Poster Presentation 51st International Society for the Study of the Lumbar Spine Annual Meeting 2025

A Clinical Overview of SI-6603 (Condoliase) for Radicular Leg Pain Associated With Lumbar Disc Herniation (#222)

Kee D Kim 1 , Douglas Beall 2 , Kenneth Candido 3 , Kevin E Macadaeg 4 , Anand Patel 5 , Pragya B Gupta 6 , Jose Rivera 7 , Alan E Miller 8 , Ferdinand J Formoso 9 , Kazuhiro Chiba 10 , Yukihiro Matsuyama 11 , Jun Watanabe 12 , Takayuki Seo 13 , Timothy R Deer 14
  1. Department of Neurological Surgery, University of California, Davis, Sacramento, CA, USA
  2. Clinical Radiology of Oklahoma, Edmond, OK, USA
  3. Chicago Anesthesia Pain Specialists, Chicago, IL, USA
  4. Indiana Spine Group, Carmel, IN, USA
  5. Conquest Research, Winter Park, FL, USA
  6. Otrimed Clinical Research, Edgewood, KY, USA
  7. Tampa Pain Relief Centers, Tampa, FL, USA
  8. Coastal Spine & Pain Center, Fernandina Beach, FL, USA
  9. Coastal Spine & Pain Center, Jacksonville, FL, USA
  10. National Defense Medical College, Tokorozawa, Saitama, Japan
  11. Department of Orthopedic Surgery, Hamamatsu University School of Medicine, Hamamatsu, Japan
  12. Seikagaku North American Corporation, Toronto, Ontario, Canada
  13. Clinical Development Department, Research & Development Division, Seikagaku Corporation, Tokyo, Japan
  14. The Spine and Nerve Center of the Virginias, Charleston, WV, USA

INTRODUCTION: Chemonucleolysis recently re-emerged as a nonsurgical treatment for lumbar disc herniation (LDH). SI-6603 (condoliase; 1.25 unit [U]), a glycosaminoglycan-degrading mucopolysaccharidase, is approved in Japan for LDH-associated radicular leg pain. Efficacy and safety data from two pivotal phase 3 studies alongside integrated safety data from phase 2 and 3 clinical trials in the United States (US) and Japan are summarized.

METHODS: In two studies in the US (NCT03607838) and Japan, participants with radicular leg pain and contained posterolateral LDH were randomized 1:1 to receive a single injection of condoliase (1.25 U) or control (US: sham injection; Japan: placebo injection). The primary endpoint was the change from baseline (CFB) to Week 13 in worst leg pain assessed by visual analogue scale. The integrated safety analysis used data from 6 completed phase 2/3 clinical trials (2 open-label) of condoliase (≥1.25 U).

RESULTS: The US (N=341) and Japanese studies (N=163) met the primary endpoint, with condoliase showing significantly greater CFB in worst leg pain at Week 13 vs sham (p=0.0263) and placebo (p=0.001), respectively. In the US trial, no treatment-related serious adverse events (SAEs) occurred; one SAE (back pain) was considered possibly related to condoliase in the Japanese trial. In the integrated safety analysis (condoliase ≥1.25 U; N=1679), 69.0% of participants reported treatment-emergent adverse events (TEAEs), 4.9% SAEs, and 0.8% TEAEs leading to discontinuation.

DISCUSSION: Condoliase was effective in improving radicular leg pain at Week 13 in adults with LDH and was well tolerated, demonstrating its therapeutic potential in the US.