Phase 3 Trial of RNAi Therapeutic Givosiran for Acute Intermittent Porphyria.

BACKGROUND: Up-regulation of hepatic delta-aminolevulinic acid synthase 1 (ALAS1), with resultant accumulation of delta-aminolevulinic acid (ALA) and porphobilinogen, is central to the pathogenesis of acute attacks and chronic symptoms in acute hepatic porphyria. Givosiran, an RNA interference therapy, inhibits ALAS1 expression. METHODS: In this double-blind, placebo-controlled, phase 3 trial, we randomly assigned symptomatic patients with acute hepatic porphyria to receive either subcutaneous givosiran (2.5 mg per kilogram of body weight) or placebo monthly for 6 months. The primary end point was the annualized rate of composite porphyria attacks among patients with acute intermittent porphyria, the most common subtype of acute hepatic porphyria. (Composite porphyria attacks resulted in hospitalization, an urgent health care visit, or intravenous administration of hemin at home.) Key secondary end points were levels of ALA and porphobilinogen and the annualized attack rate among patients with acute hepatic porphyria, along with hemin use and daily worst pain scores in patients with acute intermittent porphyria. RESULTS: A total of 94 patients underwent randomization (48 in the givosiran group and 46 in the placebo group). Among the 89 patients with acute intermittent porphyria, the mean annualized attack rate was 3.2 in the givosiran group and 12.5 in the placebo group, representing a 74% lower rate in the givosiran group (P<0.001); the results were similar among the 94 patients with acute hepatic porphyria. Among the patients with acute intermittent porphyria, givosiran led to lower levels of urinary ALA and porphobilinogen, fewer days of hemin use, and better daily scores for pain than placebo. Key adverse events that were observed more frequently in the givosiran group were elevations in serum aminotransferase levels, changes in serum creatinine levels and the estimated glomerular filtration rate, and injection-site reactions. CONCLUSIONS: Among patients with acute intermittent porphyria, those who received givosiran had a significantly lower rate of porphyria attacks and better results for multiple other disease manifestations than those who received placebo. The increased efficacy was accompanied by a higher frequency of hepatic and renal adverse events. (Funded by Alnylam Pharmaceuticals; ENVISION ClinicalTrials.gov number, NCT03338816.).

Maternal and fetal outcomes in acute hepatic porphyria: A Swedish National Cohort Study.

Current knowledge of pregnancy and perinatal outcomes in women with acute hepatic porphyria (AHP) is largely based on biochemical disease models, case reports, and case series. We performed a nationwide, registered-based cohort study to investigate the association between maternal AHP and the risk of adverse pregnancy and perinatal outcomes. All women in the Swedish Porphyria Register with confirmed AHP aged 18 years or older between 1987 and 2015 and matched general population comparators, with at least one registered delivery in the Swedish Medical Birth Register were included. Risk ratios (RRs) of pregnancy complications, delivery mode and perinatal outcomes were estimated and adjusted for maternal age at delivery, area of residency, birth year and parity. Women with acute intermittent porphyria (AIP), the most common form of AHP, were further categorized according to maximal lifetime urinary porphobilinogen (U-PBG) levels. The study included 214 women with AHP and 2174 matched comparators. Women with AHP presented with a higher risk for pregnancy-induced hypertensive disorder (aRR 1.73, 95% CI 1.12-2.68), gestational diabetes (aRR 3.41, 95% CI 1.69-6.89), and small-for-gestational-age birth (aRR 2.08, 95% CI 1.26-3.45). In general, RRs were higher among women with AIP who had high lifetime U-PBG levels. Our study shows an increased risk for pregnancy induced hypertensive disease, gestational diabetes, and small for gestational age births for AHP women, with higher relative risks for women with biochemically active AIP. No increased risk for perinatal death or malformations was observed.

Risk for incident comorbidities, nonhepatic cancer and mortality in acute hepatic porphyria: A matched cohort study in 1244 individuals.

