Acute hepatic porphyrias: Recommendations for diagnosis and management with real-world examples

Acute hepatic porphyria (AHP) is a group of four rare inherited diseases, each resulting from a deficiency in a distinct enzyme in the heme biosynthetic pathway. Characterized by acute neurovisceral symptoms that may mimic other medical and psychiatric conditions, lack of recognition of the disease often leads to a delay in diagnosis and initiation of effective treatment. Biochemical testing for pathway intermediates that accumulate when the disease is active forms the basis for screening and establishing a diagnosis. Subsequent genetic analysis identifies the pathogenic variant, supporting screening of family members and genetic counseling. Management of AHP involves avoidance of known exogenous and hormonal triggers, symptomatic treatment, and prevention of recurrent attacks. Here we describe six case studies from our own real-world experience to highlight current recommendations and challenges associated with the diagnosis and long-term management of the disease.

Researching COVID to Enhance Recovery (RECOVER) adult study protocol: Rationale, objectives, and design

IMPORTANCE

SARS-CoV-2 infection can result in ongoing, relapsing, or new symptoms or other health effects after the acute phase of infection; termed post-acute sequelae of SARS-CoV-2 infection (PASC), or long COVID. The characteristics, prevalence, trajectory and mechanisms of PASC are ill-defined. The objectives of the Researching COVID to Enhance Recovery (RECOVER) Multi-site Observational Study of PASC in Adults (RECOVER-Adult) are to: (1) characterize PASC prevalence; (2) characterize the symptoms, organ dysfunction, natural history, and distinct phenotypes of PASC; (3) identify demographic, social and clinical risk factors for PASC onset and recovery; and (4) define the biological mechanisms underlying PASC pathogenesis.

METHODS

RECOVER-Adult is a combined prospective/retrospective cohort currently planned to enroll 14,880 adults aged ≥18 years. Eligible participants either must meet WHO criteria for suspected, probable, or confirmed infection; or must have evidence of no prior infection. Recruitment occurs at 86 sites in 33 U.S. states, Washington, DC and Puerto Rico, via facility- and community-based outreach. Participants complete quarterly questionnaires about symptoms, social determinants, vaccination status, and interim SARS-CoV-2 infections. In addition, participants contribute biospecimens and undergo physical and laboratory examinations at approximately 0, 90 and 180 days from infection or negative test date, and yearly thereafter. Some participants undergo additional testing based on specific criteria or random sampling. Patient representatives provide input on all study processes. The primary study outcome is onset of PASC, measured by signs and symptoms. A paradigm for identifying PASC cases will be defined and updated using supervised and unsupervised learning approaches with cross-validation. Logistic regression and proportional hazards regression will be conducted to investigate associations between risk factors, onset, and resolution of PASC symptoms.

DISCUSSION

RECOVER-Adult is the first national, prospective, longitudinal cohort of PASC among US adults. Results of this study are intended to inform public health, spur clinical trials, and expand treatment options.

REGISTRATION

NCT05172024.

Development of a Definition of Postacute Sequelae of SARS-CoV-2 Infection

Importance

SARS-CoV-2 infection is associated with persistent, relapsing, or new symptoms or other health effects occurring after acute infection, termed postacute sequelae of SARS-CoV-2 infection (PASC), also known as long COVID. Characterizing PASC requires analysis of prospectively and uniformly collected data from diverse uninfected and infected individuals.

Objective

To develop a definition of PASC using self-reported symptoms and describe PASC frequencies across cohorts, vaccination status, and number of infections.

Design, Setting, and Participants

Prospective observational cohort study of adults with and without SARS-CoV-2 infection at 85 enrolling sites (hospitals, health centers, community organizations) located in 33 states plus Washington, DC, and Puerto Rico. Participants who were enrolled in the RECOVER adult cohort before April 10, 2023, completed a symptom survey 6 months or more after acute symptom onset or test date. Selection included population-based, volunteer, and convenience sampling.

Exposure

SARS-CoV-2 infection.

Main Outcomes and Measures

PASC and 44 participant-reported symptoms (with severity thresholds).

Results

A total of 9764 participants (89% SARS-CoV-2 infected; 71% female; 16% Hispanic/Latino; 15% non-Hispanic Black; median age, 47 years [IQR, 35-60]) met selection criteria. Adjusted odds ratios were 1.5 or greater (infected vs uninfected participants) for 37 symptoms. Symptoms contributing to PASC score included postexertional malaise, fatigue, brain fog, dizziness, gastrointestinal symptoms, palpitations, changes in sexual desire or capacity, loss of or change in smell or taste, thirst, chronic cough, chest pain, and abnormal movements. Among 2231 participants first infected on or after December 1, 2021, and enrolled within 30 days of infection, 224 (10% [95% CI, 8.8%-11%]) were PASC positive at 6 months.

Conclusions and Relevance

A definition of PASC was developed based on symptoms in a prospective cohort study. As a first step to providing a framework for other investigations, iterative refinement that further incorporates other clinical features is needed to support actionable definitions of PASC.

Comparison of thrombotic and clinical outcomes in SARS-CoV-2-pneumonia versus other viral pneumonia in an urban academic medical center

BACKGROUND

Infection with viral pneumonia (PNA) is known to offset the coagulation cascade. Recent studies assessing novel SARS-CoV-2 infection observed a high frequency of systemic thrombotic events resulting in ambiguity if severity of infection or specific viral strain drive thrombosis and worsen clinical outcomes. Furthermore, limited data exists addressing SARS-CoV-2 in underrepresented patient populations.

