[Face to a bilateral pneumothorax, just scratch your head!]

Head and neck skin angiosarcoma is a rare and aggressive tumor (1 % of head and neck tumors). Prognosis remains poor, with a 5-year survival rate ranging from 10 to 54%, depending on the initial stage. Metastatic disease markedly worsens the prognosis. Metastatic lung involvement is classic and can take on several forms. The cystic form is responsible for numerous complications, particularly pneumothorax. In this case, an 83-year-old patient was diagnosed with bilateral pneumothorax complicating cystic interstitial lung disease, which was revealed by hemoptoic sputum. Skin examination revealed two large necrotic lesions of the calvaria. Anatomo-pathological examination confirmed cutaneous angiosarcoma on both skin biopsy and lung resection. At a metastatic stage, only systemic treatment with paclitaxel can be proposed. The clinical course was unfavorable, leading to death before any specific treatment. This observation highlights the importance of a complete clinical skin examination in the assessment of pulmonary cystic lesions.

AB1586-PARE MULTI-CENTER, RANDOMIZED, OPEN-LABEL, 2-ARM PARALLEL STUDY TO COMPARE THE PHARMACOKINETICS, SAFETY AND TOLERABILITY OF AVT02 ADMINISTERED SUBCUTANEOUSLY VIA PREFILLED SYRINGE OR AUTOINJECTOR IN HEALTHY ADULT VOLUNTEERS

Background

AVT02 is an investigational biosimilar to adalimumab. It is approved in Europe, Canada, and the UK. It is not approved by the US Food and Drug Administration (FDA).

Objectives

To evaluate the pharmacokinetic similarity of 100 mg/mL AVT02, an investigational biosimilar of adalimumab, when administered either via a pre-filled syringe, or with a newly developed autoinjector in healthy adult subjects.

Methods

This was a Phase 1, randomized, open-label, parallel-group study in which 207 healthy adult subjects were randomized in a 1:1 ratio to receive 100 mg/mL AVT02 either via a pre-filled syringe, or with an autoinjector, stratified by body weight. Subjects received a single subcutaneous 40 mg dose on Day 1. Pharmacokinetics, immunogenicity, local injection site reactions, and adverse events were assessed prior to, and up to 64 days after, study drug administration.

Results

The results observed supported the assessment of pharmacokinetic similarity of investigational AVT02 administered by pre-filled syringe or with an autoinjector. The 90% CIs for the ratios of geometric least square means for the primary pharmacokinetic parameters Cmax, AUC0-t, and AUC0-∞ were contained within prespecified margins 80% and 125%, based on an analysis of variance model with treatment as a fixed effect. The mean serum concentration-time profile of adalimumab by treatment group is shown in Figure 1.

Figure 1.

Mean Serum Concentration-Time Profile of Adalimumab by Treatment Group on Semilogarithmic Scale (Pharmacokinetic Population)

Binding anti-drug antibodies were detectable at the end of study visit on Day 64 in 100% and 97.0% of subjects in the pre-filled syringe administration and the autoinjector groups, respectively. Of those subjects positive for anti-drug antibodies, 85.7% and 86.5% further tested positive for neutralizing antibodies in the pre-filled syringe administration and autoinjector groups, respectively. The frequency of local administration site reactions was 11.8% overall and similar between treatment groups. The most frequently reported treatment-emergent adverse events in both treatment groups were under the SOC: Infections and infestations (56.0% in the AVT02-pre-filled syringe group and 45.2% in the AVT02-autoinjector group). The safety profiles were generally similar between treatment groups.

Conclusion

The results observed supported the assessment of pharmacokinetic similarity between the pre-filled syringe and autoinjector delivery systems after a single subcutaneous 40 mg dose. The autoinjector delivery system was generally well tolerated in healthy subjects, with a safety and immunogenicity profile similar to that observed with 100 mg/mL AVT02 administered using a pre-filled syringe.

