Acute myeloid leukemia survivor shows no signs of cancer after clinical trial

Connor Johnson was eager to return to his job as a licensed electrician after recovering from COVID-19 last spring. But his enthusiasm was short-lived when, only three weeks after going back to work, he was diagnosed with acute myeloid leukemia (AML), a type of blood and bone marrow cancer.

“I knew something was wrong, because my smartwatch kept alerting me that my heart rate was elevated,” he recalls. “I’d rest a while, then I’d be fine. I thought I was just weak from COVID.”

But one day, Connor’s heart rate climbed to a dangerously high level, and stayed there.

His local doctor in Stillwater, Oklahoma at first thought he had long COVID – an assortment of lingering health problems that some people experience after recovering from the virus. She ordered bloodwork, which revealed something unexpected: Connor’s red blood cell count was alarming low.

His odds of having leukemia were 50-50, the doctor said.

“Suddenly, my world changed,” he recalls. “I hoped and prayed I had long COVID, not cancer.”

An acute myeloid leukemia diagnosis

A referral to a local oncologist brought the news Connor didn’t want to hear: Abnormal, immature white blood cells known as myeloblasts, or leukemic “blasts,” had invaded 96% of his bone marrow. A normal blast count is 5% or less. Connor had leukemia.

The blasts were rapidly multiplying, crowding out and competing for space with other healthy cells. The bone marrow could no longer do what it is supposed to do – make healthy blood cells. If the blasts spilled into Connor’s bloodstream, they would be carried to other parts of his body, such as the lymph nodes, liver, brain and spinal fluid.

“I’m sending you to Oklahoma City for treatment immediately,” the oncologist said. “Without it, you have weeks, maybe days, to live.”

On the road to MD Anderson

For the next two months, Connor remained in an Oklahoma City hospital where he received infusions of a variety of chemotherapy drugs. The goal was to lower his blast count to less than 5%. His count never fell below 70%.

Connor’s doctor leveled with him: “Your best hope is to participate in a clinical trial at MD Anderson. You’ll have access to potential treatments before they’re widely available.”

The doctor assured Connor that all clinical trial medications must pass rigorous Food and Drug Administration (FDA) standards before they can be tested on clinical trial participants.

“Count me in,” said Connor. “I’m 26 years old. I still have a lot of living to do.”

An ambulance delivered Connor to MD Anderson the next day.

Genetic testing, and a leukemia clinical trial

When Connor arrived, leukemia specialist Abhishek “Abhi” Maiti, M.D., was ready with a plan. He’d already reviewed Connor’s medical history. Because chemotherapy had failed, Maiti suspected that a genetic flaw might be driving the cancer.

Genetic testing confirmed Maiti’s theory. Connor had a rare chromosomal translocation – a phenomenon that occurs when pieces of gene-containing chromosomes break off and switch places with one another. Fragments from two of Connor’s chromosomes had swapped places, resulting in the genetic havoc that caused his leukemia.

This discovery meant Connor could enroll in an MD Anderson clinical trial led by leukemia specialist Ghayas Issa, M.D. The trial, named AUGMENT-101, was testing an experimental drug named SNDX-5613 in patients whose leukemia was driven either by a particular genetic mutation that causes 30% of all AML cases, or by a chromosomal translocation. Even though Connor' s particular translocation was not the main one being studied in the clinical trial, Maiti and Issa believed the drug might successfully target and kill his cancer.

They were right. Within three months of joining the clinical trial, the blasts in Connor’s bone marrow dropped from 70% to 7%.

“To finally get good news after months of hearing that nothing was working,” he says, “was absolutely exhilarating.”

Chemotherapy and a stem cell transplant

But Connor soon encountered another roadblock on the path to remission. Bone marrow biopsies showed that his blast count stayed at 7%, just shy of the normal 5% or below. Had the drug stopped working?

Maiti didn’t think so. The most likely explanation, he says, is that while the drug successfully targeted and cleared out the cells that carried Connor’s specific genetic defect, those cells may have produced clones that lacked the defect the drug was designed to target. Those clones may have accounted for the remaining 7% of blasts in Connor’s bone marrow.

Maiti prescribed one week of chemotherapy to wipe out the remaining leukemic cells, followed by a stem cell transplant that would replenish Connor’s bone marrow with healthy stem cells from a donor.

The stem cell transplant was a success. Connor’s bone marrow showed no visible signs of cancer, and he was pronounced “in remission.” With no cancer cells left to kill, he discontinued the clinical trial drug.

Short telomere syndrome

Still, the question remained: What caused Connor’s cancer? Leukemia specialist Courtney DiNardo, M.D., heads an MD Anderson program on hereditary leukemias. She suspected Connor might have a condition called short telomere syndrome.

“Telomeres are protective caps on the ends of our thread-like chromosomes that protect the DNA inside from damage and erosion,” DiNardo explains. “But if the telomeres are abnormally short, protection of our genetic information is lost. This leads to a significantly increased risk of cancer development, particularly blood cancers like AML.”

DiNardo’s hunch was right. A telomere-length test determined that Connor, indeed, had abnormally short telomeres.

“Five to 10% of people with blood cancers may have an underlying predisposition to cancer which includes the short  telomere syndromes,” DiNardo says.

Preventing future cancers

Today, Connor shows no signs of cancer. The clinical trial drug killed his leukemia cells, and the stem cell transplant provided him with new bone marrow to produce normal blood cells. But short telomere syndrome leaves him susceptible to developing future cancers.

He takes several preventive medications and will have head-to-toe checkups at MD Anderson for years to come.

“That’s just fine by me,” he says. “My cancer was very complicated, but the brilliant minds at MD Anderson figured it out. I wouldn’t be here today without them.”

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