Aro Biotherapeutics, a start-up company based at the University of Pennsylvania’s Pennovation Center, said it raised a total of $13 million from Johnson & Johnson’s venture capital arm and from Cleveland-based BioMotiv LLC to develop its Centyrin group of protein-based drugs that target cancers and other diseases.

The company, founded by Sue Dillon and Karyn O’Neil, uses technology O’Neil developed at, and exclusively licensed from, the founders’ former employer, J&J’s Janssen Pharmaceutical Cos., the founders said in an interview. They are raising a second round of investment capital to bring the drugs toward clinical development, Dillon said.

Centyrins “are small, structurally simple, ultra-stable, highly soluble proteins” containing around 100 amino acids, so they are far smaller and simpler to manipulate than the antibody molecules used in familiar therapies, Dillon said.

Focusing the proteins on “potent anti-tumor activity,” she said, Aro is developing Centyrins in bacteria, including the E. coli bacteria endemic in human intestines, and plans to scale production up for clinical testing and rapid manufacture: “It should be very cost-effective.” She predicted Centyrin-based medicines will prove “disruptive to existing therapeutics” and can be targeted to so-far “undruggable” diseases. The founders say the proteins can be used to deliver high concentrations of medicine with low toxicity.

The firm’s lead research program targets advanced, non-small-cell lung cancer. Other applications are in the works.

Dillon, Aro’s chief executive, was global therapeutic area head for immunology at Janssen. She received her doctorate in immunology from Thomas Jefferson University in Philadelphia and completed a postdoctoral fellowship in immunology at Duke.

O’Neil, Aro’s chief scientific officer, was director of antibody discovery and venture leader at Janssen’s Centyrex unit, and is co-inventor on the Centyrin patents, among her 30 total patents. O’Neil received her doctorate from the University of Pennsylvania, where she focused on protein engineering and protein biophysics. She is an editor of Protein Engineering, Design and Selection.

Their new hires include Steve Nadler, Ph.D., Aro’s vice president of discovery and translational research, a Rutgers Medical School teacher and former executive director and head of immunoscience and cancer translational research at Bristol-Myers Squibb; Derek Miller, Aro’s chief business officer, who formerly held that title at Celator Pharmaceuticals; and Mark Laurenzi, a Johnson & Johnson veteran and biotech lawyer who is now Aro’s vice president of finance and operations.