Pamidronate is ineffective for inflammatory-like low back pain associated with Modic type 1 changes: A double-blind, randomised controlled trial.

OBJECTIVE

Modic type 1 (MC-1) vertebral endplate changes are associated with chronic low back pain (LBP) and often reflect an inflammatory process. Pamidronate has demonstrated analgesic effects in conditions involving bone marrow oedema. Our study aimed to evaluate the efficacy of intravenous pamidronate in patients with inflammatory-like LBP and MRI-confirmed MC-1 changes.

METHOD: In the PEPTIDE study, a single-centre, randomised, double blind, placebo-controlled trial, adults aged 18-60 years with chronic inflammatory-like LBP unresponsive or intolerant to NSAIDs, and MRI-confirmed MC-1 were randomised (1:1) to receive either two consecutive daily infusions of pamidronate (90 mg) or placebo. The primary endpoint was the change in LBP intensity (VAS pain) after 3 months. Secondary outcomes included functional disability, quality of life, inflammatory symptoms, and analgesic consumption.

RESULTS

Forty-four participants (mean age 49.4 ± 8.9 years; 57% women) were randomised. At 3 months, the between-group difference in VAS pain reduction was not significant (difference -6.4 mm; 95%CI: -22.0 to 9.3). At 6 weeks, there was a trend toward pain improvement with pamidronate (difference -14.15 mm; 95% CI -28.85 to 0.55). Significantly more patients in the pamidronate group achieved predefined pain improvement thresholds, although this effect was not maintained at 3 or 6 months. Adverse events occurred more frequently in the pamidronate group (54.6% vs 27.3%), primarily flu-like symptoms.

CONCLUSION

These findings are consistent with previous studies suggesting that bisphosphonates may provide a transient analgesic effect at 6 weeks but do not confer sustained clinical benefit at 3 or 6 months in MC-1-associated low back pain.