Pharmacologic management of neuropathic pain: evidence-based recommendations

Patients with neuropathic pain (NP) are challenging to manage and evidence-based clinical recommendations for pharmacologic management are needed. Systematic literature reviews, randomized clinical trials, and existing guidelines were evaluated at a consensus meeting. Medications were considered for recommendation if their efficacy was supported by at least one methodologically-sound, randomized clinical trial (RCT) demonstrating superiority to placebo or a relevant comparison treatment. Recommendations were based on the amount and consistency of evidence, degree of efficacy, safety, and clinical experience of the authors. Available RCTs typically evaluated chronic NP of moderate to severe intensity. Recommended first-line treatments include certain antidepressants (i.e., tricyclic antidepressants and dual reuptake inhibitors of both serotonin and norepinephrine), calcium channel alpha2-delta ligands (i.e., gabapentin and pregabalin), and topical lidocaine. Opioid analgesics and tramadol are recommended as generally second-line treatments that can be considered for first-line use in select clinical circumstances. Other medications that would generally be used as third-line treatments but that could also be used as second-line treatments in some circumstances include certain antiepileptic and antidepressant medications, mexiletine, N-methyl-D-aspartate receptor antagonists, and topical capsaicin. Medication selection should be individualized, considering side effects, potential beneficial or deleterious effects on comorbidities, and whether prompt onset of pain relief is necessary. To date, no medications have demonstrated efficacy in lumbosacral radiculopathy, which is probably the most common type of NP. Long-term studies, head-to-head comparisons between medications, studies involving combinations of medications, and RCTs examining treatment of central NP are lacking and should be a priority for future research.     

Cytokine activation during attacks of the hyperimmunoglobulinemia D and periodic fever syndrome

The hyperimmunoglobulinemia D and periodic fever (hyper-IgD) syndrome is typified by recurrent febrile attacks with abdominal distress, joint involvement (arthralgias/arthritis), headache, skin lesions, and an elevated serum IgD level (> 100 U/mL). This familial disorder has been diagnosed in 59 patients, mainly from Europe. The pathogenesis of this febrile disorder is unknown, but attacks are joined by an acute-phase response. Because this response is considered to be mediated by cytokines, we measured the acute-phase proteins C-reactive protein (CRP) and soluble type-II phospholipase A2 (PLA2) together with circulating concentrations and ex vivo production of the proinflammatory cytokines interleukin-1 alpha (IL-1 alpha), IL-1 beta, IL-6, and tumor necrosis factor alpha (TNF alpha) and the inhibitory compounds IL-1 receptor antagonist (IL-1ra), IL-10, and the soluble TNF receptors p55 (sTNFr p55) and p75 (sTNFr p75) in 22 patients with the hyper-IgD syndrome during attacks and remission. Serum CRP and PLA2 concentrations were elevated during attacks (mean, 213 mg/L and 1,452 ng/mL, respectively) and decreased between attacks. Plasma concentrations of IL-1 alpha, IL-1 beta, or IL-10 were not increased during attacks. TNF alpha concentrations were slightly, but significantly, higher with attacks (104 v 117 pg/mL). Circulating IL-6 values increased with attacks (19.7 v 147.9 pg/mL) and correlated with CRP and PLA2 values during the febrile attacks. The values of the antiinflammatory compounds IL-1ra, sTNFr p55, and sTNFr p75 were significantly higher with attacks than between attacks, and there was a significant positive correlation between each. The ex-vivo production of TNF alpha, IL-1 beta, and IL-1ra was significantly higher with attacks, suggesting that the monocytes/macrophages were already primed in vivo to produce increased amounts of these cytokines. These findings point to an activation of the cytokine network, and this suggests that these inflammatory mediators may contribute to the symptoms of the hyper-IgD syndrome.     

