Johns Hopkins University

Biomed Valley Discoveries, Inc.

KiBem Kim

Bert Vogelstein

Kenneth W Kinzler

Shibin Zhou

Saurabh Saha

The presently disclosed subject matter provides methods and kits for treating solid tumors in a subject by using a combination of anti-CTLA-4 and/or anti-PD-1 antibodies with at least one member of the group consisting of a bacterium, bacterial product, and an immunoregulatory entity. In particular embodiments, the bacteria are toxin-depleted, anaerobic bacteria, such as-NT.

Use of bacteria, bacterial products, and other immunoregulatory entities in combination with anti-CTLA-4 and/or anti-PD-1 antibodies to treat solid tumor malignancies

Impressive responses have been observed in patients treated with checkpoint inhibitory anti-PD-1 or anti-CTLA-4 antibodies. However, immunotherapy against poorly immunogenic cancers remains a challenge. Treatment with both anti-PD-1 and anti-CTLA-4 antibodies were unable to eradicate large, modestly immunogenic CT26 tumors or metastatic 4T1 tumors. However, co-treatment with epigenetic modulating drugs and checkpoint inhibitors markedly improved treatment outcomes, curing more than 80% of them. Functional studies revealed that the primary targets of the epigenetic modulators were myeloid-derived suppressor cells (MDSCs). A PI3K-inhibitor that reduced circulating MDSCs also cured 80% of mice with metastatic 4T1 tumors when combined with immune checkpoint inhibitors. Thus, cancers resistant to immune checkpoint blockade can be cured by eliminating MDSCs.

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Lutherville, MD, United States of America

KiBem Kim