Benzinga | Sep 28, 2021 08:09AM EDT

Aptevo Therapeutics Announces Publication Of Scientific Article In Peer-Reviewed Journal, Frontiers In Aging

Aptevo Therapeutics Inc. ("Aptevo") (NASDAQ:APVO), a clinical-stage biotechnology company focused on developing novel immuno-oncology therapeutics based on its proprietary ADAPTIR(tm) and ADAPTIR-FLEX(tm) platform technologies, today announced that the prestigious medical journal Frontiers in Aging, published a peer-reviewed article by Fatih Uckun, M.D., Ph.D., Chief Clinical Advisor at Aptevo who is coordinating the APVO436 clinical development program.

The article discusses the clinical impact potential of bispecific antibodies (BiAB) capable of redirecting host T-cell cytotoxicity to malignant clones as well as immunosuppressive myeloid-derived suppressor cells (MDSC) as a new class of anti-MDS drug candidates.

The article, "CD123-Directed Bispecific Antibodies for Targeting MDS Clones and Immunosuppressive Myeloid-Derived Suppressor Cells (MDSC) in High-Risk MDS Patients," has been published in Frontiers in Aging, section "Neoplastic Pathologies of Aging,"

and it is available online. To view the online publication, click here:

http://journal.frontiersin.org/article/10.3389/fragi.2021.757276/full?&utm_source=Email_to_authors_&utm_medium=Email&utm_content=T1_11.5e1_author&utm_campaign=Email_publication&field=&journalName=Frontiers_in_Aging&id=757276.

Citation Reference: Uckun FM and Watts J (2021) CD123-Directed Bispecific Antibodies for Targeting MDS Clones and Immunosuppressive Myeloid-Derived Suppressor Cells (MDSC) in High-Risk Adult MDS Patients. Front. Aging 2:757276. doi: 10.3389/fragi.2021.757276

Adult myelodysplastic syndrome (MDS), a heterogeneous group of clonal malignant hematologic disorders with an incidence rate of 4.5 per 100,000 persons per year, is characterized by an enhanced risk of transformation to acute myeloid leukemia (AML). There is no effective standard treatment that will prevent the leukemic transformation or result in sustained deep remissions in high-risk adult MDS patients.

The immunosuppressive bone marrow microenvironment (BMME) in adult MDS has been implicated in clonal evolution and disease progression. Expanded populations of myeloid-derived suppressor cells (MDSC) contribute to the immunosuppressive tumor microenvironment (TME) by inhibiting both memory and cytotoxic effector T-cell populations as well as natural killer (NK) cells, thereby promoting the immune evasion of MDS clones. The abundance of MDSC is associated with a higher risk of rapidly progressive disease and poor survival outcomes in adult MDS.

The expression of CD123 on MDSC as well as MDS clones provides a compelling rationale for targeting CD123 antigen on the malignant clones as well as the MDSC in the immunosuppressive BMME of adult MDS patients in an effort to delay disease progression and transformation to AML.

In a recently completed APTEVO study the results of which have been published in the respected oncology journal, Cancers, APVO436 induced bone marrow complete remissions in 3 of 6 evaluable high-risk MDS patients, providing the first proof of concept that APVO436 is a new candidate anti-MDS drug.

"There is an urgent need to identify effective strategies to prevent leukemic transformation and induce sustained deep remissions in adult high-risk myelodysplastic syndrome (MDS) patients," explained Fatih Uckun, M.D. Ph.D., the study's lead author. "T-cell engaging bispecific antibodies targeting the CD123 antigen like our lead drug candidate APVO436 may help delay disease progression in high-risk adult MDS and potentially reduce the risk of transformation to secondary AML."

"Emerging data that show APVO436 can sufficiently empower dysfunctional and exhausted T-cells to induce remissions in relapsed AML and MDS patients is the driving motivation behind our current clinical development plan for our lead clinical candidate," said Marvin White, CEO of Aptevo.