PENTOSAN POLYSULFATE AND VISION: Findings from an International Survey of Exposed Individuals

Age-Related Macular Degeneration Masquerade: A Review of Pentosan Polysulfate Maculopathy and Implications for Clinical Practice

ABSTRACT

Pentosan polysulfate (PPS) sodium (Elmiron) is the only Food and Drug Administration (FDA)-approved oral medication to treat interstitial cystitis, also known as bladder pain syndrome. A symptomatic pigmentary maculopathy associated with PPS was reported in 2018. Since then, recognition of this unique drug toxicity has increased rapidly. This potentially sight-threatening side effect prompted the FDA in June 2020 to update the label for PPS to warn about "retinal pigmentary changes." A challenging feature of pentosan maculopathy is its ability to mimic many other retinal conditions, including inherited retinal dystrophies such as pattern dystrophy, mitochondrially inherited diabetes and deafness, and Stargardt disease, and age-related macular degeneration. In this review, we discuss the history of PPS maculopathy and its implications for thousands of at-risk interstitial cystitis patients. We use published literature and an illustrative case from our institution to highlight the importance of diagnosing PPS maculopathy. We also compare PPS maculopathy to age-related macular degeneration, explain why differentiating between the 2 is clinically important, and highlight avenues for further research. Finally, we highlight the paucity of data on patients of color and why this lack of understanding may impact patient care.

Pentosan Polysulfate Sodium-Associated Pigmentary Retinopathy: Risk Factors and Fundus Findings

Purpose

To evaluate the risk factors and fundus findings of patients with potential PPS-associated retinopathy.

Patients and Methods

A retrospective chart review was performed of patients exposed to PPS who had a dilated fundus examination at a large retina-only practice from 2018–21. Multimodal images were evaluated by masked reviewers.

Results

A total of 148 patients were included, of whom 33 (22%) had PPS-associated retinopathy, and 115 (78%) did not. The mean age was 60.3 years old, and the mean follow-up was 11.8 months. The PPS-associated retinopathy group had higher mean cumulative doses of PPS (1600g±849 vs 864g±852, P < 0.0001, Mann–Whitney test) and longer duration of PPS use (13.6 years vs 7.48, P < 0.0001). There was no statistically significant difference based on a history of kidney or liver disease or the dosage per day for the weight, body mass index, body surface area, or lean body weight. Of the patients with PPS-associated retinopathy whose genetic results were available, 15 of 16 (93%) were heterozygous for variants of uncertain significance.

Conclusion

A longer duration of PPS use and higher cumulative dosage of PPS were associated with an increased risk of developing PPS-associated pigmentary retinopathy. The role of genetic mutations in patients exposed to PPS is still to be determined.

Pentosan polysulfate maculopathy

Pentosan polysulfate sodium (PPS), a semisynthetic sulfated polysaccharide, is the only FDA-approved oral therapy for interstitial cystitis. Recent studies have described a progressive, vision-threatening macular condition associated with long-term PPS use. We reviewed all publications concerning PPS maculopathy to consolidate known clinical features and to evaluate the strength of this association. Current literature supports a strong dose-dependent association between PPS exposure and a progressive maculopathy impacting the retinal pigment epithelium (RPE) and RPE-photoreceptor interface that may worsen even after drug cessation. Initial symptoms may include prolonged dark adaptation and difficulty reading with relative visual acuity preservation. Fundus examination often shows macular pigment clumps corresponding to lesions of focal RPE thickening. Fundus autofluorescence most clearly depicts the condition, with a distinctive pattern of hypo- and hyperautofluorescent spots in the posterior pole that sometimes extends to the retinal periphery. Many cases also show a characteristic peripapillary hypoautofluorescent halo. Near infrared reflectance may aid in early detection. RPE atrophy, cystoid macular edema, and macular neovascularization may also occur, potentially resulting in loss of central acuity. This newly described association implies significant public health risk. Ophthalmologists should screen PPS users with multimodal retinal imaging, and prescribers should minimize dose and duration of PPS use.