Ambrx Biopharma Inc., recently released positive preliminary results from its current Phase 1 trial, APEX-01 (NCT04662580), which is examining ARX517, Ambrx's patented anti-PSMA ADC, in patients with prostate cancer.
Patients with advanced prostate cancer who have progressed on at least two prior FDA-approved treatments are enrolled in the Phase 1, first-in-human, open label dose escalation and dose expansion experiment known as APEX-01. In the US, APEX-01 is the only clinical trial that uses an ADC to treat PSMA. The trials revealed
• No grade ≥3 treatment-related adverse events (AEs) or drug-related serious adverse events (SAEs) have been reported in the 22 individuals who were evaluable for safety. ARX517 was well-tolerated otherwise with grade 1 or 2 treatment-related adverse events were observed. It is yet to reach the maximum tolerated dose (MTD) • Starting with the second to lowest dose of 0.64 mg/kg, PSA reductions of > 30% have been seen in Cohorts 2-5 • 3 (100%) patients in Cohort 6 (2.0 mg/kg dosage) had a PSA level reduction of at least 50%. PSA levels were reduced by more than 90% in 2 out of 3 patients. At the initial on-treatment scan, soft tissue measurable disease was found in 1 of the 3 patients, and showed a partial RECIST v1.1 response • In Cohort 7, three patients received doses with no DLTs
Daniel J. O’Connor, CEO of Ambrx, said, “While recent advances have considerably reduced the number of men who die from prostate cancer, it remains the second-most common form of death from cancer in the United States. Approximately 1 man in 41 will die of prostate cancer. Thus, there remains an urgent need for better treatments, in particular for men with advanced prostate cancer.” He further added, “We are very pleased to see a significant reduction of greater than 50% in PSA levels in the first three patients at 2.0 mg/kg, two of which went on to see a greater than 90% PSA level reduction, without any serious drug-related adverse events.”
(Source – Business Wire)
About Ambrx
Ambrx Inc., is a clinical-stage biopharmaceutical company. It develops precision biologics using an extended genetic code. Synthetic amino acids are incorporated into proteins using Ambrx technology, which is carried out entirely within a living cell. Precision Biologics, a novel therapeutic class with significant potential uses these synthesized amino acids.