CellBion, which is developing the first domestically made radiopharmaceutical (RPT) drug, will apply this month for conditional approval in Korea based on phase 2 results.
The industry sees little obstacle to approval because the criteria have already been met, but the market's focus is different.
Attention is centered on whether the objective response rate (ORR), a key metric to gauge competitiveness and commercial potential in the global market, will rebound from earlier readouts.
According to the biotech industry on the 9th, CellBion is set to receive the clinical study report (CSR) soon for the phase 2 trial of the prostate cancer RPT drug "Forcubotide." The company plans to apply for conditional marketing authorization with the Ministery of Food and Drug Safety within this month as soon as it secures the results.
Forcubotide was designated in 2023 as part of the Global Innovative product Fast Track (GIFT) program by the Ministery of Food and Drug Safety, making it eligible for marketing approval based on phase 2 results alone. While GIFT items receive an approval decision within 90 days, shorter than the standard 120-day review, the review period can be paused if the agency requests supplements, which could delay approval until the fourth quarter of next year.
RPT is a treatment modality that attaches a radioactive isotope to a targeted molecule that binds to cancer cells, attacking only the cancer cells, similar in principle to an antibody-drug conjugate (ADC). Compared with traditional chemotherapy, it offers shorter development timelines and fewer side effects.
The global prostate cancer RPT market is effectively monopolized by Switzerland's Novartis with "Pluvicto." Approved by the U.S. Food and Drug Administration (FDA) in 2022, Pluvicto surpassed 1 trillion won in annual sales within a year of launch.
Major global drugmakers such as the U.S. Eli Lilly and Company, Bristol Myers Squibb (BMS), and the U.K.'s AstraZeneca have also rushed to secure related technologies, but recent clinical results fell short of expectations, highlighting the clinical value of domestic corporations. In Korea, SK Biopharmaceuticals has also made RPT a new business and expanded investment.
If Forcubotide wins conditional approval now, it will become the first Korean-made RPT. In Korea, Pluvicto has been prescribed at 17 hospitals since its approval in May, but demand is high for new treatment options due to side effects such as dry mouth, decreased red blood cells, and anemia, as well as the out-of-pocket expense reaching 200 million won.
CellBion plans to target the domestic market first by setting the price at around 27 million won if it secures approval. It is aiming for 20 billion won in domestic sales, and, according to the outlook presented at the time of listing, it projected 20.9 billion won in 2026 and 40.1 billion won in 2027. If the plan proceeds as intended, prescriptions would be possible by 2027 at the latest.
The key is the ORR in the final phase 2 analysis. ORR is the proportion of patients whose tumor size significantly decreased and is a key indicator for evaluating the efficacy of anticancer therapies.
Forcubotide's ORR released in September was 35.9%, higher than Pluvicto's 29.8%, but about 10 percentage points lower than the interim readout in June (47.6%).
Immediately after the announcement, CellBion's stock fell more than 30% in a single day to the lower limit. The company said this was "a matter of timing of assessment and patient composition, not diminished efficacy."
CellBion maintains that there is no issue with domestic marketing authorization criteria. It said both ORR and safety outperformed Pluvicto and that it has data exceeding the domestic approval threshold of an ORR of 21.3%. The incidence of dry mouth was also lower at 13.2%, compared with Pluvicto's 35.3%.
A CellBion official said, "There can be numerical fluctuations depending on the difference in the number of subjects between the interim and final analyses," and added, "Even with the indicators released in September, we proved efficacy and statistical significance, and the results are better than Pluvicto's phase 2 in Japan."
Market attention remains on whether the final ORR will rebound. This is a core metric to gauge not only domestic approval, but also whether the drug can secure competitiveness on par with global rivals and future marketability.
CellBion is pursuing not only Forcubotide monotherapy but also a combination strategy with an immunotherapy. The company is preparing a phase 1 trial of a combination with the U.S. Merck (MSD) drug "Keytruda," with first dosing planned for early next year. It said that, depending on the initial results, talks with MSD on a technology transfer are also possible.