Interchangeability of biosimilars: A study of expert views and visions regarding the science and substitution

Healthcare systems have reached a critical point regarding the question of whether biosimilar substitution should become common practice. To move the discussion forward, the study objective was to investigate the views of experts from medicines agencies and the pharmaceutical industry on the science underpinning interchangeability of biosimilars. We conducted an empirical qualitative study using semi-structured interviews informed by a cross-disciplinary approach encompassing regulatory science, law, and pharmaceutical policy. In total 25 individuals with experience within biologics participated during September 2018-August 2019. Eight participants were EU national medicines authority regulators, and 17 had pharmaceutical industry background: five from two originator-only companies, four from two companies with both biosimilar and originator products, and eight from seven biosimilar-only companies. Two analysts independently conducted inductive content analysis, resulting in data-driven themes capturing the meaning of the data. The participants reported that interchangeability was more than a scientific question of likeness between biosimilar and reference products: it also pertained to regulatory practices and trust. Participants were overall confident in the science behind exchanging biosimilar products for the reference products via switching, i.e., with physician involvement. However, their opinions differed regarding the scientific risk associated with biosimilar substitution, i.e., without physician involvement. Almost all participants saw no need for additional scientific data to support substitution. Moreover, the participants did not believe that switching studies, as required in the US, were appropriate for obtaining scientific certainty due to their small size. It is unclear why biosimilar switching is viewed as scientifically safer than substitution; therefore, we expect greater policy debate on biosimilar substitution in the near future. We urge European and UK policymakers and regulators to clarify their visions for biosimilar substitution; the positions of these two frontrunners are likely to influence other jurisdictions on the future of biosimilar use.

Optimizing Pediatric Medicine Developments in the European Union Through Pragmatic Approaches

The European Union's Pediatric Regulation has strengthened the development of medicines for children in Europe through its system of obligations and rewards. However, opportunities remain to further optimize pediatric medicine developments, notably in relation to the implementation of the regulatory framework. This paper therefore describes bottlenecks identified by industry that occur during the medicinal development process, including those relating to the scientific advice process, pediatric investigation plan (PIP) development, compliance checks, and study submissions, and offers some considerations and insights to address these. Considerations, which are workable within the current legislative framework, focus on an integrated scientific discussion, optimization of PIP procedures and compliance checks, and an alignment of study-reporting requirements.

Evolving Biosimilar Clinical Requirements: A Qualitative Interview Study with Industry Experts and European National Medicines Agency Regulators

BACKGROUND

A biosimilar is a biological medicine highly similar to another already approved biological medicine (reference product). The availability of biosimilars promotes competition and subsequently lower prices. Changing the current biosimilar clinical comparability trial requirements may lead to lower biosimilar development costs that potentially could increase patients' access to biologics.

OBJECTIVE

The aim was to determine the perceptions of industry and medicines agency regulators regarding the value, necessity, and future developments of the European biosimilar clinical comparability trial requirements for establishing biosimilarity.

METHODS

Semi-structured interviews were conducted with eight European national medicines agency regulators and 17 pharmaceutical company employees or consultants with experience in biologics between September 2018 and August 2019. Data were subjected to content analysis.

RESULTS

In general, the participants expected that clinical comparability trial requirements will continue to be reduced, in particular based on advancements in analytical testing and knowledge generated from prior biosimilar approvals. However, there are also competing issues at play, such as competition, physician's trust, and ethical considerations. Participants also reported that any new initiative to reduce or waive biosimilar clinical requirements needs to be scientifically sound and could potentially lower biosimilar development costs.

CONCLUSION

The main findings are that biosimilar clinical comparability trial requirements are likely to change in the near future. Clarity is needed on how to ensure adequate correlation between physicochemical data, pharmacokinetic/pharmacodynamic studies, and the drugs' performance in the clinic, as well as how to continue sufficient immunogenicity assessment. Obtaining this clarity can facilitate regulatory assessment of the next biosimilars.

