Evaluation of correlation between dose and clinical outcomes in subcutaneous immunoglobulin replacement therapy

The importance of serum immunoglobulin (Ig)G concentration in IgG replacement therapy for primary immunodeficiency diseases is established in certain settings. Generally, IgG is infused via the intravenous (IVIG) or subcutaneous (SCIG) route. For IVIG infusion, published data demonstrate that higher IgG doses and trough levels provide patients with improved protection from infection. The same conclusions are not yet accepted for SCIG; data from two recent Phase III studies and a recent post-hoc analysis, however, suggest the same correlation between higher SCIG dose and serum IgG concentration and decreased incidence of infection seen with IVIG. Other measures of clinical efficacy have not been considered similarly. Thus, combined analyses of these and other published SCIG studies were performed; a full comparison of the 13 studies was, however, limited by non-standardized definitions and reporting. Despite these limitations, our analyses indicate that certain clinical outcomes improve at higher SCIG doses and associated higher serum IgG concentrations, and suggest that there might be opportunity to improve patient outcomes via SCIG dose adjustment.

C1 esterase inhibitor concentrate in 1085 Hereditary Angioedema attacks--final results of the I.M.P.A.C.T.2 study

BACKGROUND

The placebo-controlled study International Multicentre Prospective Angioedema C1-INH Trial 1 (I.M.P.A.C.T.1) demonstrated that 20 U/kg C1 esterase inhibitor (C1-INH) concentrate (Berinert®; CSL Behring, Marburg, Germany) is effective in treating acute abdominal and facial Hereditary Angioedema (HAE) attacks.

METHODS

I.M.P.A.C.T.2 was an open-label extension study of I.M.P.A.C.T.1 to evaluate the safety and efficacy of long-term treatment with 20 U/kg C1-INH for successive HAE attacks at any body location. Efficacy outcomes included patient-reported time to onset of symptom relief (primary) and time to complete resolution of all symptoms (secondary), analysed on a per-patient and per-attack basis. Safety assessments included adverse events, vital signs, viral safety and anti-C1-INH antibodies.

RESULTS

During a median study duration of 24 months, 1085 attacks were treated in 57 patients (10-53 years of age). In the per-patient analysis, the median time to onset of symptom relief was 0.46 h and was similar for all types of attacks (0.39-0.48 h); the median time to complete resolution of symptoms was 15.5 h (shortest for laryngeal attacks: 5.8 h; 12.8-26.6 h for abdominal, peripheral and facial attacks). Demographic factors, type of HAE, intensity of attacks, time to treatment, use of androgens and presence of anti-C1-INH antibodies had no clinically relevant effect on the efficacy outcomes. There were no treatment-related safety concerns. No inhibitory anti-C1-INH antibodies were detected in any patient.

CONCLUSIONS

A single dose of 20 U/kg C1-INH concentrate is safe and provides reliable efficacy in the long-term treatment of successive HAE attacks at any body location.

Pharmacokinetics and safety of subcutaneous immune globulin (human), 10% caprylate/chromatography purified in patients with primary immunodeficiency disease

Subcutaneous administration of intravenous immunoglobulin G (IgG) preparations provides an additional level of patient convenience and more options for patients with poor venous access or a history of intravenous IgG reactions. An open-label, pharmacokinetic trial (n = 32) determined the non-inferiority of the subcutaneous versus intravenous route of 10% caprylate/chromatography purified human immune globulin intravenous (IGIV-C; Gamunex®) administration by comparing the steady-state area under the concentration-versus-time curve (AUC) of total plasma IgG in patients with primary immunodeficiency disease. Patients on stable IGIV-C received two intravenous infusions (administered 3 or 4 weeks apart). Seven to 10 days after the second intravenous infusion, all patients switched to a weekly infusion of subcutaneous IGIV-C, with the dose equal to 137% of the previous weekly equivalent intravenous dose, for up to 24 weeks. Samples for pharmacokinetic analysis were collected during steady state for intravenous and subcutaneous IGIV-C treatments. The AUC(0-) τ geometric least-squares mean ratio was 0·89 (90% confidence interval, 0·86-0·92) and met the criteria for non-inferiority. The overall mean steady-state trough concentration of plasma total IgG with subcutaneous IGIV-C was 11·4 mg/ml, 18·8% higher than intravenous IGIV-C (9·6 mg/ml). Subcutaneous IGIV-C was safe and well tolerated. Subcutaneous IGIV-C infusion-site reactions were generally mild/moderate and the incidence decreased over time. No serious bacterial infections were reported. Weekly subcutaneous IGIV-C infusion using 137% of the weekly equivalent intravenous immunoglobulin dose provides an AUC comparable to intravenous administration, thus allowing patients to maintain the same IgG preparation/formulation if switching between intravenous and subcutaneous infusions.

