Immune-mediated colitis associated with ocrelizumab: A new safety risk.

BACKGROUND: An association between certain immunomodulatory therapies (rituximab, ipilimumab, and other immune checkpoint inhibitors) and inflammatory (non-ischemic and non-infectious) colitis in oncologic and non-oncologic patient populations is well documented in the medical literature. OBJECTIVE: The purpose of this case series is to describe adverse event reports of new onset, inflammatory colitis in association with ocrelizumab in patients with multiple sclerosis submitted to U.S. Food and Drug Administration (FDA) or published in the medical literature. METHODS: The FDA Adverse Event Reporting System (FAERS) and medical literature were searched. RESULTS: A review of postmarketing cases from FAERS and published medical literature identified 38 cases consistent with inflammatory, non-ischemic, and non-infectious colitis in association with ocrelizumab. The median time-to-onset was 8 months. Cases were reported using the following diagnostic terms: Crohn's disease (13), unspecified colitis (11), microscopic colitis (5), ulcerative colitis (5), medication-induced colitis (3), and autoimmune colitis (2). CONCLUSIONS: This case series highlights ocrelizumab induced immune-mediated colitis that can be clinically severe and potentially life-threatening. Based on the findings of this review, the ocrelizumab Prescribing Information was amended to include immune-mediated colitis in the Warnings and Precautions section.

Acute Hyperkinetic Movement Disorders as a Multifactorial Pharmacodynamic Drug Interaction Between Methylphenidate and Risperidone in Children and Adolescents.

PURPOSE/BACKGROUND: Acute hyperkinetic movement disorders have been reported with the concomitant use of attention-deficit/hyperactivity disorder (ADHD) stimulants and antipsychotics in children and adolescents. We analyzed postmarketing reports of suspected acute hyperkinetic movement disorder associated with concomitant use of ADHD stimulants and antipsychotics. METHODS/PROCEDURES: We searched for postmarketing reports of acute hyperkinetic movement disorders associated with concomitant use of ADHD stimulants-antipsychotics in the US Food and Drug Administration Adverse Event Reporting System through December 6, 2019. PubMed and EMBASE were also searched for acute hyperkinetic movement reports with the concomitant use of ADHD stimulants-antipsychotics through January 13, 2020. FINDINGS/RESULTS: We identified 36 cases resulting in acute hyperkinetic movement disorder associated with the concomitant use of ADHD stimulants-antipsychotics, 19 of which were also identified in the medical literature. From an ADHD stimulant perspective, methylphenidate products accounted for the largest number of cases (n = 23 [64%]), followed by amphetamine products (n = 9 [25%]) and atomoxetine (n = 4 [11%]). From an antipsychotic perspective, all 36 cases were reported with second-generation antipsychotics, particularly risperidone (n = 20 [56%]). Most of the cases were reported in boys (n = 31 [86%]) aged 6 to 12 years (n = 27 [75%]). Approximately 53% of the cases reported a time to onset within 24 hours of the drug change. Acute dystonic reactions (n = 27 [75%]) were the most frequently reported movement disorder. IMPLICATIONS/CONCLUSIONS: As outlined in changes to the US prescribing information for all methylphenidate and risperidone products, health care professionals should be aware that changes to this combination may be associated with a pharmacodynamic drug-drug interaction resulting in acute hyperkinetic movement disorder.

Tumefactive multiple sclerosis in association with fingolimod initiation and discontinuation.

BACKGROUND: Tumefactive multiple sclerosis (TMS) is a rare multiple sclerosis (MS) form that usually manifests as the initial presentation or in the early stages of MS. OBJECTIVE: The aim of this study is to evaluate reports of TMS associated with fingolimod use. METHODS: The Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS) database and the medical literature were searched for cases of TMS occurring during or after fingolimod treatment. RESULTS: We identified 29 TMS cases, 19 following fingolimod initiation and 10 following fingolimod discontinuation. In these cases, a TMS diagnosis occurred at a median of 7 years after MS diagnosis, and a median of 7 and 3 months following initiation and discontinuation of fingolimod, respectively. Twenty-two cases were assessed as possible and seven as probable from a causal association perspective. A much larger crude number of TMS reports was observed for fingolimod compared to other disease-modifying therapies. CONCLUSION: TMS should be considered when a severe or atypical MS relapse occurs shortly after fingolimod initiation or discontinuation, and should prompt imaging evaluation and appropriate treatment initiation. Prescribers' awareness of the association between TMS and fingolimod may avoid unnecessary diagnostic procedures. In light of our findings, fingolimod (Gilenya) prescribing information was amended to include TMS in the Warnings and Precautions section.

