Clarity Secures Trastuzumab Supply, Shows 120% Tumour Reduction in Pre-Clinical Breast Cancer Model

Clarity’s Strategic Expansion into Breast Cancer

Clarity Pharmaceuticals (ASX: CU6) has announced a significant expansion of its oncology pipeline with the addition of 64/67Cu-SAR-trastuzumab, a novel radioimmunotherapy (RIT) candidate targeting HER2-positive breast cancer. This development aligns with Clarity’s renewed focus on breast cancer, complementing its existing SAR-Bombesin, SARTATE, and SAR-bisPSMA products.

HER2-positive breast cancer, which accounts for up to 20% of breast cancer cases, is known for its aggressive nature and poor prognosis. Despite advances in treatment, relapse remains a critical challenge, with up to 25% of patients experiencing recurrence within a decade. Clarity’s new asset aims to address this unmet clinical need by combining trastuzumab, a well-established HER2-targeting antibody, with its proprietary SAR chelator technology to deliver copper-67 based radiotherapy.

Promising Pre-Clinical Evidence

Pre-clinical studies published recently demonstrate that 67Cu-SAR-trastuzumab significantly inhibits tumour growth in HER2-positive mouse models, achieving up to 120% tumour size reduction at higher doses compared to controls. In addition, treated mice showed prolonged survival, underscoring the potential therapeutic advantage of this radiolabelled antibody over trastuzumab alone.

This theranostic approach also leverages copper-64 for diagnostic imaging, enabling precise tumour targeting and treatment monitoring. The dual diagnostic and therapeutic capabilities position 64/67Cu-SAR-trastuzumab as a compelling candidate for personalised cancer care.

Securing Supply and Clinical Development Pathway

To support clinical development, Clarity has entered into a supply agreement with EirGenix, Inc. for the provision of clinical-grade Good Manufacturing Practice (GMP) trastuzumab biosimilar EG12014. This partnership ensures a reliable and scalable supply chain critical for advancing clinical trials and eventual commercialisation.

Clarity’s established clinical trial infrastructure in the US and Australia is poised to facilitate the upcoming Phase 1/2a theranostic study in HER2-positive breast cancer patients. This trial will be pivotal in translating the encouraging pre-clinical results into human clinical outcomes.

Broader Implications for Radiopharmaceuticals

Executive Chairperson Dr Alan Taylor highlighted the strategic importance of integrating antibody-based radiopharmaceuticals into broader cancer treatment paradigms. He emphasised the advantages of copper isotopes, including supply reliability and manufacturing simplicity, over other radioisotopes currently used in the field.

Clarity’s SAR Technology platform, which enables stable copper chelation, is central to this innovation. The company’s approach could expand the application of radiopharmaceuticals beyond prostate cancer into larger oncology markets such as breast cancer, neuroblastoma, and neuroendocrine tumours.

With the trastuzumab supply secured and promising pre-clinical data in hand, Clarity is well-positioned to advance its pipeline and potentially offer new hope to patients facing aggressive HER2-positive breast cancer.