Antibody MQI‑201: Turning Cold Tumors Hot in Advanced Cancer

A new antibody called MQI‑201 is being developed as a potential treatment for advanced solid cancers that respond poorly to existing immunotherapies, such as certain types of prostate cancer, pancreatic cancer, and sarcomas. These tumors are often called “cold” because they have little immune cell infiltration and usually do not benefit from checkpoint inhibitors or other current immune‑targeted drugs. MQI‑201 aims to change that by targeting a specific ion channel on cancer cells and reshaping the local environment inside the tumor to make it more recognizable and attackable by the immune system.

The antibody works by binding to TRPV6, a calcium channel that is highly expressed on many tumor cells but largely absent in normal prostate tissue and most healthy organs. By blocking this channel, MQI‑201 disrupts calcium signaling that cancer cells use to survive, grow, and spread. In preclinical models, this leads to substantial tumor growth inhibition, with reductions in tumor size often above 70% and in some cases approaching 90%, even at relatively low doses. In pancreatic cancer models, the effect was stronger than standard chemotherapy with gemcitabine. The antibody also showed robust activity in hormone‑resistant prostate and fibrosarcoma models, which are both considered difficult‑to‑treat “cold” tumors.

Beyond direct tumor killing, MQI‑201 appears to change the tumor microenvironment in a way that makes it more “hot.” In animal studies, treatment increased the number of CD8+ T cells and natural killer cells inside the tumor, along with higher levels of granzyme B, a marker of cytotoxic activity. At the same time, the proportion of M2 macrophages (immune cells that normally support tumor growth and suppress immune responses) dropped by about half. This shift suggests the antibody not only stresses the cancer cells but also reprograms the surrounding immune landscape, creating conditions that could support more durable responses. The full effect depends on both the part of the antibody that binds the target and the Fc region, which interacts with immune effector cells; experiments with Fc‑engineered formats, including afucosylated versions, are now underway to further enhance this immune activation.

From a development standpoint, MQI‑201 is still in the preclinical and early regulatory phase, with no human trial data yet available. The profile so far is encouraging: it is a fully human IgG1 antibody with high affinity and specificity, favorable biophysical properties, and a safety signal in animal models that supports moving into clinical testing. Because it addresses a key limitation of current immunotherapy—the inability to effectively treat many “cold” tumors—MQI‑201 represents a conceptually novel approach.

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