Persica Pharmaceuticals presents new analyses of microbiology assay sensitivity and intradiscal antibiotic exposure response in chronic Low Back Pain at ASPN 2026 Annual Conference

• Poster presentation builds on Phase 1b PP353 data published in The Lancet's eClinicalMedicine, reinforcing the rationale for a targeted, non-opioid approach to chronic Low Back Pain with Modic changes
  
  

London, UK, 24 July 2026 - Persica Pharmaceuticals Limited (Persica), a clinical-stage biotechnology company developing PP353, a targeted, non-opioid treatment for vertebrogenic Lumbar Back Pain (vLBP), last week presented a new analyses of the methodological rigor of published disc microbiology studies, and antibiotic exposure-response to the American Society of Pain and Neuroscience (ASPN) 2026 Annual Conference, in Miami Beach, Florida.

The analyses reviewed literature on bacterial infection and antibiotic trials in patients with chronic Low Back Pain and Modic changes. Key findings are:

• Many published microbiology studies used low-sensitivity methods designed for acute, high-burden pyogenic infection rather than the chronic, low-bacterial burden associated with Modic changes (changes seen on MRI scans that indicate vertebrogenic, chronic Low Back Pain).
• Very few studies reported the tissue sample size, quantitation or limits of detection needed to judge whether a negative result was meaningful. Without this information, a lack of bacterial growth cannot be interpreted as evidence of the absence of infection.
• Studies using high-sensitivity quantitative microbiology methods detect the low-bioburden disc infection associated with vertebrogenic chronic Lumbar Back Pain.
• Analyses also examined the relationship between estimated intradiscal antibiotic exposure and patient outcomes across existing trials. It found a clear ranked exposure-response relationship, with increasing intradiscal antibiotic exposure associated with reduction in pain intensity (slope -0.56 LBP NRS points per rank, p<0.001, R²=0.69) and disability (slope -1.51 RMDQ points per rank, p<0.001, R²=0.62) at 12 months. Studies using lower exposure oral antibiotic regimens may therefore not have adequately tested the underlying biological hypothesis.

Persica's lead candidate, PP353, is a targeted, intradiscal, non-opioid therapeutic approach for the treatment of patients with vLBP with 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 analgesic use, including opioids.

Lloyd Czaplewski, Chief Scientific Officer of Persica Pharmaceuticals, said:

“These analyses address the question of why studies of disc microbiology and studies of antibiotics to treat vLBP have reached such different conclusions. When we looked closely at assay sensitivity across the published literature, it is clear that many studies simply were not sensitive enough to detect the low bacterial burden associated with Modic changes, and a negative result under those conditions cannot be read as evidence of absence. At the same time, we found a clear, statistically significant relationship between the estimated level of antibiotic exposure achieved at the disc and the degree of pain and disability relief reported by patients.

“This finding provides a clear pharmacological rationale that explains why studies using lower doses of antibiotic observed less effect. The highest antibiotic disc exposure, achieved with intradiscal administration, provided the greatest improvements compared to baseline. These findings further support the development of PP353 as a non-opioid therapy, delivered at sufficient concentration to the site of disease, that can meaningfully reduce pain in this specific population of sufferers with vertebrogenic Lumbar Back Pain.”

This was Persica's second presentation at a major US pain meeting in 2026, following the oral presentation of PP353's Phase 1b data at the ASIPP Annual Meeting in March. Persica continues to engage with potential strategic partners and investors to support the design and execution of the registrational programme required to bring PP353 to patients.

The poster can be accessed on https://persicapharmaceuticals.com/wp-content/uploads/2026/07/118.Gilligan-v3.pdf.

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 targeted, non-opioid treatment for vertebrogenic Lumbar Back Pain (vLBP; chronic Low Back Pain (cLBP) associated with Modic type changes). Modic changes are a sign of inflammation, visible on Magnetic Resonance Imaging (MRI) scans at the vertebral endplate adjacent to a degenerate lumbar disc. PP353 is a patented, targeted intradiscal injection 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 injection in development for vLBP. It is a suspension 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. Two injections, given four days apart, are designed to deliver a short, defined course of treatment directly to the site of disease.

About vertebrogenic Lumbar Back Pain

Vertebrogenic Lumbar Back Pain (cLBP with Modic Type changes) is a common patient subgroup, readily identifiable on MRI, affecting approximately ten million patients in the US and EU. These patients typically suffer moderate to severe persistent pain and disability for more than 6 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.

ENDS

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