The only treatment currently available for patients with severe infantile osteopetrosis is hematopoietic cell transplantation (HCT). HCT-related toxicity and mortality risks typically preclude its use in non-infantile patients, and other therapies are needed for these patients who have significant disease-related morbidity. Interferon gamma-1b is currently approved by the U.S. Food and Drug Administration (FDA) for treatment of severe infantile osteopetrosis (autosomal recessive osteopetrosis [ARO]). However, little is known about the effects of interferon gamma-1b in non-infantile osteopetrosis. Thus, this pilot study aimed at testing the safety and tolerability of interferon gamma-1b in patients with non-infantile osteopetrosis and assessing the clinical effects. We performed a 12-month, open-label, multi-center pilot study involving patients >1 year-old diagnosed radiographically with osteopetrosis. Patients were initiated on interferon gamma-1b subcutaneously 15 μg/m2 three times weekly, to be titrated over 3 weeks to a goal of 100 μg/m2 three times weekly. The primary aim was safety and tolerability. The secondary aims were to assess changes in peripheral quantitative computed tomography (pQCT), dual-energy x-ray absorptiometry (DXA) bone mineral density (BMD) Z-scores, bone biomarkers, and quality-of-life (QOL) measures. Four of the five participants enrolled withdrew from the study between 3 and 9 months due to intolerability of interferon gamma-1b-related flu-like symptoms. The last participant completed the study with the addition of prednisone on days of interferon gamma-1b administration. DXA and pQCT outcomes were stable over 6-12 months, and there were no clear trends in bone biomarkers or QOL measures. No serious drug-related adverse events were reported during this study. Interferon gamma-1b was only tolerable in one of five participants with the addition of prednisone. The stabilization of BMD and other measures of bone health during this study suggest possible positive effects of interferon gamma-1b on osteopetrosis; however, additional data are needed before conclusions on treatment efficacy can be made. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Friedreich ataxia (FRDA) is an autosomal recessive disorder caused by deficiency of frataxin, an essential mitochondrial protein involved in iron sulfur cluster biogenesis, oxidative phosphorylation and other processes. FRDA most notably affects the heart, sensory neurons, spinal cord, cerebellum, and other brain regions, and manifests clinically as ataxia, sensory loss, dysarthria, spasticity, and hypertrophic cardiomyopathy. Therapeutic approaches in FRDA have consisted of two different approaches: (1) augmenting or restoring frataxin production and (2) modulating a variety of downstream processes related to mitochondrial dysfunction, including reactive oxygen species production, ferroptosis, or Nrf2 activation.

Chronic granulomatous disease (CGD) is a rare but serious primary immunodeficiency with varying prevalence and rates of X-linked and autosomal recessive disease worldwide. Functional defects in the phagocyte nicotinamide adenine dinucleotide phosphate oxidase complex predispose patients to a relatively narrow spectrum of bacterial and fungal infections that are sometimes fastidious and often difficult to identify. When evaluating and treating patients with CGD, it is important to consider their native country of birth, climate, and living situation, which may predispose them to types of infections that are atypical to your routine practice. In addition to recurrent and often severe infections, patients with CGD and X-linked female carriers are also susceptible to developing many non-infectious complications including tissue granuloma formation and autoimmunity. The DHR-123 oxidation assay is the gold standard for making the diagnosis and it along with genetic testing can help predict the severity and prognosis in patients with CGD. Disease management focuses on prophylaxis with antibacterial, antifungal, and immunomodulatory medications, prompt identification and treatment of acute infections, and prevention of secondary granulomatous complications. While hematopoietic stem-cell transplantation is the only widely available curative treatment for patients with CGD, recent advances in gene therapy may provide a safer, more direct alternative.