Expanding spectrum of opportunistic infections associated with dimethyl fumarate.

BACKGROUND: Only progressive multifocal leukoencephalopathy (PML) is currently described in the dimethyl fumarate (DMF) prescribing information. OBJECTIVES: To describe opportunistic infections (OIs), other than PML, reported in association with DMF. METHODS: The FDA Adverse Event Reporting System (FAERS) and medical literature were searched. RESULTS: We retrieved 34 cases of serious OIs with a causal association with DMF, including 11 central nervous system (CNS) infections and 23 extra-CNS infections. Six OIs occurred with normal circulating absolute lymphocyte counts. The median latency from DMF initiation was 13 months and was variable. CONCLUSION: DMF is associated with the development of OIs that require invasive diagnostic and/or therapeutic procedures. Patients should be monitored for OIs when treated with DMF regardless of circulating absolute lymphocyte counts.

Hypertension: A new safety risk for patients treated with erenumab.

OBJECTIVE: To identify and analyze postmarketing case reports of elevated blood pressure (BP) associated with erenumab use. METHODS: A retrospective analysis of postmarketing (spontaneous) case reports of erenumab-associated elevated BP submitted to the FDA Adverse Event Reporting System from May 17, 2018 through April 30, 2020. A case of elevated BP was defined as (a) an initiation of a pharmacological intervention or emergency department visit or hospitalization for emergent de novo or worsening of preexisting hypertension, or (b) BP measurement of ≥140 mm Hg systolic or ≥90 mm Hg diastolic with or without baseline BP measurement reported. Reports of elevated BP associated with erenumab use were analyzed for baseline and demographic information, latency, drug-event causal association, and clinical outcome. RESULTS: Sixty-one cases of elevated BP were identified, 86% (49/57) were women and the median age was 56 [range 24-88] years. Forty-one cases were associated with a serious outcome per regulatory criteria, including seven that specified hospitalization. No case reported an outcome of death. The median systolic BP increase was 39 (interquartile range (IQR) 32, 59) mm Hg and median diastolic BP increase was 28 (IQR 18, 41) mm Hg. A total of 27/61 (44%) cases reported treatment for elevated BP (i.e., pharmacologic intervention or emergency department visit/hospitalization). Elevated BP occurred most frequently (28/61, 46%) within a week of the first dose of erenumab. Nineteen cases (19/61, 31%) reported a history of preexisting hypertension. CONCLUSIONS: This case series suggest an association between elevated BP and use of erenumab. In light of our findings, the erenumab (Aimovig) prescribing information was amended to include hypertension in the Warnings and Precautions section.

Association of eszopiclone, zaleplon, or zolpidem with complex sleep behaviors resulting in serious injuries, including death.

PURPOSE: To identify and analyze postmarketing cases of complex sleep behaviors (CSBs) resulting in serious injuries, including death, associated with eszopiclone, zaleplon, or zolpidem (Z-drugs). METHODS: Retrospective analysis of the U.S. Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS) from 16 December 1992 through 27 February 2018 and medical literature using PubMed and EMBASE. We used random sampling and descriptive statistics. RESULTS: We identified 66 cases that met inclusion and exclusion criteria, four of which were identified in the medical literature. Twenty cases reported death and 46 cases reported serious injuries in association with CSBs occurring after the use of a Z-drug. Fatal cases described events, such as carbon monoxide poisoning, drowning, falls, hypothermia, motor vehicle collisions, and apparent completed suicide. Nonfatal cases resulting in serious injuries described events, such as accidental overdoses, falls, gunshot wounds, hypothermia, third-degree burns, and self-injuries or suicide attempts. Twenty-two cases reported a previous episode of a CSB while taking a Z-drug prior to the event reported in this case series. CONCLUSIONS: The FAERS and medical literature cases support the need for increased awareness of the consequences that may occur because of CSBs associated with the use of Z-drugs. Therefore, to protect public health, regulatory actions were taken, including adding a Boxed Warning, a Contraindication in patients who have experienced a prior episode of a CSB with a Z-drug, and updating the existing Warnings and Precautions. An FDA Drug Safety Communication was also disseminated to alert healthcare professionals and the public of this potential risk.

