The patient had metastatic breast cancer that had progressed despite a severe round of chemotherapy. However, treatment with drugs that target cancer cells with laser-accurate accuracy has been surprisingly successful, slowing tumor growth and extending lifespan to a degree rarely seen in advanced cancers.
With new studies presented at the American Society of Clinical Oncology’s annual meeting Published in The New England Journal of Medicine on SundayCancer experts said, would change the way medicine is practiced.
“This is a new standard of care,” said Dr. Eric Winer, a breast cancer expert, director of the Yale Cancer Center, and head of ASCO, who was not involved in the study. “It affects a huge number of patients,” he added.
This study focused on HER2, a specific mutant protein that is a common villain in breast and other cancers. Drugs that block HER2 are surprisingly effective in treating breast cancer in which protein is almost completely present, transforming HER2-positive breast cancer from breast cancer with the worst prognosis to breast cancer that is very successful for patients.
However, only about 15% to 20% of breast cancer patients are HER2-positive, said Dr. Halle Moore, head of breast oncology at the Cleveland Clinic. Patients with low HER2 cells (a condition known as low HER2) did not help with these drugs. Only a small percentage of their cancer cells had HER2, but other mutations primarily promoted cancer growth. And it caused problems because the cancer cells avoided chemotherapy treatment.
A clinical trial sponsored by pharmaceutical company Daiichi Sankyo and AstraZeneca and led by Dr. Shanumodi of the Memorial Sloan-Kettering Cancer Center enrolled 557 patients with metastatic breast cancer with low HER2. Two-thirds took trastuzumab dercustecan, an experimental drug sold as Enhertu. The rest received standard chemotherapy.
In patients taking trastuzumab delkistecan, the tumor stopped growing for about 10 months compared to 5 months in patients receiving standard chemotherapy. Patients who received the experimental drug survived for 23.9 months, compared to 16.8 months for those who received standard chemotherapy.
“It’s unprecedented to improve patient survival by 6 months in chemotherapy trials for metastatic breast cancer,” said Dr. Moore, who enrolled some patients in the study. She usually says that her success in clinical trials is that she has a few weeks to live or has no survival benefit, except for improved quality of life.
The results were so impressive that the researchers received a standing ovation when presenting the data at the Oncology Conference in Chicago on Sunday.
Trastuzumab delkistecan has already been approved for patients with HER2-positive breast cancer, but few could expect it because other cancer treatments did not work for patients with low HER2.
The drug consists of antibodies that look for HER2 proteins on the cell surface. Antibodies are attached to chemotherapeutic drugs. When trastuzumab delxtecan finds a cell with HER2 on its surface, it enters the cell and the chemotherapeutic drug separates it from the antibody and kills the cell.
However, Dr. Modi adds that the “unique and clear point” of trastuzumab derkustecan is that the chemotherapeutic drug penetrates through the cell membrane. From there, it can move to nearby cancer cells and kill them.
Like all chemotherapy, trastuzumab delxtecan has side effects such as nausea, vomiting, blood disorders, especially lung damage, and three patients died in the study.
But Dr. Winner said, “If I’m a patient with metastatic breast cancer and I’m taking a drug that has side effects of chemotherapy, I prefer this drug.”
Doctors say they plan to try treatment for breast cancer patients with metastatic HER2 low cancer.
New developments in cancer research
Progress in the field. In recent years, advances in research have changed the way cancer is treated. The latest updates are:
Dr. Susan Domcheck, a breast cancer specialist at the Abramson Cancer Center at the University of Pennsylvania, said: She confirms that data from the new study is sufficient to convince insurers to approve the drug, even before the Food and Drug Administration approves trastuzumab derkustecan for patients with low HER2. I say. several weeks.
Dr. Winner emphasized that trastuzumab delkistecan is not a treatment for early-stage breast cancer. Still, it should be tested with patients in that group. But as with testing drugs in other cancers and extending that strategy beyond HER2, it’s probably the next step.
“This strategy is a true breakthrough,” he said, explaining that it would allow researchers to zoom in on molecular targets on tumor cells that were sparsely present.
“This isn’t just about this drug or breast cancer,” Dr. Winner said. “The real advantage is that powerful treatments can be applied directly to cancer cells.”
One patient in the current study, 55-year-old Mary Smureker of Medina, Ohio, said she felt she had received a temporary amnesty from a particular death.
She was diagnosed with breast cancer in 2010 and underwent surgery, chemotherapy and radiation therapy. Her cancer was in remission.
“I thought it was free and clear,” she said.
However, the cancer recurred in 2019. It had spread to her pelvis. She received chemotherapy, but this time there was little improvement.
Two years ago, she attended a trial on the Cleveland Clinic site. Her cancer hasn’t disappeared, but her tumor has stopped growing.
“I’m very happy to have another two years,” Smrekar said. “My daughter will get married next month. I didn’t think she could go to the wedding.”
