A highly anticipated drug trial is in its final stages as its 350 participants receive their single dose to treat chronic low back pain. If successful, the experimental medication could be a breakthrough therapeutic for people with the common but debilitating condition.

This week, Australian biotechnology company Mesolab announced that its Phase 3 trial of rexlemestrocel-L for chronic low back pain (CLBP) now moves beyond the patient-treatment stage.

The trial was originally set to test the drug on 300 people, but due to demand from trial investigators to include more of their patients, the researchers expanded the pool of participants to 350.

Half received the active therapeutic via a single intra-discal injection, and the other half received a "sham" (control) shot. The goal is for those who received the active dose to see a marked, long-term reduction in pain. As such, the study's primary endpoint will assess how participants feel after 12 months.

While the main goal is key, secondary endpoints remain important. These include improved physical function and quality of life and discontinuation of pain medications for the condition.

“Completing treatment of 350 patients in our pivotal low back pain trial is a momentous milestone for the company as we now count down to the 12-month read-out for what we hope will be the basis of our first blockbuster product," Mesoblast's chief executive Silviu Itescu said in a statement.

Derived from human bone marrow, rexlemestrocel-L was designed to be an off-the-shelf, targeted injection to regenerate worn spinal discs. When the discs degenerate, vertebrae lose the spongy buffer between bones, resulting in pain.

This new stromal cell injection shifts the focus from traditional pain management to regenerative treatment. Rebuilding the buffers between joints is something we've covered for years, so it's not hard to see why this trial is being watched closely.

Those enrolled have experienced CLBP due to degenerative disc disease (DDD) for less than five years.

The condition is also the leading cause of back pain. Estimates suggest that around 20% of US adults show disc degeneration by age 65. A novel treatment that could rebuild, or at the very least bolster, degraded discs could be life-changing for millions of people.

Rexlemestrocel-L is also being developed for the treatment of heart failure, and has shown promising results so far. The drug currently has Regenerative Medicine Advanced Therapy (RMAT) designation from the US Food and Drug Administration (FDA) for CLBP treatment – which essentially means that, if this Phase 3 study meets its goals, it can be prioritized for approval.

We'll know if it's been successful by mid-2027, when all participants have had their 12-month evaluation.

Source: Mesoblast

Fact-checked by Mike McRae.