IRIS International completes study of 85 post-prostatectomy patients using investigational NADiA PSA assay

IRIS International Inc. has announced that its Iris Molecular Diagnostics (IMD) group has successfully completed a retrospective study of stored leftover serum of 85 post-prostatectomy patients, men who had their prostate removed due to prostate cancer, using its investigational NADiA (Nucleic Acid Detection ImmunoAssay) PSA Assay.

In this study, the NADiA PSA Assay detected levels and increasing levels of PSA that were previously undetectable using conventional ultra sensitive assays, thus potentially enabling the detection of biochemical recurrence (BCR) an average 2-1/2 years earlier than with the most sensitive commercially available tPSA assays.

“ We are extremely pleased with the ‘ highly statistically significant ' results of this study and we congratulate our IMD team on this significant accomplishment, which we believe, once these findings are replicated and validated, could become the basis for an algorithm to monitor biochemical recurrence of PSA much earlier than conventional PSA assay. It is also important to note that in the retrospective study, the NADiA PSA clearly separated those patients with and without BCR. Although the regulatory process is going slower than anticipated, we are optimistic that our program will continue to generate data that will support the clearance of strong clinical claims for the NADiA PSA Assay, which should enable us to maximize value and accelerate clinical acceptance, ” said C é sar Garc í a, Chairman, President and Chief Executive Officer of IRIS International, Inc. “ The results of this study have prompted us to review our regulatory strategy as we do not wish to take short cuts at the expense of compromising the potentially high reimbursement for NADiA PSA and other NADiA applications currently in research and development. Discussions with the FDA are in progress, ” he said.

Dr. Thomas H. Adams, Ph.D, Chief Technology Officer and Corporate Vice President, noted that “ We are very satisfied with the progress made with the FDA thus far and this work sets a foundation and a body of knowledge that should help us in future regulatory applications. We are also strengthening our intellectual property and have filed a provisional patent application to protect our new NADiA method. In addition to these highly encouraging results, our team continues to make significant headway on the research and development of our NADiA HIV assay and is on schedule with this project as well. ”

The retrospective study was performed by IMD in collaboration with Dr. Eleftherios P. Diamandis MD, PhD, Head of Clinical Biochemistry at the University of Toronto and Director of Pathology and Laboratory Medicine at Mt. Sinai Hospital in Toronto. Dr. Diamandis currently serves on boards of 25 scientific journals and has published more than 400 original papers. Dr. Diamandis has received numerous awards for his contributions to cancer research including most recently, Investigator of the Year Award from the American Association of Clinical Chemistry and the Morton K. Schwartz Award for Significant Contributions in Cancer Research Diagnostics. He currently serves as a consultant to Iris Molecular Diagnostics.

Collectively, the 85 patient cohort had 435 serial blood samples collected between 100 and 3,200 days after a radical prostatectomy and all 85 men had an initial serum PSA level that could not be detected ( < 100 pg/mL) using a conventional PSA assay. With currently available technology, it is the recommendation of experts that a cut-off point of 200 pg/ml be used as the classifier of biochemical recurrence of prostate disease, according to a recent article published by the Journal of Urology.

In the study, retained blood samples of 42 men that had confirmed biochemical recurrence of PSA were compared to 42 men that did not recur according to results from an ultrasensitive experimental research PSA assay designed by Dr. Diamandis. IRIS compared the results from the ultrasensitive experimental research PSA assay against those determined by the NADiA PSA assay. Results using the NADiA PSA assay correlated very well with the research PSA assay and showed excellent clinical concordance for identifying the men with and without biochemical recurrence. The difference in PSA concentrations between these two patient groups was highly statistically significant.

Prior to this study, the actual levels of PSA in this group of patients was not known and results are routinely reported as “ less than 100 pg/ml ” or zero due to the sensitivity limitations of conventional assays. In the NADiA PSA study, we have observed for the first time that the PSA levels in patients that do not experience biochemical recurrence drop to an average of 3.5 pg/ml following surgery and do not rise substantially. Biochemically recurrent patients, however, were observed to have a steady exponential rise in the PSA concentrations after dropping to a baseline value following surgery. In this study, the NADiA PSA assay detected a rise of PSA concentration on an average 2-1/2 years before tPSA values reached 100 pg/mL (0.1ng/mL), the sensitivity level of conventional PSA assays. We believe that if these results are replicated and validated, these findings could become the basis for an algorithm to monitor biochemical recurrence of PSA earlier than conventional PSA assay. Also, the low concentrations measured by NADiA-PSA were not detected by the most sensitive FDA-cleared PSA assay tested in the study.

The Company plans to conduct a larger retrospective study to validate this data. This study will be conducted at leading medical institutions in the coming months to support regulatory clearance of the test. In addition, a scientific publication of this study has been accepted for presentation at the 40 th AACC Oak Ridge Conference - Breakthrough Technologies for Clinical Diagnostics, on April 17, 2008.