Star Therapeutics has raised $90m in an oversubscribed Series C financing round to bolster plans for its portfolio companies and antibody therapies.

Star’s portfolio consists of two companies: Vega Therapeutics and Electra Therapeutics. Both are developing antibody therapies for treating rare diseases. Vega’s monoclonal antibody VGA039 has been granted an orphan drug designation by the US Food and Drug Administration (FDA) for the treatment of von Willebrand disease (VWD), a rare bleeding disorder.

The Series C financing will support the clinical development of VGA039, which is currently in a Phase I trial (NCT05776069). The drug promotes thrombin generation, which is involved in blood coagulation and clot formation, by targeting the thrombin co-factor, protein-S.

Electra on the other hand focuses on targeting signal-regulatory protein (SIRP). The company raised $84m in Series B funding for the clinical development of ELA026, which is currently in Phase I/II of development for treating the rare SARS CoC-2 induced hyperinflammatory event secondary hemophagocytic lymphohistiocytosis (sHLH). Electra also has two undisclosed immunology and immuno-oncology candidates as part of its drug pipeline.

The Series C funding proceeds will also fund the expansion of Star’s company portfolio. Star’s CEO, Adam Rosenthal, stated in a press release: “To date, we have unveiled two biotech companies that have rapidly advanced antibodies from idea stage to the clinic, and we aim to replicate this success with additional biotech companies in the Star portfolio.”

Research into rare drug therapies has increased in recent years, with the number of drugs receiving the US FDA’s orphan drug designations tripling in the past decade compared with previous years.