Broadband mid-IR frequency comb with CdSiP2 and AgGaS2 from an Er,Tm:Ho fiber laser

We report on the generation of a 2500 nm bandwidth frequency comb at 6.5 μm central wavelength based on critically phase-matched parametric down-conversion in the nonlinear crystal CdSiP(2) (CSP), driven by a compact Er,Tm:Ho fiber laser. The generated ultra-broadband pulses show a transform-limited duration of 2.3 optical cycles and carry up to 150 pJ of energy at a 100 MHz pulse repetition rate. For comparison, the spectrum generated in AgGaS(2) (AGS) spans from 6.2 to 7.4 μm at full-width at half-maximum (FWHM) with a pulse energy of 3 pJ. A full 3D nonlinear wave propagation code is used for optimization of the noncollinear angle, propagation direction, and crystal thickness.

Fiber chirped pulse amplifier at 2.08 μm emitting 383-fs pulses at 10 nJ and 7 MHz

An all-polarization maintaining (PM) fiber chirped pulse amplifier system at 2.08 μm based on thulium:holmium codoped gain fibers is reported. An inhouse built oscillator emits pulses at a repetition rate of 7 MHz with a spectral full width at half-maximum (FWHM) bandwidth of 23.5 nm at 2.8 mW average output power. The pulses are temporally stretched and subsequently amplified in a double-stage amplifier setup. The stretched pulses are compressed to 383 fs by use of a Martinez-style setup at an output pulse energy of 10.2 nJ. By neglecting temporal stretching, high peak powers in a single amplifier stage led to Raman soliton formation at 2.3 μm.

All-PM coherent 2.05 µm Thulium/Holmium fiber frequency comb source at 100 MHz with up to 0.5 W average power and pulse duration down to 135 fs

We report on a dual output all-PM fiber laser system running at 100 MHz repetition rate offering coherent broadband and narrowband pulses centered at 2.05 µm with a spectral FWHM bandwidth of 60 nm and 1.5 nm at up to 360 mW and 500 mW, respectively. The broadband pulses are compressed down to 135 fs. The multi-stage double-clad amplifier based on Tm/Ho codoping is seeded by a supercontinuum light source, spanning from around 1 µm up to 2.4 µm.

An evidence-based mobile decision support system for subaxial cervical spine injury treatment

Bringing evidence to practice is a key issue in modern medicine. The key barrier to information searching is time. Clinical decision support systems (CDSS) can improve guideline adherence. Mounting evidence exists that mobile CDSS on handheld computers support physicians in delivering appropriate care to their patients. Subaxial cervical spine injuries account for almost half of spine injuries, and a majority of spinal cord injuries. A valid and reliable classification exists, including evidence-based treatment algorithms. A mobile CDSS on this topic was not yet available. We developed and tested an iPhone application based on the Subaxial Injury Classification (SLIC) and 5 evidence-based treatment algorithms for the surgical approach to subaxial cervical spine injuries. The application can be downloaded for free. Users are cordially invited to provide feedback in order to direct further development and evaluation of CDSS for traumatic lesions of the spinal column.

The effect of sacral nerve stimulation on uterine activity: a pilot study

INTRODUCTION

Sacral nerve stimulation (SNS) is a treatment for consecutive therapy resistant faecal incontinence or constipation. Little is known about the effects of SNS on uterocervical function. Therefore, it is advised to turn off the stimulator during pregnancy or to wait with permanent implantation of the stimulator until family completion. Diagnostic ultrasound provides an, non-invasive, opportunity to study various aspects of uterine activity. The purpose of this pilot study was to assess the influence of SNS on endometrial waves of the nonpregnant uterus by ultrasound recordings.

METHOD

Six patients with an implanted SNS were included. Ultrasound recordings were performed with the stimulator turned off and in three stimulation frequencies. Uterine activity is described as wave frequency and wave direction.

RESULTS

All three premenopausal patients showed endometrial activity with the stimulator turned off. This activity was maintained with the stimulator turned on in two patients, but disappeared in one patient. All three postmenopausal patients had no endometrial activity with the stimulator turned off. In one patient there was activity with the stimulator turned on at a frequency of 21 Hz.

CONCLUSION

We have shown some effect of SNS on uterine activity. In premenopausal women we discovered that SNS seems to exhibit no effect or an inhibitory effect rather than an excitatory effect on uterine activity. Based on the preliminary results of this study, we can not recommend any guidelines for SNS usage during conception and pregnancy. A larger study in premenopausal women with SNS is needed to investigate the significance of these changes.

