Patient With Leukemia Subtype Undergoes Stem Cell Transplant After Receiving Novel Monotherapy in Early-Phase Trial

Treatment with a novel monotherapy in a patient with relapsed/refractory acute myeloid leukemia was effective enough that a successful, as indicated by a significant reduction in bone marrow blasts, stem cell transplant was performed.

A patient with relapsed/refractory acute myeloid leukemia is currently experiencing a significant reduction in bone marrow blasts after undergoing a stem cell transplant following treatment with APVO436 in a phase 1b trial, according to the agent’s manufacturer, Aptevo Therapeutics.

In particular, bone marrow blasts precede mature, circulating blood cells like monocytes, neutrophils, erythrocytes and lymphocytes. Patients diagnosed with acute myeloid leukemia have at least 20% blasts in bone marrow or blood compared with 5% or less in patients without the disease.

“We are very pleased to report that a refractory secondary (acute myeloid leukemia) patient, after receiving APVO436 as monotherapy, experienced a significant reduction in bone marrow blasts, tolerated the treatment well, experienced clinical benefit and was therefore able to proceed to allogeneic transplant,” said Dr. Justin Watts, an associate professor of medicine and chief of the leukemia section at the University of Miami Sylvester Comprehensive Cancer Center, in the release. “Prior to trial entry, this patient had refractory disease after receiving multiple other lines of therapy and had a very poor prognosis. There were few therapeutic options left with which to fight the disease.”

Watts, who is a treating investigator in this phase 1b trial, and colleagues are assessing the benefits of APVO436 in up to 90 adults with acute myeloid leukemia, according to the release. Patients are assigned APVO436 with or without standard-of-care chemotherapies.

APVO436 was assessed in a 2021 trial in patients with both acute myeloid leukemia and myelodysplastic syndrome or myelodysplastic syndrome alone. In this previous study, APVO was safe and tolerable with manageable drug-related side effects, according to the release. In addition, 27.5% of patients in the study had promising clinical activity, which included three complete marrow responses in patients with myelodysplastic syndrome and two complete remissions in patients with acute myeloid leukemia.

“We are excited that a patient receiving monotherapy proceeded to transplant in the expansion trial, further demonstrating APVO436 clinical activity in (acute myeloid leukemia) and in support of our findings from the dose-escalation part of the trial reported last year,” said Dr. Dirk Huebner, senior medical advisor at Aptevo, in the release. “While our clinical evaluation of APVO436 is still in early stages, the safety profile, overall tolerability and clinical activity reported to date demonstrate the potential for APVO436 to have meaningful impact on the (acute myeloid leukemia) treatment paradigm.”

APVO436 was designed as a result of the overexpression of CD123, which is commonly seen in patients with many forms of leukemia, according to the release. The drug is meant to redirect the immune system to destroy leukemia cells that express the CD123 molecule on its surface.

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