The Food and Drug Administration on Thursday approved an innovative new treatment for patients with a form of lung cancer. It should be used only by patients who have exhausted all other options for treating small cell lung cancer and have a life expectancy of four to five months.
The drug tarlatamab, or Imdelltra, manufactured by the company Amgen, tripled the life expectancy of patients, giving them a median survival of 14 months after taking the drug. Forty percent of those given the drug responded.
After decades without real advances in treatments for small cell lung cancer, tarlatamab offers the first real hope, said Dr. Anish Thomas, a lung cancer specialist at the National Cancer Institute, who was not involved in the trial. .
“I feel like it’s a light after a long time,” he added.
Dr. Timothy Burns, a lung cancer specialist at the University of Pittsburgh, said the drug will be “practice-changing.”
(Dr. Burns was not an investigator on the study, but served on an Amgen advisory committee for a different drug.)
However, the drug has a side effect that can be serious: cytokine release syndrome. It is an overreaction of the immune system that can cause symptoms such as rash, tachycardia, and low blood pressure.
Each year, about 35,000 Americans are diagnosed with small cell lung cancer and face a grim prognosis. Usually, the cancer has spread beyond the lung by the time it is detected.
The standard treatment is traditional chemotherapy, which has not changed for decades, combined with immunotherapies that add about two months to patients’ life expectancy. But, almost inevitably, cancer resists treatment.
“Ninety-five percent of the time it will come back, often within months,” Dr. Burns said. And when he comes back, he added, patients find it harder to tolerate chemotherapy and the chemotherapy is even less effective.
Most patients live only eight to 13 months after their diagnosis, despite receiving chemotherapy and immunotherapy. The group of patients in the clinical trial had already received two or even three rounds of chemotherapy, which is why their life expectancy without the drug was so short.
The dismal prognosis of small cell lung cancer stands in stark contrast to the situation for the other, more common non-small cell lung cancer, which has been a triumph of the revolution in cancer treatments. New targeted therapies look for molecules that these cancers need to grow and contain their spread.
As a result, Dr. Thomas said, many patients with that form of lung cancer live so long that their disease becomes “almost like a chronic disease.”
There were several reasons why small cell lung cancer patients had been left behind.
One is the type of genetic mutation that cancer depends on to grow.
Dr. Jay Bradner, chief scientific officer at Amgen, explained that other cancers are caused by aberrant genes that are turned on. Treatment involves medications to turn off those genes.
But small cell lung cancer is driven by genes that are turned off, making them difficult to target, Dr. Bradner explained. Another reason is cancer’s ability to block immune system cells that try to destroy it.
Tarlatamab is an antibody created to overcome those obstacles. It has two arms, the first of which attaches to the growth-promoting molecule that sticks out like a flag from the surface of cancer cells. It serves as an identification tag for the drug, allowing tarlatamab to find cancer cells. The other arm grabs a T cell floating in the bloodstream. The T cell, a white blood cell, can kill cancers if it gets close to them.
The drug binds T cells and cancer cells, punching holes in the cancer or activating genes that cause it to self-destruct.
Patients in the clinical trial say they have gotten their lives back.
Martha Warren, 65, of Westerly, Rhode Island, discovered last year that she had small cell lung cancer. She joined Facebook groups and immediately saw the bad news: Most patients don’t live long. She decided her best hope was a clinical trial. After chemotherapy and immunotherapy, with her cancer growing rapidly, she was accepted into the Amgen study and began going to Yale to receive infusions of the drug.
Almost immediately his cancer began to shrink dramatically.
“I feel as normal as I did before I had cancer,” Ms. Warren said. “There is a lot of hope with this medication,” she added.
However, the Amgen study and approval involved patients like Ms. Warren, who had already gone through a couple of rounds of treatment. Could tarlatamab help sooner?
Amgen is starting such a study now, testing the drug immediately after initial chemotherapy.