The acute hepatic porphyrias (AHP) are associated with long-term complications such as primary liver cancer, hypertension, and chronic kidney disease. Data on other related comorbidities are scarce. In this register-based, matched cohort study, we assessed the risks of nonhepatic cancers, cardiovascular diseases, renal diseases, psychiatric disorders, and mortality in relation to porphyria type, sex, and biochemical disease activity. All patients in the Swedish porphyria register with a verified AHP diagnosis during 1987-2015 were included. The biochemical activity of acute intermittent porphyria was assessed using recorded maximal urinary porphobilinogen (U-PBG). Data on incident comorbidities and mortality were collected from national health registries. Cumulative incidences, rates, and hazards were compared to reference individuals from the general population, matched 1:10 by age, sex, and county. We identified 1244 patients with AHP with a median follow-up of 19 years. Health registries identified 149 AHP-subjects (12.0%) with nonhepatic cancer, similar to 1601 (13.0%) in the matched reference population (n = 12 362). Patients with AHP had a higher risk of kidney cancer (0.8% vs. 0.2%, p < 0.001), hypertension, and chronic kidney disease but no increase in risk for cardiovascular disease, except for cerebrovascular disease in patients with elevated U-PBG, (aHR = 1.40 [95% CI:1.06-1.85]). Mortality risk during follow-up was higher among patients with AHP (21% vs. 18%, p = 0.001), and associated with primary liver cancer, female sex, and biochemical activity. In conclusion, AHP is associated with an increased risk of kidney cancer, hypertension, chronic kidney disease, and mortality but not with cardiovascular disease or other nonhepatic cancers.

Porphyrin precursors and risk of primary liver cancer in acute intermittent porphyria: A case-control study of 188 patients.

Acute intermittent porphyria (AIP) is a rare hereditary metabolic disease characterized by acute attacks and accumulation of the porphyrin precursors 5-aminolevulinic acid (ALA) and porphobilinogen (PBG). Patients with AIP have a high risk of primary liver cancer (PLC). We aimed to assess the association between porphyrin precursor excretion and the risk for PLC in patients with AIP. We studied 48 patients with AIP who developed PLC between 1987 and 2015 and 140 age and sex matched controls with AIP but no PLC. Data on all available urinary PBG and ALA samples collected from 1975 until 1 year before PLC diagnosis were analyzed and compared between cases and controls using logistic regression. Porphyrin precursor excretion was higher in patients with PLC (PBG median 7.9 [IQR 4.4-21.9] mmol/mol creatinine) than in controls (3.8 [1.2-9.8]) (adjusted odds ratio 1.07, 95% confidence interval: 1.02-1.12). None of the 28 patients with all registered samples below the upper limit of normal (ULN) developed PLC, and only one of the 45 patients with all samples <2× ULN developed PLC. Among non-PLC controls, ALA and PBG levels decreased after age 50-60 while an increasing trend was observed after age 65 among those who developed PLC. Increased urinary porphyrin precursors are associated with a high risk of developing PLC. Patients with normal levels appear to have a low risk while high or increasing ALA and PBG after age 65 indicates high risk, which should be considered in surveillance decisions.

Phase 1 Trial of an RNA Interference Therapy for Acute Intermittent Porphyria.

