Pin Therapeutics advances TPD clinical development, eyes solid tumor

Despite a challenging investment climate, South Korea-based Pin Therapeutics has drawn significant funding and is moving forward with clinical development of its targeted protein degrader (TPD) pipeline. The company is leveraging its proprietary molecule glue degrader (MGD) technology, which improves on limitations of first-generation PROTACs, to develop treatments for solid tumors -- a market significantly larger than that of hematologic cancers.

Pin Therapeutics has raised 68.3 billion won ($48.3 million) from major Korean venture capital firms including KB Investment and Korea Investment Partners. With these funds, the company has completed key research milestones and is accelerating drug development with an initial public offering (IPO) targeted for 2026. Korea Investment & Securities has been appointed as lead manager. Korea Biomedical Review spoke with CEO Jo Hyun-sun about the company's TPD strategy and its commercialization roadmap post-IPO.

PIN-5018 begins phase 1 targeting solid tumors, starting with colorectal cancer

Pin Therapeutics recently received FDA clearance for a phase 1 clinical trial of its lead candidate, PIN-5018. The company plans to submit a similar IND application to Korea’s Ministry of Food and Drug Safety (MFDS) this year to support global clinical development.

“We hope to begin dosing the first patient in August, with the trial enrolling around 40 patients with solid tumors,” Jo said. “We expect early clinical data by the second or third quarter of next year, which will form the basis for discussions on potential technology transfer with global pharmaceutical partners.”

PIN-5018 is a TPD-based candidate targeting casein kinase 1 alpha (CK1α), a serine/threonine kinase involved in critical cellular processes such as cell cycle regulation, DNA repair, and immune response. Given its association with key cancer survival pathways including p53 and Wnt signaling, CK1α was selected as a high-potential therapeutic target.

The initial indication under development is colorectal cancer, where current immunotherapies have shown limited efficacy and widely used drugs such as Avastin, Erbitux, and Braftovi suffer from low response rates. Pin Therapeutics aims to address this unmet need.

“Our preclinical data show that PIN-5018 performs better than existing first-line treatments,” Jo noted. “We're focusing on MSS-type colorectal cancer, which accounts for 75 percent of cases, and we aim to validate markers that support combination use with approved therapies to position PIN-5018 as a first-line option.”

The company also plans to expand indications to include salivary gland and prostate cancers, aiming to broaden the market potential of its pipeline. PIN-5018 is an orally administered, once-daily formulation, which the company sees as a key advantage over conventional injectable therapies.

“The drug’s oral formulation, with bioavailability between 80 and 120 percent, offers both convenience and strong therapeutic potential,” Jo said. “Its high solubility also contributes to lower production and quality control (CMC) costs, which will be critical during commercialization.”

Building a DAC payload platform for sustainable commercialization

Recognizing that Korean biotech companies often rely on licensing and collaborative research for revenue generation, Pin Therapeutics has also developed a degrader antibody conjugate (DAC) platform to support long-term R&D commercialization.

While antibody and linker technologies in ADCs are well-established, Jo pointed out that innovation in payloads remains limited.

“Global pharma is investing heavily in ADCs, and we believe payload innovation is the next frontier,” Jo said. “Current ADCs mostly use cell cycle-based payloads, which often result in hematologic toxicity.”

Jo cited Enhertu, a leading ADC, as an example: “ADC blockbuster drug Enhertu has a variety of hematologic side effects in its payload with mechanisms including microtubule inhibitors, topoisomerases, and DNA damage inducers, with grade 3 or higher neutropenia and lymphopenia as major adverse reactions.”

To address this, Pin Therapeutics developed a DAC platform focused on identifying TPD-based payloads with minimal hematologic toxicity.

“Our payloads offer unique organelle targeting, enabling protein degradation at multiple intracellular sites such as the cytosol, trans-Golgi network, and membrane proteins,” Jo explained. “We believe this opens the door to expanding the range of druggable targets and are conducting additional validation to further enhance the platform.”

He added, “We are already in co-development discussions with partners based on this DAC payload platform. Given the lower toxicity profile, we see strong potential for collaborations with domestic and global companies pursuing ADC pipelines.”

Jo founded Pin Therapeutics in 2018. He holds degrees in life sciences and chemistry from Seoul National University, where he also earned a PhD focused on obesity and diabetes research. He completed a postdoctoral fellowship at the University of California, San Francisco (UCSF), and later founded Embedbio in Silicon Valley.