Chiesi and Arbor Biotechnologies Forge $2.1B Alliance for Rare Disease Gene Editing Therapies

Italian pharmaceutical company Chiesi Group has entered into a landmark collaboration with Arbor Biotechnologies, a U.S.-based gene editing startup, in a deal potentially worth over $2.1 billion. The partnership, announced on October 6, 2025, centers around the development of innovative gene editing treatments for rare diseases, with a primary focus on primary hyperoxaluria type 1 (PH1).

ABO-101: A Breakthrough in PH1 Treatment

At the heart of this collaboration is ABO-101, Arbor's lead gene therapy candidate for PH1, a rare genetic disorder affecting the liver and kidneys. PH1 is characterized by the overproduction of oxalate, leading to severe kidney stones and potential organ damage. ABO-101 employs CRISPR technology to target the HAO1 gene in the liver, aiming to suppress oxalate production and prevent its toxic accumulation.

Chiesi will gain exclusive global rights to ABO-101, which is currently being evaluated in the Phase I/II redePHine clinical trial. The study, which began enrolling patients in July 2025, targets 23 participants and has a primary completion date set for March 2029.

Deal Structure and Financial Terms

Under the terms of the agreement, Chiesi will provide Arbor with up to $115 million in upfront and near-term payments. The deal structure includes:

• Potential milestone payments of up to $2 billion
• Low double-digit tiered royalties on future product sales
• Option for Chiesi to license additional liver-targeting gene editing treatments from Arbor for rare diseases

This substantial investment underscores Chiesi's commitment to expanding its rare disease portfolio and highlights the growing interest in gene editing technologies within the pharmaceutical industry.

Strategic Implications and Market Outlook

The collaboration between Chiesi and Arbor represents a significant step forward in the development of gene editing therapies for rare diseases. It comes at a time when the U.S. Food and Drug Administration (FDA) has expressed interest in accelerating the development of gene therapies for rare conditions.

Currently, two FDA-approved treatments exist for PH1: Alnylam Pharmaceuticals' Oxlumo and Novo Nordisk's Rivfloza. Both require frequent injections, whereas ABO-101 is designed as a one-time treatment with potential lifelong effects.

Giacomo Chiesi, Executive Vice President of Chiesi Global Rare Diseases, described the partnership as "a transformative moment" for both the company and the rare disease community. The alliance aims to explore gene editing's potential to provide more comprehensive therapeutic options for patients with rare diseases.

As the pharmaceutical industry continues to invest in genetic medicines, this collaboration between Chiesi and Arbor Biotechnologies stands out as a prime example of the sector's commitment to addressing unmet needs in rare disease treatment through cutting-edge gene editing technologies.