Barriers to Treatment – Developing CD47 Antibody Therapy

“A new antibody therapy could dramatically improve outcomes for pediatric tumors.”

What This Project Does

Kathleen Sakamoto
  • Kathleen Sakamoto, MD, PhD
  • Shelagh Galligan Professor in the School of Medicine
    Stanford University

A research team at Stanford University led by Drs. Kathleen Sakamoto and Irv Weissman has received a $1.37 million grant from CureSearch titled “Development of CD47 Monoclonal Antibody Therapy for Pediatric Tumors.” Drs. Sakamoto and Weissman are developing a Phase I tumors using a new antibody treatment. Phase I clinical trials are the earliest stage of testing a new treatment. In a Phase I trial, researchers test a new treatment on a small group of patients to find out if a drug is safe, what its side effects are, and most importantly, whether it works to treat cancer.

In a healthy person, when the body makes abnormal cells or cells become old, the body’s scavenger cells, called macrophages, eliminate them in a process defined as programmed cell removal. When a person has cancer, the abnormal cells are not eliminated by the macrophages. Researchers under the leadership of Dr. Irv Weissman discovered that pediatric brain tumor, leukemia, bone tumor and neuroblastoma cells overproduce a cell surface protein known as CD47. The overproduction of CD47 on cancer cells tells macrophages “don’t eat me,” allowing the disease to progress. The members of Dr. Weissman’s team (Drs. Sam Cheshier, Jens Peter-Volkmer, and Sid Mitra) have successfully tested an antibody to block the “don’t eat me signal” in a variety of cancer cells and in animals. The CureSearch grant will support this research team in conducting a Phase I clinical trial at the Lucile Packard Children’s Hospital at Stanford University. Their study will test whether anti-CD47 monoclonal antibody will decrease the size of tumors in children, by blocking the CD47 “don’t eat me” signal and allowing macrophages to eliminate cancer cells.

Potential Impact on Children

There many types of childhood tumors, but brain tumors are the most common solid tumor in children. The clinical trial developed by Dr. Sakamato and Dr. Weissman will treat children with brain tumors using their novel antibody therapy. In early studies, Dr. Weissman has shown that the antibody treatment is more effective and better tolerated than standard chemotherapy. Because antibody therapy uses the body’s own immune system to kill cancer cells, it is easier to tolerate and has fewer side effects than toxic chemotherapies. If the trial is successful, this therapy could be widely used to treat childhood tumors.

Project Updates

1-Year Research Update – October 2014

Dr. Sakamoto and Dr. Weissman at Stanford University have been working on a novel treatment for malignant tumors in children, with a focus on pediatric brain tumors. The team recently completed preclinical experiments on Hu5F9-G4, an innovative treatment that harnesses the body’s own immune system to fight cancer. Their recent experiments used various different models of childhood cancers, including 5 different tumor types, to test this treatment. Their studies evaluated whether the treatment was effective, what side effects its had, and helped to determine an adequate dose for patients.

The results of this work are promising. Hu5F9-G4, the anti-CD47 treatment, reduced the size of tumors without significant side effects. Stanford has recently started an adult clinical trial for test the safety of Hu5F9-G4 in cancer patients. The results will be released at the end of the trial as per standard protocol which will help establish the doses which should be tested in children. This ensures that patients and the researcher administering the treatment remain unbiased. The team is poised to start enrolling patients in their clinical trial in 2015. They also hope to develop a parallel clinical trial for AML patients using the anti-CD47 antibody.

Barriers to Treatment – Developing CD47 Antibody Therapy was last modified: December 9th, 2014 by Geoff Duncan

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