Interferons are signaling proteins that belong to the large class of cytokines and human interferons which are classified based on the type of receptor interactions: type I, II and III. IFNα2b belongs to the type I interferon class with a major therapeutic application for the treatment of hepatitis B and C infections. A recombinant form of IFNα2b expressed in E. coli, known as IntronA, has been approved by US Food and Drug Administration (FDA). IFN γ, also known as type II interferon, plays a significant role in the inhibition of viral replication. Actimmune® is a US Food and Drug Administration (FDA) approved version of IFN γ for the indication of reducing infections associated with chronic granulomatous disease and severe malignant osteopetrosis. In this study we have applied advanced analytical methods for the characterization of IFNα2b and IFN γ produced from Pichia pastoris. The multi-enzyme digestion approach has been developed to allow measurement of 100% sequence coverage and detailed analysis of post-translational variants and degradation products. In this manner, we identified the following variants in IFN α2b: N-terminal residual leader sequence, an amino acid substitution, oxidation of methionine residues and two sites of high mannose N-glycosylation. In the Pichia IFN γ produced material, our approach detected variants resulting from glycosylation, C-terminal proteolysis, oxidation of methionine residues and deamidation. In this manner, the analytical program was able to support rapid process development as well as identify product variants and degradation products in the resulting product.

In autosomal dominant osteopetrosis type 2 (ADO2) CLCN7 mutations cause impaired osteoclast function. Severe consequences include skeletal fragility despite high bone mass, osteomyelitis, osteonecrosis, bone marrow failure, and severe cranial nerve impingement. There is no effective medical treatment for ADO2. We recruited subjects with ADO2 into a 14-week, open-label, pilot clinical trial of interferon gamma-1b. Doses were titrated based on tolerability and if fasting serum C-telopeptide (CTX) was <25% above baseline at week 8, targeting doses of 100 µg/m2 three times a week. The primary outcomes were change from baseline in CTX and N-telopeptide/creatinine ratio (NTX/Cr) at week 14. Secondary outcomes included changes in urine calcium/creatinine ratio, bone formation markers and tolerability. Nine adults and three children were recruited. Severe manifestations of ADO2 included histories of fractures (100%), osteomyelitis (16.7%), vision loss (50%), and anemia (58.3%). Baseline CTX and NTX/Cr were generally low-normal. Procollagen type I N-terminal propeptide was elevated or in the upper-normal range in 11 of 12 (91.6%) subjects. Elevations of aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) were common. One subject withdrew due to rash. Five subjects achieved doses of 50 µg/m2 3 days a week, while six reached the full dose of 100 µg/m2 3 days a week. Only 3 of 11 (27.3%) completing subjects achieved the primary outcome of increasing CTX ≥25% above baseline at week 14. The mean ± SD change from baseline in CTX at week 14 was +2.2% ± 43.2%, p = 0.86). Likewise, there was no significant change in NTX/Cr (mean change -2.1%, p = 0.81). Interferon gamma-1b was poorly tolerated. Most subjects had adverse events, and the Mental Health and Mental Component Scales of the SF-36v2 health survey declined slightly (p < 0.05). Over 14 weeks, interferon gamma-1b failed to significantly increase bone turnover markers in ADO2 and was poorly tolerated. Consequently, interferon gamma-1b is unlikely to be effective for decreasing bone mass in ADO2. © 2019 American Society for Bone and Mineral Research.

Interferon gamma is a normal component of human milk. No data are available on the use of exogenous interferon gamma 1b during breastfeeding. However, the amounts of the similar drugs, interferon alfa and interferon beta-1a, excreted into milk are very low. Any interferon in breastmilk is probably destroyed in the infant's gastrointestinal tract and not absorbed, except perhaps in neonates. Holder pasteurization (62.5 degrees C for 30 minutes) decreases the concentration of endogenous interferon-gamma by an average about 10%.[1]

Ovarian cancer has no definitive second line therapeutic options, and largely recurs in the peritoneal cavity. Locoregional immune therapy using both interferons and monocytes can be used as a novel approach. Interferons have both cytostatic and cytotoxic properties, while monocytes stimulated with interferons have potent cytotoxic properties. Due to the highly immune suppressive properties of ovarian cancer, ex vivo stimulation of autologous patient monocytes with interferons and infusion of all three agents intraperitoneally (IP) can provide a strong pro-inflammatory environment at the site of disease to kill malignant cells.

