Benzinga | Sep 1, 2020 09:05AM EDT

Aptevo Therapeutics Provides Update On Ongoing APVO436 Phase 1 Clinical Trial

Trial Advancing on Schedule and Second Patient Dosed in Cohort 7

No Evidence of Drug-Induced Anti-Drug Antibodies Observed to Date

SEATTLE, WA / ACCESSWIRE / September 1, 2020 / Aptevo Therapeutics Inc. (NASDAQ:APVO), a biotechnology company focused on developing novel immuno-oncology therapeutics based on its proprietary ADAPTIR(tm) bispecific technology platform, today provided an update on its ongoing APVO436 Phase 1/1b clinical trial. APVO436 is a novel anti-CD123 x anti-CD3 targeted investigational bispecific antibody therapy being evaluated for the treatment of acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS).

Dosing in cohorts 1 through 6 has been completed, and two patients have been dosed in cohort 7. A total of 30 patients have been enrolled and treated with APVO436 to date. No evidence of dose-limiting toxicities (DLTs) was observed in cohort 6. Also, importantly, no evidence of drug-induced anti-drug antibodies (ADA) has been observed in the 20 patient blood samples analyzed to date.

"The evolving data from our Phase 1 study of APVO436 continues to look promising," said Marvin L. White, President and Chief Executive Officer. "While still preliminary, we are encouraged by the early evidence of a clinical response in bone marrow observed with APVO436 for a patient in cohort 4. Notably, we believe this is a sub-optimal dose, so the potential clinical activity observed is especially intriguing. Although this patient did ultimately progress, we are encouraged by this preliminary evidence of activity," continued Mr. White.

"Importantly, we are now in a critical phase of the study, as pharmacokinetic modelling suggests that dosing in cohorts 5 through 8 is in a therapeutic range, which could result in potential clinical activity of the drug. We look forward to continuing the dose escalation and monitoring potential clinical responses as we advance through the upcoming dose cohorts," Mr. White concluded.

Aptevo believes that its differentiated ADAPTIR bispecific technology platform has the potential to offer a more convenient and cost-effective solution compared to other immunotherapies such as CAR-T therapies. While CAR-T therapies have proven effective in generating robust and durable treatment responses, they remain challenging and expensive to manufacture and administer to patients. In contrast, bispecific technologies may represent a simpler, more competitive 'off-the-shelf' solution in the rapidly advancing field of cancer immunotherapy.