Spine BioPharma's Phase 3 Trial for Chronic Low Back Pain Treatment Misses Primary Endpoint

Spine BioPharma, a biotechnology company focusing on chronic low back pain treatments, has announced that its phase 3 trial for the TGF-β antagonist SB-01 has failed to meet its primary endpoint. The company attributes this outcome to an unexpectedly high response rate in the sham control group, particularly at certain study sites.

Trial Design and Results

The phase 3 trial enrolled 417 patients with chronic low back pain associated with degenerative disc disease. Participants were randomized to receive either a single injection of SB-01 into the affected intervertebral disc or a sham control treatment. The primary endpoint was assessed after six months, evaluating changes in patients' scores on both a disability index and pain scale.

Despite 67% of patients in the SB-01 arm meeting the primary endpoint response criteria, which the company describes as clinically meaningful and consistent with phase 2 findings, the trial failed to achieve statistical significance due to the high sham control response.

Analysis of Sham Response and Subset Data

Fran Magee, Spine BioPharma's chief technology officer, expressed surprise at the "very high sham control response" that prevented the study from reaching statistical significance. The company noted that this elevated response was observed only at certain trial sites.

In a subset analysis of 227 patients from sites with an anticipated sham response rate consistent with the phase 2 study, 70% of patients in the SB-01 arm met the primary endpoint response criteria compared to 59% in the control arm. This analysis suggests potential efficacy for SB-01 when controlling for unexpected sham responses.

Next Steps and Regulatory Strategy

Despite the setback, Spine BioPharma remains committed to pursuing the development of SB-01. The company plans to complete its data analysis and meet with the FDA to explore potential pathways for approval. This discussion will include presenting the phase 3 results alongside data from earlier phase 1 and 2 studies.

The outcome of this trial highlights the challenges faced in chronic pain research, particularly the impact of placebo effects and the importance of rigorous trial design in accounting for sham responses. As Spine BioPharma moves forward, the pharmaceutical industry will be watching closely to see how regulators respond to this complex dataset and whether alternative analyses or additional studies will be required to demonstrate the efficacy of SB-01 for chronic low back pain treatment.