Genetic variants associated with Hermansky-Pudlak syndrome.

Hermansky-Pudlak syndrome (HPS) is a rare autosomal recessive disorder characterized by defective biogenesis of lysosome-related organelles. Clinical manifestations include a bleeding diathesis due to a platelet delta storage pool deficiency, oculocutaneous albinism, inflammatory bowel disease, neutropenia, and pulmonary fibrosis. Ten genes associated with HPS are identified to date, and each gene encodes a protein subunit of either Biogenesis of Lysosome-related Organelles Complex (BLOC)-1, BLOC-2, BLOC-3, or the Adaptor Protein-3 complex. Several genetic variants and phenotypic heterogeneities are reported in individuals with HPS, who generally exhibit easy bruisability and increased bleeding. Desmopressin, pro-coagulants, or platelet transfusion may be used as prophylaxis or treatment for excessive bleeding in patients with HPS. However, response to desmopressin can be variable. Platelets are effective in preventing or treating bleeding in individuals with HPS, but platelets should be transfused judiciously to limit alloimmunization in patients with HPS who are at risk of developing pulmonary fibrosis and may be potential candidates for lung transplantation. The discovery of new genes associated with HPS in people with excessive bleeding and hypopigmentation of unknown etiology may be facilitated by the use of next-generation sequencing or panel-based genetic testing.

Prolonged treatment with open-label pirfenidone in Hermansky-Pudlak syndrome pulmonary fibrosis.

PURPOSE: Limited information is available regarding chronic treatment with pirfenidone, an anti-fibrotic drug. Effects of long-term open-label pirfenidone were evaluated in a small cohort with Hermansky-Pudlak syndrome (HPS), a rare autosomal recessive disorder with highly penetrant pulmonary fibrosis. RESULTS: Three patients with HPS pulmonary fibrosis treated with open-label pirfenidone and twenty-one historical controls randomized to placebo were studied at a single center. Mean duration of treatment with pirfenidone for 3 patients with HPS pulmonary fibrosis was 13.1 years. Annual changes in FVC and DLCO with pirfenidone treatment were 0.46 and - 0.93% predicted, respectively. In comparison, historical controls randomized to receive placebo experienced mean annual changes in FVC and DLCO of -4.4 and - 2.3% predicted, respectively. High-resolution computed tomography (HRCT) scans revealed improved ground glass opacities with development of minimal interstitial reticulations in 1 patient after 12.8 years of treatment with pirfenidone. Slowly progressive increase in bilateral interstitial fibrosis developed in a different patient, who received pirfenidone for 18.1 years and died at 73 years of age due to HPS pulmonary fibrosis. Another patient treated with pirfenidone for 8.4 years had attenuated ground glass opacification on HRCT scan and improved oxygenation; this patient died due to chronic complications from colitis, and not pulmonary fibrosis. Adverse effects were generally limited to mild gastrointestinal discomfort and transient elevations of alanine aminotransferase in one patient. CONCLUSIONS: Chronic treatment with pirfenidone may provide clinical benefit with few adverse effects for some patients with HPS pulmonary fibrosis. These results suggest that compassionate use of pirfenidone could be considered on a case-by-case basis for patients with HPS pulmonary fibrosis.

Long-term nintedanib treatment for progressive pulmonary fibrosis associated with Hermansky-Pudlak syndrome type 1 followed by lung transplantation.

Hermansky-Pudlak syndrome (HPS) is a rare autosomal recessive disease that often causes progressive pulmonary fibrosis (HPS-PPF) in some genetic types with high mortality rates. No effective treatment for HPS-PPF other than lung transplantation has been established. Herein, we report a case of HPS type 1 with progressive pulmonary fibrosis treated with long-term nintedanib administration followed by lung transplantation. The resected lungs revealed diffuse interstitial lung lesions, including fibroblastic foci, suggesting the potential beneficial effects of anti-fibrotic drugs in HPS-PPF. Together with previous reports, the present case suggests that nintedanib might be a safe and effective drug for HPS-PPF.

