Chiesi Group has entered into an exclusive global partnership with Arbor Biotechnologies to develop and commercialise ABO-101, a clinical-stage gene editing therapy for primary hyperoxaluria type 1 (PH1), alongside an option to advance additional liver-targeted rare disease programmes.

Under the agreement, Chiesi will hold worldwide rights to develop and market ABO-101 while gaining access to Arbor’s proprietary knockout and reverse transcriptase gene editing technologies. The deal combines a global collaboration and licence for ABO-101 with a multitarget research option covering other rare liver disease indications.

Arbor will receive up to $115m in upfront and near-term payments, and could earn as much as $2bn in development, regulatory and commercial milestones, in addition to low double-digit tiered royalties on product sales.

“This collaboration marks a transformative moment—not just for us, but for the entire rare disease community,” said Giacomo Chiesi, executive vice president, Chiesi Global Rare Diseases. “It reflects our commitment to working towards more comprehensive therapeutic options. Achieving this means looking beyond current approaches and exploring the potential of gene editing.”

He added that partnering with Arbor, which has expertise in clinical-stage gene editing, would support Chiesi’s goal of bringing meaningful innovation to rare and ultra-rare disease communities.

Arbor’s lead candidate, ABO-101, is being evaluated in the Phase 1/2 redePHine clinical study for PH1. The one-time, liver-directed therapy is designed to permanently inactivate the HAO1 gene, which plays a key role in the disease’s overproduction of oxalate. By targeting the root cause, the therapy aims to reduce or eliminate the need for lifelong treatment and organ transplantation.

“We’re proud to join forces with Chiesi, a company that shares our deep commitment to improving outcomes for patients with rare and life-threatening diseases,” said Devyn Smith, chief executive officer of Arbor Biotechnologies. “Chiesi brings a strong track record in rare disease innovation, and combined with our platform of advanced gene editors, we aim to deliver significant solutions that can redefine care for patients living with PH1 and other rare genetic diseases.”

The redePHine study is an open-label, global, multi-centre trial assessing safety, tolerability and early efficacy of ABO-101 in adults and children with PH1. The collaboration will also explore additional liver-directed gene editing approaches to expand therapeutic reach across rare genetic disorders.

“Genomic medicines offer vast potential to impact the lives of patients around the world, especially those living with rare genetic diseases,” said Dan Ory, chief medical officer of Arbor. “We look forward to partnering with Chiesi’s experienced and committed team to help accelerate ABO-101 in the clinic and advance development of liver-targeted gene editing therapeutics for patients with PH1 and other rare diseases.”

The partnership reflects growing momentum in applying precision gene editing platforms to rare metabolic and liver conditions, with Chiesi and Arbor both emphasising the potential for single-dose, durable interventions that move beyond symptom management.