OBJECTIVES

Assess clinical outcomes events and death in patients diagnosed with SARS-CoV-2 pneumonia compared to patients with other types of viral pneumonia.

METHODS

Retrospective cohort study evaluated electronic medical records in adult patients admitted to University of Illinois Hospital and Health Sciences System (UIHHSS) with primary diagnosis of SARS-CoV-2 PNA or other viral (H1N1 or H3N2) PNA between 10/01/2017 and 09/01/2020. Primary composite outcome was the following event incidence rates: death, ICU admission, infection, thrombotic complications, mechanical ventilation, renal replacement therapy, and major bleeding.

RESULTS

Of 257 patient records, 199 and 58 patients had SARS-CoV-2 PNA and other viral PNA, respectively. There was no difference in primary composite outcome. Thrombotic events (n = 6, 3%) occurred solely in SARS-CoV-2 PNA patients in the ICU. A significantly higher incidence of renal replacement therapy (8.5% vs 0%, p=0.016) and mortality (15.6% vs 3.4%, p=0.048) occurred in the SARS-CoV-2 PNA group. Multivariable logistic regression analysis revealed age, presence of SARS-CoV-2, and ICU admission, aOR 1.07, 11.37, and 41.95 respectively, was significantly associated with mortality risk during hospitalization; race and ethnicity were not.

CONCLUSION

Low overall incidence of thrombotic events occurred only in the SARS-CoV-2 PNA group. SARS-CoV-2 PNA may lead to higher incidence of clinical events than those observed in H3N2/H1N1 viral pneumonia, and that race/ethnicity does not drive mortality outcomes.

Effect of P2Y12 Inhibitors on Organ Support-Free Survival in Critically Ill Patients Hospitalized for COVID-19: A Randomized Clinical Trial

Importance

Platelet activation is a potential therapeutic target in patients with COVID-19.

Objective

To evaluate the effect of P2Y12 inhibition among critically ill patients hospitalized for COVID-19.

Design, Setting, and Participants

This international, open-label, adaptive platform, 1:1 randomized clinical trial included critically ill (requiring intensive care-level support) patients hospitalized with COVID-19. Patients were enrolled between February 26, 2021, through June 22, 2022. Enrollment was discontinued on June 22, 2022, by the trial leadership in coordination with the study sponsor given a marked slowing of the enrollment rate of critically ill patients.

Intervention

Participants were randomly assigned to receive a P2Y12 inhibitor or no P2Y12 inhibitor (usual care) for 14 days or until hospital discharge, whichever was sooner. Ticagrelor was the preferred P2Y12 inhibitor.

Main Outcomes and Measures

The primary outcome was organ support-free days, evaluated on an ordinal scale that combined in-hospital death and, for participants who survived to hospital discharge, the number of days free of cardiovascular or respiratory organ support up to day 21 of the index hospitalization. The primary safety outcome was major bleeding, as defined by the International Society on Thrombosis and Hemostasis.

Results

At the time of trial termination, 949 participants (median [IQR] age, 56 [46-65] years; 603 male [63.5%]) had been randomly assigned, 479 to the P2Y12 inhibitor group and 470 to usual care. In the P2Y12 inhibitor group, ticagrelor was used in 372 participants (78.8%) and clopidogrel in 100 participants (21.2%). The estimated adjusted odds ratio (AOR) for the effect of P2Y12 inhibitor on organ support-free days was 1.07 (95% credible interval, 0.85-1.33). The posterior probability of superiority (defined as an OR > 1.0) was 72.9%. Overall, 354 participants (74.5%) in the P2Y12 inhibitor group and 339 participants (72.4%) in the usual care group survived to hospital discharge (median AOR, 1.15; 95% credible interval, 0.84-1.55; posterior probability of superiority, 80.8%). Major bleeding occurred in 13 participants (2.7%) in the P2Y12 inhibitor group and 13 (2.8%) in the usual care group. The estimated mortality rate at 90 days for the P2Y12 inhibitor group was 25.5% and for the usual care group was 27.0% (adjusted hazard ratio, 0.96; 95% CI, 0.76-1.23; P = .77).

Conclusions and Relevance

In this randomized clinical trial of critically ill participants hospitalized for COVID-19, treatment with a P2Y12 inhibitor did not improve the number of days alive and free of cardiovascular or respiratory organ support. The use of the P2Y12 inhibitor did not increase major bleeding compared with usual care. These data do not support routine use of a P2Y12 inhibitor in critically ill patients hospitalized for COVID-19.

Trial Registration

ClinicalTrials.gov Identifier: NCT04505774.

Effect of Thromboprophylaxis on Clinical Outcomes After COVID-19 Hospitalization

BACKGROUND

Patients hospitalized with COVID-19 have an increased incidence of thromboembolism. The role of extended thromboprophylaxis after hospital discharge is unclear.

OBJECTIVE

To determine whether anticoagulation is superior to placebo in reducing death and thromboembolic complications among patients discharged after COVID-19 hospitalization.

DESIGN

Prospective, randomized, double-blind, placebo-controlled clinical trial. (ClinicalTrials.gov: NCT04650087).

SETTING

Done during 2021 to 2022 among 127 U.S. hospitals.

PARTICIPANTS

Adults aged 18 years or older hospitalized with COVID-19 for 48 hours or more and ready for discharge, excluding those with a requirement for, or contraindication to, anticoagulation.

INTERVENTION

2.5 mg of apixaban versus placebo twice daily for 30 days.

MEASUREMENTS

The primary efficacy end point was a 30-day composite of death, arterial thromboembolism, and venous thromboembolism. The primary safety end points were 30-day major bleeding and clinically relevant nonmajor bleeding.

