Cost-effectiveness analysis of adding omega-3 or vitamin D supplementation to standard therapy in treating painful crises of pediatric sickle cell disease patients

OBJECTIVE

Painful crises represents a predominant complication of sickle cell disease (SCD). The only approved treatments for painful crises in many countries are hydroxyurea plus potent analgesics. Our earlier clinical trial concluded that omega-3 and vitamin D had a potential therapeutic impact on painful crises. However, there is limited research evaluating their therapeutic applications and cost-effectiveness. This paper aims at comparing the cost-effectiveness of omega-3 and vitamin D supplementation to the standard therapy in treating painful crises among children with SCD.

PATIENTS AND METHODS

Cost-effectiveness analyses of daily supplementation of omega-3 and vitamin D were performed. The economic evaluation was based on data derived from a prospective 10-month randomized clinical trial (n = 165 patients; 15 patients dropped). 50 patients were recruited into the omega-3 + standard therapy group (hydroxyurea and folic acid daily with ibuprofen as needed), 50 patients into the vitamin D + standard therapy group, and 50 patients receiving standard therapy alone served as a control group. Outcome measures from the randomized clinical trial were used to determine incremental effectiveness. Cost estimates were calculated from the healthcare payer's perspective. The analysis considered the improvement in various outcome measures and are presented here as percent change from baseline to determine the incremental effectiveness and the incremental cost for the treatment of both interventions.

RESULTS

Adding omega-3 or vitamin D to the standard therapy was more cost-effective than standard treatment alone. Vitamin D was a cheaper but less cost-effective alternative for most outcomes between the two treatments, including LDL-C and HDL-C. It was also more cost-effective but less clinically effective in reducing vaso-occlusive crisis episodes and pain severity. Omega-3 supplementation was significantly more cost-effective than vitamin D supplementation and the standard treatment for those measures.

CONCLUSIONS

The present study showed that using vitamin D and omega-3 as add-on treatments for a painful crisis in pediatric sickle cell disease could have overall cost-saving and clinical benefits. However, further studies with a longer treatment duration are needed to establish more significant effects of the interventions for better policy and clinical decision-making.

Comparative effectiveness of adding Omega-3 or Vitamin D to standard therapy in preventing and treating episodes of painful crisis in pediatric sickle cell patients

OBJECTIVE

Sickle Cell Anemia (SCA), also called the Sickle Cell Disease (SCD), is an inherited hematological disorder characterized by a syndrome of acute anemia and a painful crisis. The sickling hemoglobin, Hgb-S causes viscosity and inflammation of blood vessels. Eventually, the red blood cells get eliminated from the circulation process, which leads to hemolytic anemia. This study examined the comparative effectiveness of supplementation of Omega-3 or vitamin-D to standard therapy (hydroxyurea + Ibuprofen) used for prevention and treatment of pain crises in pediatric patients living with SCD.

PATIENTS AND METHODS

165 patients participated in this randomized, double-blind, standard therapy-controlled, parallel-design trial. The patients were randomly divided into three groups, receiving three capsules of either 1,000 mg Omega-3 fish oil (400 mg EPA and 300 mg DHA) or 1.5 mL vitamin-D (2,800 IU/7 ml) daily for 10 months plus the standard therapy. Lactate dehydrogenase, high-density lipoprotein (HDL), low-density lipoprotein (LDL), hematocrit, reticulocyte count, and white-blood-cell count were determined at baseline (month zero) and end of the 10th month. The pain severity was measured using the visual analog scale method (VAS). Therefore, a 10-cm ruler with a VAS design was used to determine the patient pain intensity. The baseline time point was defined as the time spot before starting to deliver the experimental medication to the patients (month zero). At that time, the biodata of the patient on the frequency of pain episodes and the rest of the variables were collected, and the baseline data were one-year retrospective data.

RESULTS

Of 165 patients enrolled in the trial, 150 were included in the final analysis. At the end of the study, there was a significant increase in serum LDL and HDL in the Omega-3 group as compared with the control group (mean of 82 mg/dL vs. 57 mg/dL; p < 0.01 and mean of 47 mg/dL vs. 43 mg/dL; p < 0.028, respectively). Other laboratory parameters were significantly influenced. The number of painful crises and pain levels was significantly decreased in the Omega-3 group compared with the control group (mean of one-episode vs. mean of three episodes; p = 0.01, mean of three on pain scale vs. six on pain scale; p = 0.018).