Subcutaneous immunoglobulin: opportunities and outlook

Immunoglobulin (Ig) administration via the subcutaneous (s.c.) route has become increasingly popular in recent years. The method does not require venous access, is associated with few systemic side effects and has been reported to improve patients' quality of life. One current limitation to its use is the large volumes which need to be administered. Due to the inability of tissue to accept such large volumes, frequent administration at multiple sites is necessary. Most studies conducted to date have investigated the use of subcutaneous immunoglobulin (SCIg) in patients treated previously with the intravenous (i.v.) formulation. New data now support the use of s.c. administration in previously untreated patients with primary immunodeficiencies. SCIg treatment may further be beneficial in the treatment of autoimmune neurological conditions, such as multi-focal motor neuropathy; however, controlled trials directly comparing the s.c. and i.v. routes are still to be performed for this indication. New developments may further improve and facilitate the s.c. administration route. For example, hyaluronidase-facilitated administration increases the bioavailability of SCIg, and may allow for the administration of larger volumes at a single site. Alternatively, more concentrated formulations may reduce the volume required for administration, and a rapid-push technique may allow for shorter administration times. As these developments translate into clinical practice, more physicians and patients may choose the s.c. administration route in the future.

Fluticasone propionate/salmeterol hydrofluoroalkane via metered-dose inhaler with integrated dose counter: Performance and patient satisfaction

Currently, patients have to keep track of doses to determine when to replace their metered-dose inhalers (MDIs). This study evaluated the performance and patient satisfaction of a novel MDI with an integrated dose counter. In an open-label study at 38 outpatient centres, patients > or =12 years old with asthma or chronic obstructive pulmonary disease (COPD) received two actuations of fluticasone propionate/salmeterol 125/25 microg (115/21 microg ex-actuator) hydrofluoroalkane (ADVAIR) HFA) via MDI with counter twice a day until all 120 actuations were completed. Concordance between counter and diary recordings in patients who reported use of > or =90% of labelled actuations (completer population, n = 228) was high (discrepancy rate of 0.94%) and the incidence of device firing without changes in counter readings was low (0.13%). Mean expected actuations based on canister weights (114) were slightly lower than mean counter (121) and diary reported actuations (120). Upon study completion, 95% of patients were satisfied with the dose counter and 92% agreed it would help prevent them from running out of medication. Safety assessments (intent-to-treat population, n = 237) indicated that the drug was well tolerated. This integrated MDI counter may help patients maintain better disease control by enabling them to accurately track their medication supply.

Cephaloskeletal dysplasia (Taybi-Linder syndrome: osteodysplastic primordial dwarfism type III): report of two cases and review of the literature

We report two unrelated infants with cephaloskeletal dysplasia or Taybi-Linder syndrome, also referred to as osteodysplastic primordial dwarfism Type III. They presented with peculiar facial features, microcephaly and skeletal and cerebral abnormalities documented radiographically and with cranial MRI and/or CT. Some dissimilarities were observed in the skeletal findings between the two patients, most likely reflecting phenotypic variability within the same disorder. Some radiographic features were shown to evolve with time in both patients. Also of interest is the unusually long survival of these patients, more than 4 years in the first and of over 6 years in the second.