A 3-year-old girl with the diagnosis of chronic granulomatous disease (CGD) was hospitalized for bronchopneumonia and congestive heart failure. Her medical history included methylprednisolone medication for autoimmune gastric outlet obstruction. Computed tomography revealed pneumonic infiltrations and pericardial thickening. A pulsed-wave Doppler recording revealed E/A >1. During a pericardiectomy, multiple islands of thick, firm-walled, fibrinous exudate-containing, small abscess formations were observed. Histopathological evaluation of pericardial tissue revealed granulomatous inflammation. Aspergillus fumigatus was cultured from the abscess. In conclusion, development of constrictive aspergillus pericarditis should be considered in patients with CGD because immediate initiation of antifungal management with aggressive surgical treatment is life-saving.

Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease of unknown etiology and pathogenic mechanisms. From an etiopathogenic point of view, alveolar macrophages play a key role in accumulation of fibroblasts and deposition of collagen and extracellular matrix by releasing specific cytokines and inflammatory mediators. IPF seems to be also associated with circulating fibrocytes, which might be involved with an abnormal pulmonary vascular repair and remodeling. Based on its hypothesized pathologic mechanisms, anti-inflammatory, anti-fibrotic and immunosuppressive therapies are often used. For these reasons, Interferon-g (IFN-g) has been used to exploit its activity on macrophages and fibroblasts. The aim of this study was to investigate the response to corticosteroids and/or IFN-g 1b treatments based on pulmonary function tests and on inflammatory cytokine patterns of expression on bronchoalveolar lavage (BAL), at baseline and during and after the therapies. Unlike previous studies, we analyzed a period of therapy longer than 1 year. Our results demonstrated the effectiveness of IFN-γ in a group of IPF patients in whom the treatment was prolonged for over a year. These data suggest a positive role of IFN-γ; treatment in patients in the initial stage of the disease.

Human interferon gamma is a cytokine belonging to a diverse group of interferons which have a crucial immunological function against mycobacteria and a wide variety of viral infections. To date, it has been approved for treatment of chronic granulomatous disease and malignant osteopetrosis, and its application as an immunotherapeutic agent against cancer is an increasing prospect. Recombinant human interferon gamma, as a lucrative biopharmaceutical, has been engineered in different expression systems including prokaryotic, protozoan, fungal (yeasts), plant, insect and mammalian cells. Human interferon gamma is commonly expressed in Escherichia coli, marketed as ACTIMMUNE®, however, the resulting product of the prokaryotic expression system is unglycosylated with a short half-life in the bloodstream; the purification process is tedious and makes the product costlier. Other expression systems also did not show satisfactory results in terms of yields, the biological activity of the protein or economic viability. Thus, the review aims to synthesise available information from previous studies on the production of human interferon gamma and its glycosylation patterns in different expression systems, to provide direction to future research in this field.

IFN-γ-1b is currently US FDA approved as an orphan drug for the treatment of chronic granulomatous disease and severe malignant osteopetrosis. It is administered via subcutaneous injection and is a potential therapy for Friedreich ataxia (FRDA), a rare degenerative neurological condition. Ongoing Phase II and III trials in both adults and children with FRDA were preceded by a small Phase I, open-label trial in children that showed that IFN-γ-1b was reasonably well-tolerated and improved overall neurological function as measured by the Friedreich Ataxia Rating Scale after 12 weeks of treatment, though the primary outcome measure of frataxin level showed no improvement. Although there is an established dose of IFN-γ-1b prescribed for the current indications, the efficacy and tolerability of these dose levels in the FRDA population remains the subject of ongoing investigation.