CONCLUSIONS

Results showed that Omega-3 was more effective than vitamin-D or standard treatment alone relative to pain crises and most of the other studied items. Vitamin-D was more effective than standard therapy alone. Clinicians should consider the addition of Omega-3 supplements to the standard therapy and a de-escalation dose plan for the hydroxyurea medication.

A first-in-human study of the safety, tolerability, pharmacokinetics and pharmacodynamics of PF-06741086, an anti-tissue factor pathway inhibitor mAb, in healthy volunteers

Essentials Tissue factor pathway inhibitor (TFPI) is an antagonist of FXa and the TF-FVIIa complex. PF-06741086 is an IgG1 monoclonal antibody that targets the Kunitz-2 domain of TFPI. Single doses of PF-06741086 were evaluated in a phase 1 study in healthy volunteers. Data from this study support further investigation of PF-06741086 in individuals with hemophilia.

SUMMARY

Background Tissue factor pathway inhibitor (TFPI) is a protease inhibitor of the tissue factor-activated factor VII complex and activated FX. PF-06741086 is a mAb that targets TFPI to increase clotting activity. Objectives This study was a randomized, double-blind, sponsor-open, placebo-controlled, single intravenous or subcutaneous dose escalation study to evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of PF-06741086. Patients/Methods Volunteers who provided written informed consent were assigned to cohorts with escalating dose levels. Safety endpoints included treatment-emergent adverse events (TEAEs), infusion/injection site reactions, vital signs, electrocardiogram, and coagulation and hematology laboratory parameters. Pharmacokinetic (PK) and pharmacodynamic (PD) endpoints included exposures of PF-06741086 in plasma and measures of PF-06741086 pharmacology, respectively. Results Forty-one male volunteers were recruited overall. Thirty-two were dosed with PF-06741086 from 30 mg subcutaneously to 440 mg intravenously. All doses were safe and well tolerated. TEAEs were mild or moderate in severity, laboratory abnormalities were transient, there were no serious adverse events, there were no infusion/injection site reactions, and no dose escalation stopping criteria were met. Plasma exposures of PF-06741086 increased greater than proportionally with dose under the same dosing route. Coagulation pharmacology was demonstrated via total TFPI, dilute prothrombin time, D-dimer, prothrombin fragment 1 + 2 and thrombin generation assay parameters. Conclusions Single doses of PF-06741086 at multiple dose levels were safe and well tolerated in a healthy adult male population. The safety, PK and PD data from this study support progression to a multiple-dose study in hemophilic patients.

The Impact of Pathologic Complete Response in Patients with Neoadjuvantly Treated Locally Advanced Rectal Cancer-a Large Single-Center Experience

Small cohort studies demonstrated better oncologic outcomes for patients with pathologic complete response (PathCR) after neoadjuvant treatment for locally advanced rectal cancer. This study reviews long-term outcomes of a large cohort of clinically stage II/III rectal cancer patients who received neoadjuvant chemoradiation and surgery. This is a retrospective analysis of a single-center cohort, including all clinical stage II/III rectal cancer patients who received neoadjuvant chemoradiation and surgery between 2004 and 2014 (n = 271). Cox regressions were done to assess the influence of PathCR on recurrence-free survival (RFS) and overall survival (OS), adjusting for postoperative chemotherapy, clinical AJCC staging, comorbidity, and age where appropriate. PathCR patients had significantly lower distant recurrence rates (4 vs. 15.8%; P = 0.028) and lower disease-specific mortality rates (0 vs. 8.1%; P = 0.052), compared to patients with residual disease. PathCR was associated with longer RFS (HR, 5.6 [95% CI 1.3-23.1] P = 0.018) and longer OS (HR, 3.4 [1.31-10.0] P = 0.014) compared to having pathological residual disease. This large single-center study shows that patients with PathCR have significant longer RFS and OS than patients with residual disease on pathology after neoadjuvant chemoradiation.

A Double-Blind Controlled Trial of ‘Vivalan’ (Viloxazine Hydrochloride) and Imipramine Hydrochloride in the Treatment of Depression in General Practice

One hundred and twenty-three patients with mild to moderate depressive illness were entered into a double-blind between-patient study of viloxazine hydrochloride (150 mg/day, expressed as base) and imipramine hydrochloride (75 mg/day, expressed as salt) by nine general practitioners. Sixty-two took viloxazine and sixty-one took imipramine. Both drugs produced a statistically highly significant improvement in both the depressive and anxiety symptoms over the period of the study, an effect being seen as early as the seventh day of treatment. Viloxazine produced fewer side-effects than imipramine, in particular significantly less drowsiness and dry mouth. The only side-effect seen with viloxazine was an upper gastro-intestinal disturbance with nausea and occasional vomiting, but this was transient. It is concluded that viloxazine hydrochloride is an effective anti-depressant in mild to moderate cases of depression in general practice and has the advantage of fewer side-effects than imipramine. The absence of sedation with viloxazine is of particular value in the treatment of ambulant patients.

