Sutro-Celgene partnership a strategic fit

SAN FRANCISCO, Calif.—Sutro Biopharma will collaborate withCelgene Corp. to design and develop novel antibody drug conjugates (ADCs) andbispecific antibodies for two undisclosed targets and to manufacture aproprietary Celgene antibody. The deal could be worth more than $500 million toSutro, which will receive a substantial upfront payment, an equity investmentin the company and payments for the completion of research, development andregulatory milestones, plus royalties on product sales.

"The collaboration between Sutro and Celgene arose due tothe strong strategic fit for both companies, as Sutro has built a platform forcreating the next-generation ADC and bispecific products Celgene seeks todevelop and commercialize," says William Newell, CEO of Sutro. The companiesmet at the JPMorgan Healthcare conference in January 2012.

Newell explains that Sutro has developed a cell-freebiochemical protein synthesis technology that allows the creation of"best-in-class ADCs and bispecific antibodies," which are made up of pieces oftwo separate antibodies and can bind to two different antibody-producingantigens. Additionally, Sutro has established a Good Manufacturing Practice(cGMP) facility for the production of clinical supplies of materials using itsbiochemical protein synthesis platform and is "an expert in the field ofprotein engineering," he says.

Celgene, a global biopharmaceutical company, "has aworld-class reputation for the discovery of breakthrough medicines and hassignificant expertise in development and commercialization of therapeuticproducts in various disease areas," Newell adds. It focuses on the discovery,the development, and the commercialization of products for the treatment ofcancer and other severe, immune or inflammatory conditions.

More than 300 clinical trials at major medical centers usecompounds from Celgene. Investigational compounds are being studied forpatients with incurable hematological and solid-tumor cancers, includingmultiple myeloma, myelodysplastic syndromes, chronic lymphocyte leukemia,non-Hodgkin's lymphoma, myelofibrosis, small-cell lung cancer and prostate cancer.

Dr. Thomas Daniel, Celgene's president of global researchand early development, says, "We look forward to working with the team at Sutroand to exploring their platform's potential to accelerate the discovery anddevelopment of superior multifunctional biologics."

Celgene was interested in applying Sutro's platform togenerate many types of proteins and using Sutro's cGMP manufacturing facility,thus reducing the time for the preclinical development, according to Daniel.

Sutro's antibody-based therapeutics for targeted cancertherapies will "significantly extend the clinical impact of current oncologytherapeutic approaches and are beyond what can be envisioned with current,cell-based expression technologies," Newell says. Sutro's biochemical synthesistechnology "allows the rapid and systematic exploration of many protein drugvariants to identify drug candidates." Once these product candidates areidentified, production can be rapidly and predictably scaled up to commerciallevels.

"Sutro aims to successfully complete the research,development and regulatory milestones in the Celgene collaboration," Newellsays. "Additionally, Sutro continues to develop its own pipeline and toestablish additional collaborations with pharma and biotech companies interestedin developing next-generation ADCs and bispecific antibodies."

Sutro will be responsible for product design and productionof preclinical materials and will make clinical batches of a Celgene-developed"naked" antibody that works without carrying a drug.

As to the state of ADC technology, Newell explains that ADCsare a new class of targeted therapies that "hold much promise, especially inoncology." Technology platforms for the development of next-generation ADCs"should provide control over the number and placement of the drugs conjugatedto the antibody," he says. "The current state of the art results in mixtures ofmultiple species of ADCs which potentially results in suboptimalpharmacokinetics, stability and efficacy."

Sutro's cell-free biochemical protein synthesis technologyenables the introduction of site-specific chemical modifications, includingnon-natural amino acids, generating hundreds of variants of proteins, such asantibodies, and also enables the rapid and systematic screening forbest-in-class therapeutics, according to Newell.

"The candidate selected can be manufactured utilizing thesame platform in accordance with current GMP standards," he concludes.