Periocular and Systemic Administration of Recombinant Human Proteoglycan 4 (rhPRG4) Ameliorates Ocular and Systemic Graft versus Host Disease

Abstract

Purpose : Evaluate the effect of intraperitoneal and subconjunctival injections of recombinant human PRG4 (rhPRG4) on systemic and ocular outcomes in a murine pre-clinical model of graft versus host disease (GVHD).

Methods : Minor-mismatch hematopoietic stem cell transplant was performed in 8-10 week-old C3H.SW mice (Jackson Labs), treated with 10.5 cGy total body irradiation and replenished with 5x10⁶ T cell-depleted bone marrow (BM) cells, with (BMT) or without (BMO) 2.3x10⁶ T cells from C57.BL/6 mice. BMT mice groups were: QOD intraperitoneal injections (i.p.) of 1.3 mg/mL rhPRG4 (n=5), QOD subconjunctival injections (sub-conj) of 0.45 mg/mL rhPRG4 (n=5), and QOD sub-conj injections of PBS as controls (n=3). Systemic assessments for survival and a composite score (total 14 pts, 0–2 pts/parameter) comprised by weight loss, activity, posture, fur texture, alopecia, skin integrity, and diarrhea were performed twice weekly. An ocular composite score (total 12 pts, 0-4 pts/parameter) of eyelid edema, meibomian gland (MG) plugging, and corneal fluorescein epitheliopathy was performed twice weekly. Flow cytometry and assessment of MG atrophy were performed at the end of the study. Animal care and standards were overseen by the Duke IACUC. Data is mean±SD.

Results : Systemic (i.p.) administration of rhPRG4 significantly reduced GVHD total systemic score (3.0±0.2 vs. 5.8±0.4, p=0.1) and weight loss (15.2±3.4% vs 25.5±5.3%, p=0.1). Significantly, i.p. administration also improved ocular GVHD scores including meibomian gland atrophy grades (0.4±0.1 vs. 1.2±0.3, p<0.05), corneal fluorescein staining (25±4 vs. 40±2, p<0.05) and eyelid edema (0.4±0.2 vs. 1.1±0.3, p<0.05) compared to BMT, and trended towards significance in improvements of corneal opacity (0.5±0.1 vs. 1.0±0.3, p=0.08). Moreover, rhPRG4 sub-conj periocular delivery, showed similar improvements in MG plugging, atrophy, staining, edema & opacity, with no statistical impact on systemic parameters (5.7±0.4 vs 5.8±0.4). In general, the rhPRG4-treated mice showed clinical scores roughly halfway between BMT and BMO groups.

Conclusions : Systemic administration of rhPRG4 significantly ameliorated systemic and ocular manifestations of GVHD. Importantly, periocular/local administration of rhPRG4 also improves ocular manifestations of GVHD opening the possibility to use it as an ocular therapy to prevent or treat GVHD.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.