Sail Biomedicines Provides Update on Research with Cystic Fibrosis Foundation and Pioneering Medicines

Sail Biomedicines, Inc., a Flagship Pioneering company and leader in RNA-based programmable medicines, today provided an update on its research funded by the Cystic Fibrosis Foundation (CF Foundation), with preclinical data that suggest that Sail's Endless RNAtm (eRNAtm) may offer the potential to treat the 10%-15% of people with CF for whom existing treatments are not an option.

Sail's programmable eRNA platform is designed to enable the in vivo expression of any protein, potentially targeting any tissue. Sail has designed an eRNA therapeutic encoding functional full-length cystic fibrosis transmembrane conductance regulator (CFTR) protein, with the goal of developing treatments that would restore CFTR function in people with cystic fibrosis with high unmet medical needs (i.e., those with nonsense and rare mutations and those ineligible for or intolerant of CFTR modulator treatments). Initial studies have demonstrated extended expression and functionality of eRNA-produced CFTR versus an mRNA comparator.

Cystic fibrosis is a progressive, genetic disease caused by mutations in the CFTR gene that affect the lungs, pancreas, and other organs. When the CFTR protein is not working correctly, or missing, it can cause persistent and worsening lung congestion and infections that limit a person's ability to breathe. According to the CF Foundation, there are almost 40,000 children and adults living with CF in the United States, and an estimated 105,000 people have been diagnosed globally. While breakthroughs have been made in the treatment of CF, current therapies are ineffective for about 10%-15% of individuals living with CF.

"We are thrilled to continue our research, supported by the Cystic Fibrosis Foundation to advance eRNA as a potential treatment option for people living with CF, particularly for the 10%-15% of people for whom existing modulator treatments are not an option," said Guillaume Pfefer, Ph.D., MBA, Chief Executive Officer, Sail Biomedicines and CEO-Partner, Flagship Pioneering. "We are extremely hopeful about the impact this work could have for the CF community."

"The collaboration between Pioneering Medicines and the Cystic Fibrosis Foundation aims to accelerate the path to potential treatments and cures for all people living with cystic fibrosis," said Paul Biondi, President, Pioneering Medicines and Executive Partner, Flagship Pioneering. "We are excited for Sail to continue to be part of this effort and are encouraged by the progress and potential we are already seeing with eRNA technology."

About Sail Biomedicines

Sail Biomedicines, a Flagship Pioneering company, is generating tomorrow's medicines today through the language of life. Sail's platform combines first-in-category translatable circular RNA technology (Endless RNAtm or eRNA), and proprietary programmable nanoparticles, utilizing natural components, to comprehensively program medicines for the first time. By leveraging its rapid prototyping and testing bioplatform, Sail is building a wealth of data, enabling unparalleled use of state-of-the-art AI techniques for the integrative design of RNA medicines with unprecedented performance and broad applicability. For more, visit www.sail.bio and follow us on X (formerly Twitter) @SailBiomeds and on LinkedIn.

About Flagship Pioneering

Flagship Pioneering is a biotechnology company that invents and builds platform companies, each with the potential for multiple products that transform human health or sustainability. Since its launch in 2000, Flagship has originated and fostered more than 100 scientific ventures, resulting in more than $70 billion in aggregate value. To date, Flagship has deployed over $3.6 billion in capital toward the founding and growth of its pioneering companies alongside more than $27 billion of follow-on investments from other institutions. The current Flagship ecosystem comprises 40 companies, including Denali Therapeutics (NASDAQ: DNLI), Foghorn Therapeutics (NASDAQ: FHTX), Generate:Biomedicines, Inari, Indigo Agriculture, Moderna (NASDAQ: MRNA), Omega Therapeutics (NASDAQ: OMGA), Sana Biotechnology (NASDAQ: SANA), Seres Therapeutics (NASDAQ: MCRB) and Tessera Therapeutics.

Pioneering Medicines is a strategic initiative within Flagship Pioneering that is dedicated to conceiving and developing a broad portfolio of life-changing treatments by leveraging and expanding the use of Flagship's innovations. By harnessing the power of Flagship's multiple scientific platforms, Pioneering Medicines creates and advances novel medicines together with Flagship's bioplatform companies to accelerate the extension of their portfolios into previously unexplored areas and show that they can be applied more broadly, thereby delivering benefits to more patients, sooner. In addition to its internally financed programs, Pioneering Medicines works with external strategic partners including Novo Nordisk, Pfizer, and the Cystic Fibrosis Foundation to jointly conceive medicine concepts by combining partners' R&D priorities with Flagship Pioneering's unique platform capabilities.