RESULTS

Enrollment was terminated early, after 1217 participants were randomly assigned, because of a lower than anticipated event rate and a declining rate of COVID-19 hospitalizations. Median age was 54 years, 50.4% were women, 26.5% were Black, and 16.7% were Hispanic; 30.7% had a World Health Organization severity score of 5 or greater, and 11.0% had an International Medical Prevention Registry on Venous Thromboembolism risk prediction score of greater than 4. Incidence of the primary end point was 2.13% (95% CI, 1.14 to 3.62) in the apixaban group and 2.31% (CI, 1.27 to 3.84) in the placebo group. Major bleeding occurred in 2 (0.4%) and 1 (0.2%) and clinically relevant nonmajor bleeding occurred in 3 (0.6%) and 6 (1.1%) apixaban-treated and placebo-treated participants, respectively. By day 30, thirty-six (3.0%) participants were lost to follow-up, and 8.5% of apixaban and 11.9% of placebo participants permanently discontinued the study drug treatment.

LIMITATIONS

The introduction of SARS-CoV-2 vaccines decreased the risk for hospitalization and death. Study enrollment spanned the peaks of the Delta and Omicron variants in the United States, which influenced illness severity.

CONCLUSION

The incidence of death or thromboembolism was low in this cohort of patients discharged after hospitalization with COVID-19. Because of early enrollment termination, the results were imprecise and the study was inconclusive.

PRIMARY FUNDING SOURCE

National Institutes of Health.

Therapeutic trials for long COVID-19: A call to action from the interventions taskforce of the RECOVER initiative

Although most individuals recover from acute SARS-CoV-2 infection, a significant number continue to suffer from Post-Acute Sequelae of SARS-CoV-2 (PASC), including the unexplained symptoms that are frequently referred to as long COVID, which could last for weeks, months, or even years after the acute phase of illness. The National Institutes of Health is currently funding large multi-center research programs as part of its Researching COVID to Enhance Recover (RECOVER) initiative to understand why some individuals do not recover fully from COVID-19. Several ongoing pathobiology studies have provided clues to potential mechanisms contributing to this condition. These include persistence of SARS-CoV-2 antigen and/or genetic material, immune dysregulation, reactivation of other latent viral infections, microvascular dysfunction, and gut dysbiosis, among others. Although our understanding of the causes of long COVID remains incomplete, these early pathophysiologic studies suggest biological pathways that could be targeted in therapeutic trials that aim to ameliorate symptoms. Repurposed medicines and novel therapeutics deserve formal testing in clinical trial settings prior to adoption. While we endorse clinical trials, especially those that prioritize inclusion of the diverse populations most affected by COVID-19 and long COVID, we discourage off-label experimentation in uncontrolled and/or unsupervised settings. Here, we review ongoing, planned, and potential future therapeutic interventions for long COVID based on the current understanding of the pathobiological processes underlying this condition. We focus on clinical, pharmacological, and feasibility data, with the goal of informing future interventional research studies.

Structural racism is a mediator of disparities in acute myeloid leukemia outcomes

Non-Hispanic Black (NHB) and Hispanic patients with acute myeloid leukemia (AML) have higher mortality rates than non-Hispanic White (NHW) patients despite more favorable genetics and younger age. A discrete survival analysis was performed on 822 adult patients with AML from 6 urban cancer centers and revealed inferior survival among NHB (hazard ratio [HR] = 1.59; 95% confidence interval [CI]: 1.15, 2.22) and Hispanic (HR = 1.25; 95% CI: 0.88, 1.79) patients compared with NHW patients. A multilevel analysis of disparities was then conducted to investigate the contribution of neighborhood measures of structural racism on racial/ethnic differences in survival. Census tract disadvantage and affluence scores were individually calculated. Mediation analysis of hazard of leukemia death between groups was examined across 6 composite variables: structural racism (census tract disadvantage, affluence, and segregation), tumor biology (European Leukemia Network risk and secondary leukemia), health care access (insurance and clinical trial enrollment), comorbidities, treatment patterns (induction intensity and transplant utilization), and intensive care unit (ICU) admission during induction chemotherapy. Strikingly, census tract measures accounted for nearly all of the NHB-NHW and Hispanic-NHW disparity in leukemia death. Treatment patterns, including induction intensity and allogeneic transplant, and treatment complications, as assessed by ICU admission during induction chemotherapy, were additional mediators of survival disparities in AML. This is the first study to formally test mediators for observed disparities in AML survival and highlights the need to investigate the mechanisms by which structural racism interacts with known prognostic and treatment factors to influence leukemia outcomes.

Therapeutic Anticoagulation with Heparin in Noncritically Ill Patients with Covid-19

BACKGROUND

Thrombosis and inflammation may contribute to the risk of death and complications among patients with coronavirus disease 2019 (Covid-19). We hypothesized that therapeutic-dose anticoagulation may improve outcomes in noncritically ill patients who are hospitalized with Covid-19.

METHODS

In this open-label, adaptive, multiplatform, controlled trial, we randomly assigned patients who were hospitalized with Covid-19 and who were not critically ill (which was defined as an absence of critical care-level organ support at enrollment) to receive pragmatically defined regimens of either therapeutic-dose anticoagulation with heparin or usual-care pharmacologic thromboprophylaxis. The primary outcome was organ support-free days, evaluated on an ordinal scale that combined in-hospital death (assigned a value of -1) and the number of days free of cardiovascular or respiratory organ support up to day 21 among patients who survived to hospital discharge. This outcome was evaluated with the use of a Bayesian statistical model for all patients and according to the baseline d-dimer level.

