Immutep

New results confirm that ImmuFact IMP321 doubles clinical response rate

Immutep S.A. announced today interim results from the first three cohorts of its ongoing Phase I/II chemoimmunotherapy clinical trial in metastatic breast carcinoma. The new results confirm the clinical response rate of 50 % with IMP321 associated with paclitaxel compared to 25 % with paclitaxel alone.

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.

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 tumours.

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 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 four cohorts. The new interim results are based on tumour regression under RECIST criteria in the first three cohorts of 24 patients out of the total of 30 compared to the historical control group which is the weekly paclitaxel arm of a recent randomised phase III study (N. Engl. J. Med. 2007; 357:2666-76). The improvement is highly statistically significant with a p-value of 0.006.

In addition, immuno-monitoring confirmed that IMP321 is a potent agonist of the anti-cancer cellular immune response. Both the primary target cells (monocytes, dendritic cells) and secondary target cells (CD8 effector memory T cells) were found to be expanded/activated for several months.

Published 10/2009 by admin@immutep.com