Recombinant Interferon Alpha-2b as Primary Treatment for Ocular Surface Squamous Neoplasia

Reserve drug as first-line management: Topical interferon α-2b for vernal keratoconjunctivitis

PURPOSE

To elucidate the efficacy and safety profile of interferon α-2b in vernal keratoconjunctivitis (VKC).

METHODS

In this prospective interventional study, VKC patients fulfilling the inclusion and exclusion criteria were included and their signs and symptoms were scored based on the Clinical Scoring System. Patients were treated with topical interferon α-2b eye drop (1 MIU/ml) QID dosing for 6 weeks. Changes in symptoms and signs were evaluated at 2, 4, 8 weeks and 6 months after initiating treatment. A higher score meant severe disease, and a decline in score meant improvement in clinical signs and symptoms. Categorical variables were presented in number and percentage (%) and continuous variables as mean ± standard deviation (SD). Post-medication total subjective symptom score (TSSS) and total objective sign score (TOSS) were compared with baseline, and a P- value of <0.05 was considered significant. Possible ocular and systemic complications were evaluated.

RESULTS

The study included 40 patients (32 male and eight female) with a mean age of 8.05 ± 2.33 years. Mean baseline TSSS and TOSS were 6.71 ± 0.564 and 6.59 ± 0.262, respectively, which reduced to 2.71 ± 0.011 ( P = 0.040) and 2.96 ± 0.210 ( P = 0.032), respectively, at 4 weeks and further reduced to 0.42 ± 0.552 and 0.47 ± 0.434, respectively, at 8 weeks. After 6 months of stopping the drug, mean TSSS and TOSS did increase to 2.80 ± 0.820 ( P = 0.044) and 2.50 ± 0.520 ( P = 0.030), respectively, but was still statistically significant improvement compared to the baseline. Also, no ocular or systemic side effects were observed anytime during the study period.

CONCLUSION

Eye drop interferon α-2b (1 million IU/ml) is a safe and effective option as first-line monotherapy for VKC. No side effects and recurrence were observed for 6 months.

Construction of viral-based expression vectors for high-level production of human interferon alpha 2b in plants

Human interferon (hINF) alpha 2b is clinically important pharmaceutical product included in combinatory therapy against chronic hepatitis C and B and complex therapy against several cancer diseases. Here, we created the genetic constructions, based on genome elements of potato virus X (PVX), carrying the infα2b gene for transient expression in plant cells. The created plasmid vector constructions were tested through Agrobacterium-mediated transient gene expression method in two plant species-Nicotiana benthamiana and Ocimum basilicum (sweet basil). Production of recombinant hINF alpha 2b was more efficient in N. benthamiana than that in O. basilicum plants. The average yield of hINF alpha 2b produced in N. benthamiana plants was 0.56 mg/g of fresh leaf weight (FW) or 6% of the total soluble cell proteins (TSP). The maximal level reached up to 1.2 mg/g FW or 9% TSP. We estimated that about 0.67 mg of hINF can be obtained from one N. benthamiana plant. The yield of hINF alpha 2b obtained with the PVX-based expression cassette was about 80 times higher than the yield of hINF alpha 2b obtained with a simple expression cassette in which the infα2b gene was controlled by the 35S promoter of cauliflower mosaic virus. KEY POINTS: • PVX-based expression vectors provide efficient transient expression of infα2b gene • N. benthamiana plants can produce human interferon alpha 2b at high levels • The yield of the hINF α2b reached up to 1.2 mg/g of fresh leaf weight.

Long term study of topical interferon α-2b eye drops as primary treatment of ocular surface squamous neoplasia

PURPOSE

To assess the efficacy of topical interferon α-2β(IFN) eye drops as a primary treatment for ocular surface squamous neoplasia(OSSN) and evaluate factors that impact response to treatment and recurrence of OSSN.

METHOD

A retrospective study of 143 OSSN patients treated with topical IFN(1MIU/ml) from January 1998 to June 2021. The diagnosis was based on clinical examination and anterior segment optical coherence tomography, with histologic confirmation was present in 46.2% of patients. Data on demographic, tumor characteristics, treatment outcome, and side effects were collected. The primary outcomes were tumor resolution frequency and recurrence rate. Secondary outcomes were predictive factors for resolution and recurrence and side effects of treatment.

RESULT

Participants were mostly older (mean age, 69 years, SD 12.9, range 29-97), white(89%) males (74%). Complete tumor resolution was achieved in 80.4% of individuals with a mean time to resolution of 4.2 months (SD 2, range 0.5-12.3 months). On multivariable analysis, history of skin cancer (HR: 0.66, p = 0.05, 95%CI: 0.44-0.99) and immune system abnormalities (HR: 0.37, p = 0.009, 95%CI: 0.18-0.79) reduced the risk of tumor resolution, while a prior history of OSSN (HR: 3.49, p < 0.001, 95%CI: 1.76-6.93) increased the risk of resolution. With a mean follow-up time of 44.3 months (SD 50.9, 0-290 months), the recurrence rate was 0%, 2.3% and 3.1% at 1, 2, and 5 years respectively. Mild hyperemia(18.9%) and pain(10.6%) were the two most common side effects.

CONCLUSION

Topical IFN eye drops are a safe and effective primary treatment modality for OSSN with a reasonable side effect profile.

The Management of Ocular Surface Squamous Neoplasia (OSSN)

The rise of primary topical monotherapy with chemotherapeutic drugs and immunomodulatory agents represents an increasing recognition of the medical management of ocular surface squamous neoplasia (OSSN), which may replace surgery as the standard of care in the future. Currently, there is no consensus regarding the best way to manage OSSN with no existing guidelines to date. This paper seeks to evaluate evidence surrounding available treatment modalities and proposes an approach to management. The approach will guide ophthalmologists in selecting the most appropriate treatment regime based on patient and disease factors to minimize treatment related morbidity and improve OSSN control. Further work can be done to validate this algorithm and to develop formal guidelines to direct the management of OSSN.