ABL Bio "ABL503 Shows Multiple Complete and Partial Responses in Phase 1"

"Confirmed Case of Complete Remission in Solid Tumor Patient"

ABL Bio announced on the 4th that in the ongoing Phase 1 clinical trial of 'ABL503 (PD-L1x4-1BB)' conducted with iMab for patients with solid tumors, one complete response (CR) and three partial responses (PR) were confirmed.

ABL Bio CI. [Image provided by ABL Bio]

The newly disclosed complete response case was observed in ovarian cancer, while the partial response cases were confirmed in skin cancer, gastric cancer, and head and neck cancer.

ABL Bio is currently conducting the dose escalation and dose expansion parts of the ABL503 Phase 1 clinical trial at six institutions in the United States and three institutions in Korea. The company plans to secure safety data from monotherapy and determine the recommended phase 2 dose (RP2D) and the optimal target cancer types for Phase 2 clinical trials.

ABL503 is a bispecific antibody immuno-oncology agent targeting both PD-L1 and 4-1BB simultaneously, offering the advantage of treating various PD-(L)1-based cancers like the blockbuster immuno-oncology drug Keytruda. Additionally, it applies the 'Grabody-T' platform technology, which activates 4-1BB only in immune cells surrounding cancer cells expressing PD-L1. This minimizes the toxic side effects of 4-1BB and provides long-term anti-cancer effects to prevent recurrence. Furthermore, ABL Bio explained that it can overcome the limitations of short-term efficacy and toxicity issues pointed out in recently spotlighted CD3-based bispecific antibodies and antibody-drug conjugates (ADCs).

ABL Bio expects that ABL503 will gain a competitive edge over Genmab’s 'GEN1046' and Inhibrx’s 'INBRX-105', both PD-L1x4-1BB bispecific antibodies, through the interim results of the Phase 1 clinical trial to be announced early next year. GEN1046’s dosage was already limited to 100 mg in the Phase 1/2 dose expansion part, but ABL503 showed no toxicity even when administered at several times that dose. The company explained that this demonstrates superior safety compared to GEN1046.

An ABL Bio representative stated, "These cases, confirmed at such an early clinical stage, not only demonstrate strong anti-cancer effects in monotherapy but also open up possibilities for combination therapies with existing anti-cancer drugs. Although the anti-cancer drug market is fiercely competitive with numerous global pharmaceutical companies, we expect that these clinical results, including such cases, will be recognized for their commercial value in terms of licensing potential and late-stage combination therapy clinical trials."

Lee Sang-hoon, CEO of ABL Bio, said, "The anti-cancer drug market is highly competitive, so more time was simply needed to secure clinical results, and now the interim clinical results of 4-1BB-based pipelines are beginning to be disclosed. Since ABL Bio’s pipelines have clear differentiating factors from existing treatments, their value will also receive significant attention."