A personalized cancer vaccine used in conjunction with an immunotherapy medication appears safe and potentially beneficial for patients with solid tumors involved in breast cancer, lung cancer, and urothelial cancers, according to an early-phase study presented June 22 at the American Association for Cancer Research (AACR) Virtual Meeting II.
The new study evaluated an investigational cancer vaccine known as R07198457, given in combination with the immunotherapy drug Tecentriq (atezolizumab).
The vaccine is made for each individual patient. First, blood and tumors are sequenced to look for substances called neoantigens, which are newly formed antigens that the immune system hasn’t recognized before. A vaccine is then made that will stimulate the immune system to mount a response to the cancer.
In the study, the vaccine was given by injection once a week for six weeks and then once a month for the seventh and eighth doses. Booster doses were also provided.
Among 108 patients who had at least one tumor assessment after starting treatment, nine responded to the therapy. One patient with colorectal cancer had a complete response (no signs of cancer), and 49 percent saw their disease stabilize. Blood tests of 63 patients showed immune system responses were induced by the vaccine in 73 percent of the patients.
While the rates of patients who saw their tumors shrink was small, the study is noteworthy because researchers saw an immune response in so many of the patients, says Juanita Lopez, MBBS, PhD, a consultant medical oncologist at the Royal Marsden NHS Foundation Trust and the Institute of Cancer Research in London.
“In the majority of patients, we often never see any immune cells within the tumors,” she says. “What I’m excited about is we’ve managed to show that in a majority of patients we were able to elicit a specific immune response. But this, by itself, may not be sufficient.”
The study is important because it may point to a way for more patients to benefit from immunotherapies. Immunotherapy drugs work well for some patients but fail in many others. The therapies have, so far, not been as successful in treating some types of solid tumors, such as breast cancer and colon cancer, according to numerous studies.
A personalized cancer vaccine is aimed at the unique molecular and genetic characteristics of a patient’s tumor, says Dr. Lopez. “Because many mutations are not shared between cancers, a personalized treatment approach that targets individual tumor neoantigens may be a viable immunotherapeutic strategy for numerous patients with cancer.”
It’s possible that the vaccine in combination with other treatments may have more impact on shrinking tumors, she says. Moreover, she notes, the patients in the study had already seen their cancers progress with other treatments. They had an average of three prior therapies, and almost 40 percent had prior immunotherapy.
“While the clinical response rate overall was low, this is likely because many of the patients treated in our study had very advanced disease, and were heavily pretreated,” she says. Lopez notes that this therapeutic strategy is being explored in patients with previously untreated melanoma and in patients with early-stage non-small-cell lung cancer who had already undergone surgery.
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In Other News From AASR …
Black Americans Better Represented in Taxpayer-Funded Clinical Trials
African Americans are often underrepresented in cancer clinical trials. That disparity is important because cancer clinical trials often provide the most promising treatments for challenging diseases. A new study shows, however, that Black Americans are better represented in taxpayer-funded clinical trials compared with trials conducted by pharmaceutical companies.
The study was conducted by the SWOG Cancer Research Network, which is a member of the National Clinical Trials Network (NCTN) a publicly funded cancer trial network. The researchers used U.S. Census Bureau data to study trial participation by race.
The study included data from 358 trials — 85 pharmaceutical industry trials and 273 SWOG trials (which are taxpayer funded). They found that the rate of Black enrollment in industry trials was 3 percent compared with 9 percent in SWOG trials.
"This study confirmed that Black cancer patients are severely underrepresented in pharmaceutical company sponsored trials, with fewer than one in four of the expected number enrolled," says the study's lead author, Joseph Unger, PhD, a SWOG biostatistician and health services researcher based at Fred Hutchinson Cancer Research Center in Seattle. "Black representation in industry trials was also far below that of NCTN trials, with only one Black patient enrolled for every three enrolled in NCTN trials."
“Trials are an important way — sometimes the only way — for cancer patients to receive potentially breakthrough drugs. Everyone can get cancer, so everyone should have the same access to investigational cancer treatments,” says Dr. Unger. “In addition, it's very important from a scientific standpoint to evaluate new treatments in patients who reflect the demographics of the general cancer population."
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Blood Test May Help Diagnose and Classify Brain Tumors
A blood test can not only accurately diagnose brain tumors but can classify different types of tumors, according to research presented at AACR that was published simultaneously on June 22 in Nature Medicine.
Brain tumors are typically diagnosed after surgery to obtain tissue samples. Using a blood test could be important to improve treatment and even prevent some patients from undergoing surgery, says one of the study's coauthors, Gelareh Zadeh, MD, PhD, the medical director of the Krembil Brain Institute and the head of surgical oncology at the Princess Margaret Cancer Centre in Toronto.
The test developed by Dr. Zadeh and her colleagues looks for circulating DNA from the tumor (known as ctDNA) in a blood sample. In their study, the researchers tracked the cancer origin and type by comparing patient tumor samples with the ctDNA results in 221 patients. They were able to match the DNA found in the blood with the DNA found in the tumor, confirming the ability to detect DNA using a blood sample.
Immunotherapy After Surgery Benefits Melanoma Patients
People with stage 3 melanoma who received immunotherapy medication after surgery had better odds of survival compared with people who did not receive immunotherapy after surgery, in a study presented by researchers from Loma Linda University in California.
The study looked at people diagnosed in 2015 and 2016 and whose records were in the National Cancer Database. The study showed that survival improved for patients who receive immunotherapy after surgery compared with those who did not receive immunotherapy — a median survival period of 32 months compared with 28 months.
The drug has already been approved by the U.S. Food and Drug Administration (FDA) for melanoma patients. But sometimes the use of medications in real-world settings differs from the outcomes seen in clinical trials, said the author of the study, Justin Moyers, MD, a fellow at Loma Linda University.
The study also showed that of the patients who met inclusion criteria to receive immunotherapy, only 28 percent did receive it. Patients who had Medicare as their primary health insurance were less likely to receive immunotherapy compared with patients who had private insurance. Moreover, the analysis showed a trend toward less use of immunotherapy among people with lower income and lower educational levels.
“These data highlight the negative impact of socioeconomic background in having access to proven therapy that benefits patients,” said Antoni Ribas, MD, PhD, the president and annual meeting program chair of the AACR. Dr. Ribas was not involved in the research.
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