Siamab Therapeutics will present new preclinical data on the safety and efficacy of its flagship ST1 antibody drug conjugates program in ovarian cancer animal models at the 2017 BIO International Convention in San Diego, June 19–22.
The presentation by Jeff Behrens, Siamab’s president and chief executive officer, will also cover the company’s overall research into tumor–associated carbohydrate antigens (TACAs), including the role of Sialyl-Tn (STn) and myeloid–derived suppressor cells — which express STn antigens — as promising cancer targets in ovarian and other cancer types, according to a press release.
Behrens will also discuss Siamab’s technology platform, new antibodies against STn, and anti–STn, anti–CD3 bispecific antibodies. The presentation is on June 19.
ST1 antibodies target STn. Like other TACAs, STn is a molecule found on the surface of ovarian cancer cells. Other tumors, including pancreatic, prostate, gastric, and colon cancer, also express STn, which is linked to cancer metastasis and poor prognosis.
The presence of STn on a tumor’s surface is linked to cancer stem–cell features and allows a tumor to suppress the immune system and be unresponsive to chemotherapy. But STn is virtually absent from normal tissue, making a treatment targeting it potentially safe.
Preclinical testing of ST1 is approaching its final stages, and Siamab expects ST1 to be tested in the first human clinical studies in 2019.
In September 2016, Siamab presented data showing that ST1 antibody drug conjugates were effective in fighting ovarian cancer cells resistant to chemotherapy.
Since then, researchers have tested the treatment in non-human primates and mouse models of ovarian and pancreatic cancer. The primate study mainly focused on the treatment’s safety.
The company presented data on its new antibodies at the American Association for Cancer Research (AACR) Annual Meeting 2017 in April. The data from animal experiments showed that ST1 effectively killed cancer cells expressing STn. Based on these data, researchers said they would explore targeting STn on myeloid–derived suppressor cells to kill these cells.
They also plan to examine if ST1 can boost responses triggered by checkpoint blockade antibodies.
“Our data show that manipulating STn biology in a variety of cancers offers the potential to generate significant immune re–engagement and anti–metastatic therapeutic benefits,” Behrens said in a previous press release.