Hanmi Explores Oral EP300 Degrader Strategy for Solid Tumors

According to a recent LinkedIn post from BioSpectator Inc, Hanmi Pharmaceutical is pursuing an oral EP300-targeting targeted protein degrader (TPD) positioned for solid tumor indications. The post notes that most historical EP300/CBP drug development has focused on hematologic malignancies based on the tumor-promoting role of histone acetyltransferase activity.

The company’s LinkedIn post highlights that Hanmi is observing early in vivo efficacy and has not yet seen thrombocytopenia, a key limitation reported with EP300/CBP dual inhibitors. The post cites a presentation at AACR 2026 in which a Hanmi researcher emphasized oral bioavailability, attributed to structural differences, as a core differentiator versus competitors.

As shared in the LinkedIn post, Hanmi is using machine learning tools to identify suitable solid-tumor indications for this EP300 degrader. The lead compound reportedly binds EP300 and cereblon (CRBN), and the program remains in the lead-optimization stage, indicating it is still at a relatively early preclinical phase.

For investors, the update suggests that Hanmi is positioning itself within the emerging TPD oncology segment, where differentiated safety and oral administration could support competitive advantage if confirmed in later studies. However, with the asset in early development and no clinical data disclosed, the timing, probability of success, and eventual commercial impact remain highly uncertain.

The focus on solid tumors could broaden the addressable market beyond the hematologic niche historically associated with EP300/CBP modulation, potentially increasing long-term revenue optionality if the program progresses. At the same time, the lack of observed thrombocytopenia in early testing, while encouraging, will need validation in larger and ultimately human studies before any meaningful de-risking of the program can be inferred.