Medivation Inc, San Francisco, NanoString Technologies Inc, Seattle, and Astellas Pharma Inc, Tokyo, Japan, have joined together to pursue the translation of a novel gene expression signature algorithm from Medivation into a companion diagnostic assay using NanoString’s nCounter Dx analysis system.

Under the terms of the collaboration agreement, NanoString will be responsible for developing and validating the diagnostic test. If the parties thereafter determine to proceed, NanoString would also be responsible for seeking its regulatory approval and commercializing the diagnostic test. NanoString is eligible to receive up to $22 million for technology access, near-term milestones, and development funding, in addition to other potential undisclosed downstream payments.

Under the agreement, NanoString will modify its PAM50-based Prosigna breast cancer assay for potential use as a companion diagnostic for enzalutamide treatment of triple-negative breast cancer. The Prosigna assay provides a risk category and numerical score for assessment of the risk of distant recurrence of disease at 10 years in postmenopausal women with node-negative (Stage I or II) or node-positive (Stage II), hormone receptor-positive breast cancer. It measures gene expression levels of RNA extracted from formalin-fixed, paraffin-embedded breast tumor tissue previously diagnosed as invasive breast carcinoma.

The modified test will be based upon data from a Phase 2 trial conducted by Medivation and Astellas that evaluated enzalutamide in patients with triple-negative breast cancer.

“We are excited about the partnership with NanoString, given [its] expertise in diagnostic development and that the Prosigna assay has regulatory clearance in the US and European Union,” says Amy Peterson, MD, vice president for clinical development at Medivation. “Triple-negative breast cancer has no recognized target, and standard therapy is therefore cytotoxic chemotherapy. This diagnostic has the potential to identify patients with triple-negative breast cancer appropriate for treatment with enzalutamide. We look forward to generating additional clinical data that validates this potential in a severely underserved patient population.”

Brad Gray, Nanostring Technologies.

Brad Gray, Nanostring Technologies.

“We’re excited to work with Medivation and Astellas to translate their discoveries and Phase 2 findings into a potential label expansion for enzalutamide with a companion diagnostic,” says Brad Gray, president and CEO of NanoString. “We’re also pleased to have the opportunity to leverage our PAM50-based Prosigna breast cancer franchise, potentially expanding its role in informing breast cancer treatment decisions and enhancing the description of the intrinsic biology of breast cancer to aid in therapeutic treatment decisions.”

Xtandi (enzalutamide) capsules are currently approved for the treatment of metastatic castration-resistant prostate cancer. The medicine is not approved for use in women and is contraindicated in women who may become pregnant. Enzalutamide is not approved for women with advanced triple-negative breast cancer.

For more information, visit Medivation and NanoString Technologies.