Long-term efavirenz use is associated with worse neurocognitive functioning in HIV-infected patients.

Neurocognitive (NC) complications continue to afflict a substantial proportion of HIV-infected people taking effective antiretroviral therapy (ART). One contributing mechanism for this is antiretroviral neurotoxicity. Efavirenz (EFV) is associated with short-term central nervous system (CNS) toxicity, but less is known about its long-term effects. Our objective was to compare NC functioning with long-term use of EFV to that of a comparator, lopinavir-ritonavir (LPV/r), in a cohort of well-characterized adults. Four hundred forty-five patients were selected from the CNS HIV Antiretroviral Therapy Effects Research (CHARTER) cohort based on their use of either EFV (n = 272, mean duration 17.9 months) or LPV/r (n = 173, mean duration 16.4 months) and the lack of severe NC comorbidities. All patients had undergone standardized comprehensive NC testing. Univariable and multivariable analyses to predict NC outcomes were performed. Compared with LPV/r users, EFV users were more likely to be taking their first ART regimen (p < 0.001), were less likely to have AIDS (p < 0.001) or hepatitis C virus (HCV) coinfection (p < 0.05), had higher CD4+ T cell nadirs (p < 0.001), had lower peak (p < 0.001) and current (p < 0.001) plasma HIV RNA levels, and were less likely to have detectable HIV RNA in cerebrospinal fluid (CSF) (p < 0.001). Overall, EFV users had worse speed of information processing (p = 0.04), verbal fluency (p = 0.03), and working memory (p = 0.03). An interaction with HCV serostatus was present: Overall among HCV seronegatives (n = 329), EFV users performed poorly, whereas among HCV seropositives (n = 116), LPV/r users had overall worse performance. In the subgroup with undetectable plasma HIV RNA (n = 269), EFV users had worse speed of information processing (p = 0.02) and executive functioning (p = 0.03). Substantial differences exist between EFV and LPV/r users in this observational cohort, possibly because of channeling by clinicians who may have prescribed LPV/r to more severely ill patients or as second-line therapy. Despite these differences, EFV users had worse functioning in several cognitive abilities. A potentially important interaction was identified that could indicate that the NC consequences of specific antiretroviral drugs may differ based on HCV coinfection. The complexity of these data is substantial, and findings would best be confirmed in a randomized clinical trial.

Etravirine in CSF is highly protein bound.

OBJECTIVES: Etravirine has high affinity for plasma drug-binding proteins, such as albumin and α1-acid glycoprotein, which limits the amount of unbound etravirine available to enter the CNS. The objective of this study was to compare total and unbound etravirine concentrations in CSF with plasma concentrations and the in vitro median inhibitory concentration (IC50) for wild-type HIV (0.9 ng/mL). METHODS: Total and bound etravirine concentrations were measured in 17 CSF and plasma pairs by isotope-dilution liquid chromatography tandem mass spectroscopy, radioligand displacement and ultracentrifugation. Unbound etravirine concentrations were calculated from the bound fraction. The dynamic range of the assay was 7.8-2000 (plasma) and 0.78-200 (CSF) ng/mL. RESULTS: Subjects were mostly middle-aged (median 43 years) white (78%) men (89%). All CSF etravirine concentrations were above the limit of quantification. Total and unbound median etravirine concentrations in CSF were 9.5 (IQR 6.4, 26.4) and 0.13 (IQR 0.08, 0.27) ng/mL, respectively. Etravirine was 96% (IQR 94.5, 97.2) protein bound in plasma and 98.4% (IQR 97.8, 98.8) in CSF. Total etravirine in CSF was 4.3% (IQR 3, 5.9) of total and 101% (IQR 76, 160) of unbound etravirine in plasma. There were no significant correlations between unbound etravirine concentrations and concentrations of albumin in plasma or CSF. Unbound etravirine concentrations in CSF did not reach the wild-type IC50 in any of the specimens. CONCLUSIONS: Unbound etravirine may not achieve optimal concentrations to inhibit HIV replication in the CNS.