Evaluating children with respiratory tract infections: the role of immunization with bacterial polysaccharide vaccine

Antibody deficiency syndromes are an important cause of recurrent infections in children. Today it is possible to perform a complete evaluation of antibody-mediated immunity leading to a definitive diagnosis of either normal or abnormal immunity in most patients. However, the interpretation of the results of IgG subclass determinations and specific antibody responses is still being defined. At this time our recommendation is that patients who meet the criteria for an evaluation of antibody-mediated immunity be referred to subspecialists trained in this evaluation until better criteria for normal have been developed. The possibility that protective amounts of antibodies against pneumococcal serotypes may develop only transiently must be considered in patients with recurrent infections after initial improvement after immunization, especially if IgG2 subclass deficiency is also present. In the future it may be possible to use a faster and more economical approach to evaluate patients with recurrent infections by immunization with pneumococcal vaccine and then measuring IgM, IgG and IgA along with postimmunization specific antipneumococcal antibody titers 4 to 6 weeks later. For this approach to become feasible, further studies comparing the information obtained from the evaluation of pre- and postimmunization antibody concentrations with that obtained from the evaluation of postimmunization concentrations alone are needed.

Results of endoscopic sinus surgery in pediatric patients with chronic sinusitis and asthma

OBJECTIVE

To determine the efficacy of endoscopic sinus surgery in pediatric patients with chronic sinusitis and asthma.

SETTING

Patients were selected from the tertiary care practice of a pediatric pulmonologist (R.S.) and immunologist (R.L.W.); all underwent sinus surgery at Children's Medical Center at Dallas (Tex).

PATIENTS

Fourteen pediatric patients aged 3.5 to 13 years with severe asthma requiring at least intermittent systemic steroid therapy. All patients had a history of sinusitis aggravating asthma and all had computed tomographic evidence of chronic sinus disease.

INTERVENTION

All patients underwent endoscopic sinus surgery consisting of bilateral total ethmoidectomies and middle meatus antrostomies at a minimum.

MAIN OUTCOME MEASURES

The period 12 months prior to surgery was compared with 12 months postoperatively with regard to total hospitalization days for asthma treatment, number of school days missed, pulmonary function test results, and systemic glucocorticoid medication requirements. Symptom scores for asthma and sinusitis were assessed via parental questionnaire both preoperatively and postoperatively.

RESULTS

No significant difference was found for pulmonary function test results. Eleven of 14 patients demonstrated a significant reduction in hospitalization and school days missed. Twelve of 14 patients experienced a reduction in glucocorticoid requirements. Eleven of 14 and 13 of 14 patients experienced a significant improvement in asthma and sinusitis symptom scores.

CONCLUSION

Endoscopic sinus surgery was effective in reducing sinusitis and improving the overall management of asthma in a majority of study patients.

Persistent enterovirus infection in culture-negative meningoencephalitis: demonstration by enzymatic RNA amplification

Chronic meningoencephalitis due to enterovirus infection can occur in patients with antibody deficiencies. A modified polymerase chain reaction technique demonstrated persistent echovirus 11 infection in such a patient, despite negative routine viral cultures and negative routine nucleic acid hybridization. Although the sequence of echovirus 11 has not yet been determined, genomic conservation among the enteroviruses is significant, permitting detection of echovirus 11 with a primer pair and probe derived from enterovirus serotypes that have been fully sequenced. This study provides the first definitive evidence for the persistence of enterovirus infection with negative viral cultures.

Lack of transmission of human immunodeficiency virus from infected children to their household contacts

The possibility of transmission of the human immunodeficiency virus (HIV) from infected children to their contacts has been confronted in households, schools, day-care centers, and other child care settings. Cases reported to the Centers for Disease Control and several studies of close contacts of HIV-infected patients suggested that the risk of transmission in these settings is extremely low. However, most of these studies involved infected adults or older children. Younger children, who drool, bite, mouth toys, and are incontinent, may be more likely to transmit HIV in these settings. To assess this possibility, the authors tested 89 members of households in which 25 children with HIV infection, most of whom were preschool-aged, resided. Household members had close personal contact with the infected children. They shared many items likely to be soiled with blood and body fluids, such as toys, toothbrushes, eating utensils, toilets, and bathtubs. Hugging, kissing, sharing a bed, and bathing together were common. Household members were tested no sooner than 4 months after initial contact with the infected child, to allow adequate time for sero-conversion. All 89 participating household members were anti-HIV seronegative, and 78 who were tested were serum p24 antigen negative. It was concluded from this study and other evidence that the risk of transmission from children to their contacts is extremely low and has not been clearly documented in the household setting.

