Personal Cancer Vaccine Induces Tumor Shrinkage

Julie Bauman (Kris Hanning, Univ of Arizona Health Sciences)

11 Nov. 2020. Interim results from a clinical trial show some head and neck cancer patients receiving a personalized vaccine and immunotherapy report tumor shrinkage. Findings from the study of patients with solid tumor cancers at University of Arizona Cancer Center in Tucson were reported on Monday at a meeting of Society for Immunotherapy of Cancer, and published in Journal for Immunotherapy of Cancer.

The trial is testing the safety of a personalized cancer vaccine made by biotechnology company Moderna Inc. in Cambridge, Massachusetts. Moderna develops therapeutic proteins with a technology that synthesizes messenger RNA, a nucleic acid with the genetic code from DNA used by cells to produce the amino acids in proteins for cellular functions. Moderna engineers the coding region in the messenger RNA chemistry to provide instructions for cells to produce proteins with specific therapeutic properties.

Moderna’s mRNA-4157 is designed to provoke an immune response that attacks targets called neoantigens, unique sets of mutations expressed in cancer patients’ tumors. Thus mRNA-4157 is expected to act like a vaccine to induce immune responses specifically targeted to those unique mutations, addressing 20 specific regions on the neoantigen targets.

The clinical trial is mainly testing the safety of mRNA-4157 for 21 days, but also looking for evidence of anti-tumor activity over 50 days. The ongoing early-stage study is enrolling 90 individuals at six sites in the U.S. with a variety of solid-tumor cancers, including colorectal and head and neck cancer, that cannot be removed by surgery. Science & Enterprise reported on the start of the trial in November 2017.

Participants are assigned to receive mRNA-4157 at various dosage levels, to find the maximum tolerated dose, both alone and when combined with the immunotherapy drug pembrolizumab, marketed by drug maker Merck as Keytruda. In addition, researchers are tracking response rates to the drugs in the patients’ tumors, as well as overall and progression-free survival time. Merck is a co-sponsor of the trial.

Keytruda is in a class of drugs called checkpoint inhibitors that limit the actions of tumor cells to block the immune system. In this case, Keytruda stops receptor proteins on the surface of tumor cells from blocking the activation of T-cells in the immune system to attack tumors. Keytruda is already approved by Food and Drug Administration to treat a number of solid tumor and blood-related cancers.

The conference and journal paper reports on trial results of 10 patients with head and neck cancer, and 17 patients with colorectal cancer, enrolled at University of Arizona Cancer Center, receiving both mRNA-4157 and Keytruda. The results show five of the 10 head and neck cancer patients experienced at least some shrinkage of their cancer tumors, with two of those patients experiencing a complete response and no more detectable disease. Patients with colorectal cancer, however, are not yet responding to the treatments. Moderna says mRNA-4157 is well tolerated among the patients, with adverse effects so far considered low grade and reversible.

The clinical response rate of 50 percent for head and neck cancer patients, say the authors, compares favorably to published response rates of about 15 percent for Keytruda alone. Likewise, median progression-free survival time for head and neck cancer patients is 9.8 months, compared to published median survival time of 2 months for Keytruda alone.

“A phase I trial is about safety first and foremost,” says Julie Bauman, deputy director of the cancer center in a university statement, “and we now know this treatment is safe and tolerable.” Bauman, also first author of the conference and journal paper adds, “we also have a strong signal to point us to further study this in head and neck cancer.”

Moderna and the university say the trial is expanding enrollment to 40 head and neck cancer patients.

More from Science & Enterprise:

• Better Precision Medicine Outcomes Shown for Leukemia
• Precision Drug Trial Shows Solid Tumor Shrinkage
• Cancer Center, Biotech Partner on Off-the-Shelf T-Cells
• Precision Cancer Therapy Start-Up Gains $110M in Early Funds
• Advanced Solid Tumor Precision Meds. Trial Begins

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