XMT-1536, a first-in-class ADC targeting the sodium-dependent phosphate transport protein NaPi2b, utilizes the Dolaflexin platform to deliver an average of 10-12 DolaLock payload molecules per antibody. The NaPi2b antigen is broadly expressed in non-small cell lung cancer (NSCLC) adenocarcinoma and ovarian cancer. XMT-1536 is in a Phase 1 proof-of-concept clinical trial in patients with ovarian cancer and NSCLC adenocarcinoma. For more information on our clinical trial, visit clinicaltrials.gov (NCT03319628).
Interim data from the ongoing XMT-1536 Phase 1 dose escalation study presented at ASCO in June 2019 showed encouraging clinical activity with confirmed responses and prolonged stable disease in heavily pretreated patients, without pre-selection for NaPi2b expression. The initial data showed that XMT-1536 was well-tolerated without the severe toxicities commonly seen with other ADCs such as neutropenia, ocular toxicities, or peripheral neuropathy.
We are continuing dose escalation studies in parallel with expansion studies for ovarian cancer and NSCLC adenocarcinoma. The expansion study is designed to demonstrate proof of concept and inform the path to approval in these indications with high unmet medical need.