Sutro Biopharma announced it is refocusing its 2014 immuno-oncology collaboration with Celgene on four programs that are advancing through preclinical development, including an antibody drug conjugate (ADC) program targeting B-Cell maturation antigen (BCMA) previously disclosed by Celgene. Sutro may also produce both GLP and cGMP material as the BCMA ADC program progresses.

These programs are additive to Sutro's proprietary pipeline which includes two 2018 investigational new drug (IND) candidates: STRO-001, an ADC targeting CD74, a cell surface protein associated with B-cell malignancies, including non-Hodgkin lymphoma and multiple myeloma; and STR0-002, an ADC which targets folate receptor alpha which is overexpressed in platinum-resistant ovarian cancer and other solid tumors.  Sutro is also advancing six ADC programs under the 2014 collaboration with Merck KGaA. 

In the 2014 agreement, Celgene had worldwide rights to the first collaboration program to reach IND status. Under the newly modified agreement, Celgene can acquire worldwide rights to a second collaboration program to reach IND status. Sutro will retain U.S. development and commercialization rights, and Celgene will retain ex-U.S. rights, to the next two programs to reach IND status from the four programs. Under the revised agreement, Sutro receives an undisclosed amount upon signing of the revised agreement and continues to be entitled to development and regulatory milestone payments and royalties.

To acquire worldwide rights to the second program to reach IND status, Celgene must make payments to Sutro in undisclosed amounts. Additionally, Sutro grants Celgene the right to purchase shares of Sutro stock in a future private financing and a right to purchase shares in a private placement contemporaneous with an initial public offering by Sutro. In conjunction with this revision, the option to acquire Sutro has been terminated along with restrictions from Sutro entering into additional collaborations or accessing the public financial markets.