Key Highlights

  • Starpharma has increased its equity interest in Petalion Therapeutics from 22.5% to 66%.
  • Starpharma will contribute up to AUD 5.0 million, made up of AUD 3.0 million in cash and the balance in R&D services.
  • Medicxi retains a 30% interest, board representation and a strategic role.
  • The next phase focuses on generating data to select a lead candidate and define the development and partnering pathway.

Starpharma Holdings Limited (ASX:SPL) announced on 20 October 2026 that it has raised its equity interest in Petalion Therapeutics from 22.5% to 66%, giving it majority ownership, governance control and operational leadership of a fibroblast activation protein (FAP)-targeted oncology program. The company will host an online briefing and question-and-answer session at 12.00 noon AEDT on Wednesday, 21 October 2026.

Transaction and ownership structure

Following the transaction, Starpharma holds 66% of Petalion and Medicxi holds 30%. Medicxi keeps board representation and an active strategic role. Petalion becomes a UK-incorporated subsidiary of Starpharma Holdings Limited. Under the revised structure, Starpharma leads operations and supplies its DEP dendrimer platform, conjugation and development capabilities, while Medicxi continues to provide oncology development, investment and asset-centric expertise. Specialist advisers will be engaged as required.

Funding commitment

Starpharma will contribute up to AUD 5.0 million to Petalion, comprising AUD 3.0 million in cash and the balance in R&D services, to advance the program through its next phase. The company describes the spend as a use of the capital allocated to new R&D pipeline opportunities in its recent capital raise, and states that sufficient funds remain within that allocation to progress other early-stage targeted oncology assets.

About Petalion and the FAP target

Petalion was established in 2024 as an asset-centric company focused on a single FAP-targeted oncology program using Starpharma's DEP dendrimer platform. It is developing a FAP-targeted dendrimer-drug conjugate for cancer. FAP is highly expressed in the tumour microenvironment across many tumour types, with relatively limited expression in healthy tissue, which the company says makes it a pan-cancer target with potential relevance to cancers such as pancreatic, lung and breast. Initial research has supported progression into further optimisation and lead candidate selection.

Fit with the DEP platform

Starpharma states that effective FAP-targeted therapies require a balance of tumour penetration, distribution and retention, together with a payload capable of producing meaningful tumour cell killing. The DEP dendrimer platform is described as tuneable and designed to optimise tumour localisation, penetration, retention and payload delivery while limiting unnecessary exposure to healthy tissue. The company says the program adds a FAP-targeted conjugate to its focused oncology portfolio and lets development priorities, capital allocation and partnering decisions be aligned with its broader DEP strategy.

Next phase of the program

Following completion of the initial R&D stage, Starpharma will lead the next phase, applying its dendrimer, conjugation and development capabilities to generate the evidence needed for lead candidate selection. The release identifies lead candidate selection and the definition of the subsequent development and partnering pathway as the next value-inflection point, with the aim of bringing an asset into the clinic. No clinical timelines, trial dates or data results were included in the announcement.

Stated rationale

Starpharma says the investment fits its strategy of building a focused portfolio of differentiated targeted-oncology therapies and shows the versatility of its DEP platform across therapeutic payloads. Following completion of the initial R&D stage, it elected to raise its ownership before the program enters its next phase. Majority ownership allows development priorities, capital allocation and partnering decisions to be aligned with its broader oncology work.

Investor briefing

The company will host an online CEO briefing and question-and-answer session at 12.00 noon AEDT on Wednesday, 21 October 2026, with registration through a webinar link. Starpharma is listed on the ASX under the code SPL and trades in the United States over the counter under the code SPHRY.

Summary of the transaction

The announcement records a move from a 22.5% to a 66% holding in Petalion, a funding commitment of up to AUD 5.0 million, a retained 30% interest for Medicxi and a pre-clinical program that remains at the lead candidate selection stage.