Prenatal diagnosis and fetal outcome of cystic adenomatoid malformation of the lung: case report and historical survey

Diagnostic ultrasound allows prenatal diagnosis of cystic adenomatoid malformation of the lung from the second trimester onwards throughout pregnancy. If the diagnosis is made before the 24th week of pregnancy, counselling often results in termination of pregnancy. Whether or not this attitude is in agreement with good medical practice is discussed on the basis of our own experience and a review of the literature.

Dutch general practitioners' attitudes towards the climacteric and its treatment

In order to obtain insight into general practitioners' (GPs) point of view regarding climacteric problems and possible treatment, a survey was conducted among 195 GPs in the Limburg Province in the Netherlands. Ultimately, 159 GPs participated (response-rate 82%). The GPs were either members of the Society for the Improvement of the Expertise of GPs, or filled out the questionnaire previous to participation in a medical training course. The climacteric and its typically related complaints were generally well recognized by the surveyed GPs. Ninety-five percent of the GPs were of the opinion that women with climacteric complaints need some kind of medical help, and 62% were found to prescribe medication, mainly hormone replacement therapy (HRT). Remarkably, 75% of all GPs were of the opinion that prescribing HRT for climacteric complaints is a form of medicalization. Twelve percent of the GPs stated they never prescribe HRT for solely preventive purposes. In case of preventive treatment merely 32% of the GPs prescribed HRT for a period longer than 5 years.

Determination of sulphonamides in pork meat extracts by capillary zone electrophoresis

For sixteen sulphonamides the effective mobility was measured as a function of pH and from the effective mobilities determined in two different electrolyte systems the pK value and mobility at infinite dilution were calculated. A pH of 7.0 was found to be the optimum pH for the separation for both standard mixtures and mixtures of sulphonamides dissolved in pork meat extracts. For the determination of the sulphonamides in pork meat only a very simple pretreatment consisting of extraction with acetonitrile and centrifugation is suitable, as the matrix effects at pH 7.0 do not affect the separation. Calibration graphs for five sulphonamides were constructed, and regression coefficients of at least 0.999 were obtained. The limit of detection for the method varies from 2 to 9 ppm for a pressure injection time of 10 s (injection volume ca. 18 nl) using a Polymicro Technology capillary of length 116.45 cm, distance between injection and detection 109.75 cm and I.D. 50 microns.

Denaturation and renaturation of myeloperoxidase. Consequences for the nature of the prosthetic group

The effects of the chaotropic agent, guanidine HCl, on the chlorinating activity, optical absorption, EPR, and resonance Raman spectra of myeloperoxidase have been studied. In the presence of the agent the Soret optical absorption of the reduced enzyme (lambda max = 474 nm) is blue shifted to 448 nm, a position similar to heme alpha-containing enzymes. The chlorinating activity of the enzyme disappears, and EPR spectra show a loss of intensity of the rhombic high spin heme signals (gx = 6.9; gy = 5.4) and the appearance of a more axial high spin signal (gx = gy = 6.0). Surprisingly the effects of guanidine HCl are partly reversible. Upon decreasing the concentration of the chaotropic agents by dilution, both the chlorinating activity and the original optical spectrum of native reduced enzyme (lambda max = 474 nm) are partly restored. The resonance Raman spectra of denatured cyanomyeloperoxidase are less complicated than those of native myeloperoxidase, which have been interpreted previously to suggest an iron chlorin chromophore. The multiple lines in the oxidation state marker region are not seen in the spectra of the denatured species. The changes suggest that upon denaturation the macrocycle is converted into a more symmetric structure. Since the effects on the optical absorption spectrum are reversible we speculate that, in the native enzyme, an apparent porphyrin macrocycle undergoes a reversible interaction with amino acid residues in the protein which creates an asymmetry in the electronic distribution of the macrocycle. Comparison of the Raman spectra of denatured cyanomyeloperoxidase with those of analogous heme alpha model complexes suggests the presence of a formyl group in the denatured species; our data, however, demonstrate that the chromophore structure is not identical to heme alpha and may contain a different C beta substitution on the ring macrocycle.

