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News — April 11, 2018—(BRONX, NY)—In a study published online today in Science Translational Medicine, researchers report that an experimental peptide (small protein) drug shows promise against the often-lethal cancer acute myeloid leukemia (AML) and describe how the drug works at the molecular level. The findings have led to a Phase I/II clinical trial for patients with advanced AML and advanced myelodysplastic syndrome (MDS), now underway at .

In preclinical studies, the experimental drug—ALRN-6924—tripled the median survival rate in an animal model of human AML (mice transplanted with human leukemia cells) from 50 to about 150 days.

"This is a very striking response," said study leader , professor of cell biology and of medicine and the Diane and Arthur B. Belfer Faculty Scholar in Cancer Research at Einstein and associate chair for translational research in oncology at Montefiore. "Most experimental drugs for leukemia achieve an increase in survival of only a few days in these preclinical models. Even more importantly, ALRN-6924 effectively cured about 40 percent of the treated mice, meaning they were disease free more than one year after treatment—essentially a lifetime for a mouse."

AML is caused by damage to the DNA of blood-forming stem cells in the bone marrow, resulting in abnormal white blood cells, red blood cells, or platelets. About 21,000 people in the U.S. were diagnosed with AML in 2017. Only 27 percent of people diagnosed with AML survive for five or more years, an outcome that has not significantly improved in the past half-century.

ALRN-6924 was developed by Aileron Therapeutics Inc. to target p53, a protein that suppresses tumors but is inactivated in many forms of cancer including AML. The drug was designed to inhibit two naturally occurring proteins, MDMX and MDM2, whose overexpression inactivates p53, allowing cancer cells to multiply unchecked. Aileron turned to Dr. Steidl, an AML expert, to test the drug’s effectiveness in preclinical models of AML and to find out more about its mechanism of action.

Dr. Steidl and his colleagues confirmed that ALRN-6924 targets both MDMX and MDM2, blocking their interaction with p53 in AML cells. That effect was seen in both more mature AML cells and the immature stem cells that produce them. "This is important," said Dr. Steidl, "because AML is driven by stem cells—and if you don’t target stem cells, the disease will come back very quickly."

Those same molecular changes were observed in blood cells of an AML patient who was given the drug on a compassionate-use basis. “This test was not designed to assess the efficacy of the drug in humans—that has to be done in a proper clinical trial,” said Dr. Steidl. "Our goal was to determine whether it can hit the desired target in human cells in a clinical setting, which it did in this individual."

ALRN-6924 is a so-called stapled alpha-helical peptide, a promising new class of drugs whose helical structure is stabilized using hydrocarbon"staples." The stapling prevents the peptides from being degraded by enzymes before reaching their intended target, a fate that often befalls conventional peptide drugs. ALRN-6924 is the first stapled peptide therapeutic to be tested in patients.

The Montefiore trial is testing ALRN-6924 on patients with relapsed (recurred) or refractory (resistant to treatment) AML or advanced myelodysplastic syndrome (a related condition). The trial is being led by , a coauthor on the paper and a professor of medicine and of developmental and molecular biology at Einstein and director of the Myelodysplastic Syndromes Program and of the division of hematologic malignancies at Montefiore Einstein Center for Cancer Care.

Dr. Steidl suspects that the drug may be applicable to other cancers driven by MDMX/MDM2 overexpression and p53 inactivation, including some cases of breast cancer, lung cancer and skin cancers and lymphomas.

The study is titled, "Dual Inhibition of MDMX and MDM2 as a Therapeutic Strategy in Leukemia." Einstein contributors also include Luis A. Carvajal, Ph.D., Daniela Ben Neriah, Adrien Senecal, Ph.D., Lumie Benard, Victor Thiruthuvanathan, Tatyana Yatsenko, Swathi-Rao Narayanagari, M.S., M.D.-Ph.D. student Justin C. Wheat, Tihomira I. Todorova, Ph.D. student Kelly M. Mitchell, Britta Will, Ph.D., Ioannis Mantzaris, M.D., Jesus D. Anampa, M.D., Robert H. Singer, Ph.D., Robert A. Coleman, Ph.D., and M.D.-Ph.D. student Charles Kenworthy. Other authors were Vincent Guerlavais, Ph.D., D. Allen Annis, Ph.D., and Manuel Aivado, M.D., Ph.D., all at Aileron Therapeutics Inc.

This work was supported in part by grants from Aileron Therapeutics Inc. and the National Institutes of Health (NIH) (, , and ). Information on the clinical trial can be found at (NCT02909972), a database of clinical studies provided by the NIH.

The authors declare the following competing interests: Drs. Steidl and Carvajal received research funding from Aileron Therapeutics Inc. Drs. Carvajal, Guerlavais, Annis and Aivado are current employees of Aileron.

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About Albert Einstein College of Medicine
, part of , is one of the nation’s premier centers for research, medical education and clinical investigation. During the 2017-2018 academic year, Einstein is home to 697 students, 181 . students, 108 students in the , and 265 . The College of Medicine has more than 1,900 full-time faculty members located on the main campus and at its . In 2017, Einstein received more than $174 million in awards from the National Institutes of Health (NIH). This includes the funding of major at Einstein in aging, intellectual development disorders, diabetes, cancer, clinical and translational research, liver disease, and AIDS. Other areas where the College of Medicine is concentrating its efforts include developmental brain research, neuroscience, cardiac disease, and initiatives to reduce and eliminate ethnic and racial health disparities. Its partnership with , the University Hospital and academic medical center for Einstein, advances clinical and translational research to accelerate the pace at which new discoveries become the treatments and therapies that benefit patients. Einstein runs one of the largest residency and fellowship training programs in the medical and dental professions in the United States through Montefiore and an affiliation network involving hospitals and medical centers in the Bronx, Brooklyn and on Long Island. For more information, please visit , read our , follow us on , like us on , and view us on .