ClinicalTrials.gov Identifier: NCT03983876

Disclosure of Interests

Christopher Wynne: None declared, Heimo Stroissnig Employee of: Alvotech, Roshan Dias Employee of: Alvotech, Joanna Sobierska Employee of: Alvotech, Eric Guenzi Employee of: Alvotech, Hendrik Otto Employee of: Alvotech, Abid Sattar Employee of: Alvotech, Halimu N. Haliduola Employee of: Alvotech, Elin Edwald Employee of: Alvotech, Fausto Berti Employee of: Alvotech

AB0350 ASSESSMENT OF REAL-LIFE PATIENT HANDLING EXPERIENCE OF AVT02 ADMINISTERED SUBCUTANEOUSLY VIA AUTOINJECTOR IN PATIENTS WITH MODERATE-TO-SEVERE ACTIVE RHEUMATOID ARTHRITIS: AN OPEN-LABEL, SINGLE-ARM CLINICAL TRIAL, THEN AN EXTENSION PHASE OF AVT02 ADMINISTERED WITH A PRE-FILLED SYRINGE (ALVOPAD-PEN)

Background

AVT02 is an investigational biosimilar to adalimumab. It is approved in Europe, Canada, and the UK. It is not approved by the US Food and Drug Administration (FDA).

Objectives

To assess the real-life patient handling of an autoinjector (AI) in adult patients with moderate-to-severe active rheumatoid arthritis (RA) who self-inject AVT02 subcutaneously (s.c.).

Methods

This open-label study enrolled 107 adalimumab-naïve subjects with moderate-to-severe active RA to self-inject AVT02 with the proposed AI 40 mg s.c. in Week 1, and every other week thereafter through Week 8. In an optional extension phase through Week 56, subjects were switched from AVT02 AI to pre-filled syringe and followed for safety and efficacy. The primary endpoint was the percentage of successful self-injections as reported by both the trial site and by subjects using standardized questionnaires at Week 8. Additional endpoints included ease of use and robustness of the AI at Week 8, and efficacy in RA, assessment of serum trough levels of AVT02, and detection of antidrug antibodies (ADA) throughout the study.

Results

The AI success rate was 100% as reported by both the trial site and by subjects. No handling events were noted through Week 8. Approximately 80% (78.1–84.9%) of subjects found the AI ‘very easy’ to use and, in general, less difficulty was reported as the study progressed. The first 110 AIs used were inspected for robustness and none showed any sign of damage or malfunction.

All subjects who completed Week 8 (n = 106) took part in and completed the optional extension phase through Week 56.

At Week 8, 49.1%, 5.7% and 0.9% subjects achieved ACR20, -50 and -70 responses, respectively. Improvement was also reported for the SDAI, DAS28 CRP and HAQ, with scores consistently decreasing through Week 8. In the extension phase, 70.8%, 47.2% and 13.2% subjects achieved ACR20, -50 and -70 responses at Week 56. Improvement was also reported for the SDAI, DAS28 CRP and HAQ, with scores consistently decreasing through Week 56.

From Baseline through Week 8 the mean serum concentrations of investigational AVT02 increased consistently at each visit, reaching a peak at Week 24. There was no significant difference in serum concentrations of AVT02 based on injection subsite (abdomen or thigh).

ADAs were detected in 65.1% of subjects through Week 8, reducing to 49.1% by Week 56. Of ADA-positive subjects, most were also positive for neutralizing antibodies through Week 8 (62.3%) increasing through Week 56 (90.4%). Subjects who were ADA-positive had lower serum concentrations of study drug compared with the overall population at Week 8 and Week 56 as expected.

There were no clinically relevant safety or tolerability issues. Overall, treatment-emergent adverse events reported in at least 5% of subjects at the PT level were anaemia and influenza (6 subjects [5.6%)] reported 6 events each), and no local ISRs were reported.

Conclusion

The fully successful self-injection with the AI in this study supported the use of the device while administering AVT02. Furthermore, subjects typically found the AI easy to use, with ease of use increasing as time progressed.

The ACR20, -50, and -70, SDAI, DAS28 CRP and HAQ results supported the use of AVT02 to treat adult patients with moderate-to-severe RA, with the treatment effect persisting beyond Week 8 and through Week 56.

The safety and immunogenicity profiles were as expected for adalimumab.