Metal-ligand vibrations of cyanoferric myeloperoxidase and cyanoferric horseradish peroxidase: evidence for a constrained heme pocket in myeloperoxidase

The low-frequency FeCN vibrations of cyanoferric myeloperoxidase (MPO) and horseradish peroxidase (HRP) have been measured by resonance Raman spectroscopy. The ordering of the frequencies of the predominantly FeC stretching and FeCN bending normal vibrational modes in the two peroxidases differs. These normal mode vibrations are identified by their wavenumber shifts upon isotopic substitution of the cyanide ligand. For MPO, the stretching mode nu 1 (361 cm-1) occurs at a lower frequency than the bending mode delta 2 (454 cm-1). For HRP, the order is reversed as nu 1 (456 cm-1) is at a higher frequency than delta 2 (404 cm-1). Normal coordinate analyses and model complexes have been used to address the origin of this behavior. The nu 1 stretching frequencies in cyanide complexes of iron porphyrin and iron chlorin model compounds are similar to one another and to that of HRP. Thus, the inverted order and altered frequencies of the nu 1 and delta 2 vibrations in MPO, relative to those in HRP and the model compounds, are not inherent to the proposed iron chlorin prosthetic group in MPO but, rather, are attributed to distinct distal environmental effects in the MPO active site. The normal coordinate analyses for MPO and HRP showed that the nu 1 and delta 2 vibrational frequencies are not pure; the potential energy distributions for these modes respond not only to the geometry but also to the force constants of the nu(FeC) and delta(FeCN) internal coordinates.(ABSTRACT TRUNCATED AT 250 WORDS)

The influence of maternal exercise on the pulsatility index of the umbilical artery blood velocity waveform

Doppler bloodflow velocity measurements in the umbilical arteries are quite generally used as a parameter for obstetrical management, notwithstanding the fact that restricted knowledge is available about the physiological and pathophysiological mechanisms of human umbilical circulation. The possible effects of maternal haemodynamic changes on the fetal circulation are only scarcely investigated. In a prospective study the effect of maternal exercise on the Pulsatility Index (PI) values measured in the umbilical artery with a pulsed Doppler device was assessed to investigate the need of standardization with respect to maternal exertion. The studied group consisted of 23 women with uncomplicated pregnancies of various gestational age, who underwent a moderate strain. Statistical analysis showed no significant difference in FHR and PI values before and after exercise, so it is concluded that it is not necessary to introduce a period of rest to precede a Doppler investigation.

A steady-state study on the formation of Compounds II and III of myeloperoxidase

The reaction between native myeloperoxidase and hydrogen peroxide, yielding Compound II, was investigated using the stopped-flow technique. The pH dependence of the apparent second-order rate constant showed the existence of a protonatable group on the enzyme with a pKa of 4.9. This group is ascribed to the distal histidine imidazole, which must be deprotonated to enable the reaction of Compound I with hydrogen peroxidase to take place. The rate constant for the formation of Compound II by hydrogen peroxide was 3.5.10(4) M-1.s-1. During the reaction of myeloperoxidase with H2O2, rapid reduction of added cytochrome c was observed. This reduction was inhibitable by superoxide dismutase, and this demonstrates that superoxide anion radicals are generated. When potassium ferrocyanide was used as an electron donor to generate Compound II from Compound I, the pH dependence of the apparent second-order rate constant indicated involvement of a group with a pKa of 4.5. However, with ferrocyanide as an electron donor, protonation of the group was necessary to enable the reaction to take place. The rate constant for the generation of Compound II by ferrocyanide was 1.6.10(7) M-1.s-1. We also investigated the reaction of Compound II with hydrogen peroxide, yielding Compound III. Formation of Compound III (k = 50 M-1.s-1) proceeded via two different pathways, one of which was inhibitable by tetranitromethane. We further investigated the stability of Compound II and Compound III as a function of pH, ionic strength and enzyme concentration. The half-life values of both Compound II and Compound III were independent of the enzyme concentration and ionic strength. The half-life value of Compound III was pH-dependent, showing a decreasing stability with increasing pH, whereas the stability of Compound II was independent of pH over the range 3-11.