BACKGROUND: Induction of delta aminolevulinic acid synthase 1 ( ALAS1) gene expression and accumulation of neurotoxic intermediates result in neurovisceral attacks and disease manifestations in patients with acute intermittent porphyria, a rare inherited disease of heme biosynthesis. Givosiran is an investigational RNA interference therapeutic agent that inhibits hepatic ALAS1 synthesis. METHODS: We conducted a phase 1 trial of givosiran in patients with acute intermittent porphyria. In part A of the trial, patients without recent porphyria attacks (i.e., no attacks in the 6 months before baseline) were randomly assigned to receive a single subcutaneous injection of one of five ascending doses of givosiran (0.035, 0.10, 0.35, 1.0, or 2.5 mg per kilogram of body weight) or placebo. In part B, patients without recent attacks were randomly assigned to receive once-monthly injections of one of two doses of givosiran (0.35 or 1.0 mg per kilogram) or placebo (total of two injections 28 days apart). In part C, patients who had recurrent attacks were randomly assigned to receive injections of one of two doses of givosiran (2.5 or 5.0 mg per kilogram) or placebo once monthly (total of four injections) or once quarterly (total of two injections) during a 12-week period, starting on day 0. Safety, pharmacokinetic, pharmacodynamic, and exploratory efficacy outcomes were evaluated. RESULTS: A total of 23 patients in parts A and B and 17 patients in part C underwent randomization. Common adverse events included nasopharyngitis, abdominal pain, and diarrhea. Serious adverse events occurred in 6 patients who received givosiran in parts A through C combined. In part C, all 6 patients who were assigned to receive once-monthly injections of givosiran had sustained reductions in ALAS1 messenger RNA (mRNA), delta aminolevulinic acid, and porphobilinogen levels to near normal. These reductions were associated with a 79% lower mean annualized attack rate than that observed with placebo (exploratory efficacy end point). CONCLUSIONS: Once-monthly injections of givosiran in patients who had recurrent porphyria attacks resulted in mainly low-grade adverse events, reductions in induced ALAS1 mRNA levels, nearly normalized levels of the neurotoxic intermediates delta aminolevulinic acid and porphobilinogen, and a lower attack rate than that observed with placebo. (Funded by Alnylam Pharmaceuticals; ClinicalTrials.gov number, NCT02452372 .).

Acute hepatic porphyria and maternal health: Clinical and biochemical follow-up of 44 pregnancies.

BACKGROUND: Pregnancy in women with acute hepatic porphyria (AHP) has historically been associated with significant morbidity. Clinical outcomes have been the focus of previous reports on porphyria and maternal health, with little data available on the levels of heme precursors during pregnancy. We present the results of a follow-up program for women with AHP in the Swedish cohort who were pregnant between 2001 and 2020. METHODS: Thirty-three women with AHP were monitored during 44 pregnancies resulting in 44 single births. Seven of 33 women had a clinical history of acute attacks that required hospitalization. RESULTS: Four women experienced acute porphyria attacks during pregnancy and one during the puerperium. Seven women developed hypertension and four pregnancies ended with pre-eclampsia. There were no maternal or fetal pre- or postnatal deaths. One infant had a congenital cardiac anomaly. In 32 of the 38 pregnancies in which we measured heme precursors in the urine during pregnancy, the levels increased. CONCLUSION: Our observations align with contemporary reports that pregnancy in patients with AHP is frequently uncomplicated. Excretion of heme precursors increased during pregnancy, but this did not manifest as a higher frequency of clinical porphyria manifestations. The involvement of porphyria specialists in the patients' maternal care is recommended for reducing risk and improving the probability of good pregnancy outcomes.

Risk of primary liver cancer in acute hepatic porphyria patients: A matched cohort study of 1244 individuals.

BACKGROUND: The acute hepatic porphyrias (AHP) are associated with a risk of primary liver cancer (PLC), but risk estimates are unclear, and what AHP characteristics that predict PLC risk are unknown. In this register-based, matched cohort study, we assessed the PLC risk in relation to biochemical and clinical porphyria severity, genotype, age, and sex. METHODS: All patients in the Swedish porphyria register with acute intermittent porphyria (AIP), variegate porphyria (VP), or hereditary coproporphyria (HCP) during 1987-2015 were included. This AHP cohort was compared with age-, sex-, and county-matched reference individuals from the general population. National register-based hospital admissions for AHP were used to indicate the clinical severity. For AIP, the most common AHP type, patients were stratified by genotype and urinary porphobilinogen (U-PBG). Incident PLC data were collected from national health registers. RESULTS: We identified 1244 individuals with AHP (1063 [85%] AIP). During a median follow-up of 19.5 years, we identified 108 incident PLC cases, including 83 AHP patients (6.7%) and 25 of 12,333 reference individuals (0.2%). The adjusted hazard ratio for AHP-PLC was 38.0 (95% confidence interval: 24.3-59.3). Previously elevated U-PBG and hospitalizations for porphyria, but not AIP genotype or sex, were associated with increased PLC risk. Patients aged >50 years with previously elevated U-PBG (n = 157) had an annual PLC incidence of 1.8%. CONCLUSION: This study confirmed a high PLC risk and identified a strong association with clinical and biochemical AIP activity. Regular PLC surveillance is motivated in patients older than 50 years with a history of active AIP.

