3 December 2020 - - US-based oncology-focused biotechnology company Exelixis, Inc. (NASDAQ: EXEL) has exercised its exclusive option for US-based biopharmaceutical company Iconic Therapeutics, Inc's lead oncology antibody-drug conjugate program under the companies' May 2019 agreement, according to the two principals and Canada-based biopharmaceutical company Zymeworks Inc. (NYSE: ZYME).

As a result, Exelixis now has responsibility for the future clinical development, commercialisation, and manufacturing of the Tissue Factor -targeting ADC now known as XB002 (formerly ICON-2).

In May, 2019, Iconic Therapeutics entered into a licensing agreement with Zymeworks that granted to Iconic non-exclusive rights to Zymeworks' proprietary ZymeLink antibody-drug conjugate platform.

A rationally designed next-generation ADC, XB002 comprises a Tissue Factor-targeting antibody with Zymeworks' proprietary ZymeLink linker-payload, creating the potential for an improved therapeutic index and favourable safety profile as compared to earlier-generation, TF-targeting ADCs.

Exelixis plans to file an Investigational New Drug application with the US Food and Drug Administration for XB002 in the near-term and, pending the FDA's acceptance of the IND, initiate a phase 1 clinical trial of XB002 in early 2021.

Under the terms of the May 2019 agreement between Exelixis and Iconic, Exelixis gained an exclusive option to license XB002 (then ICON-2) in exchange for an upfront payment to Iconic of USD 7.5m and a commitment of preclinical development funding.

In exercising its exclusive option, Exelixis has made an additional option exercise payment of USD 20m to Iconic.

Iconic is now also eligible for future development, regulatory and commercialization milestone payments, as well as royalties on potential sales. The ZymeLink ADC technology in XB002 was originally licensed to Iconic from Zymeworks.

Under the terms of their 2019 agreement, Zymeworks will receive a share of the USD 20m option fee and is eligible to receive a share of all future revenue received by Iconic, as well as tiered royalties on worldwide sales.

Pending the completion of Exelixis' planned IND and the FDA's acceptance of the filing, Exelixis intends to initiate a phase 1 dose escalation and expansion study of XB002 in subjects with inoperable locally advanced or metastatic solid tumors early in 2021.

Founded in 1994, Exelixis, Inc. (NASDAQ: EXEL) is a oncology-focused biotechnology company that strives to accelerate the discovery, development and commercialisation of new medicines for difficult-to-treat cancers.

Iconic Therapeutics, Inc. is a biopharmaceutical company focused on leveraging its deep insight into tissue factor biology and TF's role in inflammation, tumor growth, and angiogenesis to develop new therapeutics for serious diseases including retinal disease and cancer.

The company has developed a portfolio of proprietary molecules which bind to and antagonize TF expressed in several disease states.