Identification and properties of an oxoferryl structure in myeloperoxidase compound II

Myeloperoxidase compound II has been characterized by using optical absorption and resonance Raman spectroscopies. Compared to compounds II in other peroxidases, the electronic and vibrational properties of this intermediate are strongly perturbed due to the unusual active-site iron chromophore that occurs in myeloperoxidase. Despite this difference in prosthetic group, however, other properties of myeloperoxidase compound II are similar to those observed for this intermediate in the more common peroxidases (horseradish peroxidase in particular). Two forms of the myeloperoxidase intermediate species, each with distinct absorption spectra, are recognized as a function of pH. We present evidence consistent with interconversion of these two forms via a heme-linked ionization of a distal amino acid residue with a pKa congruent to 9. From resonance Raman studies of isotopically labeled species at pH 10.7, we identify an iron-oxygen stretching frequency at 782 cm-1, indicating the presence of an oxoferryl (O = FeIV) group in myeloperoxidase compound II. We further conclude that the oxo ligand is not hydrogen bonded above the pKa but possibly exhibits oxygen exchange with the medium at pH values below the pKa due to hydrogen bonding of the oxo ligand to the distal protein group.

Singlet oxygen production by human eosinophils

Human eosinophils, stimulated with phorbol myristate acetate, were found to produce 1268 nm chemiluminescence characteristic of singlet oxygen. Singlet oxygen generation required the presence of bromide ion. A bromide ion concentration of 100 microM, comparable to the total bromine content of whole blood, was sufficient for the eosinophils to generate measurable amounts of singlet oxygen. For the conditions used (10(7) cells/ml and 10 micrograms/ml phorbol myristate acetate), the duration of the singlet oxygen generation was brief, about 5 min, and the total yield of singlet oxygen was modest, 1.0 +/- 0.1 microM. The cells remained viable after the singlet oxygen production ceased. This is the first demonstration of singlet oxygen production from living cells. The singlet oxygen generated by eosinophils likely results from a peroxidase-catalyzed mechanism, since a purified eosinophil peroxidase-hydrogen peroxide-bromide system was also shown to produce singlet oxygen. The unique properties of eosinophil peroxidase are illustrated by the fact that at p2H 7.0 and with 100 microM bromide, eosinophil peroxidase generated 20 +/- 2% of the theoretical yield of singlet oxygen, whereas under identical conditions, myeloperoxidase and lactoperoxidase produced only 1.0 +/- 0.1% and -0.1 +/- 0.1%, respectively.

Spectral properties of myeloperoxidase compounds II and III

In order to resolve the confusion about the spectral properties of myeloperoxidase Compound II and Compound III (myeloperoxidase is donor:hydrogen-peroxide oxidoreductase, EC 1.11.1.7), the absorbance spectra in the visible and ultraviolet regions were measured under conditions where either Compound II or Compound III was present. Peak positions, isosbestic points and absorption coefficients are presented. We conclude that in most studies on Compound II or Compound III, mixtures of these compounds had been present. Our data indicate that the relative contributions of Compound II and Compound III in a sample can be determined from the absorbance ratio A625nm/A456nm. The optical absorbance spectrum of myeloperoxidase compound III was not affected by pH (pH 3-8). The absorbance spectrum of Compound II, however, was dependent on pH. The absorbance spectrum of Compound II at high pH is described.

The effect of D-penicillamine on myeloperoxidase: formation of compound III and inhibition of the chlorinating activity

The inhibitory effect of the anti-arthritic drug D-penicillamine on the formation of hypochlorite (HOCl) by myeloperoxidase from H2O2 and Cl- was investigated. When D-penicillamine was added to myeloperoxidase under turnover conditions, Compound III was formed, the superoxide derivative of the enzyme. Compound III was not formed when D-penicillamine was added in the presence of EDTA or in the absence of oxygen. However, when H2O2 was added to myeloperoxidase, D-penicillamine and EDTA, Compound III was formed. Therefore it is concluded that formation of Compound III is initiated by metal-catalysed oxidation of the thiol group of this anti-arthritic drug, resulting in formation of superoxide anions. Once Compound III is formed, a chain reaction is started via which the thiol groups of other D-penicillamine molecules are oxidized to disulphides. Concomitantly, Compound I of myeloperoxidase would be reduced to Compound II and superoxide anions would be generated from oxygen. This conclusion is supported by experiments which showed that formation of Compound III of myeloperoxidase by D-penicillamine depended on the chloride concentration. Thus, an enzyme intermediate which is active in chlorination (i.e. Compound I) participated in the generation of superoxide anions from the anti-arthritic drug. From the results described in this paper it is proposed that D-penicillamine may exert its therapeutic effect in the treatment of rheumatoid arthritis by scavenging HOCl and by converting myeloperoxidase to Compound III, which is inactive in the formation of HOCl.