Oxypertine (Integrin) in the Treatment of Morbid Anxiety. Report of a New Low Dosage Schedule

One hundred patients were admitted to a double-blind group comparative trial of two doses of oxypertine (Integrin) in the treatment of morbid anxiety in a general practice setting. The two dosage regimes were 10 mg thrice daily and 5 mg thrice daily respectively, patients being allocated in a random manner to one or other of these. Physicians assessment were made on a modified Hamilton Anxiety Rating Scale on admission and after two and four weeks treatment. A patient's self-rating scale was also carried out on these occasions using a nine item visual analogue scale embracing some symptoms of anxiety states.

Eighty-nine completed case records were available for analysis. Each dosage regime brought about a similar and highly significant improvement after both two and four weeks of treatment.

In both the magnitude of clinical response and rapidity of onset of action the lower dose regime was found to compare favourably with the higher dosage. Each was well tolerated and associated with a very low incidence of undesirable effects.

The Addition of Oxprenolol to Hypertensive Patients Treated with Methyldopa – A General Practice Study

In eighty-seven hypertensive patients in general practice, treated with either methyldopa or the combination of methyldopa and a diuretic, oxprenolol 80 mg was added to the regime with subsequent reduction in methyldopa dosage. In the two groups of patients studied, those whose blood pressure was ‘well controlled’ and another group with a higher blood pressure, the control of blood pressure levels was improved and the incidence of reported tiredness decreased.

A Comparison between Maprotiline (Ludiomil) and Amitriptyline in the Treatment of Depressive Reaction in General Practice

In this trial in depressive reaction in general practice, maprotiline and amitriptyline, in a fixed dosage regime of 50 mg three times daily for three weeks, were equally effective therapeutic agents; all but two of the patients improving during the trial.

Thirteen patients (16% of the group) withdrew from the study due to the severity of side-effects, predominantly because of drowsiness.

In those patients who completed the trial both compounds were relatively well tolerated. The general pattern of side-effects ('mild’ drowsiness and dry mouth) was similar for both treatments, although maprotiline appeared to cause more dizziness than amitriptyline.

Non-Pharmacological Factors in Drug Therapy—The Inter-Action of Doctor, Patient and Tablet Appearance in the Treatment of Anxiety/Depressive Syndromes

The degree to which placebo response is involved in an active treatment situation in normal clinical practice, and the factors comprising the placebo response, have been analyzed in a study on patients with anxiety/depressive syndromes. Four tablet preparations of different appearance but identical pharmacological activity were used over a three week period, and a comparison of therapeutic benefits between ‘treatments', doctors, and doctor—patient groupings was made, in addition to an analysis of the relationship of patients' self-assessments with their physicians' ratings.

The results showed that although direct pharmacological effect was paramount in determining therapeutic outcome, detailed differences were related to various placebo factors. The similarity between physicians' and patients' ratings tends to decrease during the course of treatment, and possible reasons for this are reviewed in the light of previous work.

A Comparative Clinical Trial of Org GB 94 and Imipramine in the Treatment of Depression in General Practice

A double-blind controlled comparative clinical trial of Org GB 94 and imipramine was conducted in general practice. Fifty-five patients were treated with Org GB 94 (60 mg daily) and fifty-four with imipramine (150 mg daily). In the doses employed both agents were equally effective in relieving depression over a four week treatment period. Tolerance of the two agents was similar. Although no statistically significant differences emerged, with regard to both therapeutic effect and some side-effects a trend in favour of Org GB 94 was apparent.

