Telix Granted FDA Orphan Drug Designation for Bone Marrow Conditioning Treatment

Melbourne (Australia) and Indianapolis, IN (U.S.A.) – 29 March 2022. Telix announces that the FDA has granted Orphan Drug Designation for TLX66 (90Y-besilesomab), for conditioning treatment prior to hematopoietic stem cell transplant (HSCT).

Telix is pleased to announce that the United States Food and Drug Administration (FDA) has granted Orphan Drug Designation (ODD) for TLX66 (90Y-besilesomab), for conditioning treatment prior to hematopoietic stem cell transplant (HSCT).

The granting of an ODD for TLX66 qualifies Telix for various drug development incentives, which may include FDA administered market exclusivity for seven years, waived FDA prescription drug user fees, and tax credits for R&D and clinical development costs.

Bone marrow conditioning is performed prior to HSCT, a procedure where the patient’s bone marrow is cleared of cells and replaced by stem cells (cells that can develop into different types of cells), to encourage production of new bone marrow that produces healthy blood cells. Traditional conditioning regimens are associated with morbidity and mortality from chemotherapy, limiting their use, particularly in pediatric and rare diseases.

TLX66 has the potential to add to the depth of conditioning, thereby removing additional disease-causing cells. In addition, TLX66’s potential to reduce the toxicity of existing conditioning regimens could increase the number of patients that are eligible for transplant.

HSCT is being used increasingly in malignant hematological conditions, such as multiple myeloma and acute myeloid leukemia, and in non-hematological malignancies and rare / immune-mediated diseases. In 2018, 22,729 HSCTs were performed in the United States.

During 2021, the Company reported initial results for safety and tolerability for the Targeted Radiotherapy for AL-amyloidosis (TRALA), a Phase I trial conducted at the University of Southampton, United Kingdom. The study found that TLX66 was well-tolerated in patients with systemic amyloid light chain amyloidosis (SALA), enabling successful engraftment of the patients’ own transplanted stem cells without the need for toxic chemotherapy in this rare immune condition with a poor prognosis.

Telix Chief Medical Officer, Dr. Colin Hayward said, “The granting of an Orphan Drug Designation by the FDA for TLX66, combined with recent encouraging data from prior studies in hematological malignancies and autoimmune disease provides a strong impetus to advance our development plans for TLX66. This treatment has potential application in a number of hematological cancers and rare diseases and potentially also in the future for conditioning for cell and gene therapies.”

TLX66 has also previously been granted ODD status by the European Medicines Agency in Europe for treatment in hematopoietic stem cell transplantation. TLX66 (90Y-besilesomab) has not received a marketing authorisation approval in any jurisdiction.

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