Complete protein sequences of the variable regions of the cloned heavy and light chains of a human anti-cytomegalovirus antibody reveal a striking similarity to human monoclonal rheumatoid factors of the Wa idiotypic family

The complete amino acid and nucleotide sequences of the variable regions of the heavy and light polypeptide chains of a human neutralizing IgGl anti-cytomegalovirus (CMV) antibody reveal a striking homology to IgM rheumatoid factors (RFs) of the Wa idiotypic family. The anti-CMV antibody and Wa RFs have in common VKIIIb, JKl, and VHIa gene segments but use different DH and JH gene segments. The anti-CMV antibody does not have RF activity and does not express the Wa idiotype. The Wa RFs do not have anti-CMV activity. A subset of Wa RFs, however, and the anti-CMV antibody do share several idiotypes on the VHIa and VKIIIb polypeptides. Since there are major differences in the antigen binding characteristics and some of the other expressed idiotypes, these data suggest that the D and J region amino acids are crucial to such specificities. Although the use of such highly homologous gene segments in different immune responses is well-documented in murine systems, these data represent the first such example in the human.

In vitro stimulation prior to fusion generates antigen-binding human-human hybridomas

Production of useful human monoclonal antibodies has been limited by the inability to reliably generate and isolate antigen-specific B cells by in vivo immunization. An in vitro culture system employing antigen and mitogen to stimulate lymphocytes derived from solid lymphoid organs has been developed. Human tonsilar or splenic lymphocytes were stimulated in vitro with antigen and mitogen in short term culture and then fused with either of two enzyme deficient human B cell lines. This approach appears to expand antigen-specific B cell clones prior to fusion resulting in the production of a significant number of antigen-binding human hybridoma antibodies. The system has been effective in the production of human monoclonal antibodies following stimulation with KLH-ARS, a soluble antigen, and intact group B streptococcus, a particulate antigen. Hybridomas have been produced by fusion with two distinct parental human B cell lines supporting the previously reported observation that human B lymphoblastoid cell lines representing different stages of B cell differentiation may be useful fusion partners. The utility of the in vitro stimulation system in producing human-human hybridomas secreting antibody directed against two distinct classes of antigens establishes this approach as a generally useful method for the production of human monoclonal antibodies.

Ataxia-telangiectasia associated with sarcoidosis

Ataxia-telangiectasia and sarcoidosis are diseases characterized by abnormalities of the immune system. We examined a 13-year-old female with ataxia-telangiectasia who developed atrophic, violaceous plaques of the skin and a destructive, polyarticular arthritis. The histologic features of both skin and synovium were most consistent with a diagnosis of sarcoidosis. Interaction of these two immunologic disorders may have resulted in the unusual features of this patient's disease.

Caustic substance injuries

Caustic and corrosive substance ingestions are a significant cause of early and late morbidity and may cause esophageal carcinoma after a long latent period. Initial management should be directed at the assurance of adequate ventilation and cardiovascular stability as well as the prevention of vomiting. Early esophagoscopy (to the level of first lesion, if present) is useful to identify those patients who do not need hospitalization or treatment. Esophagoscopy and contrast esophagram are useful to define the full extent of esophageal injury, but should be withheld until after the acute phase. Glucocorticoids are probably useful in limiting the extent and severity of esophageal stricture, the most frequent and significant long-term sequela. Colon interposition is used in those situations in which dilation of a stricture has been unsuccessful, and may prevent the subsequent development of esophageal carcinoma.

Transfusion-associated cytomegalovirus infection and acquired immune deficiency syndrome in an infant

An infant who received multiple blood transfusions in the neonatal intensive care unit developed a transfusion-associated CMV infection at age 11 weeks and thereafter was noted to have hepatosplenomegaly, mitogen hyporesponsiveness, persistent viruria, an abnormal distribution of T-lymphocyte subpopulations, and poor growth. He has had recurrent opportunistic infections, including Pneumocystis carinii pneumonia. Six donors of blood products received by this infant were investigated; one was found to have chronic lymphadenopathy, weight loss, intermittent diarrhea, lymphopenia, and a profound depression of lymphocytes with a helper/inducer surface phenotype (T4 positive). Family members have an abnormal distribution of T cell subpopulations similar to those reported in asymptomatic homosexuals. The course of disease in our patient suggests that acquired immune deficiency syndrome may be transmitted to young infants via blood products.