An Open Study of Two Dose Levels of ‘Vivalan’ (Viloxazine Hydrochloride ICI 58 834) in Depression in General Practice

Forty-eight mild to moderate depressives were treated by six genera practitioners with a chemically novel anti-depressant, ‘Vivalan’ (viloxazine hydrochloride, ICI 58 834). Twenty-five patients took 150 mg/day in three divided doses, and twenty-three took 200 mg/day in two divided doses, each for twenty-one days. The severity of both the depressive symptoms and the anxiety symptoms showed a statistically highly significant reduction over the duration of the study. There was no difference between the efficacy of the two dose levels. Viloxazine was generally well tolerated and there was no difference between the two dose levels as far as side-effects or withdrawals were concerned. The usual sedative and anti-cholinergic side-effects of the tricyclic anti-depressants were virtually absent. The only side-effect seen was a transient upper gastro-intestinal disturbance. It was commoner at the high dose but not significantly so. It is concluded that viloxazine hydrochloride appears to be an effective anti-depressant in this type of patient and produces little or no sedative or anti-cholinergic side-effects. Either 150 mg/day or 200 mg/day would seem a reasonable dose to use in general practice.

Patient Preference for a Combined Diuretic/Potassium Regimen: Burinex K

A cross-over investigation was performed to compare patient preference of potassium supplement tablets. Seventy-seven patients requiring diuretics for the long-term management of congestive heart failure were randomly allotted to two therapeutically equivalent regimens; either Burinex K tablets + a placebo Burinex tablet or Slow K tablets + an active Burinex tablet.

Forty-two patients found Burinex K easier to swallow, 9 found Slow K easier to swallow, and 26 patients expressed no preference. There was an appreciably higher incidence of gastro-intestinal upset when patients were taking Slow K.

These results indicate that when long-term diuretic/potassium supplement therapy is required, Burinex K is a more acceptable regimen to the patient than one in which diuretic + Slow K are given separately.

Identification and function probing of an antithrombin IIIβ conformation-specific antibody

ESSENTIALS: Antithrombin III (AT)β binds heparin with higher affinity than ATα. A conformation-specific antibody against ATβ, TPP2009, was made to investigate ATβ in hemostasis. TPP2009 bound specifically to heparin-ATβ and greatly reduced the anticoagulant effect of AT. This antibody was effective in elucidating the importance of ATβ in hemostasis.

BACKGROUND

Antithrombin III (AT)β is an isoform of AT that lacks the post-translational carbohydrate modification at Asn135. This isoform binds heparin with greater affinity than ATα, and has been shown to target antithrombotic function to the extracellular vascular endothelial injury site.

OBJECTIVES

To characterize a conformation-specific antibody against ATβ and begin to investigate the role of ATβ in maintaining hemostasis.

METHODS

Surface plasmon resonance (SPR), antigen binding and functional assays were conducted to characterize the mode of action of antibodies generated against heparin-bound ATβ (ATβ*H) by the use of phage display.

RESULTS

SPR and binding studies showed that one of the antibodies, TPP2009, bound specifically to ATβ*H and glycosaminoglycan-associated ATβ on endothelial cells. In diluted prothrombin and activated factor X (FXa)-induced clotting assays, TPP2009 dose-dependently reduced the anticoagulant effect of heparin in non-hemophilic and FVIII-deficient human plasma, with half-maximal effective concentrations (EC50 ) of 10.5 nm and 4.7 nm, respectively. In AT-deficient human plasma, TPP2009 dose-dependently inhibited the effects of exogenously added ATβ and heparin. In purified systems with ATβ and pentasaccharide, TPP2009 restored > 91% of FXa activity. TPP2009 dose-dependently reversed the effects of heparin in rabbit (EC50 , 25.7 nm) and cynomolgus monkey (EC50 , 21.5 nm) plasma, but not in mouse plasma. TPP2009 was also effective in partially restoring FXa activity in rabbit and cynomolgus monkey plasma treated with FVIII function-neutralizing antibodies.

CONCLUSIONS

TPP2009 specifically targets a unique conformational epitope on ATβ*H and blocks ATβ-mediated anticoagulation. It effectively promotes coagulation in plasma, indicating the importance of ATβ in hemostasis.

Serine proteases and protease-activated receptor 2 mediate the proinflammatory and algesic actions of diverse stimulants

BACKGROUND AND PURPOSE

Although serine proteases and agonists of protease-activated receptor 2 (PAR2) cause inflammation and pain, the spectrum of proteases that are activated by proinflammatory and algesic stimuli and their contribution to inflammatory pain are uncertain.

EXPERIMENTAL APPROACH

Enzymic assays and selective inhibitors were used to characterize protease activity in mice after intraplantar injections of formalin, bradykinin, PAR2 activating peptide (AP) or vehicle. The capacity of these proteases and of recombinant mouse trypsin 4 to cleave fragments of PAR2 and to activate PAR2 in cell lines was determined. Protease inhibitors and par2 (-/-) mice were used to assess the contributions of proteases and PAR2 to pain and inflammation.