RESULTS

The trial was stopped when prespecified criteria for the superiority of therapeutic-dose anticoagulation were met. Among 2219 patients in the final analysis, the probability that therapeutic-dose anticoagulation increased organ support-free days as compared with usual-care thromboprophylaxis was 98.6% (adjusted odds ratio, 1.27; 95% credible interval, 1.03 to 1.58). The adjusted absolute between-group difference in survival until hospital discharge without organ support favoring therapeutic-dose anticoagulation was 4.0 percentage points (95% credible interval, 0.5 to 7.2). The final probability of the superiority of therapeutic-dose anticoagulation over usual-care thromboprophylaxis was 97.3% in the high d-dimer cohort, 92.9% in the low d-dimer cohort, and 97.3% in the unknown d-dimer cohort. Major bleeding occurred in 1.9% of the patients receiving therapeutic-dose anticoagulation and in 0.9% of those receiving thromboprophylaxis.

CONCLUSIONS

In noncritically ill patients with Covid-19, an initial strategy of therapeutic-dose anticoagulation with heparin increased the probability of survival to hospital discharge with reduced use of cardiovascular or respiratory organ support as compared with usual-care thromboprophylaxis. (ATTACC, ACTIV-4a, and REMAP-CAP ClinicalTrials.gov numbers, NCT04372589, NCT04505774, NCT04359277, and NCT02735707.).

Therapeutic Anticoagulation with Heparin in Critically Ill Patients with Covid-19

BACKGROUND

Thrombosis and inflammation may contribute to morbidity and mortality among patients with coronavirus disease 2019 (Covid-19). We hypothesized that therapeutic-dose anticoagulation would improve outcomes in critically ill patients with Covid-19.

METHODS

In an open-label, adaptive, multiplatform, randomized clinical trial, critically ill patients with severe Covid-19 were randomly assigned to a pragmatically defined regimen of either therapeutic-dose anticoagulation with heparin or pharmacologic thromboprophylaxis in accordance with local usual care. The primary outcome was organ support-free days, evaluated on an ordinal scale that combined in-hospital death (assigned a value of -1) and the number of days free of cardiovascular or respiratory organ support up to day 21 among patients who survived to hospital discharge.

RESULTS

The trial was stopped when the prespecified criterion for futility was met for therapeutic-dose anticoagulation. Data on the primary outcome were available for 1098 patients (534 assigned to therapeutic-dose anticoagulation and 564 assigned to usual-care thromboprophylaxis). The median value for organ support-free days was 1 (interquartile range, -1 to 16) among the patients assigned to therapeutic-dose anticoagulation and was 4 (interquartile range, -1 to 16) among the patients assigned to usual-care thromboprophylaxis (adjusted proportional odds ratio, 0.83; 95% credible interval, 0.67 to 1.03; posterior probability of futility [defined as an odds ratio <1.2], 99.9%). The percentage of patients who survived to hospital discharge was similar in the two groups (62.7% and 64.5%, respectively; adjusted odds ratio, 0.84; 95% credible interval, 0.64 to 1.11). Major bleeding occurred in 3.8% of the patients assigned to therapeutic-dose anticoagulation and in 2.3% of those assigned to usual-care pharmacologic thromboprophylaxis.

CONCLUSIONS

In critically ill patients with Covid-19, an initial strategy of therapeutic-dose anticoagulation with heparin did not result in a greater probability of survival to hospital discharge or a greater number of days free of cardiovascular or respiratory organ support than did usual-care pharmacologic thromboprophylaxis. (REMAP-CAP, ACTIV-4a, and ATTACC ClinicalTrials.gov numbers, NCT02735707, NCT04505774, NCT04359277, and NCT04372589.).

A multi-institutional comparison of mitoxantrone, etoposide, and cytarabine vs high-dose cytarabine and mitoxantrone therapy for patients with relapsed or refractory acute myeloid leukemia

Relapsed or refractory acute myeloid leukemia (R/R AML) has a poor prognosis and is best treated with salvage chemotherapy as a bridge to allogeneic stem cell transplant (alloSCT). However, the optimal salvage therapy remains unknown. Here we compared two salvage regimens; mitoxantrone, etoposide, and cytarabine (MEC) and mitoxantrone and high-dose Ara-C (Ara-C couplets). We analyzed 155 patients treated at three academic institutions between 1998 and 2017; 87 patients received MEC and 68 received Ara-C couplets. The primary endpoint was overall response (OR). Secondary endpoints included progression-free survival (PFS), overall survival (OS), duration of hospitalization, hematologic and nonhematologic toxicities, and success in proceeding to alloSCT. Baseline characteristics of the cohorts were well matched, though patients receiving Ara-C couplets had more co-morbidities (48.5% vs 33%; P = .07). OR was achieved in 43.7% of MEC and 54.4% of Ara-C couplets patients (P = .10). Ara-C couplets patients also trended towards a longer OS and PFS, more frequently proceeded to alloSCT (31% vs 54.4%; P = .003), and experienced less febrile neutropenia (94% vs 72%; P < .001) and grade 3/4 gastrointestinal toxicities (17.2% vs 2.94%; P = .005). No significant differences in other toxicities or median duration of hospitalization were noted. This is the first multi-institutional study directly comparing these regimens in a racially diverse population of R/R AML patients. Although these regimens have equivalent efficacy in terms of achieving OR, Ara-C couplets use is associated with significant reductions in toxicities, suggesting it should be used more frequently in these patients.

