Kiadis Pharma reports positive interim data from ATIR Phase II clinical study

~ Data confirms the potential of ATIR™ in partially matched hematopoietic stem cell transplants ~

Kiadis Pharma B.V. ("Kiadis Pharma"), a clinical stage biopharmaceutical company developing T-cell immunotherapy treatments for blood cancers, today announces positive interim data from the ongoing Phase II clinical study with its lead product ATIR™. The data were presented by Dr. Denis-Claude Roy, Professor of Medicine at the University of Montreal and Chair of the study, at the American Society of Hematology (ASH) Annual Meeting in San Francisco (Abstract 314).

ATIR™ is a cell-based product designed to enable stem cell transplantations from partially matched (haploidentical) family donors for blood cancer patients who do not have a standard of care stem cell donor available. The Phase II study is an international multi-center study in which a total of 23 leukemia patients, including patients with acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL) and myelodysplastic syndrome (MDS), will be enrolled and treated with ATIR™ as part of the transplant regimen.

The primary endpoint of the study is the rate of Transplant Related Mortality (TRM) at 6 months after hematopoietic stem cell transplantation (HSCT). Data from the pre-specified interim analysis of the first 10 patients showed only 2 cases of TRM at 6 months post-HSCT and both TRM cases resulted from a viral infection. Overall, 6 out of the 10 patients were completely free from severe infections (grade 3-5) after ATIR™ administration and up to 6 months after the transplant.

These data confirm the safety and efficacy of ATIR™ administration with no grade III-IV (life-threatening) acute Graft versus Host Disease (GvHD) occurring, despite the fact that no prophylactic immune suppressants were used. Only a limited number of grade I-II GvHD events were reported, all of which were treated successfully. Furthermore, no relapses were reported in any of the first 10 patients, with 4 out of the 10 patients in follow-up for more than one year at the time of the interim analysis.

These data are in line with the data previously reported from Kiadis Pharma's Phase I/II study with 19 patients. The current study is progressing well with further enrollment of patients in Canada (Hôpital Maisonneuve-Rosemont (Montreal), Juravinski Hospital and Cancer Centre (Hamilton) and Princess Margaret Cancer Centre (Toronto)), Belgium (University Hospitals Leuven, AZ Sint Jan (Bruges) and Institut Jules Bordet (Brussels)) and Germany (University Hospital of Würzburg).

Dr. Denis-Claude Roy, Professor of Medicine at the University of Montreal and Chair of the study, said: "ATIR™ has demonstrated its potential to provide potent immune protection against lethal infectious complications and residual tumor cells without causing clinically critical GvHD as an add-on for blood cancer patients who have received a stem cell transplantation from an only partially matched family member. This offers hope to patients who currently cannot be treated with a transplantation because of the limited availability of suitable matched donors."

Manfred Ruediger, PhD, Chief Executive Officer of Kiadis Pharma, commented: "The results from this interim analysis are very encouraging and show the significant potential of ATIR™ as a treatment option to enable stem cell transplantations from partially matched family donors for blood cancer patients who do not have a standard of care stem cell donor available. We also believe ATIR™ has potential as a curative treatment for blood cancer patients who have relapsed already once or more times on other treatments and who would currently not receive a stem cell transplantation because of limited donor availability. These data, presented at ASH by Dr. Denis-Claude Roy, were very well received and we look forward to providing further updates on the ongoing study in due course."