KEY RESULTS

Intraplantar injection of formalin, bradykinin or PAR2-AP led to the activation of proteases that were susceptible to the serine protease inhibitor melagatran but resistant to soybean trypsin inhibitor (SBTI). Melagatran inhibited mouse trypsin 4, which degraded SBTI. Proteases generated in inflamed tissues cleaved PAR2-derived peptides. These proteases and trypsin 4 increased [Ca(2+) ]i in PAR2-transfected but not in untransfected cells, and melagatran suppressed this activity. Melagatran or PAR2 deletion suppressed oedema and mechanical hypersensitivity induced by intraplantar formalin, bradykinin and PAR2-AP, but had no effect on capsaicin-induced pain.

CONCLUSIONS AND IMPLICATIONS

Diverse proinflammatory and algesic agents activate melagatran-sensitive serine proteases that cause inflammation and pain by a PAR2-mediated mechanism. By inducing self-activating proteases, PAR2 amplifies and sustains inflammation and pain. Serine protease inhibitors can attenuate the inflammatory and algesic effects of diverse stimuli, representing a useful therapeutic strategy.

Phase II study of gemcitabine, oxaliplatin in combination with panitumumab in KRAS wild-type unresectable or metastatic biliary tract and gallbladder cancer

BACKGROUND

Current data suggest that platinum-based combination therapy is the standard first-line treatment for biliary tract cancer. EGFR inhibition has proven beneficial across a number of gastrointestinal malignancies; and has shown specific advantages among KRAS wild-type genetic subtypes of colon cancer. We report the combination of panitumumab with gemcitabine (GEM) and oxaliplatin (OX) as first-line therapy for KRAS wild-type biliary tract cancer.

METHODS

Patients with histologically confirmed, previously untreated, unresectable or metastatic KRAS wild-type biliary tract or gallbladder adenocarcinoma with ECOG performance status 0-2 were treated with panitumumab 6 mg kg(-1), GEM 1000 mg m(-2) (10 mg m(-2) min(-1)) and OX 85 mg m(-2) on days 1 and 15 of each 28-day cycle. The primary objective was to determine the objective response rate by RECIST criteria v.1.1. Secondary objectives were to evaluate toxicity, progression-free survival (PFS), and overall survival.

RESULTS

Thirty-one patients received at least one cycle of treatment across three institutions, 28 had measurable disease. Response rate was 45% and disease control rate was 90%. Median PFS was 10.6 months (95% CI 5-24 months) and median overall survival 20.3 months (95% CI 9-25 months). The most common grade 3/4 adverse events were anaemia 26%, leukopenia 23%, fatigue 23%, neuropathy 16% and rash 10%.

CONCLUSIONS

The combination of gemcitabine, oxaliplatin and panitumumab in KRAS wild type metastatic biliary tract cancer showed encouraging efficacy, additional efforts of genetic stratification and targeted therapy is warranted in biliary tract cancer.

Glycoengineered factor IX variants with improved pharmacokinetics and subcutaneous efficacy

BACKGROUND

The rapid clearance of factor IX (FIX) necessitates frequent intravenous administration to achieve effective prophylaxis for patients with hemophilia B. Subcutaneous administration would be a preferred route of administration but is limited by bioavailability.

OBJECTIVES

To improve the pharmacokinetics (PK) and bioavailability of FIX, a screen was performed to identify positions for the introduction of novel glycosylation sites with maximal effect on PK and maintenance of coagulation activity.

METHODS

Two hundred fifty-one variants, each containing one additional N-linked glycosylation site, were screened in vitro, and the PK profiles of selected variants mapping to spatially distinct regions of FIX were evaluated in mice. Optimal variants were combined, and their PK and efficacy were determined in mice with hemophilia B.

RESULTS

Variants that mapped to spatially distinct regions of the FIX structure exhibited different degrees of improved PK and enabled selection of optimized sites while minimizing the loss of FIX activity. Combining the most effective N-glycan sites in the same FIX molecule resulted in further improvements in PK. An optimized variant containing three novel N-glycan sites (at amino acids 103, 151, and 228), and the activity enhancing 338A variant had double the specific activity of wild-type FIX, exhibited 4.5-fold reduced clearance and 2.4-fold increased subcutaneous bioavailability, and was efficacious at a fivefold lower mass dose than wild-type FIX after subcutaneous injection in a bleeding model in mice with hemophilia B.