In vitro and in vivo pharmacokinetic characterization, chiral conversion and PBPK scaling towards human PK simulation of S-MRI-1867, a drug candidate for Hermansky-Pudlak syndrome pulmonary fibrosis.

Hermansky-Pudlak syndrome (HPS) is a rare autosomal recessive disorder that affects lysosome-related organelles, often leading to fatal pulmonary fibrosis (PF). The search for a treatment for HPS pulmonary fibrosis (HPSPF) is ongoing. S-MRI-1867, a dual cannabinoid receptor 1 (CB1R)/inducible nitric oxide synthase (iNOS) inhibitor, has shown great promise for the treatment of several fibrotic diseases, including HPSPF. In this study, we investigated the in vitro ADME characteristics of S-MRI-1867, as well as its pharmacokinetic (PK) properties in mice, rats, dogs, and monkeys. S-MRI-1867 showed low aqueous solubility (< 1 µg/mL), high plasma protein binding (>99%), and moderate to high metabolic stability. In its preclinical PK studies, S-MRI-1867 exhibited moderate to low plasma clearance (CLp) and high steady-state volume of distribution (Vdss) across all species. Despite the low solubility and P-gp efflux, S-MRI-1867 showed great permeability and metabolic stability leading to a moderate bioavailability (21-60%) across mouse, rat, dog, and monkey. Since the R form of MRI-1867 is CB1R-inactive, we investigated the potential conversion of S-MRI-1867 to R-MRI-1867 in mice and found that the chiral conversion was negligible. Furthermore, we developed and validated a PBPK model that adequately fits the PK profiles of S-MRI-1867 in mice, rats, dogs, and monkeys using various dosing regimens. We employed this PBPK model to simulate the human PK profiles of S-MRI-1867, enabling us to inform human dose selection and support the advancement of this promising drug candidate in the treatment of HPSPF.

Pirfenidone for the treatment of Hermansky-Pudlak syndrome pulmonary fibrosis.

Hermansky-Pudlak syndrome (HPS) is a rare disorder of oculocutaneous albinism, platelet dysfunction, and in some subtypes, fatal pulmonary fibrosis. There is no effective treatment for the pulmonary fibrosis except lung transplantation, but an initial trial using pirfenidone, an anti-fibrotic agent, showed promising results. The current, randomized, placebo-controlled, prospective, double-blind trial investigated the safety and efficacy of pirfenidone for mild to moderate HPS-1 and 4 pulmonary fibrosis. Subjects were evaluated every 4 months at the National Institutes of Health Clinical Center, and the primary outcome parameter was change in forced vital capacity using repeated measures analysis with random coefficients. Thirty-five subjects with HPS-1 pulmonary fibrosis were enrolled during a 4-year interval; 23 subjects received pirfenidone and 12 received placebo. Four subjects withdrew from the trial, 3 subjects died, and 10 serious adverse events were reported. Both groups experienced similar side effects, especially gastroesophageal reflux. Interim analysis of the primary outcome parameter, performed 12 months after 30 patients were enrolled, showed no statistical difference between the placebo and pirfenidone groups, and the study was stopped due to futility. There were no significant safety concerns. Other clinical trials are indicated to identify single or multiple drug regimens that may be effective in treatment for progressive HPS-1 pulmonary fibrosis.

Therapy refractory menorrhagia as first manifestation of Hermansky-Pudlak syndrome.

