95% of patients diagnosed after the age of 55. While CLL is generally considered an indolent disease, meaning that it is slow to progress, a significant proportion of patients have rapidly progressing forms of the disease.
MabThera (rituximab) is a therapeutic antibody that binds to a particular protein – the CD20 antigen – on the surface of normal and malignant B-cells. It then recruits the body’s natural defences to attack and kill the marked B-cells. Stem cells (B-cell progenitors) in bone marrow lack the CD20 antigen, allowing healthy B-cells to regenerate after treatment and return to normal levels within several months.