A Proof-of-Concept Study on the Effects of STA363 on Low Back Pain in Patients with Degenerative Disc Disease

Randomized, placebo-controlled, double-blinded phase 2b study.

To compare the effects of STA363 (90 or 180 mg intradiscally) and placebo on low-back pain (LBP) in patients with lumbar degenerative disc disease (DDD).

Results from preclinical studies and a small phase 1b study have indicated that STA363 transforms the nucleus pulposus (NP) into connective tissue and thereby increases flexural rigidity. Such effects may improve LBP in DDD patients.

109 patients were equally randomized into the three treatment groups. After screening, test formulation was injected intradiscally, and patients were followed-up for up to 12 months. Primary endpoint was improvement in LBP as evaluated using the numerical rating scale.

The percentage of patients reporting ≥1 adverse event was 50, 55 and 63% in the placebo, STA363 90 mg and STA363 180 mg groups, respectively. The patients of all groups showed a marked reduction in LBP after treatment but there was no difference between placebo and STA363 at any follow-up time. Water content as reflected by decrease in T2 time (ms) was reduced in a dose-dependent manner (6 mo: placebo 1.5±9.0; STA363 90 mg 2.3±7.3; STA363 180 mg 5.7±9.2 (P=0.06 vs. placebo). The corresponding values for 12 months were 1.5±6.4, 4.0±7.3 and 5.3±13.4 (P=0.11).

While MRI results were consistent with fibrosis of the NP after treatment with STA363, these changes did not translate into any significant effects on LBP in DDD patients as compared with patients injected with placebo.