Friedreich's ataxia is an autosomal recessive progressive degenerative disorder caused by deficiency of the protein frataxin. The most common genetic cause is a homozygotic expansion of GAA triplets within intron 1 of the frataxin gene leading to impaired transcription. Preclinical in vivo and in vitro studies have shown that interferon gamma (IFNγ) is able to up-regulate the expression of frataxin gene in multiple cell types. We designed a phase IIa clinical trial, the first in Italy, aimed at assessing both safety and tolerability of IFNγ in Friedreich's patients and ability to increase frataxin levels in peripheral blood mononuclear cells. Nine patients (6 female and 3 males aged 21-38 years) with genetically confirmed disease were given 3 subcutaneous escalating doses (100, 150 and 200 μg) of IFNγ (human recombinant interferon 1 b gamma, trade name IMUKIN(®)), over 4 weeks. The primary end-point was the assessment of the safety and tolerability of IFNγ by means of standard clinical and hematological criteria. The secondary end-point was the detection of changes of frataxin levels in peripheral blood mononuclear cells after each single escalating dose of the drug. IFNγ was generally well tolerated, the main adverse event was hyperthermia/fever. Although, increases in frataxin levels could be detected in a minority of patients, these changes were not significant. A large phase III multicenter, randomized clinical trial with IFNγ in Friedreich's ataxia patients is currently ongoing. This study is expected to conclusively address the clinical efficacy of IFNγ therapy in patients with Friedreich's ataxia.

Parenteral IFN-γ was unsuccessful as a treatment for pulmonary fibrosis. Inhaled IFN-γ targeted to the lungs may be more effective. Our patient, a 56-year-old male with biopsy proven usual interstitial pneumonia (UIP) and declining pulmonary function tests (PFTs) was initially diagnosed with idiopathic pulmonary fibrosis (IPF). He enrolled in a 2-year research protocol and was treated with inhaled IFN-γ (100 μg, Actimmune, Horizon Pharma, Deerfield, IL) 3 times per week. After completion of the protocol, he was able to secure the drug and continued therapy for a total of 7 years. He felt better, returning to work. His only complaint was transient cough during inhalation. PFTs improved (e.g., DLCO, 58% at baseline, 81% at 2 years, 69% currently). Clinical monitoring showed preserved exercise tolerance and stable CT scans. He was ultimately diagnosed (year 5) with scleroderma-like connective tissue disease after he developed sclerodactyly and a positive antinuclear antibody. Inhaled IFN-γ was well tolerated for 7 years and may stabilize fibrotic lung disease.

ADO2 is a heritable osteosclerotic disorder that usually results from heterozygous missense dominant negative mutations in the chloride channel 7 gene (CLCN7). ADO2 is characterized by a wide range of features and severity, including multiple fractures, impaired vision due to secondary bony overgrowth and/or the lack of the optical canal enlargement with growth, and osteonecrosis/osteomyelitis. The disease is presently incurable, although anecdotal evidence suggests that calcitriol and interferon gamma-1b (IFN-G) may have some beneficial effects. To identify the role of these drugs for the treatment of ADO2, we utilized a knock-in (G213R mutation in Clcn7) ADO2 mouse model that resembles the human disease. Six-week-old ADO2 heterozygous mice were administered vehicle (PBS) or calcitriol or IFN-G 5 times per week for 8 weeks. We determined bone phenotypes using DXA and μCT, and analyzed serum biochemistry and bone resorption markers. ADO2 mice treated with all doses of IFN-G significantly (p<0.05) attenuated the increase of whole body aBMD and distal femur BV/TV gain in both male and female compared to the vehicle group. In contrast, mice treated with low and medium doses of calcitriol showed a trend of higher aBMD and BV/TV whereas high dose calcitriol significantly (p<0.05) increased bone mass compared to the vehicle group. The calcium and phosphorus levels did not differ between vehicle and IFN-G or calcitriol treated mice; however, we detected significantly (p<0.05) elevated levels of CTX/TRAP5b ratio in IFN-G treated mice. Our findings indicate that while IFN-G at all doses substantially improved the osteopetrotic phenotypes in ADO2 heterozygous mice, calcitriol treatment at any dose did not improve the phenotype and at high dose further increased bone mass. Thus, use of high dose calcitriol therapy in ADO2 patients merits serious reconsideration. Importantly, our data support the prospect of a clinical trial of IFN-G in ADO2 patients.

