ATIR (Allodepleted T-cell ImmunotheRapeutics) is designed to support the patient’s newly transplanted immune system before it becomes fully functional. In ATIR, T-cells causing Graft-versus-Host-Disease (GVHD) have been depleted, while T-cells protective against tumor cells and infections have been retained. This provides physicians with the opportunity to infuse potent T-cells with minimal risk of causing potential lethal severe GVHD. ATIR therefore addresses one of the biggest challenges of using haploidentical family members as stem cell donors for those patients that would otherwise not find a matching donor in time.
The Company’s lead product, ATIR101, addresses key risks and limitations of HSCT in blood cancers, specifically GVHD and cancer relapse. ATIR101 is a cellular product for infusion. It consist of donor lymphocytes (immune cells), specifically manufactured for each individual patient from a healthy, haploidentical stem cell donor.
Using the Company’s proprietary selective cytotoxic compound, TH9402, those T-cells which attack the patient, causing Graft-versus-Host Disease (GVHD), are depleted. The full immune repertoire of other donor immune cells, including immunological memory, is retained in the final product.
For patients suffering from blood cancers, an allogeneic hematopoietic stem cell transplantation (HSCT) is generally regarded as a potentially curative, yet high risk approach. During an HSCT treatment, the bone marrow, harboring the diseased cancer cells, is completely destroyed and subsequently replaced by stem cells in the graft from a healthy donor. After an HSCT treatment it usually takes the patient at least six to twelve months to recover to near-normal blood cell levels and immune cell functions. During this period, the patient is highly vulnerable to infections caused by bacteria, viruses and fungi but also to disease relapse.
ATIR101, administered as an adjunctive immunotherapeutic on top of HSCT, provides for a safe single dose donor lymphocyte infusion (DLI) with functional, mature immune cells from a partially matched (haploidentical) family member, with minimal risk of causing severe Graft-versus-Host-Disease (GVHD).
The T-cells in ATIR101 will help fight infections and remaining tumor cells and thereby bridge the time until the immune system has fully re-grown from stem cells in the transplanted graft.
In ATIR101, T-cells that would cause GVHD are depleted from the donor lymphocytes using Kiadis Pharma’s photodepletion technology, minimizing the risk of GVHD and eliminating the need for prophylactic immune-suppression. At the same time, ATIR101 contains potential cancer killing T-cells from the donor that could eliminate residual cancer cells and help prevent relapse of the disease, known as the Graft-versus-Leukema (GVL) effect.
The Company estimates that approximately 35% of patients who are eligible and in urgent need of HSCT will not find a matching donor in time. A partially matched (haploidentical) family donor, however, will be available to over 95% of patients.
Single dose Phase II data with lead product candidate ATIR101 has demonstrated substantial and clinically relevant improvements over historical observational cohort data for a similar HSCT without ATIR101, and also shows an improvement over the Post-Transplant Cyclophosphamide (PTCy), or Baltimore protocol, data reported in scientific literature.
Based on the positive results from the Phase II trial, Kiadis Pharma submitted a Marketing Authorization Application (MAA) to the European Medicines Agency (EMA) in April 2017, for approval of ATIR101 across the EU as an adjunctive treatment in HSCT for adult malignant disease.
Kiadis Pharma is conducting a Phase III trial with ATIR101 across Europe and North America (head to head against the PTCy/Baltimore protocol). The first patient was enrolled in December 2017.
In September 2017 the U.S. Food and Drug Administration (FDA) granted ATIR101 the Regenerative Medicine Advanced Therapy (RMAT) designation. ATIR101 has been granted Orphan Drug Designations both in the U.S. and Europe.