Safety and efficacy of gemtuzumab ozogamicin and venetoclax in patients with relapsed or refractory CD33+ acute myeloid leukemia: A phase Ib study

TPS7566

Background: AML is predominantly a disease of the elderly, yet outcomes remain dismal, especially for relapsed/refractory (R/R) AML patients (pts). Gemtuzumab Ozogamicin (GO) is a monoclonal antibody targeting CD33–commonly expressed on AML blasts, and, critically, AML stem cells (LSC)–that is linked to the cytotoxin calicheamicin. Recognized mechanisms of GO resistance include decreased (or aberrant) blast CD33 expression, upregulation of p-glycoprotein (re-exports calicheamicin), and decreased mitochondrial apoptosis. GO-induced apoptosis depends on pro-apoptotic Bax and Bak and is inhibited by overexpression of anti-apoptotic BCL-2 and BCL-XL. Venetoclax (VEN) is a BH3 mimetic, binding BCL-2, dislodging its binding to Bak/Bax, thus facilitating apoptosis. LSC uniquely overexpress BCL-2, however VEN resistance develops rapidly. Hypothesis: VEN targeting of BCL-2 proteins that protect LSC from GO-induced apoptosis will synergistically increase GO efficacy. Correlative studies include pre-treatment AML blast BH3 profiling and CD33 expression (& sequencing for isoforms), MRD measurement at post-therapy timepoints using digital drop PCR technology, and quality of life assessments (EORTC QLQ-C30, FACT-Fatigue). Methods: Single arm, open-label, multi-center (BTCRC), dose-escalation phase Ib study of combination of VEN and GO in R/R AML pts (18-75y), using a 3+3 design. Major eligibility: ECOG 0-2, adequate organ function, CD33+ in ≥ 20% AML blasts, ≤2 lines of prior therapy, no prior use of GO or VEN, no previous VOD, no BMT within 2 months, no CNS disease, and no history of HIV. Induction: 3-day VEN ramp-up to the target dose of 200 (cohort i), 400 (ii), or 600 (iii) mg daily x 28 d, with GO 3mg/m2 infused d 1, 4, and 7. If CR/CRi achieved, pts proceed to BMT if applicable, otherwise, if in CR/CRi (provided ANC > 1000, plts 100K) or PR (regardless of counts), they are consolidated with VEN at the prescribed dose x 28d and GO 3mg/m2 on days 1 and 4 (Cycle 2). If BMT not applicable, and then in CR/CRi or PR (as above), proceed to VEN alone as Maintenance in cycles 3+ until progression or toxicity. The primary endpoint is MTD of VEN with GO. Secondary endpoints include ORR, anti-leukemic activity, characterization of AEs, and estimates of RFS, EFS, and OS. This study is currently open and has to date enrolled 2 pts. Clinical trial information: NCT04070768 .

Myelodysplastic syndrome and acute myeloid leukemia after receipt of granulocyte colony-stimulating factors in older patients with non-Hodgkin lymphoma

BACKGROUND

Granulocyte colony-stimulating factors (G-CSFs), which are used for the prevention of complications from chemotherapy-related neutropenia, are linked to the risk of developing second primary myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). The objective of this study was to examine the correlation between using a specific G-CSF agent and the risk of MDS/AML among older patients with non-Hodgkin lymphoma (NHL).

METHODS

This was a retrospective cohort study of adults aged >65 years who were diagnosed with first primary NHL between 2001 and 2011. With data from the Surveillance, Epidemiology, and End Results-Medicare-linked database, adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated for the risk of MDS/AML associated with the receipt of G-CSF(filgrastim and pegfilgrastim) in Cox proportional-hazards models, which were stratified according to treatment accounting for confounding by indication.

RESULTS

Among 18,245 patients with NHL patients who had a median follow-up of 3.5 years, 56% received chemotherapy and/or immunotherapy, and G-CSF was most commonly used in those who received rituximab plus multiple chemotherapy regimens (77%). Subsequent MDS/AML diagnoses were identified in 666 patients (3.7%). A modest increased risk of MDS/AML was observed with the receipt of G-CSF (HR, 1.28; 95% CI, 1.01-1.62) and a trend was observed with increasing doses (Ptrend < .01). When specific agents were analyzed, an increased risk of MDS/AML was consistently observed with filgrastim (≥10 doses: HR, 1.67; 95% CI, 1.25-2.23), but not with pegfilgrastim (≥10 + doses: HR, 1.11; 95% CI, 0.84-1.45).

CONCLUSIONS

A higher of MDS/AML was observed in patients with NHL risk among those who received G-CSF that was specific to the use of filgrastim (≥10 doses), but not pegfilgrastim. Neutropenia prophylaxis is an essential component of highly effective NHL treatment regimens. The differential risk related to the types of G-CSF agents used warrants further study given their increasing use and newly available, US Food and Drug Administration-approved, biosimilar products.