Use of Epstein-Barr virus-transformed B cell lines for the generation of immunoglobulin-producing human B cell hybridomas

HGPRTase-deficient EBV-transformed B cell lines were shown to be effective fusion partners with mitogen-activated human B cells for the construction of Ig-producing human B cell hybridomas. In a series of experiments using these lines and B cells from several tissue sources, approximatley 20% of the cultures plated were consistently positive for growth after hypoxanthine-aminopterin-thymidine selection and approximatley 30% of these synthesized significant new Ig. A marked increase in Ig secretion was observed after hybridization, which was due to new Ig; Ig from the parental lime was shown to disappear in several instances. Special analyses were carried out on a human hybridoma secreting antibody specific for tetanus toxoid and tetanus toxin and stable subclones were derived. These studies suggest that EBV-transformed lines will prove useful in human hybridization studies, thus making a large library of B cell lines available for the generation of human monoclonal antibodies.

Amino acid sequence of the Fc region of a canine immunoglobulin M: interspecies homology for the IgM class

The amino acid structure for the Fc portion of a canine immunoglobulin mu chain was determined. The sequence was compared with those of two human mu chains, and a high degree of interspecies homology was observed. The preservation of primary structure between species is probably reflective of the unique functions associated with the immunoglobulin M class.

Primary structure of the variable regions of two canine immunoglobulin heavy chains

The complete amino acid sequences of the variable regions of two canine immunoglobulin heavy chains have been determined by automated Edman degradation and found to be strongly homologous to the human VHIII subgroup. The canine sequences were identical with each other at 76 of 113 residue positions. Twenty-three of the 37 differences are located within the four hypervariable regions previously defined by the sequences of several human VHIII proteins. Forty-five of 77 framework residue positions are invariant in the seven human and two canine VHIII proteins which have been completely sequences. The canine proteins are 78% homologous to the framework of the human prototype. Phylogenetically associated residues before the first hypervariable region were confirmed and several potential phylogenetically associated residues were identified between the first and third hypervariable regions. This study represents the first complete amino acid sequences of VH regions of spontaneously occurring, nonhuman homogeneous immunoglobulins. The date demonstrate a high degree of preservation of VHIII structure in another species.

The amino-terminal sequence of the VHIII subgroup of pooled porcine IgG

Pig gamma-chains contain a significant fraction of the unblocked VHIII variable region subgroup. The amino terminal sequence (30 residues) was found to be uniform and more than 90% homologous with the prototype sequence of the human VHIII subgroup. An additional VHIII phylogenetically associated residue, glutamic acid in position 2 was identified in these porcine heavy chains.

Phylogenetically associated residues within the VH3 subgroup of several mammalian species. Evidence for a "pauci-gene" basis for antibody diversity

Immunoglobulin heavy chains from IgG pools of several mammalian species have been subjected to Edman degradation on an automated protein sequencer. The percentage of unblocked vs. blocked heavy chains was estimated from the yield of the invariant valine in the second position. Further analysis of these unblocked polypeptides unequivocally placed them in the V(HIII) subgroup on the basis of homology with known human heavy chain sequences. The mammals studied could be divided into three distinct categories on the basis of the distribution of the V(HIII) subgroup. In several species the V(HIII) subgroup could not be detected while, in others, virtually all of the heavy chains belonged to this subgroup. Several species had intermediate amounts with the level of the V(HIII) subgroup restricted to between 19 and 29% of the total pool. Within experimental error, all members of a given order had a similar V(HIII) subgroup distribution. Further amino acid sequence studies illustrated a high degree of structural homogeneity in the heavy chains of IgG isolated from pooled sera of a number of mammalian species. The very close amino acid sequence homologies of the amino terminal 24 residues of the various pools corroborated conclusions previously obtained using several myeloma proteins from some of these same species. In particular, certain phylogenetically associated residues were identifiable at characteristic positions in the pools in confirmation of their identification in the myeloma proteins. The simplest assumptions would suggest that these findings are more compatible with a pauci-gene than a multi-gene basis for the generation of antibody diversity.