R&D Pipeline

Currently, our disclosed development pipeline is following.

Development Pipeline


Development code,
substance name 
Indication Developed in Stage Remarks
Lumbar disc herniation USA Phase III Exclusive Worldwide License
Agreement (excluding Japan)
for SI-6603 with Ferring
Pharmaceuticals (Switzerland)
Hyaluronic Acid-
Diclofenac Conjugates
Knee osteoarthritis USA Phase II  
Hyaluronic Acid-
Diclofenac Conjugates
Enthesopathy Japan Late-stage Phase II Definitive agreement related to
co-development and marketing
collaboration on SI-613 with
Ono Pharmaceutical
Modified Hyaluronate
Dry eye USA Phase III  
Chondroitin Sulfate-
Steroid Conjugates

Interstitial Cystitis and

Bladder Pain Syndrome

USA Phase I/II  

<Medical Devices> 

Development code,
substance name
Description Developed in Stage Remarks
Cross-linked Chondroitin Sulfate
Adhesion barrier Japan Pivotal study  

(As of September 30, 2021)



Outline of development theme

SI-6603 (treatment for lumbar disc herniation - developed in the U.S.)

SI-6603, which contains condoliase as its active pharmaceutical ingredient, is a treatment for lumbar disc herniation directly injected into the intervertebral disc. It has the special characteristic of not requiring general anesthesia and being less invasive to patients than surgical treatment. Since a single injection is expected to improve the symptoms of lumbar disc herniation by reducing intervertebral disc pressure and relieving pressure on the nerve root, SI-6603 can contribute to improving patients’ quality of life as a new treatment option.

In Japan, marketing approval was obtained from the Ministry of Health, Labour and Welfare in March 2018, and SI-6603 was launched on August 1, 2018 as HERNICORE 1.25 units for intradiscal injection.

In the U.S., although the expected pharmacological effect was demonstrated in a Phase III clinical study, the study did not meet its primary endpoint of improvement in leg pain. In response to this, we began an additional Phase III clinical study in February 2018, with a plan to complete follow-up observations in November 2022. However, the spread of COVID-19 infection has led to some medical institutions suspending clinical trials or halt hospital visits, which has caused delays in trial schedules. As of the end of March 2021, in addition to the operational status of trial facilities trending toward resuming their activities, promotion of subject enrollment has been successful, with enrollment making steady progress. We continue to seek to minimize delays, while also devising measures to reduce COVID-19 infection risk.

SI-613 (treatment for osteoarthritis - developed in the U.S.)
SI-613-ETP (treatment for enthesopathy - developed in Japan)

SI-613 is a formulation in which hyaluronic acid and diclofenac (an anti-inflammatory drug) are chemically bound using a drug binding technology proprietary to Seikagaku. By releasing diclofenac through hydrolysis, relief for osteoarthritis and enthesopathy can be expected.

In Japan, marketing approval was obtained for SI-613 for its efficacy and effect on osteoarthritis (knee joint and hip joint) on March 23, 2021, and it was launched as joint function improvement agent JOYCLU 30mg Intra-articular Injection in May of the same year. It is the first joint function improving agent in Japan indicated for osteoarthritis.

In the U.S., a Phase II clinical study targeting osteoarthritis has been completed, and we are considering a Phase III study while proceeding with selection of a sales partner.

In April 2020, Seikagaku entered into an agreement with Eisai Co., Ltd. concerning co-development of SI-613 and a marketing alliance in China, and in September 2020, an agreement was made with that same company for a marketing alliance in South Korea.

Data analysis of a late-stage Phase II clinical study in Japan of SI-613-ETP for the treatment of enthesopathy has been completed, and we are considering the next clinical study together with co-development and marketing partner Ono Pharmaceutical Co., Ltd.

SI-614 (treatment for dry eye - developed in the U.S.)

SI-614 is a substance produced by introducing a hydrophobic group into hyaluronic acid using Seikagaku’s own proprietary technology. Ocular instillation of SI-614 in patients is expected to improve symptoms of dry eye by stabilizing the tear film and promoting corneal epithelial wound healing. Through development of SI-614, the Company aims to provide a new option for the treatment of dry eye.

In the U.S., clinically beneficial effects were confirmed in Phase II/III clinical studies, in May 2022 the Company initiated a Phase III clinical study to evaluate efficacy and safety.

SI-722 (treatment for interstitial cystitis and bladder pain syndrome - developed in the U.S.)

SI-722 is a novel chemical compound in which a steroid is conjugated with chondroitin sulfate using Seikagaku's proprietary glycosaminoglycan modification technology and drug delivery systems. SI-722 injected into the bladder is thought to demonstrate an improvement effect in symptoms such as of frequent urination and bladder pain, by releasing a steroid with an anti-inflammatory effect.

While a Phase I/II clinical trial in the U.S. experienced delays in the trial schedule due to the spread of COVID-19, subject enrollment was completed in January 2021, and tolerability in the patients of this trial has been confirmed. Currently, we are exploring the next phase of trials based on the data we have obtained.

SI-449 (adhesion barrier - developed in Japan)

SI-449 is a powdered adhesion barrier whose main ingredient is cross-linked chondroitin sulfate developed using Seikagaku’s own glycosaminoglycan cross-linking technology. SI-449, which has the property of absorbing moisture and swelling, is expected to prevent or mitigate post-operative adhesion formation by forming a barrier between the surgical wound site and surrounding tissues after application. Development of this subject is progressing with an eye not only on domestic development, but also globally. 

A pivotal study to confirm effect, safety, and operability was initiated in May 2020, but the trial schedule has experienced delays due to the spread of COVID-19 infections. We are currently exploring measures to make up these delays, such as expanding trial facilities, and are working remotely with facilities that have restricted visits.