MEDIPOST said on the 13th that Cartistem, its stem cell therapy for knee osteoarthritis, met all efficacy endpoints in a phase 3 clinical trial in Japan.
Cartistem, which received Ministery of Food and Drug Safety approval in Korea in 2012 and has been used in clinical practice for more than 10 years, has now proven its efficacy in Japan as well. The company said it plans to speed up its Japanese marketing application within the year.
On this day, Lee Seung-jin, head of global business at MEDIPOST, held a press briefing at the Four Seasons Hotel in Jung-gu, Seoul, and said, "Experts said there should be no problem obtaining marketing authorization based on these results," adding, "With the clinical success, we have done 'half' the work. We will focus on the remaining steps, including responding to CMC (chemistry, manufacturing and controls) documentation and on-site inspections of production facilities."
◇Both knee pain and cartilage condition improved
The trial was conducted at 13 hospitals in Japan with 130 patients with knee osteoarthritis. Participants were divided into a Cartistem group (59) and a comparator group that received hyaluronic acid (HA) injections (61), and efficacy and safety were followed for 52 weeks, or one year. HA injections are currently the most widely used treatment for knee osteoarthritis in Japan.
Both of the two primary endpoints were met. The first was the change in the WOMAC (The Western Ontario and McMaster Universities Arthritis Index) score. It is an international standard questionnaire that quantifies the pain, joint stiffness, and functional limitations felt by arthritis patients; the lower the score, the better the condition.
The Cartistem group showed a statistically significant improvement compared with the HA group (p-value<0.0001). A p-value below 0.0001 means the probability that this result is due to simple chance is less than 0.01%.
The second was the improvement rate in the ICRS grade (International Cartilage Repair Society grade). This is an international standard that directly measures the degree of cartilage damage via arthroscopy or MRI, and the proportion of patients in the Cartistem group who improved by at least one grade was statistically significantly higher than in the HA group (p-value=0.0002). Simply put, it not only reflected patients feeling less pain, but it also objectively demonstrated, with measurable numbers, that the cartilage visibly regenerated.
All secondary endpoints, including VAS (self-reported pain intensity), IKDC (knee functional assessment index), and KOOS (overall knee status index), also showed statistically significant improvement. All serious adverse events (SAEs) that occurred during the trial were determined to be unrelated to the drug.
The company particularly emphasized that it included ICRS as a primary endpoint in this trial design. Previous osteoarthritis trials were largely based on patient questionnaires, and it said it is unusual to adopt ICRS, which directly measures cartilage regeneration, as a key endpoint. Lee said, "It will be useful in future interactions with regulators." More specific figures will be released next year through a paper currently in preparation.
◇Japan results will even reshape the U.S. strategy
Another point MEDIPOST is focusing on in these results is the link to the United States. The primary endpoints of the ongoing U.S. phase 3 trial are WOMAC and 100 mm VAS, and both showed significant efficacy in the Japanese trial.
Direct comparison is difficult, but obtaining the same outcomes under the same yardsticks could serve as a favorable basis to persuade the U.S. Food and Drug Administration (FDA). Lee noted, "The FDA's recent stance is shifting toward reducing clinical patient exposure and using real-world evidence (RWE)."
RWE refers to patient data collected in real clinical settings. MEDIPOST is currently conducting an RWE study of about 550 domestic Cartistem surgery patients. These patients are an average of 6.9 years post-surgery, and so far, the rate of conversion to total knee replacement is understood to be under 1%.
Detailed results are scheduled to be released at the end of the year, and the company plans to use this data in both Japanese and U.S. marketing authorization reviews and pricing negotiations. It said it is also discussing with the FDA ways to shorten certain clinical stages.
Before Japanese approval, it will also explore entry into two to three Southeast Asian countries. Using the Japanese trial results as a basis, the company aims to preemptively expand the market even before U.S. approval.
◇Japan launch in 2028… "Targeting the gap between HA injections and artificial joints"
MEDIPOST aims to file for Japanese marketing authorization by the end of the year and obtain approval next year. Considering the time for price negotiations, actual patient dosing is expected to be possible around 2028.
Distribution will be handled by Teikoku Pharma, which signed a licensing agreement in December last year. The deal size with Teikoku Pharma, considered a powerhouse in Japanese orthopedics, is about 450 billion won. MEDIPOST will produce the raw material in Korea and retain the rights through final release in Japan, while Teikoku Pharma will handle transportation, delivery, sales, and marketing.
Lee said, "We set a percentage share for MEDIPOST out of the supply price," emphasizing there is no issue with profitability. Upon approval, the company will also receive a milestone of about $10 million (about 13.5 billion won).
Currently in Japan, the practical options for treating knee osteoarthritis are essentially limited to HA injections and artificial joint surgery. HA injections have limits in pain relief, and many patients are reluctant to choose joint replacement due to Japan's distinctive aversion to surgery.
This is the niche market MEDIPOST is targeting. Lee said, "Cartistem does not insert a foreign object but promotes self-regeneration, so it could lower the psychological barrier."
There are challenges, however. Lee added, "When it launched in Korea, physicians did not recommend it to patients until they personally performed the procedure, so adoption took a very long time," and said, "Based on that experience, we have already started advance preparations with Teikoku Pharma targeting major hospitals."
The company aims to sell 40,000 vials annually in Japan within 10 years. Though that represents about a 2% market penetration, the company expects actual sales contribution to exceed that figure because local drug prices are two to four times higher than in Korea.
MEDIPOST posted consolidated revenue of 73.6 billion won and an operating loss of 67.9 billion won last year. Looking only at the domestic business, it recorded 76.8 billion won in revenue and 1.6 billion won in operating profit, but global clinical expenses in the United States and Japan increased by about 30% from the previous year, weighing on overall results. Analysts say the 2028 launch in Japan is, for now, the most realistic inflection point for a turnaround.