ClinicalTrials.gov Identifier: NCT04224194

Disclosure of Interests

Nemanja Damjanov: None declared, Heimo Stroissnig Employee of: Alvotech, Matjaz Steiger Employee of: Alvotech, Joanna Sobierska Employee of: Alvotech, Eric Guenzi Employee of: Alvotech, Hendrik Otto Employee of: Alvotech, Abid Sattar Employee of: Alvotech, Halimu N. Haliduola Employee of: Alvotech, Elin Edwald Employee of: Alvotech, Fausto Berti Employee of: Alvotech

Resistance determinants for beta-lactam antibiotics in laboratory mutants of Streptococcus pneumoniae that are involved in genetic competence

Laboratory mutants of Streptococcus pneumoniae resistant to either cefotaxime or piperacillin reveal defects in competence development independent of the selective beta-lactam. A resistance determinant ciaH encoding a putative histidine kinase of a two-component signal-transducing system that is also involved in competence regulation was recently identified in cefotaxime-resistant mutants. We show now that the CiaH protein can be phosphorylated by ATP in vitro, and that it also phosphorylates the cognate response regulator CiaR. The mutant C306 containing the CiaH mutation Thr-230-Pro is completely noncompetent. It does not release competence-inducing activity (competence factor) into the medium nor can such an activity be released from the cells. Competence in C306 cannot be induced upon addition of external competence factor, in contrast to the competence-defective piperacillin-resistant mutants P506 and P408. A novel resistance determinant cpoA specific for piperacillin was identified in piperacillin-resistant mutants. CpoA is responsible for the competence defect in P506 but not in P408. The results document a tight link between the action of beta-lactams and competence development in the pneumococcus and confirm that the two beta-lactams piperacillin and cefotaxime act via different primary targets.

Characterization of the syringomycin synthetase gene cluster. A link between prokaryotic and eukaryotic peptide synthetases

With this work we have completed the characterization of the syringomycin synthetase gene cluster. In particular, by sequencing additional 28.5 kilobase pairs we show that the nine modules involved in the binding of the nine amino acids of syringomycin are localized on SyrB and SyrE, with SyrE carrying eight modules. The recombinant SyrB and the first and second modules of SyrE (SyrE1 and SyrE2) have been expressed in Escherichia coli and purified. The biochemical data indicate that SyrB binds threonine, the putative precursor of the last amino acid of syringomycin, whereas SyrE1 and SyrE2 bind serine, the first and the second amino acids of syringomycin, respectively. On the basis of the sequence analysis and the biochemical data presented here, it appears that syringomycin synthetase is unique among peptide synthetases in that its genetic organization does not respect the "colinearity rule" according to which the order of the amino acid binding modules along the chromosome parallels the order of the amino acids on the peptide. This feature, together with the absence of a single transcription unit and the absence of epimerase-like domains make syringomycin synthetase more related to the eukaryotic peptide synthetases than to the bacterial counterparts.

Coordinate transcription and physical linkage of domains in surfactin synthetase are not essential for proper assembly and activity of the multienzyme complex

Bacterial peptide synthetases have two common features that appear to be strictly conserved. 1) The enzyme subunits are co-regulated at both transcriptional and translational level. 2) The organization of the different enzymatic domains constituting the enzyme fulfills the "colinearity rule" according to which the order of the domains along the chromosome parallels their functional hierarchy. Considering the high degree of conservation of these features, one would expect that mutations such as transcription uncoupling and domain dissociations, deletions, duplications, and reshuffling would result in profound effects on the quality and quantity of synthesized peptides. To start testing this hypothesis, we designed two mutants. In one mutant, the operon structure of surfactin synthetase was destroyed, thus altering the concerted expression of the enzyme subunits. In the other mutant, the thioesterase domain naturally fused to the last amino acid binding domain of surfactin was physically dissociated and independently expressed. When the lipopeptides secreted by the mutant Bacillus subtilis strains were purified and characterized, they appeared to be expressed approximately at the same level of the wild type surfactin and to be identical to it, indicating that specific domain-domain interactions rather than coordinated transcription and translation play the major role in determining the correct assembly and activity of peptide synthetases.