Darunavir is predominantly unbound to protein in cerebrospinal fluid and concentrations exceed the wild-type HIV-1 median 90% inhibitory concentration.

OBJECTIVES: Higher CSF antiretroviral concentrations may be associated with better control of HIV replication and neurocognitive performance, but only the unbound fraction of antiretrovirals is available to inhibit HIV. Therefore, the objective of this study was to determine total and unbound darunavir concentrations in CSF and compare findings with plasma concentrations as well as the wild-type HIV-1 90% inhibitory concentration (IC(90)). METHODS: Subjects with HIV infection were selected based on the use of darunavir-containing regimens with a twice-daily dosing schedule and availability of stored CSF and matched plasma. Total darunavir was measured by HPLC for plasma or liquid chromatography-tandem mass spectroscopy (LC/MS/MS) for CSF. Plasma unbound darunavir was measured by ultrafiltration and LC/MS/MS. CSF protein binding was determined by competitive binding exchange with radiolabelled darunavir. RESULTS: Twenty-nine matched CSF-plasma pairs were analysed and darunavir was detected in all CSF specimens (median total concentration 55.8 ng/mL), with a CSF unbound fraction of 93.5%. Median fractional penetrance was 1.4% of median total and 9.4% of median unbound plasma concentrations. Unbound darunavir concentrations in CSF exceeded the median IC(90) for wild-type HIV in all subjects by a median of 20.6-fold, despite the relatively low fractional penetrance. Total darunavir concentrations in CSF correlated with both total and unbound darunavir concentrations in plasma. CONCLUSIONS: Darunavir should contribute to the control of HIV replication in the CNS as a component of effective combination antiretroviral regimens.

Increases in brain white matter abnormalities and subcortical gray matter are linked to CD4 recovery in HIV infection.

MRI alterations in the cerebral white (WM) and gray matter (GM) are common in HIV infection, even during successful combination antiretroviral therapy (CART), and their pathophysiology and clinical significance are unclear. We evaluated the association of these alterations with recovery of CD4+ T cells. Seventy-five HIV-infected (HIV+) volunteers in the CNS HIV Anti-Retroviral Therapy Effects Research study underwent brain MRI at two visits. Multi-channel morphometry yielded volumes of total cerebral WM, abnormal WM, cortical and subcortical GM, and ventricular and sulcal CSF. Multivariable linear regressions were used to predict volumetric changes with change in current CD4 and detectable HIV RNA. On average, the cohort (79 % initially on CART) demonstrated loss of total cerebral WM alongside increases in abnormal WM and ventricular volumes. A greater extent of CD4 recovery was associated with increases in abnormal WM and subcortical GM volumes. Virologic suppression was associated with increased subcortical GM volume, independent of CD4 recovery. These findings suggest a possible link between brain alterations and immune recovery, distinct from the influence of virologic suppression. The association of increasing abnormal WM and subcortical GM volumes with CD4+ T cell recovery suggests that neuroinflammation may be one mechanism in CNS pathogenesis.

Therapeutic amprenavir concentrations in cerebrospinal fluid.

Antiretrovirals that reach higher concentrations in cerebrospinal fluid (CSF) are associated with better control of HIV in CSF and possibly better neurocognitive performance. The objective of this study was to determine whether amprenavir (APV) concentrations in CSF are in the therapeutic range. Individuals were selected based on the use of regimens that included fosamprenavir (FPV), a prodrug of APV, and the availability of stored CSF and matched plasma. Total APV was measured in 119 matched CSF-plasma pairs from 75 subjects by high-performance liquid chromatography (HPLC) (plasma) or liquid chromatography tandem mass spectrometry (LC/MS/MS) (CSF). Concentrations were compared to the 50% inhibitory concentration (IC50) for wild-type HIV (5.6 ng/ml). Subjects were predominantly middle-aged (median 44 years) white (57%) men (78%) with AIDS (77%). APV was detected in all but 4 CSF specimens, with a median concentration of 24.8 ng/ml (interquartile range [IQR], 16.2 to 44.0). The median CSF-to-plasma ratio was 0.012 (IQR, 0.008 to 0.018). CSF concentrations correlated with plasma concentrations (rho = 0.61; P < 0.0001) and with postdose sampling interval (rho = -0.29; P = 0.0019). APV concentrations in CSF exceeded the median IC50 for wild-type HIV in more than 97% of CSF specimens with detectable APV by a median of 4.4-fold (IQR, 2.9 to 7.9). We conclude that administration of fosamprenavir should contribute to control of HIV replication in the central nervous system (CNS) as a component of effective antiretroviral regimens.