Treatment with assisted reproduction technologies in women with acute hepatic porphyria.

INTRODUCTION: Acute porphyrias are rare disorders of the heme biosynthetic pathway and present with acute neurovisceral symptoms that can be induced by hormonal changes and medications. Women are far more likely to present with clinical symptoms than men, particularly during parts of their lifetime with changes in the level of female sex hormones such as ovulation, menstruation, and pregnancy. Treatment of ovulatory dysfunction and controlled ovarian hyperstimulation require the administration of hormones, which are considered porphyrinogenic. Women with acute hepatic porphyria have therefore been considered unsuitable for such treatments in the past. MATERIAL AND METHODS: We report on nine women with acute hepatic porphyria who underwent in vitro fertilization (IVF), preceded by ovarian stimulation. Their mean age at the start of IVF was 33.2 years (range 27-38 years). Two women had been diagnosed with polycystic ovarian syndrome, two were treated for hyperprolactinemia, two had hypothyroidism, of which one also had type 1 diabetes, one had a uterus malformation, one had anovulatory cycles, and one used a sperm donor. RESULTS: All patients were able to undergo fertility treatment without experiencing severe porphyria attacks. CONCLUSIONS: Women with acute hepatic porphyria considering fertility treatments should be assessed individually for potential risks, treatment should be planned in close collaboration with a porphyria specialist, and biochemical activity should be monitored regularly during ovarian stimulation. As we gather more knowledge, we hope that the porphyrinogenicity of the stimulation agents is re-assessed and that more studies will shed light on the reproductive health of women living with acute hepatic porphyria.

Comment on Ramai et al. Risk of Hepatocellular Carcinoma in Patients with Porphyria: A Systematic Review. Cancers 2022, 14, 2947.

We read with interest this review by Ramai et al. [...].

Integrating virtual patients into courses: follow-up seminars and perceived benefit.

CONTEXT: The use of virtual patients (VPs) suggests promising effects on student learning. However, currently empirical data on how best to use VPs in practice are scarce. More knowledge is needed regarding aspects of integrating VPs into a course, of which student acceptance is one key issue. Several authors call for looking beyond technology to see VPs in relation to the course context. The follow-up seminar is proposed as an important aspect of integration that warrants investigation. METHODS: A cross-sectional explanatory study was performed in a clinical clerkship introduction course at four teaching hospitals affiliated to the same medical faculty. The VP-related activities were planned collaboratively by teachers from all four settings. However, each setting employed a different strategy to follow up the activity in the course. Sixteen questionnaire items were grouped into three scales pertaining to: perceived benefit of VPs; wish for more guidance on using VPs, and wish for assessment and feedback on VPs. Scale scores were compared across the four settings, which were ranked according to the level of intensity of students' processing of cases during VP follow-up activities. RESULTS: The perceived benefit of VPs and their usage were higher in the two intense-use settings compared with the moderate- and low-intensity settings. The wish for more guidance was high in the low- and one of the high-intensity settings. Students in all settings displayed little interest in more assessment and feedback regarding VPs. CONCLUSIONS: High case processing intensity was related to positive perceptions of the benefit of VPs. However, the low interest in more assessment and feedback on the use of VPs indicates the need to clearly communicate the added value of the follow-up seminar. The findings suggest that a more intense follow-up pays off in terms of the benefit perceived by students. This study illustrates the need to consider VPs from the perspective of a holistic course design and not as isolated add-ons.

A Drug-Drug Interaction Study Evaluating the Effect of Givosiran, a Small Interfering Ribonucleic Acid, on Cytochrome P450 Activity in the Liver.