A quantitative test to estimate neutralizing antibodies to the hepatitis C virus: cytofluorimetric assessment of envelope glycoprotein 2 binding to target cells

Hepatitis C virus (HCV) is a major cause of chronic hepatitis. The virus does not replicate efficiently in cell cultures, and it is therefore difficult to assess infection-neutralizing antibodies and to evaluate protective immunity in vitro. To study the binding of the HCV envelope to cell-surface receptors, we developed an assay to assess specific binding of recombinant envelope proteins to human cells and neutralization thereof. HCV recombinant envelope proteins expressed in various systems were incubated with human cells, and binding was assessed by flow cytometry using anti-envelope antibodies. Envelope glycoprotein 2 (E2) expressed in mammalian cells, but not in yeast or insect cells, binds human cells with high affinity (Kd approximately 10(-8) M). We then assessed antibodies able to neutralize E2 binding in the sera of both vaccinated and carrier chimpanzees, as well as in the sera of humans infected with various HCV genotypes. Vaccination with recombinant envelope proteins expressed in mammalian cells elicited high titers of neutralizing antibodies that correlated with protection from HCV challenge. HCV infection does not elicit neutralizing antibodies in most chimpanzees and humans, although low titers of neutralizing antibodies were detectable in a minority of infections. The ability to neutralize binding of E2 derived from the HCV-1 genotype was equally distributed among sera from patients infected with HCV genotypes 1, 2, and 3, demonstrating that binding of E2 is partly independent of E2 hypervariable regions. However, a mouse monoclonal antibody raised against the E2 hypervariable region 1 can partially neutralize binding of E2, indicating that at least two neutralizing epitopes, one of which is hypervariable, should exist on the E2 protein. The neutralization-of-binding assay described will be useful to study protective immunity to HCV infection and for vaccine development.

A two-component signal-transducing system is involved in competence and penicillin susceptibility in laboratory mutants of Streptococcus pneumoniae

Penicillin resistance in Streptococcus pneumoniae has been attributed so far to the production of penicillin-binding protein (PBP) variants with decreased affinities for beta-lactam antibiotics. Cefotaxime-resistant laboratory mutants, selected after several steps on increasing concentrations of this beta-lactam, become deficient in transformation as well. A DNA fragment conferring both cefotaxime resistance and transformation deficiency was isolated and cloned from the mutant C306. The cefotaxime resistance associated with this resistance determinant was not accompanied with apparent changes in PBP properties, and it mapped on the chromosome distinct from the known resistance determinants, genes encoding PBP2x, PBP1a or PBP2b. Determination of a 2265 bp DNA sequence of the resistance determinant revealed two open reading frames, ciaR and ciaH, whose deduced amino acid sequence identified the corresponding proteins as the response regulator and histidine kinase receptor, respectively (members of the two families of bacterial signal-transducing proteins). Two hydrophobic peptide regions divided the histidine kinase CiaH into two putative domains: an N-terminal extracellular sensor part, and an intracellular C-terminal domain with the conserved His-226 residue, the presumed phosphorylation site. The single point mutations responsible for cefotaxime-resistance and transformation deficiency of C306 and of another two independently isolated cefotaxime-resistant mutants were each located in the C-terminal half of CiaH. A small extracellular protein, the competence factor, is required for induction of competence. Neither C306 nor the transformants obtained with the mutated ciaH gene produced competence factor, and exogenous competence factor could not complement the transformation deficiency, indicating that the signal-transducing system cia is involved in early steps of competence regulation.

A highly conserved repeated DNA element located in the chromosome of Streptococcus pneumoniae

We report the discovery of a group of highly conserved DNA sequences located, in those cases studied, within intergenic regions of the chromosome of the Gram positive Streptococcus pneumoniae. The S. pneumoniae genome contains about 25 of these elements called BOX. From 5' to 3', BOX elements are composed of three subunits (boxA, boxB, and boxC) which are 59, 45 and 50 nucleotides long, respectively. BOX elements containing one, two and four copies of boxB have been observed; boxB alone was also detected in one instance. These elements are unrelated to the two most thoroughly documented families of repetitive DNA sequences present in the genomes of enterobacteria. BOX sequences have the potential to form stable stem-loop structures and one of these, at least, is transcribed. Most of these elements are located in the immediate vicinity of genes whose product has been implicated at some stage in the process of genetic transformation or in virulence of S. pneumoniae. This location raises the intriguing possibility that BOX sequences are regulatory elements shared by several coordinately controlled genes, including competence-specific and virulence-related genes.