Could one injection relieve back pain for a year?

For millions of Australians living with persistent back pain, treatment can become a frustrating cycle of medication, physiotherapy, injections and simply learning to live with discomfort.

Now an experimental treatment being put through its final major clinical trial could offer a very different approach: a single injection designed to provide long-lasting relief from chronic lower back pain.

Australian biotechnology company Mesoblast has completed treatment of 350 patients in a Phase 3 trial of its investigational therapy rexlemestrocel-L, bringing the closely watched study another step closer to its final results.

The outcome could be significant, especially for older Aussies.

About 4 million Australians, or 16 per cent of the population, were estimated to be living with back problems in 2022. The prevalence increases with age, affecting about 28 per cent of Australians aged 75 and over.

Back problems are also a major source of disability and ill health, accounting for 4.3 per cent of Australia’s total disease burden in 2023.

A different way of treating back pain

The experimental treatment is aimed specifically at people suffering chronic lower back pain associated with degenerative disc disease.

Rather than simply attempting to mask pain, rexlemestrocel-L is an investigational cell therapy being developed to target the damaged spinal disc itself.

The therapy uses cells derived from human bone marrow and is delivered through a single injection directly into the affected disc.

Degenerative disc disease occurs when the discs cushioning the vertebrae deteriorate. These discs normally act as shock absorbers between the bones of the spine, but changes to them can contribute to persistent pain and reduced mobility.

The hope is that rexlemestrocel-L can help address the inflammatory and degenerative processes associated with the damaged disc and provide sustained improvement in pain and function.

Importantly, however, researchers are still testing whether the treatment can deliver those benefits.

350 patients now being followed

The Phase 3 trial was initially expected to enrol 300 participants but was expanded to 350 following demand from investigators who wanted additional patients included.

Participants have experienced chronic lower back pain associated with degenerative disc disease for less than five years.

Half received a single injection of rexlemestrocel-L, while the other half underwent a sham procedure as the control group.

Researchers will now follow the patients, with the crucial assessment coming 12 months after treatment.

The primary measure is whether patients receiving rexlemestrocel-L experience a significant and sustained reduction in their back pain. Researchers will also examine physical function, quality of life and whether participants have been able to reduce or stop taking pain medication for their condition.

Mesoblast chief executive Silviu Itescu described completion of the treatment phase as a major milestone for the Australian company.

“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,” Itescu said.

Important outcomes

Anyone who has lived with chronic back pain knows its effects can extend well beyond an aching spine.

Pain can interfere with walking, exercise, sleep, work and everyday activities, while reduced mobility can have an increasing impact on independence as people grow older.

Australian Institute of Health and Welfare figures show chronic musculoskeletal conditions become considerably more common with age, affecting 69 per cent of Australians aged 75 and over.

Back problems alone cost Australia’s health system an estimated $3.4 billion in 2020–21, while there were about 177,000 hospitalisations principally attributed to back problems in 2021–22.

Chronic pain is similarly widespread. Almost one in five Australians aged 45 and over were estimated to be living with chronic pain, with those affected substantially more likely to report limitations in their everyday activities.

That helps explain the interest surrounding a treatment that could potentially provide meaningful relief following a single procedure.

But there’s still an important hurdle

Despite encouraging earlier research, rexlemestrocel-L remains an experimental therapy.

The Phase 3 trial is designed to provide much stronger evidence about whether the treatment works, how substantial any improvement is and whether those benefits last.

The drug has received Regenerative Medicine Advanced Therapy designation from the US Food and Drug Administration for chronic lower back pain. The designation is intended to accelerate development and regulatory review of promising regenerative therapies, but it does not mean the treatment has been approved or proven effective.

The decisive results are expected once all participants have completed their 12-month assessments, currently anticipated in 2027.

Until then, rexlemestrocel-L remains a promising treatment under investigation rather than an available alternative to existing back-pain therapies.

But with millions of Australians affected by back problems, there will be considerable interest in what those 350 patients reveal.

If this article was helpful, you might want to read our story on five habits for ageing well.