The utility of inhaled protein therapeutics to treat lung-resident diseases is limited by protein degradation in the lungs and rapid clearance. This study therefore aimed to evaluate the impact of PEGylation on the lung and systemic exposure of interferon (IFN) α2 after intratracheal administration to rats. An inverse correlation was observed between PEG chain length and systemic exposure, where bioavailability was 5.5% for the 31 kDa PEGylated construct and <0.4% for the 60 kDa PEGylated construct when compared with 15% for native IFN (19 kDa). Retention of PEGylated IFNα within the lungs increased 2.5-fold to threefold when compared with native IFN. When comparing the lung and systemic exposure of PEGylated and native IFN in terms of protein biological activity, the 31 kDa PEGylated construct increased exposure by 50% and 100%, respectively, when compared with native IFN, but the 60 kDa PEG construct offered no benefit. Preliminary work also indicated that the conjugation of IFNγ with 10 kDa PEG significantly increases the retention of the protein within the lung. Optimal PEGylation may therefore be used as a means to improve the exposure of lung-resident diseases to therapeutic cytokines and potentially reduce systemic exposure and side effects as well as dosing frequency.

The Gender-Age-Physiology (GAP) model is a validated, baseline-risk prediction model for mortality in idiopathic pulmonary fibrosis. Longitudinal variables have been shown to contribute to risk prediction in idiopathic pulmonary fibrosis and may improve the predictive performance of the baseline GAP model. Our aims were to further validate the GAP model and evaluate whether the addition of longitudinal variables improves its predictive performance. The study population was derived from a large clinical trials cohort of patients with idiopathic pulmonary fibrosis (n=1109). Model performance was determined by improvement in the C-statistic, net reclassification improvement, clinical net reclassification improvement, and a goodness-of-fit test. The GAP model had good discriminative performance with a C-statistic of 0.757 (95% CI 0.750-0.764). However, the original GAP model tended to overestimate risk in this cohort. A novel, easy to use model, consisting of the original GAP predictors plus history of respiratory hospitalisation and 24-week change in forced vital capacity (the longitudinal GAP model) improved model performance with a C-statistic of 0.785 (95% CI 0.780-0.790), net reclassification improvement of 8.5%, clinical net reclassification improvement of 25%, and a goodness-of-fit test of 0.929. The Longitudinal GAP model, along with the original GAP model, may unify baseline and longitudinal mortality risk prediction in idiopathic pulmonary fibrosis.

6-min walk distance (6MWD) has recently been shown to be associated with the risk of mortality in patients with idiopathic pulmonary fibrosis (IPF); however, the independent contribution of 6MWD to the prediction of mortality risk has not been evaluated in a large, well-defined population of patients with IPF. A Cox proportional hazards model was used to characterise the relationship between risk factors of interest and all-cause mortality in IPF patients who completed a week 24 study visit in a clinical trial evaluating interferon γ-1b (n=748). Risk factors of interest included the independent predictors of mortality in the previously published clinical prediction model together with 6MWD and 24-week change in 6MWD. Baseline 6MWD <250 m was associated with a two-fold increase in the risk of mortality (hazard ratio 2.12, 95% CI 1.15-3.92) and a 24-week decline in 6MWD >50 m was associated with a nearly three-fold increase in mortality risk (hazard ratio 2.73; 95% CI 1.60-4.66). Inclusion of 6MWD data improved model discrimination compared with the original model (C-statistic 0.80 (95% CI 0.76-0.85) versus 0.75 (0.71-0.79)). Both 6MWD and change in 6MWD are independent predictors of mortality in patients with IPF. The addition of 6MWD to the clinical prediction model improves model discrimination compared with the original model.