Antibodies (Mar 2016)

Development of PF-06671008, a Highly Potent Anti-P-cadherin/Anti-CD3 Bispecific DART Molecule with Extended Half-Life for the Treatment of Cancer

  • Adam R. Root,
  • Wei Cao,
  • Bilian Li,
  • Peter LaPan,
  • Caryl Meade,
  • Jocelyn Sanford,
  • Macy Jin,
  • Cliona O’Sullivan,
  • Emma Cummins,
  • Matthew Lambert,
  • Alfredo D. Sheehan,
  • Weijun Ma,
  • Scott Gatto,
  • Kelvin Kerns,
  • Khetemenee Lam,
  • Aaron M. D’Antona,
  • Lily Zhu,
  • William A. Brady,
  • Susan Benard,
  • Amy King,
  • Tao He,
  • Lisa Racie,
  • Maya Arai,
  • Dianah Barrett,
  • Wayne Stochaj,
  • Edward R. LaVallie,
  • James R. Apgar,
  • Kristine Svenson,
  • Lidia Mosyak,
  • Yinhua Yang,
  • Gurunadh R. Chichili,
  • Liqin Liu,
  • Hua Li,
  • Steve Burke,
  • Syd Johnson,
  • Ralph Alderson,
  • William J. J. Finlay,
  • Laura Lin,
  • Stéphane Olland,
  • William Somers,
  • Ezio Bonvini,
  • Hans-Peter Gerber,
  • Chad May,
  • Paul A. Moore,
  • Lioudmila Tchistiakova,
  • Laird Bloom

Journal volume & issue
Vol. 5, no. 1
p. 6


Read online

Bispecific antibodies offer a promising approach for the treatment of cancer but can be challenging to engineer and manufacture. Here we report the development of PF-06671008, an extended-half-life dual-affinity re-targeting (DART®) bispecific molecule against P-cadherin and CD3 that demonstrates antibody-like properties. Using phage display, we identified anti-P-cadherin single chain Fv (scFv) that were subsequently affinity-optimized to picomolar affinity using stringent phage selection strategies, resulting in low picomolar potency in cytotoxic T lymphocyte (CTL) killing assays in the DART format. The crystal structure of this disulfide-constrained diabody shows that it forms a novel compact structure with the two antigen binding sites separated from each other by approximately 30 Å and facing approximately 90° apart. We show here that introduction of the human Fc domain in PF-06671008 has produced a molecule with an extended half-life (-4.4 days in human FcRn knock-in mice), high stability (Tm1 > 68 °C), high expression (>1 g/L), and robust purification properties (highly pure heterodimer), all with minimal impact on potency. Finally, we demonstrate in vivo anti-tumor efficacy in a human colorectal/human peripheral blood mononuclear cell (PBMC) co-mix xenograft mouse model. These results suggest PF-06671008 is a promising new bispecific for the treatment of patients with solid tumors expressing P-cadherin.