Breakthrough Objective Response Rate (ORR) Achieved in Bactosertib-Imfinzi Combination Phase 2a Trial
Oral Presentation on Initial Results of Bactosertib Biomarker 'VRGS' Development Scheduled for the 13th
[Asia Economy Reporter Eunmo Koo] MedPacto, a biomarker-based innovative drug development company, announced on the 10th that the abstracts and posters related to its presentation at the Society for Immunotherapy of Cancer (SITC 2020) in the United States have been released.
MedPacto will present two items at SITC, held online from the 9th (local time): the interim results of the phase 1b/2a combination therapy of Vactosertib and Imfinzi, and clinical outcomes of biomarker-based cancer treatments.
The first presentation covers the interim results of the phase 2a combination therapy of Vactosertib and Imfinzi for second-line treatment of non-small cell lung cancer (NSCLC) patients. MedPacto reported that the objective response rate (ORR) for patients with PD-L1 expression of 25% or higher was 57.1% in the phase 2a combination therapy interim results. This is a remarkable improvement compared to the ORR of 19.8% for Imfinzi monotherapy. Considering that Imfinzi monotherapy has not been approved as a second-line treatment, the company expects these clinical results to increase the possibility of approval for a second-line treatment.
The median progression-free survival (mPFS) was 4.7 months. Compared to the PFS of 1.7 months with Imfinzi monotherapy, these results demonstrate a significant extension in patient survival. Notably, one patient achieved a complete response (CR) in this clinical trial.
Meanwhile, the ORR for patients with PD-L1 expression of 50% or higher was 50.0%. MedPacto stated, "Considering that Keytruda's ORR was 30.2% when approved as a second-line treatment for NSCLC, the interim results of this combination therapy show a considerably encouraging ORR compared to existing treatments."
They added, "These clinical results exceed the values commercialized as global standard therapies, reaffirming the synergy of combination therapy. It is expected that global pharmaceutical companies will be able to enter markets where monotherapy has not been approved."
Additionally, an abstract was presented on the early results of developing the biomarker VRGS (Vactosertib Response Gene Signature). Currently, MedPacto is developing the VRGS biomarker by analyzing microsatellite stable (MSS) colorectal cancer patients treated with a combination of Vactosertib and Keytruda.
Progressive colorectal cancer patients are broadly classified into microsatellite instability (MSI) and microsatellite stable (MSS) types. Among them, the MSS group, which accounts for 86%, has not received approval for Keytruda due to an ORR of 0%.
MedPacto analyzed tumor tissues from patients eligible for biomarker analysis and identified a specific gene signature that is highly expressed in responders compared to non-responders among combination therapy patients, developing this as the VRGS biomarker.
MedPacto used the clinical benefit rate (CBR), which reflects ORR and progression-free survival rate (PFS rate), as an indicator for patient selection in developing the VRGS biomarker. The overall CBR of analyzed patients was 33.3%, while the CBR for patients with high biomarker expression was confirmed to be 85.7%.
A MedPacto official said, "If the VRGS biomarker development succeeds, it will enable patient selection for treatment, significantly improving therapeutic effects and survival rates, and is expected to shorten the new drug development period."
Meanwhile, on the 13th (local time), the initial results of the Vactosertib biomarker ‘VRGS’ are scheduled to be disclosed.
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