Sources of Evidence Triggering and Supporting Safety-Related Labeling Changes: A 10-Year Longitudinal Assessment of 22 New Molecular Entities Approved in 2008 by the US Food and Drug Administration.

INTRODUCTION: New safety issues concerning US FDA-approved drugs are commonly communicated through safety-related labeling changes. Therefore, to optimize and refine postmarket safety surveillance strategies, it is important to comprehensively characterize the sources of data giving rise to safety-related labeling changes. OBJECTIVES: Our objective was to characterize the sources of data triggering and supporting the identification of new safety risks of FDA-approved drugs communicated through safety-related labeling changes. METHODS: We conducted a retrospective study with a 10-year observation period using FDA's internal electronic data repositories for all prescription new molecular entities (NME) approved in 2008. We collected and analyzed information on new safety issues, the section of the full prescribing information updated, initiators (FDA, drug manufacturer), and triggering and supporting sources of evidence. RESULTS: Among 22 NMEs approved in 2008, 189 new safety issues for 18 NMEs were identified. Compared to drug manufacturer, FDA initiated safety-related labeling changes in nine of the ten changes to the Boxed Warnings, 28 of the 52 changes to the Warnings and Precautions, and 43 of the 134 changes to the Adverse Reactions sections of the full prescribing information. The most frequent triggering sources of evidence included the drug manufacturer safety database (32.3%) and FDA Adverse Event Reporting System (FAERS) safety reports (15.3%) for all relevant sections of the full prescribing information, and class-labeling changes (17.5%) for Boxed Warnings and the Warnings and Precautions sections. The most frequent triggering source of evidence was FAERS safety reports (69%) in the first year after drug approval and the drug manufacturer safety database in subsequent years. CONCLUSIONS: Our findings emphasize the continued importance of safety reports from FAERS and drug manufacturer safety databases and a comprehensive drug safety surveillance program throughout a drug's lifecycle.

Effect of imaging and catheter characteristics on clinical outcome for patients in the PRECISE study.

The PRECISE study used convection enhanced delivery (CED) to infuse IL13-PE38QQR in patients with recurrent glioblastoma multiforme (GBM) and compared survival to Gliadel Wafers (GW). The objectives of this retrospective evaluation were to assess: (1) catheter positioning in relation to imaging features and (2) to examine the potential impact of catheter positioning, overall catheter placement and imaging features on long term clinical outcome in the PRECISE study. Catheter positioning and overall catheter placement were scored and used as a surrogate of adequate placement. Imaging studies obtained on day 43 and day 71 after resection were each retrospectively reviewed. Catheter positioning scores, catheter overall placement scores, local tumor control and imaging change scores were reviewed and correlated using Generalized Linear Mixed Models. Cox PH regression analysis was used to examine whether these imaging based variables predicted overall survival (OS) and progression free survival (PFS) after adjusting for age and KPS. Of 180 patients in the CED group, 20 patients did not undergo gross total resection. Of the remaining 160 patients only 53% of patients had fully conforming catheters in respect to overall placement and 51% had adequate catheter positioning scores. Better catheter positioning scores were not correlated with local tumor control (P = 0.61) or imaging change score (P = 0.86). OS and PFS were not correlated with catheter positioning score (OS: P = 0.53; PFS: P = 0.72 respectively), overall placement score (OS: P = 0.55; PFS: P = 0.35) or imaging changes on day 43 MRI (P = 0.88). Catheter positioning scores and overall catheter placement scores were not associated with clinical outcome in this large prospective trial.

Total raltegravir concentrations in cerebrospinal fluid exceed the 50-percent inhibitory concentration for wild-type HIV-1.