Haploidentical Peripheral Blood Stem Cell Transplantation Demonstrates Stable Engraftment in Adults with Sickle Cell Disease

We report on the screening and development of haploidentical hematopoietic stem cell transplantation (HSCT) for adult patients with clinically aggressive sickle cell disease (SCD) at our institution. Of 50 adult SCD patients referred for HSCT between January 2014 and March 2017, 20% were denied by insurance. Of 41 patients initially screened, 10% lacked an available haploidentical donor, 29% had elevated donor-specific antibodies (DSAs), and 34% declined to proceed to HSCT. All 10 patients who were transplanted received peripheral blood stem cells. The initial 2 were conditioned with alemtuzumab/total body irradiation (TBI) 3 Gy followed by post-transplant cyclophosphamide and failed to engraft. The next 8 patients received the regimen developed at Johns Hopkins University with TBI 3 Gy. Granulocyte colony-stimulating factor was administered from day +12 in those with HbS < 30%. All 8 patients engrafted with a median time to neutrophil >.5 × 109/L of 22 days (range, 18 to 23). One patient subsequently lost the graft, and 7 (87.5%) maintained >95% donor cell chimerism at 1-year post-HSCT. Two patients developed acute graft-versus-host disease (GVHD) of at least grade II. One had chronic GVHD and died >1 year after HSCT of unknown causes. With a median follow-up of 16 months (range, 11 to 29), 7 patients (87.5%) are alive. Our findings suggest that limited insurance coverage, high rate of DSAs, and patient declining HSCT may limit the availability of haploidentical HSCT in adult SCD patients. The modified Hopkins regimen used here demonstrates high engraftment and low morbidity rates and should be tested in larger, multicenter, prospective clinical trials.

miR-9 upregulation leads to inhibition of erythropoiesis by repressing FoxO3

MicroRNAs (miRNAs) are emerging as critical regulators of normal and malignant hematopoiesis. In previous studies of acute myeloid leukemia miR-9 overexpression was commonly observed. Here, we show that ectopic expression of miR-9 in vitro and in vivo significantly blocks differentiation of erythroid progenitor cells with an increase in reactive oxygen species (ROS) production. Consistent with this observation, ROS scavenging enzymes, including superoxide dismutase (Sod2), Catalase (Cat), and glutathine peroxidase (Gpx1), are down-regulated by miR-9. In addition, miR-9 suppresses expression of the erythroid transcriptional regulator FoxO3, and its down-stream targets Btg1 and Cited 2 in erythroid progenitor cells, while expression of a constitutively active form of FoxO3 (FoxO3-3A) reverses miR-9-induced suppression of erythroid differentiation, and inhibits miR-9-induced ROS production. Thus, our findings indicate that aberrant expression of miR-9 blocks erythropoiesis by deregulating FoxO3-mediated pathways, which may contribute to the ineffective erythropoiesis observed in patients with hematological malignancies.

A novel drug interaction between busulfan and blinatumomab

Busulfan is an alkylating agent used in pre-transplant conditioning for patients undergoing hematopoietic stem cell transplantation. Several factors contribute to variations in busulfan drug disposition including bioavailability, age, liver function, genetic polymorphisms, and concurrent administration of other drugs. Busulfan is metabolized by hepatic oxidation via the cytochrome P450 3A4 system as well as through conjugation with glutathione. Interactions with drugs such as phenytoin, itraconazole, and metronidazole have been reported to alter busulfan clearance and result in sub- or supra-therapeutic concentrations. We report a case of a clinically significant drug interaction between intravenous busulfan and the bifunctional T-cell engager, blinatumomab, observed through busulfan therapeutic drug monitoring. We found that busulfan clearance was reduced resulting in a higher area under the concentration-time curve when it was administered 48 h after blinatumomab. Repeat busulfan pharmacokinetic testing two weeks later demonstrated increased clearance of the drug and a 31% higher dose recommendation.

Similar to other protein therapeutics, cytokine elevations during blinatumomab treatment can lead to cytochrome 3A4 suppression. We hypothesize that the increased busulfan levels observed could be related to a cytokine-mediated CYP3A4 suppression. This represents a unique pharmacologic consideration in hematopoietic stem cell transplantation which would impact several drugs that undergo CYP3A4 metabolism, including calcineurin inhibitors, cyclophosphamide, sirolimus, and triazole antifungals. Additionally, this mechanism of CYP3A4 suppression may be relevant in treatments and disease states where cytokine levels are elevated such as haploidentical stem cell transplantation, graft-versus-host disease, and use of chimeric antigen receptor T-cell therapy.

A treatment algorithm to identify therapeutic approaches for leg ulcers in patients with sickle cell disease

Sickle cell leg ulcers (SCLUs) are a common complication of sickle cell disease (SCD). Patients who develop ulcers appear to have a more severe haemolysis-associated vasculopathy than individuals who do not develop them, and manifest other complications such as priapism and pulmonary hypertension. SCLUs are slow to heal and often recur, affecting both the emotional and physical well-being of patients. Here we summarise what is known about the pathophysiology of SCLUs, describe available treatment options and propose a treatment algorithm.

Nonmyeloablative Stem Cell Transplantation with Alemtuzumab/Low-Dose Irradiation to Cure and Improve the Quality of Life of Adults with Sickle Cell Disease

Allogeneic hematopoietic stem cell transplantation (HSCT) is rarely performed in adult patients with sickle cell disease (SCD). We utilized the chemotherapy-free, alemtuzumab/total body irradiation 300 cGy regimen with sirolimus as post-transplantation immunosuppression in 13 high-risk SCD adult patients between November 2011 and June 2014. Patients received matched related donor (MRD) granulocyte colony-stimulating factor-mobilized peripheral blood stem cells, including 2 cases that were ABO incompatible. Quality-of-life (QoL) measurements were performed at different time points after HSCT. All 13 patients initially engrafted. A stable mixed donor/recipient chimerism was maintained in 12 patients (92%), whereas 1 patient not compliant with sirolimus experienced secondary graft failure. With a median follow-up of 22 months (range, 12 to 44 months) there was no mortality, no acute or chronic graft-versus-host disease (GVHD), and no grades 3 or 4 extramedullary toxicities. At 1 year after transplantation, patients with stable donor chimerism have normalized hemoglobin concentrations and improved cardiopulmonary and QoL parameters including bodily pain, general health, and vitality. In 4 patients, sirolimus was stopped without rejection or SCD-related complications. These results underscore the successful use of a chemotherapy-free regimen in MRD HSCT for high-risk adult SCD patients and demonstrates a high cure rate, absence of GVHD or mortality, and improvement in QoL including the applicability of this regimen in ABO mismatched cases (NCT number 01499888).