T cells from patients with Hodgkin's disease have a defective T-cell receptor zeta chain expression that is reversible by T-cell stimulation with CD3 and CD28

To investigate the mechanisms underlying the deficiency of T lymphocytes from patients with Hodgkin's disease, we investigated the expression of the T-cell receptor (TCR) zeta chain in patients with Hodgkin's disease. By flow cytometry using an anti-zeta chain monoclonal antibody, peripheral blood T lymphocytes from patients with untreated Hodgkin's disease were shown to express decreased levels of the TCR zeta chain. After stimulation by combined CD3 and CD28 cross- linking, T cells from Hodgkin's disease patients upregulated zeta chain protein expression to normal values within 48 hours and achieved a cytolytic potential and levels of interleukin (IL)-2 secretion that were not different from T cells obtained from healthy controls. These results show that downregulation of the TCR zeta chain in Hodgkin's T lymphocytes is a reversible event. Costimulation of CD3 and CD28 is a novel approach for overcoming the T-cell deficiency in Hodgkin's disease and might be exploited clinically. As upregulation of the zeta chain can also be achieved using bispecific monoclonal antibodies (BI- MoAbs) with specificity for tumor antigens and CD3 and CD28, respectively, an immunotherapy with CD3/CD30 and CD28/CD30 Bi-MoAbs may overcome and should therefore, not be jeopardized by the inherent T- cell deficiency in patients with Hodgkin's disease.     

A randomized study of high-dose cytarabine in induction in acute myeloid leukemia [see comments]

High-dose cytarabine (ara-c) may overcome cytarabine resistance in leukemic blasts. It has been used as a successful salvage and in postremission therapy but not as initial induction treatment. Patients aged 15 to 60 years, presenting with newly diagnosed acute myeloid leukemia (AML) were randomized to receive either high-dose cytarabine, 3 g/m2 12 hourly on days 1, 3, 5, and 7 for 8 doses, daunorubicin 50 mg/m2 days 1 to 3, etoposide 75 mg/m2 days 1 to 7, (HIDAC-3-7) or standard dose cytarabine 100 mg/m2 continuous intravenous infusion for 7 days with daunorubicin and etoposide at the same dose and schedule as above (7-3-7). Patients could receive a second or third induction course if complete remission (CR) was not achieved. All patients received the same postinduction consolidation therapy (5-2-5) for 2 courses. Eligible patients had no prior chemotherapy or myelodysplastic disease. Patients have been followed for a median of 4.5 years. Of 301 patients treated, complete response (CR) was achieved in 71% with HIDAC- 3-7 and 74% with 7-3-7. For patients in CR, the estimated median remission duration was 45 months with HIDAC-3-7 and 12 months with 7-3- 7 (P = .0005 univariate analysis, P = .0004 multivariate analysis). The estimated percentage of patients relapse free 5 years after achieving a CR was 49% on HIDAC-3-7 and 24% on 7-3-7. Patients in CR tended to survive longer with HIDAC-3-7 but there were no overall survival differences between the two arms. HIDAC-3-7 was associated with significantly more toxicity in induction with more leukopenia, thrombocytopenia, nausea, and vomiting and eye toxicity (all P < .001) but a similar incidence of severe central nervous system and cerebellar toxicity compared to 7-3-7. The consolidation treatment was the same in both arms but caused significantly more leukopenia and thrombocytopenia in patients previously treated with HIDAC-3-7 induction (P < .0001). We conclude that a dose-effect exists for cytarabine in AML and that HIDAC- 3-7 prolongs remission duration and disease-free survival and is tolerable when used as initial induction therapy in patients with de novo AML.     

