Graphite Raises $150 Million to Advance Gene Editing Therapies for Rare Diseases

Rare Daily Staff

Graphite Bio said it closed an oversubscribed $150 million series B financing that it will use to expand and advance its pipeline of experimental targeted gene integration therapies for rare diseases into the clinic.

The financing brings the total raised to $195 million since Graphite’s launch in September 2020.

RA Capital Management and Rock Springs Capital led the financing with significant participation from new investors Cormorant Asset Management, Deerfield Management Company, Federated Hermes Kaufmann Funds, Fidelity Management & Research Company, Janus Henderson Investors, Logos Capital, OrbiMed, Perceptive Advisors, Surveyor Capital (a Citadel company), and Venrock Healthcare Capital Partners, which joined existing investor Samsara BioCapital and founding investor Versant Ventures.

“This milestone provides further validation for our highly differentiated gene integration platform and enables us to advance our pipeline through initial clinical milestones,” said Josh Lehrer, CEO of Graphite Bio.

Graphite Bio’s technology platform draws from gene-editing research conducted in the lab of Stanford professor Matthew Porteus, an academic founder of CRISPR Therapeutics, and gene therapy expertise from Stanford professor Maria Grazia Roncarolo, who helped advance multiple gene therapy products into the clinic when she served as director of Telethon Institute for Cell and Gene Therapy at the San Raffaele Scientific Institute in Milan.

While many existing gene editing and gene therapy approaches are based on knocking out, or randomly integrating genes, Graphite Bio is focused on correcting defective genes by high-efficiency site-specific integration of new genetic sequences. This technology has the potential to precisely repair a damaged portion of a gene, completely replace a malfunctioning gene while retaining normal regulatory control, or to insert a wide range of therapeutic genetic cargoes into precise regions of the genome.

In addition, Graphite says its technology has the potential to provide for durable expression while minimizing toxicity from off-target insertions. CRISPR-Cas9 gene editing has transformed the biotechnology landscape due to its ability to specifically induce double-stranded DNA breaks that can disrupt genes or genetic control regions, but it has been challenging to harness it for the high-efficiency insertion of new genetic cargo.

Graphite Bio’s gene editing platform includes several complementary technologies that enable targeted and permanent DNA integration at very high efficiency. The platform builds on seminal work led by Danny Dever in Porteus laboratory at Stanford University demonstrating an increase in integration efficiency from less than 1 percent to greater than 50 percent across diverse genetic lesions in a wide range of cell types. The efficiency improvements enable clinically meaningful levels of targeted integration for therapeutic applications. The company says its medicines therefore can replace defective genes, insert genetic cargo into specific loci and significantly limit undesirable, indiscriminate transgene expression.

The company has received IND clearance from the U.S. Food and Drug Administration to initiate its first phase 1/2 clinical trial evaluating investigational candidate GPH101 in sickle cell disease. GPH101 is designed to specifically correct the single nucleotide point mutation in the sickle β globin gene. In cells from patients with the disease, the company has shown that its gene correction approach efficiently restores healthy hemoglobin protein and eliminates sickle cell hemoglobin.

The company is also completing IND-enabling studies to advance investigational therapies GPH201 and GPH301 in severe combined immune deficiency with IL2RG deficiency, known as x-linked SCID (XSCID), and Gaucher Disease (Types 1 and 3, respectively).

Photo: Josh Lehrer, CEO of Graphite Bio