INTRODUCTION: Oculocutaneous albinism (OCA) in combination with a platelet function defect caused by a disturbed release reaction from platelet δ-granules (storage pool defect - SPD) is typical for the autosomal recessive inherited Hermansky-Pudlak syndrome (HPS). CASE REPORT: A girl (age: 13 years) with OCA was hospitalized with transfusion-requiring menorrhagia. The suspicion of HPS was confirmed by results of lumi-aggregometry. Suspecting a disorder in primary haemostasis treatment with tranexamic acid (10 mg/kg body weight every 8 h i. v.), desmopressin (0.3 µg/kg body weight every 8 to 12 h) and hormonal therapy (norethisterone) was started but the menorrhagia persisted. Clinical response was finally achieved by a single injection of 100 µg/kg body weight recombinant factor VIIa (rFVIIa). CONCLUSION: The diagnosis of HPS should be suspected in patients with OCA and bleeding symptoms and is confirmed by the proof of SPD. In case of absent clinical response to desmopressin the application of rFVIIa should be considered. Hormones and antifibrinolytics are useful options in the treatment of extensive menorrhagia.

A rare cause of interstitial lung disease: Hermansky-Pudlak syndrome.

Hermansky-Pudlak syndrome is a rare disease characterized by bleeding diathesis, oculocutaneous albinism and lysosomal ceroid lipofuscin pigment deposits. Pulmonary fibrosis may also accompany with the disease. A 48-year-old male patient with a diagnosis of Hermansky-Pudlak syndrome admitted with dyspnea. A thorax computed tomography revealed bilateral diffuse interlobular septal thickness which was more prominent in the basal segments of lower lobes. Although pirfenidone therapy was planned, clinical deteroriation developed and patient died because of respiratory failure. In conclusion; this report describes a patient with pulmonary fibrosis caused by lung involvement of Hermansky-Pudlak syndrome which is an extremely rare and mortal disease.

Retinal biomarkers and pharmacological targets for Hermansky-Pudlak syndrome 7.

Deletion of dystrobrevin binding protein 1 has been linked to Hermansky-Pudlak syndrome type 7 (HPS-7), a rare disease characterized by oculocutaneous albinism and retinal dysfunction. We studied dysbindin-1 null mutant mice (Dys-/-) to shed light on retinal neurodevelopment defects in HPS-7. We analyzed the expression of a focused set of miRNAs in retina of wild type (WT), Dys+/- and Dys-/- mice. We also investigated the retinal function of these mice through electroretinography (ERG). We found that miR-101-3p, miR-137, miR-186-5p, miR-326, miR-382-5p and miR-876-5p were up-regulated in Dys-/-mice retina. Dys-/- mice showed significant increased b-wave in ERG, compared to WT mice. Bioinformatic analysis highlighted that dysregulated miRNAs target synaptic plasticity and dopaminergic signaling pathways, affecting retinal functions of Dys-/- mice. Overall, the data indicate potential mechanisms in retinal neurodevelopment of Dys-/- mice, which may have translational significance in HSP-7 patients, both in terms of diagnostic/prognostic biomarkers and novel pharmacological targets.

Treatment of Hermansky-Pudlak syndrome Associated granulomatous colitis with anti-TNF agents: case series and review of literature.

Hermansky-Pudlak syndrome is a rare syndrome characterized by bleeding diathesis due to platelet dysfunction, oculocutaneous albinism and other systemic involvements. Granulomatous colitis may occur in the disease course and have similarities with Crohn's disease. Herein, we present four cases with Hermansky-Pudlak syndrome associated colitis with the longest follow-up period having various responses to different anti-TNF agents. Four patients with Hermansky-Pudlak syndrome colitis were started on anti-TNF agents between 2008 and 2013. After a mean follow-up period of 7.5 years, two of four patients exhibited a significant improvement in symptoms, whereas the other two experienced undesirable disease course. Although having many similarities with Crohn's disease; Hermansky-Pudlak syndrome colitis appears to have lower anti-TNF response rates. Pathophysiological differences need to be enlightened to find more appropriate therapeutic targets for Hermansky-Pudlak syndrome colitis.

Hermansky-Pudlak syndrome with interstitial pneumonia without mutation of HSP1 gene.