CONCLUSIONS

Glycoengineering was used to significantly improve the subcutaneous PK and efficacy of FIX and may have advantages for subcutaneous dosing.

Stable transformation of soybean by electroporation and root formation from transformed callus

Soybean protoplasts from a number of commercially important cultivars have been genetically engineered by way of electroporation using chimeric genes coding for resistance to the aminoglycoside antibiotics kanamycin and G418. Effective electroporation conditions were determined by monitoring transient expression from aminoglycoside 3'-phosphotransferase II (APHII) expression plasmids. Electroporation of protoplasts with a chimeric APHII gene and subsequent selection on media supplemented with kanamycin resulted in the recovery of calli resistant to the antibiotic. Enzyme assays for APHII activity and Southern blot hybridization confirmed the expression of the foreign DNA and its stable integration into the soybean genome. Root formation was induced from transformed calli, and these roots maintained expression of the APHII gene.

Nanoparticle shape and configuration analysis by transmission electron tomography

Tomographic reconstruction by transmission electron microscopy is used to reveal three-dimensional nanoparticle shapes and the stacking configurations of nanoparticle ensembles. Reconstructions are generated from bright-field image tilt series, with a sample tilt range up to +/- 70 degrees, using single or dual tilt axes. We demonstrate the feasibility of this technique for the analysis of nanomaterials, using appropriate acquisition conditions. Tomography reveals both cubic and hexagonal close-packing configurations in multi-layered arrays of size-selected In nanospheres. By tomography and phase-contrast lattice imaging, we relate the three-dimensional shape of PbSe octahedral nanoparticles to the underlying crystal structure. We also confirm simple-cubic packing in multi-layers of PbSe nanocubes and see evidence that the particle shapes have cubic symmetry. The shapes of TiO(2) nanorod bundles are shown by tomographic reconstruction to resemble flattened ellipsoids.

Early migration of Sarcocystis neurona in ponies fed sporocysts

Sarcocystis neurona is the most important cause of equine protozoal myeloencephalitis (EPM), a neurologic disease of the horse. In the present work, the kinetics of S. neurona invasion is determined in the equine model. Six ponies were orally inoculated with 250 x 10(6) S. neurona sporocysts via nasogastric intubation and killed on days 1, 2, 3, 5, 7, and 9 postinoculation (PI). At necropsy, tissue samples were examined for S. neurona infection. The parasite was isolated from the mesenteric lymph nodes at 1, 2, and 7 days PI; the liver at 2, 5, and 7 days PI; and the lungs at 5, 7, and 9 days PI by bioassays in interferon gamma gene knock out mice (KO) and from cell culture. Microscopic lesions consistent with an EPM infection were observed in brain and spinal cord of ponies killed 7 and 9 days PI. Results suggest that S. neurona disseminates quickly in tissue of naive ponies.

Development and evaluation of a Sarcocystis neurona-specific IgM capture enzyme-linked immunosorbent assay

Equine protozoal myeloencephalitis (EPM) is a serious neurologic disease of horses caused primarily by the protozoal parasite Sarcocystis neurona. Currently available antemortem diagnostic testing has low specificity. The hypothesis of this study was that serum and cerebrospinal fluid (CSF) of horses experimentally challenged with S neurona would have an increased S neurona-specific IgM (Sn-IgM) concentration after infection, as determined by an IgM capture enzyme linked immunoassay (ELISA). The ELISA was based on the S neurona low molecular weight protein SNUCD-1 antigen and the monoclonal antibody 2G5 labeled with horseradish peroxidase. The test was evaluated using serum and CSF from 12 horses experimentally infected with 1.5 million S neurona sporocysts and 16 horses experimentally infected with varying doses (100 to 100,000) of S neurona sporocysts, for which results of histopathologic examination of the central nervous system were available. For horses challenged with 1.5 million sporocysts, there was a significant increase in serum Sn-IgM concentrations compared with values before infection at weeks 2-6 after inoculation (P < .0001). For horses inoculated with lower doses of S neurona, there were significant increases in serum Sn-IgM concentration at various points in time after inoculation, depending on the challenge dose (P < .01). In addition, there was a significant increase between the CSF Sn-IgM concentrations before and after inoculation (P < .0001). These results support further evaluation of the assay as a diagnostic test during the acute phase of EPM.