Givosiran (trade name GIVLAARI) is a small interfering ribonucleic acid that targets hepatic delta-aminolevulinic acid synthase 1 (ALAS1) messenger RNA for degradation through RNA interference (RNAi) that has been approved for the treatment of acute hepatic porphyria (AHP). RNAi therapeutics, such as givosiran, have a low liability for drug-drug interactions (DDIs) because they are not metabolized by cytochrome 450 (CYP) enzymes, and do not directly inhibit or induce CYP enzymes in the liver. The pharmacodynamic effect of givosiran (lowering of hepatic ALAS1, the first and rate limiting enzyme in the heme biosynthesis pathway) presents a unique scenario where givosiran could potentially impact heme-dependent activities in the liver, such as CYP enzyme activity. This study assessed the impact of givosiran on the pharmacokinetics of substrates of 5 major CYP450 enzymes in subjects with acute intermittent porphyria (AIP), the most common type of AHP, by using the validated "Inje cocktail," comprised of caffeine (CYP1A2), losartan (CYP2C9), omeprazole (CYP2C19), dextromethorphan (CYP2D6), and midazolam (CYP3A4). We show that givosiran treatment had a differential inhibitory effect on CYP450 enzymes in the liver, resulting in a moderate reduction in activity of CYP1A2 and CYP2D6, a minor effect on CYP3A4 and CYP2C19, and a similar weak effect on CYP2C9. To date, this is the first study evaluating the DDI for an oligonucleotide therapeutic and highlights an atypical drug interaction due to the pharmacological effect of givosiran. The results of this study suggest that givosiran does not have a large effect on heme-dependent CYP enzyme activity in the liver.

Integration of whole genome sequencing into a healthcare setting: high diagnostic rates across multiple clinical entities in 3219 rare disease patients.

BACKGROUND: We report the findings from 4437 individuals (3219 patients and 1218 relatives) who have been analyzed by whole genome sequencing (WGS) at the Genomic Medicine Center Karolinska-Rare Diseases (GMCK-RD) since mid-2015. GMCK-RD represents a long-term collaborative initiative between Karolinska University Hospital and Science for Life Laboratory to establish advanced, genomics-based diagnostics in the Stockholm healthcare setting. METHODS: Our analysis covers detection and interpretation of SNVs, INDELs, uniparental disomy, CNVs, balanced structural variants, and short tandem repeat expansions. Visualization of results for clinical interpretation is carried out in Scout-a custom-developed decision support system. Results from both singleton (84%) and trio/family (16%) analyses are reported. Variant interpretation is done by 15 expert teams at the hospital involving staff from three clinics. For patients with complex phenotypes, data is shared between the teams. RESULTS: Overall, 40% of the patients received a molecular diagnosis ranging from 19 to 54% for specific disease groups. There was heterogeneity regarding causative genes (n = 754) with some of the most common ones being COL2A1 (n = 12; skeletal dysplasia), SCN1A (n = 8; epilepsy), and TNFRSF13B (n = 4; inborn errors of immunity). Some causative variants were recurrent, including previously known founder mutations, some novel mutations, and recurrent de novo mutations. Overall, GMCK-RD has resulted in a large number of patients receiving specific molecular diagnoses. Furthermore, negative cases have been included in research studies that have resulted in the discovery of 17 published, novel disease-causing genes. To facilitate the discovery of new disease genes, GMCK-RD has joined international data sharing initiatives, including ClinVar, UDNI, Beacon, and MatchMaker Exchange. CONCLUSIONS: Clinical WGS at GMCK-RD has provided molecular diagnoses to over 1200 individuals with a broad range of rare diseases. Consolidation and spread of this clinical-academic partnership will enable large-scale national collaboration.

Challenges in the management of acute intermittent porphyria with recurrent attacks during pregnancy: A case report.

In cases of recurrent attacks of acute porphyria during pregnancy, prophylactic administration of heme arginate should be considered. Clinical and biochemical monitoring of the disease and a close collaboration with a porphyria center are crucial.

[Hereditary metabolic diseases with onset in adulthood. Early and correct treatment of acute symptoms can be life-saving]. / Ärftliga metabola sjukdomar med symtomdebut i vuxen ålder - Tidig och korrekt behandling vid akuta symtom kan vara livräddande.