HIV-associated neurocognitive disorders continue to be common. Antiretrovirals that achieve higher concentrations in cerebrospinal fluid (CSF) are associated with better control of HIV and improved cognition. The objective of this study was to measure total raltegravir (RAL) concentrations in CSF and to compare them with matched concentrations in plasma and in vitro inhibitory concentrations. Eighteen subjects with HIV-1 infection were enrolled based on the use of RAL-containing regimens and the availability of CSF and matched plasma samples. RAL was measured in 21 CSF and plasma pairs by liquid chromatography-tandem mass spectrometry, and HIV RNA was detected by reverse transcription-PCR (RT-PCR). RAL concentrations were compared to the 50% inhibitory concentration (IC(50)) for wild-type HIV-1 (3.2 ng/ml). Volunteers were predominantly middle-aged white men with AIDS and without hepatitis C virus (HCV) coinfection. The median concurrent CD4(+) cell count was 276/µl, and 28% of CD4(+) cell counts were below 200/µl. HIV RNA was detectable in 38% of plasma specimens and 4% of CSF specimens. RAL was present in all CSF specimens, with a median total concentration of 14.5 ng/ml. The median concentration in plasma was 260.9 ng/ml, with a median CSF-to-plasma ratio of 0.058. Concentrations in CSF correlated with those in with plasma (r(2), 0.24; P, 0.02) but not with the postdose sampling time (P, >0.50). RAL concentrations in CSF exceeded the IC(50) for wild-type HIV in all specimens by a median of 4.5-fold. RAL is present in CSF and reaches sufficiently high concentrations to inhibit wild-type HIV in all individuals. As a component of effective antiretroviral regimens or as the main antiretroviral, RAL likely contributes to the control of HIV replication in the nervous system.

Phase I/II dose escalation trial of concurrent temozolomide and whole brain radiation therapy for multiple brain metastasis.

This study sought to establish the recommended phase II dose and efficacy of temozolomide (TMZ) with concurrent radiotherapy in patients with brain metastases. Patients were stratified by prior systemic therapy (≤1 vs. ≥2) and enrolled in cohorts of escalating doses of daily TMZ for 14 days (group A: 75, 95, 115, 135, or 150 mg/m(2), group B: 75, 90, 105, 120, or 135 mg/m(2)). Endpoints included safety and clinical activity. For group A (≤1 prior chemotherapy) no dose limiting toxicity was seen at 75 and 95 mg/m(2). Five of eight patients experienced dose limiting toxicities at 115 mg/m(2), thus the recommended phase II dose was 95 mg/m(2). Arm B (≥2 prior chemotherapy regimens) was closed due to poor enrollment. In the phase II portion, 17 patients in group A were treated. There were 0 patients with complete radiographic response, three with a partial response, ten remained stable, and four demonstrated early progression. The 3 and 6 month progression-free survival (PFS) rates were 41 and 18% with a median PFS time of 2.4 months. Overall survival at 3 and 6 months was 53 and 41%, respectively, with a median survival time of 4.1 months. The maximum tolerated dose of daily TMZ with concurrent WBRT was 95 mg/m(2). Despite dose escalation, outcomes did not appear to be improved in the sample treated.

Acute acalculous cholecystitis: A new safety risk for patients with MS treated with alemtuzumab.

OBJECTIVE: To evaluate acute acalculous cholecystitis (AAC) as a potential safety risk for patients treated with alemtuzumab. METHODS: The Food and Drug Administration Adverse Event Reporting System and the medical literature were searched for cases of AAC in conjunction with alemtuzumab for all clinical indications. RESULTS: Eight spontaneously reported cases meeting the case definition of AAC in close temporal association with alemtuzumab use were identified. Based on established criteria within the Food and Drug Administration Division of Pharmacovigilance for causality assessment, 4 cases were assessed as probable while 4 were possible. All cases occurred in patients with relapsing-remitting multiple sclerosis. Seven of the 8 cases presented with AAC during or shortly after alemtuzumab treatment, thereby suggesting an acute cytokine release syndrome as a putative pathogenic mechanism. The cases identified in this review differ from the typical AAC cases described in the medical literature based on female preponderance, lack of concurrent critical illnesses, inconsistent presence of other risk factors, and resolution with conservative treatment in the majority of cases. CONCLUSIONS: AAC represents a new and potentially life-threatening adverse event associated with alemtuzumab use in relapsing-remitting multiple sclerosis. In cases seen to date, early and conservative treatment resulted in good clinical outcome, although the natural history of AAC in this population without critical illness is not well defined. Awareness of this safety risk by general and specialty neurologists is important for prompt recognition and optimal management.

