Mersana and Takeda expand partnership to advance XMT-1522

Mersana Therapeutics and Takeda have entered a new strategic partnership granting Takeda rights to Mersana’s lead product candidate, XMT-1522, outside the United States and Canada.

The deal also expands an existing collaboration between the companies to provide Takeda with additional access to Mersana’s Fleximer antibody-drug conjugate (ADC) platform and grants Mersana an option at the end of Phase 1 to co-develop and co-commercialise one of these programmes in the United States. In addition, the companies will co-develop new payloads for use with ADCs.

XMT-1522 is an investigational, Fleximer-based ADC therapy that targets HER2-expressing tumours, including breast, gastric and non-small cell lung cancers. Preclinical data suggest that XMT-1522 may have anti-tumour activity in patients with HER2 low-expressing cancers as well as in patients with HER2 high-expressing cancers that do not respond to currently available HER2-targeting therapies. Mersana anticipates filing an Investigational New Drug application (IND) for XMT-1522 with the US. Food and Drug Administration (FDA) in mid-2016.

XMT-1522 has the potential to make ‘a dramatic difference’

Commenting on the partnership, Anna Protopapas, President and Chief Executive Officer, Mersana, said: “We believe XMT-1522 has the potential to make a dramatic difference for HER2 low-expressing patients who currently have limited treatment options, and are confident that our Fleximer-based technology can address significant patient needs not currently met by other ADC platform technologies. Takeda’s knowledge of oncology and commitment to ADCs as a key therapeutic approach make the company the best partner for us to progress our transformative platform and advance XMT-1522 into the clinic.”

Andrew Plump M.D., Ph.D., Chief Medical and Scientific Officer, Takeda, added: “This is our third collaboration with Mersana in less than two years. We see great potential for Mersana’s Fleximer technology, combined with our oncology expertise and resources, to extend the benefits of targeted therapy with ADCs to underserved cancer patient populations.”

Takeda and Mersana will co-develop XMT-1522, and Mersana will lead execution of the Phase 1 trial. Mersana will receive an upfront payment of $40 million and an additional payment of $20 million upon clearance of the IND for XMT-1522 by the FDA. Subject to the success of the XMT-1522 and ADC programmes, Mersana is eligible to receive milestone payments of more than $750 million combined, as well as royalties. Takeda will also invest up to $20 million in equity in future rounds of Mersana financing.