Persica Pharmaceuticals publishes new analysis of assay sensitivity in disc microbiology studies, reinforcing the potential for PP353 in vertebrogenic Lumbar Back Pain

• Publication strengthens the scientific rationale for PP353 as a precisely targeted, non-opioid treatment for patients with vertebrogenic Lumbar Back Pain
  
  
• Manuscript submitted to the European Spine Journal and is available from their preprint server¹
  
  

London, UK, 11 September 2026 - Persica Pharmaceuticals Limited (“Persica”), a clinical-stage biotechnology company developing PP353, a targeted, non-opioid treatment for vertebrogenic Lumbar Back Pain (vLBP), today announced publication of a new analysis examining why previous disc microbiology studies have reported divergent findings on bacterial presence in spinal discs.

The publication, a methodological scoping review of published culture-based disc microbiology studies, shows significant variation in the sensitivity of methods used to detect bacteria in disc tissue. Differences in sensitivity were substantial. Studies using good microbiology practices consistently detected a low-bioburden infection in approximately 50% of all evaluated discs, with around 80% of infections caused by Cutibacterium acnes.

Cutibacterium acnes is well documented as causing low bioburden infection in a range of human diseases, for example, infection associated with joint replacement and bacterial endocarditis. Low-sensitivity methods might detect bacteria in only 11% of samples which would otherwise be identified as positive by high-sensitivity methods.   Low-sensitivity methods would also have quantified infection in less than 1% of samples examined in the published series of surgically obtained samples.

These findings from the published disc microbiology studies suggest that negative results may often reflect methodological limitations rather than absence of bacteria, helping explain perceived variation in the published dataset.

Persica's lead candidate, PP353, is a targeted, intradiscal, non-opioid therapeutic for patients with vLBP and Modic changes. The Company's Phase 1b trial, published in The Lancet's eClinicalMedicine in February 2026, showed that PP353 produced statistically significant and durable improvements in pain and disability over 12 months, along with reduced use of pain medication, including opioids.

Dr Lloyd Czaplewski, Chief Scientific Officer of Persica Pharmaceuticals, said: "Our analysis of 22 published studies shows that microbiology findings may depend critically on whether studies use methods sensitive enough to detect low-burden infection. We believe this adds further validation to our hypothesis that vertebrogenic Lumbar Back Pain and Modic changes observed in a significant group of patients is caused by low grade bacterial infection, strengthening the scientific rationale for PP353 as a precisely targeted, non-opioid treatment for these patients."

PP353 has been evaluated in an initial Phase 1b study. In this randomised, double-blind, sham-controlled Phase 1b (MODIC) study with 40 participants, PP353 demonstrated statistically significant and clinically meaningful durable improvements in pain and disability. More than 60% of treated patients achieved a pain reduction of 50% or more and decreased opioid usage after 12-months. The Phase 1b trial of PP353 was published in The Lancet eClinicalMedicine in February 2026.

Persica continues to engage with potential strategic partners and investors to support the execution of the registrational programme required to bring PP353 to patients.

ENDS

For further information:
ICR Healthcare - Tracy Cheung, Chris Welsh, Emily Johnson
persica@icrhealthcare.com

About Persica Pharmaceuticals

Persica Pharmaceuticals is a clinical-stage biotechnology company developing PP353, a potentially disease-modifying, non-opioid treatment for vertebrogenic Lumbar Back Pain (vLBP), a common type of chronic Low Back Pain (cLBP) associated with Modic type changes, which represents approximately 15% of cLBP patients. Modic changes are a sign of inflammation, visible on MRI at the vertebral endplate adjacent to a degenerate lumbar disc. PP353 is a patented, targeted intradiscal antibiotic delivered directly to the site of disease. It is designed as an alternative to long-term analgesic use, including opioids, and addresses an underlying cause of vLBP rather than just the symptoms. Persica is seeking a strategic partner or investor to progress PP353 into registrational Phase 3 trials.

About PP353

PP353 is a non-opioid intradiscal therapy in development for vLBP, a precisely defined condition affecting an estimated 10 million patients in the US and Europe. PP353 is uniquely formulated to deliver linezolid, a well characterised antibiotic, directly into the affected intervertebral disc. Two administrations of PP353, four days apart, provide the necessary antibiotic exposure within the disc in order to target the low bioburden bacterial infection and treat the underlying cause of vLBP.

PP353 is a novel formulation of linezolid powder in a thermosensitive vehicle that is liquid at room temperature but increases in viscosity when injected at the site of disease and warmed to body temperature, thereby preventing leakage into adjacent tissue. PP353 also contains a radio-opaque dye, allowing physicians to confirm correct placement using image guidance. 

About vertebrogenic Lumbar Back Pain

Vertebrogenic Lumbar Back Pain (chronic Low Back Pain with Modic Type changes) represents approximately 15% of all cLBP cases, affecting around 10 million patients in the US and EU. vLBP patients can be easily identified with MRI and typically suffer moderate to severe persistent pain and disability for more than six months, with limited relief from current standard of care, which includes physiotherapy and analgesia such as opioids. Other treatment options provide only limited short-term relief or involve invasive, irreversible nerve ablation, neither of which addresses the suspected underlying cause of the pathology.

¹ https://doi.org/10.21203/rs.3.rs-10748711/v1