SEATTLE, Wash. (Ivanhoe Newswire) — Mylotarg was heralded as the first targeted therapy in the U.S. in 2000. The FDA fast-tracked its approval for leukemia, but it was withdrawn when further testing showed increased mortality. After extensive genetic testing, Mylotarg is back on the market with new dosing and a specific target. More on the amazing turnaround that is saving lives.
When doctors told Michelle Yim-Karpan she had AML, a form of leukemia, she knew only 27 percent of patients live five years after diagnosis. Chemo treatments had her in and out of remission. Then, in 2014, she was able to get Mylotarg and has been disease-free ever since.
“It gives you a lot of hope. It gives you a lot of hope, because when you originally read the stats for AML, the stats are not very good,” Yim-Karpan told Ivanhoe.
Doctor Irwin Bernstein developed the antibody that delivered a highly toxic drug to the protein CD33, found on leukemia cells. He watched it get rapid FDA approval, then be taken off the market ten years later.
“We were convinced it really worked and it was probably a matter of time and it was a matter the economics and the companies; something that we can’t control. But fortunately, the data was good enough and it came back,” Irwin Bernstein, MD, of Fred Hutchinson Cancer Research Center and Professor at University of Washington explained.
Researchers like Soheil Meshinchi say the breakthrough involved picking more appropriate patients, like Michelle, whose tumors express the CD33 antigen. This means that the protein of interest is present in the tumor.
“If it’s not expressed, there’s no place for Mylotarg to bind to, thus no effect,” Soheil Meshinchi, MD, PhD, a Pediatric Oncologist at Fred Hutchinson Cancer Research Center said. (Read Full Interview)
Dr. Meshinchi says patients with higher CD33-positive AML are showing a 35 to 40 percent increase in survival.
Dr. Bernstein stated, “As for many other targeted drugs, we’re learning how to use this better and better and we’ll give it to the right people and anticipate more effective results.”
It’s allowing Michelle to look ahead with more confidence.
Mylotarg is approved for kids as young as two. It’s given along with standard chemotherapy drugs, usually after most leukemia cells have been cleared from the bloodstream.
Contributors to this news report include: Wendy Chioji, Field Producer; Rusty Reed, Videographer; Cyndy McGrath, Supervising Producer; Gabriella Battistiol, Assistant Producer; Roque Correa, Editor.
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TOPIC: MYLOTARG MAKES A COMEBACK FOR LEUKEMIA
REPORT: MB #4362
BACKGROUND: Acute myeloid leukemia (AML) is a fast-growing form of cancer of the blood and bone marrow. It is the most common type of acute leukemia and occurs when the bone marrow begins to make cells that have not yet completely matured. These normally develop into white blood cells, but in AML, these cells do not develop and are unable to ward off infections. In AML the bone marrow may also make abnormal red blood cells and platelets. The number of these abnormal cells increases rapidly, and the leukemia cells begin to crowd out the normal white and red blood cells as well as platelets that the body needs. There are eight different subtypes of AML.
TREATMENT OPTIONS: As in most cancer care, doctors work together to create a patient’s overall treatment plan that combines different types of treatments, or a multidisciplinary team. They may work with physicians, oncology nurses, social workers, pharmacists, dietitians, counselors etc. Most common treatment options depend on several factors, including the subtype, morphology, and cytogenetics of AML, as well as possible side effects, and the patient’s preferences and overall health. Intensive chemotherapy may be an option, including being given via intravenous tube, injection, pill/capsule, or a subcutaneous injection. Targeted therapy may also be used, as well as radiation therapy.
MYLOTARG: Mylotarg received accelerated approval in May 2000 as treatment for older patients with CD33-positive AML who had experienced a relapse. It was withdrawn from the market after trials failed to verify clinical benefit and demonstrated safety concerns, including a high number of early deaths. Now, it has been approved at a lower recommended dose and in combination with chemotherapy or on its own, depending on the patient. The new dosing regimen has shown benefits of the treatment that outweigh the risk.
MORE FROM DR. MESHINCHI: As we learned more about AML, we realized we might be able to deliver Mylotarg more effectively and to patients that would most benefit from this drug. The reason Mylotarg went away was because when they gave it to all patients regardless of CD33 expression, they saw really large toxicities. The reason it came back is that with additional studies, we noticed that there was effectiveness and learned about how we can more accurately target patients that are more likely to respond. We also learned that Mylotarg can be given at lower doses if it is combined with chemotherapy, thus decreasing side effects. The genetic test to see if CD33-positive AML patients are likely to respond to mylotarg is widely available and can show results in as little as four hours.
MORE FROM DR. BERNSTEIN: Mylotarg was the first approved antibody-drug conjugate, a form of targeted therapy, and was also an early form of treatment directed at cancer stem cells. After extensive additional clinical experience, Mylotarg is back on the market with new dosing.
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