HIV, prospective memory, and cerebrospinal fluid concentrations of quinolinic acid and phosphorylated Tau.

There is mounting evidence that prospective memory (PM) is impaired during HIV infection despite treatment. In this prospective study, 66 adults (43 HIV+ and 23 HIV negative) underwent PM assessment and cerebrospinal fluid (CSF) examination. HIV+ participants had significantly lower PM but significantly higher CSF concentrations of CXCL10 and quinolinic acid (QUIN). Higher CSF phosphorylated Tau (pTau) was associated with worse PM. In a secondary analysis excluding outliers, higher QUIN correlated with higher pTau. CSF QUIN is thus elevated during HIV infection despite antiretroviral therapy and could indirectly contribute to impaired PM by influencing the formation of pTau.

Clinical utility of a patient-specific algorithm for simulating intracerebral drug infusions.

Convection-enhanced delivery (CED) is a novel drug delivery technique that uses positive infusion pressure to deliver therapeutic agents directly into the interstitial spaces of the brain. Despite the promise of CED, clinical trials have demonstrated that target-tissue anatomy and patient-specific physiology play a major role in drug distribution using this technique. In this study, we retrospectively tested the ability of a software algorithm using MR diffusion tensor imaging to predict patient-specific drug distributions by CED. A tumor-targeted cytotoxin, cintredekin besudotox (interleukin 13-PE38QQR), was coinfused with iodine 123-labeled human serum albumin (123I-HSA), in patients with recurrent malignant gliomas. The spatial distribution of 123I-HSA was then compared to a drug distribution simulation provided by the software algorithm. The algorithm had a high sensitivity (71.4%) and specificity (100%) for identifying the high proportion (7 of 14) of catheter trajectories that failed to deliver drug into the desired anatomical region (p = 0.021). This usually occurred when catheter trajectories crossed deep sulci, resulting in leak of the infusate into the subarachnoid cerebrospinal fluid space. The mean concordance of the volume of distribution at the 50% isodose level between the actual 123I-HSA distribution and simulation was 65.75% (95% confidence interval [CI], 52.0%-79.5%), and the mean maximal inplane deviation was less than 8.5 mm (95% CI, 4.0-13.0 mm). The use of this simulation algorithm was considered clinically useful in 84.6% of catheters. Routine use of this algorithm, and its further developments, should improve prospective selection of catheter trajectories, and thereby improve the efficacy of drugs delivered by this promising technique.

Real-time image-guided direct convective perfusion of intrinsic brainstem lesions. Technical note.

Recent preclinical studies have demonstrated that convection-enhanced delivery (CED) can be used to perfuse the brain and brainstem with therapeutic agents while simultaneously tracking their distribution using coinfusion of a surrogate magnetic resonance (MR) imaging tracer. The authors describe a technique for the successful clinical application of this drug delivery and monitoring paradigm to the brainstem. Two patients with progressive intrinsic brainstem lesions (one with Type 2 Gaucher disease and one with a diffuse pontine glioma) were treated with CED of putative therapeutic agents mixed with Gd-diethylenetriamene pentaacetic acid (DTPA). Both patients underwent frameless stereotactic placement of MR imaging-compatible outer guide-inner infusion cannulae. Using intraoperative MR imaging, accurate cannula placement was confirmed and real-time imaging during infusion clearly demonstrated progressive filling of the targeted region with the drug and Gd-DTPA infusate. Neither patient had clinical or imaging evidence of short- or long-term infusate-related toxicity. Using this technique, CED can be used to safely perfuse targeted regions of diseased brainstem with therapeutic agents. Coinfused imaging surrogate tracers can be used to monitor and control the distribution of therapeutic agents in vivo. Patients with a variety of intrinsic brainstem and other central nervous system disorders may benefit from a similar treatment paradigm.