The Concise Guide to PHARMACOLOGY 2013/14: overview

The Concise Guide to PHARMACOLOGY 2013/14 provides concise overviews of the key properties of over 2000 human drug targets with their pharmacology, plus links to an open access knowledgebase of drug targets and their ligands (www.guidetopharmacology.org), which provides more detailed views of target and ligand properties from the IUPHAR database. The full contents can be found at http://onlinelibrary.wiley.com/doi/10.1111/bph.12444/full. This compilation of the major pharmacological targets is divided into seven areas of focus: G protein-coupled receptors, ligand-gated ion channels, ion channels, catalytic receptors, nuclear hormone receptors, transporters and enzymes. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. A new landscape format has easy to use tables comparing related targets. It is a condensed version of material contemporary to late 2013, which is presented in greater detail and constantly updated on the website www.guidetopharmacology.org, superseding data presented in previous Guides to Receptors & Channels. It is produced in conjunction with NC-IUPHAR and provides the official IUPHAR classification and nomenclature for human drug targets, where appropriate. It consolidates information previously curated and displayed separately in IUPHAR-DB and GRAC and provides a permanent, citable, point-in-time record that will survive database updates.

Differential effects of epigenetic modifiers on the expansion and maintenance of human cord blood stem/progenitor cells

Epigenetic therapies, including DNA methyltransferase and histone deacetylase (HDAC) inhibitors, are increasingly being considered to treat hematological malignancies, but their effects on normal hematopoietic stem cells (HSCs) remain largely unexplored. We compared the effects of several HDAC inhibitors, including valproic acid (VPA) and trichostatin A (TSA), alone or in combination with 5-aza-2'-deoxycytidine (5azaD) on the expansion of HSCs. VPA induced the highest expansion of CD34+CD90+ cells and progenitor cells compared with other HDAC inhibitors or the sequential addition of 5azaD/TSA in culture. Xenotransplantation studies demonstrated that VPA prevents HSC loss, whereas 5azaD/TSA treatment leads to a net expansion of HSCs that retain serial transplantation ability. 5azaD/TSA-mediated HSC expansion was associated with increased histone acetylation and transient DNA demethylation, which corresponded with higher gene transcript levels. However, some genes with increased transcript levels lacked changes in methylation. Importantly, a global microarray analysis revealed a set of differentially expressed genes in 5azaD/TSA- and VPA-expanded CD34+ cells that might be involved in the expansion and maintenance of transplantable HSCs, respectively. In summary, our data indicate that treatment of HSCs with different chromatin-modifying agents results in either the expansion or maintenance of HSCs, an observation of potential therapeutic importance.

Heme and FLVCR-related transporter families SLC48 and SLC49

Heme is critical for a variety of cellular processes, but excess intracellular heme may result in oxidative stress and membrane injury. Feline leukemia virus subgroup C receptor (FLVCR1), a member of the SLC49 family of four paralogous genes, is a cell surface heme exporter, essential for erythropoiesis and systemic iron homeostasis. Disruption of FLVCR1 function blocks development of erythroid progenitors, likely due to heme toxicity. Mutations of SLC49A1 encoding FLVCR1 are noted in patients with a rare neurodegenerative disorder: posterior column ataxia with retinitis pigmentosa. FLVCR2 is highly homologous to FLVCR1 and may function as a cellular heme importer. Mutations of SLC49A2 encoding FLVCR2 are observed in Fowler syndrome, a rare proliferative vascular disorder of the brain. The functions of the remaining members of the SLC49 family, MFSD7 and DIRC2 (encoded by the SLC49A3 and SLC49A4 genes), are unknown, although the latter is implicated in hereditary renal carcinomas. SLC48A1 (heme responsive gene-1, HRG-1), the sole member of the SLC48 family, is associated with the endosome and appears to transport heme from the endosome into the cytosol.

Control of intracellular heme levels: heme transporters and heme oxygenases

Heme serves as a co-factor in proteins involved in fundamental biological processes including oxidative metabolism, oxygen storage and transport, signal transduction and drug metabolism. In addition, heme is important for systemic iron homeostasis in mammals. Heme has important regulatory roles in cell biology, yet excessive levels of intracellular heme are toxic; thus, mechanisms have evolved to control the acquisition, synthesis, catabolism and expulsion of cellular heme. Recently, a number of transporters of heme and heme synthesis intermediates have been described. Here we review aspects of heme metabolism and discuss our current understanding of heme transporters, with emphasis on the function of the cell-surface heme exporter, FLVCR. Knockdown of Flvcr in mice leads to both defective erythropoiesis and disturbed systemic iron homeostasis, underscoring the critical role of heme transporters in mammalian physiology. This article is part of a Special Issue entitled: 11th European Symposium on Calcium.