Inherited metabolic diseases usually present in the neonatal period or before school age. A growing portion of the disorders can be treated successfully, and an increasing number of patients are now treated in adult medicine. Several of the disorders also exist as attenuated variants without distinct symptoms in childhood. They can present as an acute onset event during metabolic stress in adulthood. We describe three patients with acute clinical decompensation in adulthood with severe sequelae and propose investigations to help diagnose such patients. One patient was unconscious from ammonia intoxication and developed severe neurological sequelae because of a defect in the urea cycle. A second patient had seizures caused by a defect in the conversion of homocysteine to methionine, resulting in lack of S-adenosylmethionine. A third patient had a stroke and grossly elevated homocysteine caused by undiagnosed homocystinuria. Recently there have been dramatic improvements in diagnostic methods, and new therapies are continuously being developed. Knowledge of these disorders is therefore of increasing importance also in adult medicine.

Differential expression of osteopontin and bone sialoprotein in bone metastasis of breast and prostate carcinoma.

Breast and prostate cancer often metastasise to the skeleton. Interestingly, the histopathological characteristics of the bone lesions that arise from these two cancer types differ. Breast tumours give rise to metastases in the skeleton with a mixed lytic/sclerotic pattern, whereas a predominantly sclerotic pattern is seen in metastases from prostate tumours. Osteopontin (OPN) and bone sialoprotein (BSP) are bone matrix proteins that have been implicated in the selective affinity of cancer cells for bone. In the present study, 21 patient cases with skeletal metastasis and their respective primary tumours (12 with breast cancer, 9 with prostate cancer) were investigated by immunohistochemistry in order to assess the level of OPN and BSP. Moderate to strong OPN expression was found in 42% of all breast tumours and in 56% of all prostate tumours. Significantly more breast cancer bone metastases exhibited high OPN expression, 83%, as compared with prostate tumour bone metastases, 11% (P = 0.0019). In contrast, moderate to strong BSP expression was found in 33% of breast tumours and in 89% of prostate tumours. In the bone lesions, only 33% of breast tumour metastases showed moderate/strong BSP expression compared to 100% of prostate tumour metastases (P = 0.0046). This divergent pattern of OPN/BSP expression could be an important determinant for the different characteristics of these two types of bone metastasis, i.e., lytic vs. sclerotic, consistent with the proposed role of OPN in differentiation and activation of osteoclasts and of BSP as a stimulator of bone mineralisation.

Differential expression of tartrate-resistant acid phosphatase isoforms 5a and 5b by tumor and stromal cells in human metastatic bone disease.

Tartrate-resistant acid phosphatase (TRAP) exists in human serum as two major isoforms, monomeric 5a and proteolytically processed enzymatically active 5b. The 5b isoform is secreted by osteoclasts and has recently been advocated as a serum marker for bone metastasis in breast cancer patients. The 5a isoform, on the other hand, is not bone-derived and has been proposed to be a marker of activated macrophages and chronic inflammation. In this study, expression of TRAP protein and enzymatic activity in bone metastases from different primary sites was examined. TRAP activity was high in bone metastases from prostate cancer, intermediate in breast cancer, and low in lung and kidney cancers. The partially purified TRAP from breast cancer bone metastasis samples exhibited the enzymatic characteristics of purple acid phosphatase. Both 5a and 5b isoforms were expressed in bone metastases of different histogenetic origins, i.e. prostate, breast, lung and kidney, and also a novel previously unreported 42 kDa variant of the TRAP 5a isoform was identified in bone metastases. This novel TRAP 5a isoform was absent in human bone, indicating that the 42 kDa variant is specific to metastatic cancer tissue. Immunohistochemistry revealed that metastatic cancer cells were the predominant source of TRAP 5a, whereas tumor-associated macrophages and occasionally multinucleated giant cells in the tumor stroma preferentially expressed the proteolytically processed TRAP 5b variant. Our results indicate the presence of a previously unstudied variant of monomeric TRAP 5a in cancer cells, which may have functional and diagnostic implications. Moreover, the presence of TRAP-positive macrophages in bone metastases could, together with cancer cells and osteoclasts, contribute to the elevated levels of serum TRAP activity observed in patients with bone metastases.