Immutep Announces Positive Interim Results in Phase I/II Chemoimmunotherapy Trial in Breast Cancer
News Jan 07, 2009
Immutep S.A. has announced interim results from its ongoing Phase I/II chemoimmunotherapy clinical trial in metastatic breast carcinoma. ImmuFact IMP321 was administered the day after weekly paclitaxel for six months.
The interim results show a clinical response rate of 50 per cent compared to 25 per cent with paclitaxel alone. In addition, a robust immune response was observed in clinically-responding patients.
IMP321 is a first-in-class immunopotentiator that agonizes MHC class II molecules thereby stimulating antigen-presenting cells, such as dendritic cells and monocytes, leading to markedly improved cytotoxic CD8 T-cells responses against tumors.
Chemoimmunotherapy is a new approach to the treatment of cancer. Chemotherapy drugs induce tumour cell apoptosis and cause modulation of the immunological environment combined with a burst of tumour antigen release. The resulting T-cell immune response contributes to the regression of the tumour and, importantly, may seek out and destroy metastases. However, this initial immune response needs to be sustained and amplified by a T-cell booster that is non-toxic and can be given repeatedly, such as ImmuFact IMP321.
The design of the study is a multi-centre open-label fixed dose-escalation trial. One of the lead centre's main Principal Investigators, Maya Gutierrez, is coordinating the team carrying out the trial at the René Huguenin Cancer Centre, Saint Cloud, near Paris.
Patients receive 6 cycles of low-dose weekly paclitaxel at Day 1, Day 8 and Day 15 of a 4-week cycle as first line chemotherapy plus bi-weekly IMP321 administered the day after the paclitaxel to make a total of 12 injections of IMP321 over 24 weeks. Three dose levels of IMP321 are being studied in three cohorts of 8 patients each.
The interim results are based on tumour regression under RECIST criteria in the first two cohorts of 16 patients out of the total of 24 compared to the historical control group which is the weekly paclitaxel arm of a recent randomized phase III study (N. Engl. J. Med. 2007; 357:2666-76). The improvement is statistically significant with a p-value of 0.03.
"Such sequential chemo- and then non-toxic immunotherapeutic combos may be a way to improve the response rate and/or consolidate or stabilize the partial tumour responses obtained with chemotherapy alone," said Dr Maya Gutierrez, Principal Investigator of this Phase I trial. "We are very pleased to be testing this innovative therapeutic approach at our Institute."
"Boosting the dendritic cell network when it is loaded with tumour antigens following chemotherapy with repeated injections of IMP321 is an effective way to amplify the cytotoxic CD8 T-cell responses observed in first-line chemotherapy," said Frederic Triebel, Scientific & Medical Director of Immutep. "A similar approach will shortly be tested in the first trial of IMP321 in the USA in pancreatic cancer patients receiving first-line gemcitabine."
"These positive results have encouraged us to engage in discussions with potential partners over Immutep's plans for the advanced development stages of IMP321 as we continue to collect data from this study at the highest dose," added John Hawken, CEO.