In a Hong Kong laboratory, researchers have cracked open a door that seemed permanently sealed: how to give patients with the most aggressive form of blood cancer a real second chance at survival. The discovery centers on QUIZOM, a two-drug combination developed by Professor Anskar Leung Yu-hung and his team at the University of Hong Kong's School of Clinical Medicine, which pauses the relentless growth of acute myeloid leukemia cells carrying FLT3 mutations—the genetic hallmark of roughly 30% of all AML cases and historically the sign of a death sentence.
For decades, FLT3 mutations have spelled poor prognosis. These mutations drive aggressive disease, cause frequent relapses, and rob patients of time. While existing FLT3 inhibitors could temporarily slow the cancer, they left the underlying risk of relapse untouched. Patients often had no choice but to race toward bone marrow transplants before their disease roared back. QUIZOM changes this equation.
The combination pairs Quizartinib, a targeted FLT3 inhibitor, with Omacetaxine Mepesuccinate, a protein synthesis inhibitor. Between November 2017 and September 2020, the team enrolled 40 patients—ages 23 to 81—whose leukemia had already resisted standard chemotherapy. The results were striking: 83% achieved composite complete remission, a rate that transforms the landscape for people facing this diagnosis. Thirteen patients who would likely have been considered too fragile or too ill to transplant became eligible for and successfully received allogeneic bone marrow transplants after QUIZOM treatment.
What makes QUIZOM genuinely innovative is not just the numbers, but the mechanism. Using single-cell gene expression profiling and multi-omics analysis, Leung's team revealed something unexpected: the combination works by a one-two punch. It disrupts protein metabolism in cancer cells, strangling their growth. Simultaneously, it awakens the patient's own T-cell immune system—a dual action that mirrors the synergy between chemotherapy and immunotherapy, but achieved through a wholly different route. This finding matters because it explains why the therapy works and opens pathways to improve it further.
Even more revealing was what the team discovered about resistance. In patients who did relapse, researchers identified populations of stem cell-like leukemic cells that survive by rewiring their metabolism through a protein called PLD1. These therapy-resistant cells essentially rebuild their armor by optimizing how they fold proteins, allowing them to evade treatment. But knowing the enemy's strategy is half the battle. When the researchers added a PLD1 inhibitor to the equation, they could suppress these resistant cells and restore treatment effectiveness—a finding the team has already moved to protect through a patent application.
The implications ripple outward from Hong Kong to leukemia wards worldwide. Professor Leung noted that QUIZOM "provides an effective and feasible treatment option for patients with FLT3-mutated AML who are unfit for conventional chemotherapy," and by improving remission rates, it extends the window for bone marrow transplants. With post-transplant maintenance and monitoring, the majority of patients can achieve sustained remission—a reality that would have seemed like science fiction just years ago. The findings, published in Nature Communications, represent not just a new drug combination, but a clearer map of how to outsmart one of blood cancer's most lethal variants.