Investigation of a putative role for FLVCR, a cytoplasmic heme exporter, in Diamond-Blackfan anemia

Diamond-Blackfan anemia (DBA) is a rare congenital pure red cell aplasia. Previous studies indicate that mutations of a gene on chromosome 19q13.2, which encodes a ribosomal protein, are responsible for 25% of cases. Recent investigations suggest both the presence of a second candidate region on chromosome 8p and non-19q, non-8p disease. In linkage analysis studies of 28 multiplex DBA families, we identified 8 families with disease linkage to chromosome 1q31. In 4 families, the disease linked exclusively to 1q31. Here, we report that the FLVCR gene on 1q31, which encodes a cytoplasmic heme exporter associated with red cell aplasia in cats, is not involved in DBA in these families.

Improved transduction of human sheep repopulating cells by retrovirus vectors pseudotyped with feline leukemia virus type C or RD114 envelopes

Gene therapy for hematopoietic diseases has been hampered by the low frequency of transduction of human hematopoietic stem cells (HSCs) with retroviral vectors pseudotyped with amphotropic envelopes. We hypothesized that transduction could be increased by the use of retroviral vectors pseudotyped with envelopes that recognize more abundant cellular receptors. The levels of mRNA encoding the receptors of the feline retroviruses, RD114 and feline leukemia virus type C (FeLV-C), were significantly higher than the level of gibbon ape leukemia virus (GaLV) receptor mRNA in cells enriched for human HSCs (Lin- CD34+ CD38-). We cotransduced human peripheral blood CD34+ cells with equivalent numbers of FeLV-C and GALV or RD114 and GALV-pseudotyped retroviruses for injection into fetal sheep. Analysis of DNA from peripheral blood and bone marrow from recipient sheep demonstrated that FeLV-C- or RD114-pseudotyped vectors were present at significantly higher levels than GALV-pseudotyped vectors. Analysis of individual myeloid colonies demonstrated that retrovirus vectors with FeLV-C and RD114 pseudotypes were present at 1.5 to 1.6 copies per cell and were preferentially integrated near known genes We conclude that the more efficient transduction of human HSCs with either FeLV-C- or RD114-pseudotyped retroviral particles may improve gene transfer in human clinical trials.

Identification of a human heme exporter that is essential for erythropoiesis

FLVCR, a member of the major facilitator superfamily of transporter proteins, is the cell surface receptor for feline leukemia virus, subgroup C. Retroviral interference with FLVCR display results in a loss of erythroid progenitors (colony-forming units-erythroid, CFU-E) and severe anemia in cats. In this report, we demonstrate that human FLVCR exports cytoplasmic heme and hypothesize that human FLVCR is required on developing erythroid cells to protect them from heme toxicity. Inhibition of FLVCR in K562 cells decreases heme export, impairs their erythroid maturation and leads to apoptosis. FLVCR is upregulated on CFU-E, indicating that heme export is important in primary cells at this stage. Studies of FLVCR expression in cell lines suggest this exporter also impacts heme trafficking in intestine and liver. To our knowledge, this is the first description of a mammalian heme transporter.

Genomic structure and evolutionary context of the human feline leukemia virus subgroup C receptor (hFLVCR) gene: evidence for block duplications and de novo gene formation within duplicons of the hFLVCR locus

In this paper we sought to analyze the genomic structure and context of human feline leukemia virus subgroup C receptor (hFLVCR), a human glucarate transporter-like gene at chromosome 1q31, and compare it to that of a paralog (FLVCR14q) at chromosome 14q24. Splicing, polyadenylation, and expression patterns, as estimated by in silico analysis, differed between the two FLVCR genes despite their similar genomic structures, suggesting active and independent evolution of transcriptional and messenger RNA processing patterns after gene duplication. Promoter activity was bi-directional for hFLVCR, but not for its 14q paralog. The upstream 1q transcribed sequences were determined to comprise a novel gene of unknown function, LQK1. Annotation of contigs centered at hFLVCR and FLVCRL14q also revealed highly conserved gene clusters on chromosomes 1 and 14, inferred to result from a duplication. The clusters contained members of the FLVCR, Angel (KIAA0759), JDP, p21SNFT, and TGF- families, as well as two uncharacterized families. The genome-wide locations of both previously recognized and four de novo in silico predicted genes belonging to these seven families were determined. Phylogenetic analyses of these families were consistent with the hypothesis that the 1q/14q duplication occurred early within, or immediately prior to the vertebrate divergence, after the protostome-deuterostome divergence but before the amniote-amphibian divergence.

Cloning of the cellular receptor for feline leukemia virus subgroup C (FeLV-C), a retrovirus that induces red cell aplasia

Feline leukemia virus-C (FeLV-C) causes red cell aplasia in cats, likely through its interaction with its cell surface receptor. We identified this receptor by the functional screening of a library of complementary DNAs (cDNA) from feline T cells. The library, which was cloned into a retroviral vector, was introduced into FeLV-C-resistant murine (NIH 3T3) cells. The gene conferring susceptibility to FeLV-C was isolated and reintroduced into the same cell type, as well as into FeLV-C-resistant rat (NRK 52E) cells, to verify its role in viral infection. The receptor cDNA is predicted to encode a protein of 560 amino acids with 12 membrane-spanning domains, termed FLVCR. FLVCR has significant amino acid sequence homology with members of the major facilitator superfamily and especially D-glucarate transporters described in bacteria and in C. elegans. As FeLV-C impairs the in vivo differentiation of burst-forming unit-erythroid to colony-forming unit-erythroid, we hypothesize that this transporter system could have an essential role in early erythropoiesis. In further studies, a 6-kb fragment of the human FLVCR gene was amplified by polymerase chain reaction from genomic DNA, using homologous cDNA sequences identified in the human Expressed Sequence Tags database. By radiation hybrid mapping, the human gene was localized to a 0.5-centiMorgan region on the long arm of chromosome 1 at q31.3.