High-dose intravenous gammaglobulin in alloimmunized platelet transfusion recipients

High-dose intravenous gammaglobulin (polyvalent immunoglobulin G) has been shown to be of benefit in some patients with immune thrombocytopenic purpura (ITP), possibly by producing reticuloendothelial system blockade. We studied this approach in patients refractory to random donor platelet transfusion using an IV IgG preparation manufactured by the Swiss Red Cross. Eleven adult patients with acute leukemia received either 0.4 g IgG/kg/d intravenously X five days (four patients) or 0.6 g/kg/d X five days (seven patients). All patients had high levels of lymphocytotoxic antibody and poor responses to random donor platelets. Except for mild headaches in two patients, there were no side effects related to the IgG infusions. All patients had significant elevations of serum IgG on the day after completion of treatment. Either random donor or partially HLA-matched platelet transfusions were administered the day after and, in some cases, during the IgG therapy. No patient had an improvement in one hour posttransfusion platelet count increments. Two additional patients received pooled platelet concentrates incubated for 30 minutes at 37 degrees C with IgG at a final concentration of 3 g% prior to transfusions. These results indicate that high-dose IgG, an extremely expensive treatment, cannot be recommended for alloimmunized adults with leukemia.     

High incidence of monoclonal proteins in the serum and urine of chronic lymphocytic leukemia patients

Chronic lymphocytic leukemia (CLL) is generally considered a nonsecretory B cell immunoproliferative disorder. Conventional electrophoretic and immunoelectrophoretic methods have revealed serum monoclonal proteins in less than 10% of these patients. However, there is increasing experimental evidence from in vitro studies demonstrating that CLL cells may secrete immunoglobulins, particularly free light chains. We examined the serum and urine of 36 consecutive CLL patients for monoclonal proteins using sensitive immunochemical methods (high resolution agarose gel electrophoresis combined with immunofixation). The results obtained were correlated with the Rai stage, quantitative immunoglobulin levels, and lymphocyte membrane immunoglobulin phenotype of the leukemic cells. Twenty-three monoclonal proteins were identified in the serum or urine of 22 patients, an incidence of 61%. Six patients had serum monoclonal proteins, seven had only urinary monoclonal proteins, and nine had monoclonal proteins in serum and urine. In every instance the monoclonal protein was the same light chain type as expressed on the leukemic cells. Our findings suggest that the monoclonal proteins observed in the serum or urine of CLL patients are secretory products of the tumor cells and that their discovery is a function of the sensitivity of the method used for their detection.     

Inactivation of purified human alpha 2-antiplasmin and purified human C1 inhibitor by synthetic fibrinolytic agents

3-Hydroxypropyl flufenamide (Flu-HPA) is one of a series of flufenamic acid derivatives that enhances blood clot lysis in vitro. Studies of possible mechanisms of action of Flu-HPA were undertaken. The profibrinolytic activity of Flu-HPA in clot lysis assays was found to be dependent on plasminogen. The influence of Flu-HPA on the ability of purified alpha 2-antiplasmin to inhibit purified plasmin was studied. Plasmin activity was determined using 125I-fibrin plates or the spectrophotometric tripeptide substrate, Val-Leu-Lys-paranitroanilide. At Flu-HPA concentrations greater than 1 mM, the inhibitory activity of alpha 2-antiplasmin was abolished in a time-dependent and concentration- dependent manner. The influence of Flu-HPA on the ability of purified Cl inhibitor to inhibit purified plasma kallikrein and beta-Factor XIIa was also studied. Cl inhibitor activity was abolished by Flu-HPA at concentrations greater than 2 mM. Notably, Flu-HPA up to 60 mM did not affect the amidolytic activities of plasmin, kallikrein, or beta-Factor XIIa. Flu-HPA did not release enzyme activity from preformed complexes of either alpha 2-antiplasmin and plasmin of Cl inhibitor and kallikrein. A water-soluble derivative of flufenamic acid, N-flufenamyl- glutamic acid, also inactivated alpha 2-antiplasm and Cl inhibitor. This inactivation was shown to be reversible. These results indicate that synthetic fibrinolytic compounds such as flufenamic acid derivatives may promote fibrinolysis by directly inactivating alpha 2- antiplasmin and Cl inhibitor.