On April 21, 2026 Starpharma (ASX: SPL, US OTC: SPHRY), an innovative biotechnology company with two decades of experience in advancing dendrimer technology from the lab to the patient, reported that the company has met with the United States Food and Drug Administration (US FDA) in a Type C guidance meeting and received positive feedback on the proposed clinical development strategy and design of the first-in-human (FIH) phase 1 clinical study for its DEP HER2 radiotherapy candidate ("DEP HER21").
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DEP HER2 is a HER2 receptor-targeting dendrimer conjugate with a lutetium-177 radionuclide payload. Starpharma is developing DEP HER2 for the treatment of locally advanced or metastatic HER2-overexpressing gastric/gastro-oesophageal junction cancers and other HER2 expressing advanced cancers in patients who have received prior HER2-targeted therapy.
Key highlights for investors
• FDA alignment on FIH phase 1 study design and overall clinical development approach for DEP HER2
• FDA feedback supports plans to initiate the FIH phase 1 study
• FDA confirms that patients with advanced HER2-expressing cancers who have exhausted available HER2-directed therapies represent a population with significant unmet medical need
• FIH phase 1 study remains on track to enter the clinic in H2 CY 2026
Unmet need
Overexpression of HER2 is a key driver in aggressive breast and gastric cancers, and there are limited treatment options available to patients after progression, resistance, or toxicity from current HER2-directed therapies. Starpharma is developing DEP HER2 to address these clinical challenges.
The FDA confirmed that patients with advanced HER2-expressing cancers who have exhausted available HER2-directed therapies represent a population with significant unmet medical need, meaning that there is potential to pursue Fast Track designation and other accelerated development pathways for DEP HER2 in the future.
Clinical pathway
Starpharma plans to conduct a FIH phase 1 study in Europe initially in up to 15 patients to evaluate safety and tolerability, and to characterise pharmacokinetics, biodistribution and organ radiation dosimetry of DEP HER2 in patients with advanced HER2-positive cancers.
The FDA confirmed that the clinical data generated outside of the US, together with the currently available DEP HER2 preclinical data package, including a recently completed formal toxicology study, should be adequate to support future US-based clinical studies under an Investigational New Drug (IND) application.
The FDA provided clear guidance on chemistry, manufacturing and controls (CMC) expectations for DEP HER2, and agreed with Starpharma’s current approach to the manufacture and characterisation of Starpharma’s novel dendrimer-based radioligand therapy.
Professor Tony Lahoutte, MD, PhD, a physician and Head of the Department of Nuclear Medicine at University Hospital (UZ) Brussel, and Head of Molecular Imaging and Therapy Research (MITH) at the Vrije Universiteit Brussel (VUB) in Belgium, advised Starpharma on the DEP HER2 radiotherapy clinical development strategy. He attended the FDA meeting as a representative of Starpharma, contributing expert clinical nuclear medicine input to the discussion of our radiopharmaceutical study design.
Following the meeting with the FDA, Prof. Lahoutte commented:
"The FDA’s feedback provides important confirmation that Starpharma’s first-in-human phase 1 design and overall clinical strategy for DEP HER2 are in line with regulatory expectations. From a nuclear medicine and radiopharmaceutical perspective, the proposed approach to patient selection, dosimetry and safety evaluation is appropriate. DEP HER2 combines a HER2-targeting moiety with Starpharma’s novel, dendrimer-based delivery platform. The planned clinical study is well positioned to demonstrate the benefit of the dendrimer technology in targeted radioligand therapy, and to support further clinical development of the product for this high unmet-need population with HER2-expressing cancers."
Next steps
Starpharma is currently undertaking the activities required to commence the FIH phase 1 study and remains on track to begin in H2 CY 2026. Clinical site selection is complete, and the company is progressing radiopharmacy preparations, site onboarding and required ethics and regulatory approvals.
Cheryl Maley, Starpharma’s Chief Executive Officer, commented:
"DEP HER2 is a key strategic asset for Starpharma, supported by comprehensive preclinical data and a clinically validated platform technology. We are particularly excited by the encouraging data generated to date, which have shown important benefits in targeted delivery for radiotherapeutics.
"This FDA feedback is an important milestone, providing regulatory clarity and validation for the proposed clinical development pathway and marking the exciting transition from preclinical to clinical development. The guidance provides confidence that our current preclinical package, together with the data generated in the forthcoming first-in-patient study, would support a subsequent IND application and clinical development in the US. "
By exemplifying the value of DEP technology in the high-growth area of radiotherapy in a clinical setting, Starpharma aims to broaden the therapeutic applications and commercial opportunities of its dendrimer platform, whilst continuing to deliver meaningful outcomes for patients."
(Press release, Starpharma, APR 21, 2026, View Source [SID1234664556])