Pfizer turns to upstart CytomX for $635M deal on armed antibody tech

Pfizer ($PFE) is partnering up with South San Francisco-based CytomX Therapeutics on a discovery program, putting the biotech's R&D platform to work on finding some next-gen antibody-drug conjugates for cancer targets. Pfizer is keeping the targets under wraps for now. CytomX gets $25 million in near-term payments and research support with a promise of up to $610 million more in payments from back-ended sales and regulatory milestones, along with a royalty stream on any approved therapies.

CytomX's claim to fame rests on its "Probodies," antibody-drug conjugates that deliver a payload of highly toxic agents directly to cancer cells. The Probody, though, is designed to stay inactive in healthy tissue and then arm itself once it arrives at a tumor, activated by proteases in the disease tissue after binding only to antigens found in that tissue.

The biotech was set up back in 2008, spinning out of UC Santa Barbara and grabbing $30 million in funding from Third Rock Ventures and Roche Ventures in 2010. Then Canaan Partners stepped in last summer and added $11 million to the round, pointing the biotech down the road to its first collaboration with Pfizer. And CEO Sean McCarthy says that the plan is to ink more such pacts eventually.

"We are enthusiastic in terms of doing a few more," he tells FierceBiotech. "There's a general perception that the low-hanging fruit in terms of target selection on ADCs has been used up." That's left Big Pharma looking for new ideas, giving CytomX an opening it can capitalize on. And the CEO says the technology can also work for anti-inflammatories, pointing to potential for new rheumatoid arthritis programs.

The company has been working on engineering an antibody that only hits the EGF receptor on cancer cells, tying on a toxin that can destroy the cancer cell and shrink tumors. The big idea here is that this approach can avoid some of the side effects seen with drugs like Erbitux and Vectibix, EGFR therapies that indiscriminately hit targets in healthy tissue, triggering rashes and gastrointestinal problems. And McCarthy says the company is on track to get its own internal program in the clinic in 2015.

For Pfizer, the deal marks another new foray in the world of early-stage drug development. Investigators from both groups will work together on preclinical programs, with Pfizer stepping in to take charge of anything that reaches the clinic. The pharma giant has been stepping up its dealmaking activities recently after completing a global R&D restructuring, carving billions of dollars out of its R&D budget, and forming research alliances with small companies such as Nodality in autoimmune disease and Bind Therapeutics for nanotech drugs.

"This partnership is a great example of how Pfizer is seeking to innovate new capabilities in cutting-edge science and technology platforms with the aim of delivering safer, more effective cancer medicines to patients," said Robert Abraham, the senior vice president and chief scientific officer of Pfizer's Oncology Research Unit. "Pfizer's investment in CytomX's emerging Probody Platform is an important component of our overall strategic focus to advancing the next generation of ADCs and reflects the disruptive potential of this approach."

CytomX is moving into new digs in South San Francisco, providing some added space for its 28 staffers, most of whom joined the company in the last 18 months, after the company moved to the Bay Area from Santa Barbara. The company is likely to do a little more hiring over time, depending on their success on the dealmaking front, says McCarthy. But he's happy with the size the company has grown to.

- here's the press release

Related Articles:
New technique could fast-track discovery of antibody drugs
CytomX's antibody therapies target cancer, leave healthy tissue intact
Abbott doubles down on ADC cancer drugs in $245M-plus Seattle Genetics pact
Third Rock leads $30M round for antibody upstart

Suggested Articles

The deal gives J&J a stake in the development and commercialization of anticoagulants including phase 2-ready secondary stroke candidate BMS-986177.

Boehringer gained the global rights to OSE's SIRP-alpha antagonist, which is in development for solid tumors.

Lilly is diving into encapsulated beta cell treatments, designed to restore insulin production in patients with Type 1 diabetes.