A 57-year-old man with occulocutaneous albinism was admitted to our hospital because of exertional dyspnea and an abnormal shadow on chest roentgenogram. Chest CT revealed diffuse interstitial shadows with reticulonodular opacities in the bilateral whole lung fields and his pulmonary function test was consistent with a restrictive finding. Histologically, intraluminal diffuse fibrosis and interstitial fibrosis existed and ceroid-like materials within alveolar macrophages were demonstrated in a transbronchial lung biopsy specimen. In addition, because platelet dysfunction and ceroid-like materials within the reticuloendothelial cells of urine and bone marrow aspiration were recognized, we made a diagnosis of Hermansky-Pudlak syndrome (HPS). Gene analysis of the patient's peripheral blood cells did not reveal that he was a compound homogeneity for HPS1 gene mutations. Concerning treatment, although corticosteroid therapy was administered, his clinical symptoms and abnormal chest shadow have not changed.

An intractable case of Hermansky-Pudlak syndrome.

A 52-year-old Japanese man with congenital amblyopia and oculocutaneous albinism was admitted to our hospital. Chest CT showed reticular opacities and traction bronchiectasis without honeycombing. Specimens obtained by a video-assisted thoracoscopic surgery showed patchy chronic fibrotic lesions. We diagnosed him with Hermansky-Pudlak syndrome (HPS). A mutation in the HPS1 gene was detected, and the diagnosis was confirmed. The patient was treated with prednisolone, pirfenidone, and azathioprine, but he nevertheless died within four months. Autopsy lung specimens showed diffuse alveolar damage suggesting comparatively rapid deterioration, although this presentation was not typical of an acute exacerbation. These pathological changes may be a possible progression pattern in HPS patients.

Susceptibility of Hermansky-Pudlak mice to bleomycin-induced type II cell apoptosis and fibrosis.

Pulmonary inflammation, abnormalities in type II cell and macrophage morphology, and pulmonary fibrosis are features of Hermansky-Pudlak Syndrome (HPS), a recessive disorder associated with intracellular trafficking defects. We have previously reported that "Pearl" (HPS2) and "Pale Ear" (HPS1) mouse models have pulmonary inflammatory dysregulation and constitutive alveolar macrophage (AM) activation (Young LR et al., J Immunol 2006;176:4361-4368). In the current study, we used these HPS models to investigate mechanisms of lung fibrosis. Unchallenged HPS1 and HPS2 mice have subtle airspace enlargement and foamy AMs, but little or no histologic evidence of lung fibrosis. Seven days after intratracheal bleomycin (0.025 units), HPS1 and HPS2 mice exhibited increased mortality and diffuse pulmonary fibrosis compared to strain-matched C57BL/6J wild-type (WT) mice. HPS mice had significantly increased collagen deposition, and reduced quasi-static and static compliance consistent with a restrictive defect. The early airway and parenchymal cellular inflammatory responses to bleomycin were similar in HPS2 and WT mice. Greater elevations in levels of TGF-beta and IL-12p40 were produced in the lungs and AMs from bleomycin-challenged HPS mice than in WT mice. TUNEL staining revealed apoptosis of type II cells as early as 5 h after low-dose bleomycin challenge in HPS mice, suggesting that type II cell susceptibility to apoptosis may play a role in the fibrotic response. We conclude that the trafficking abnormalities in HPS promote alveolar apoptosis and pulmonary fibrosis in response to bleomycin challenge.

Granulomatous enterocolitis associated with Hermansky-Pudlak syndrome.

