Celltrion and Onconic team up on ovarian cancer combo with dual-target PARP drug

Korean biotech Onconic Therapeutics is teaming up with biosimilar giant Celltrion to develop a new treatment option for relapsed ovarian cancer, combining Onconic’s dual-mechanism small molecule nesuparib with Vegzelma, Celltrion’s bevacizumab biosimilar already approved in major markets for colorectal and breast cancers.

The companies announced Wednesday that they have entered a joint R&D agreement to explore the combo in ovarian cancer maintenance therapy, where treatment options remain sparse and long-term efficacy is limited. 

Financial terms were not disclosed.

Nesuparib is a synthetic lethality agent that inhibits PARP, a DNA repair enzyme, and tankyrase, a modulator of the Wnt/β-catenin signaling pathway that drives tumor growth and metastasis in several solid tumors. 

The aim is to expand the reach of PARP inhibition into tumors that have proven resistant to earlier-generation drugs.

In a small phase 1 trial in high-grade serous ovarian cancer, Onconic said nesuparib monotherapy delivered an 80 percent objective response rate and 100 percent disease control, drawing early interest in its potential for post-platinum treatment. 

The company says the dual mechanism could allow broader tumor coverage than PARP inhibitors alone, particularly in Wnt-activated cancers.

While current PARP inhibitors are primarily used in BRCA-mutant patients, nesuparib is being positioned as a broader play. Onconic is also testing the drug in a phase 1b/2 pancreatic cancer trial and a Keytruda (pembrolizumab)-combo study in endometrial cancer. 

In 2021, the FDA and Korea’s Ministry of Food and Drug Safety designated it an orphan drug (ODD) for pancreatic cancer. Earlier this year, the FDA granted a second ODD for gastric and gastroesophageal junction cancer.

A spokesperson for Onconic called the Celltrion partnership “a meaningful boost” for nesuparib’s global development and said it could serve as a model for scaling Korean cancer drug innovation beyond domestic borders.

Celltrion, best known for biosimilars like Remsima (infliximab) and Truxima (rituximab), brings regulatory experience and global commercialization muscle. The company is positioning Vegzelma, its FDA- and EMA-approved bevacizumab biosimilar, as a flexible backbone for targeted oncology combos. The anti-VEGF agent inhibits angiogenesis and is already approved for colorectal, lung, and breast cancers.

Celltrion described the collaboration as a “significant initiative” that could help build momentum in its push beyond biosimilars and into novel drug development. A spokesperson said the alliance also reflects Celltrion’s strategy of reinforcing Korea’s broader biotech ecosystem, leveraging the synergy between therapeutic innovation and commercial infrastructure.

Onconic, a spinout of Jeil Pharmaceutical, previously developed Korea’s 37th approved a new drug, Jaqbo (zastaprazan), for gastroesophageal reflux. The nesuparib-bevacizumab combo represents its most precise shot yet at building a pipeline with global relevance. Clinical development timelines for the new combo have not yet been announced.