BACKGROUND: Hermansky-Pudlak syndrome (HPS) is a rare autosomal recessive disorder. It consists of a triad of tyrosinase-positive oculocutaneous albinism (Ty-pos OCA), bleeding diathesis resulting from platelet dysfunction, and systemic complications associated with accumulation of ceroid lipofuscin. Many patients are from a small area in northwestern Puerto Rico. HPS has been associated with granulomatous enterocolitis in up to 20% of affected patients. It is not known whether this granulomatous colitis is a part of the syndrome, or represents an independent but associated process, such as Crohn's disease. This colitis can be severe, and has been reported to be poorly responsive to medical therapies including sulfasalazine, mesalamine, steroids, and metronidazole. CASE REPORT: We report a series of four patients with refractory enterocolitis in the setting of HPS who were treated at Mount Sinai Hospital between 1998 and 2005. A trial of infliximab was attempted in all four, and produced a complete response in two. CONCLUSIONS: Many phenotypic and pathologic similarities exist between granulomatous enterocolitis in HPS and Crohn's disease. However, it is unclear whether the granulomatous enterocolitis in HPS is because of ceroid deposition or reflects the coexistence of Crohn's disease and HPS. The occurrence of ileal involvement and perianal fistulization in our cases suggests that in at least some instances, HPS and Crohn's disease are truly associated.

Complicated granulomatous colitis in a patient with Hermansky-Pudlak syndrome, successfully treated with infliximab.

Hermansky-Pudlak syndrome (HPS) is a rare autosomal recessive disorder which is characterised by the triad of oculocutaneous albinism, platelet dysfunction and accumulation of ceroidlike pigment in tissues. Complications of the syndrome, such as fatal pulmonary fibrosis, renal failure and cardiomyopathy have been described. Granulomatous colitis has been documented in several families with the HPS. The bowel disease of the HPS is a unique type of inflammatory bowel disease with clinical features suggestive of idiopathic ulcerative colitis (UC) and pathologic features suggestive of Crohn's disease. We report a patient with HPS which was complicated by granulomatous colitis with perineal and rectovaginal fistulas refractory to antibiotics and azathioprine but dramatically responded to repeated infusions of infliximab.

Poor response to desmopressin acetate (DDAVP) in children with Hermansky-Pudlak syndrome.

BACKGROUND: Hermansky-Pudlak syndrome (HPS) is a common genetic disorder in Puerto Rico. In children with HPS, bleeding is the most disturbing and incapacitating problem. Desmopressin (1-deamino-8-D-arginine vasopressin, (DDAVP)) has been recommended in the management of bleeding disorders characterized by platelet dysfunction, such as HPS. METHODS: Nineteen pediatric Puerto Rican patients with HPS and prolonged bleeding time (BT) were tested for response to administration of DDAVP. RESULTS: Baseline BT was abnormal in 18 (95%) of the patients. The BT following DDAVP administration improved in two cases (11%): one from 7.2 to 5.6 min and the other from 8 to 6 min (Tables II and III). BT measurements remained very prolonged (>15 min) in 17 (89%) of the patients. Patients with the HPS 1 gene mutation had a statistically significant correlation with the poor response following DDAVP (P = 0.03). CONCLUSIONS: DDAVP seldom improves the BT of Puerto Rican children with HPS. Response to DDAVP should be determined individually and platelet transfusion should remain the treatment of choice for a major bleeding episode or surgical procedure.

Sequential testing for efficacy in clinical trials with non-transient effects.

This paper describes a new type of sequential testing for clinical trials. The sequential nature of the data is not from additional patients, but rather from longer follow-up times. At each analysis, the null hypothesis that all treatments are equivalent in effect on the outcome after that amount of time is tested. The trial might still have staggered entry or not, but the key feature is that a different statistical hypothesis is tested at each analysis. It is assumed that any effect of treatment is non-transient, allowing a conclusion to be drawn in favour of one treatment or the other based on a difference at a single follow-up time. It is shown that a general method based on the Bonferroni inequality can be used to obtain critical cutpoints for sequential testing, that controls the chance of a type I error for the clinical decision. This method is applicable regardless of the test used at each analysis. In the case of a two-armed trial with a Gaussian outcome variable, it is shown how simulation can be used to obtain critical cutpoints that maintain the chance of a type I error for the clinical decision. The methods are compared by Monte-Carlo simulation, and it is seen that in most practical cases the Bonferroni method is not very conservative. The Bonferroni procedure is illustrated on the results of a real clinical trial of Pirfenidone on pulmonary fibrosis in Hermansky-Pudlak Syndrome.