Financial evaluation of value-creating biosimilar development candidates: a business case study of low-, medium- and high-sales biosimilars.

BACKGROUND: Selection of a biosimilar development candidate requires detailed and careful analysis to ensure value creation. RESEARCH DESIGN AND METHODS: We applied the net present value (NPV) model for financial evaluation of biosimilar development candidates for the global market. Biosimilar development candidates from three categories were identified based on the global sales of their respective original biological products (OBPs): >$1 and ≤$4 billion, >$4 and ≤$7 billion and >$7 and ≤$10 billion. The standard NPV and risk-adjusted NPV (rNPV) were calculated under the base-case and various scenarios related to development costs, sales, selling, general and administrative expense, cost of goods sold, and discount rates. RESULTS: A biosimilar to an OBP with sales of $1.6 billion has some financial risk. Biosimilars to OBPs with sales of $5.5 billion and $9.4 billion have very less financial risk under the base-case scenario of analysis. Sales of an OBP had impact on the financial valuation and attractiveness of a biosimilar. Sensitivity of rNPV to different parameters varied for three biosimilars. Discount rates, sales and development costs were important parameters affecting financial valuation of biosimilars. CONCLUSION: Biosimilar development candidate selection requires a thorough financial evaluation considering product-, company- and market-specific aspects.

Implications of the Sap47 null mutation for synapsin phosphorylation, longevity, climbing proficiency and behavioural plasticity in adult Drosophila.

The Sap47 gene of Drosophila melanogaster encodes a highly abundant 47 kDa synaptic vesicle-associated protein. Sap47 null mutants show defects in synaptic plasticity and larval olfactory associative learning but the molecular function of Sap47 at the synapse is unknown. We demonstrate that Sap47 modulates the phosphorylation of another highly abundant conserved presynaptic protein, synapsin. Site-specific phosphorylation of Drosophila synapsin has repeatedly been shown to be important for behavioural plasticity but it was not known where these phospho-synapsin isoforms are localized in the brain. Here, we report the distribution of serine-6-phosphorylated synapsin in the adult brain and show that it is highly enriched in rings of synapses in the ellipsoid body and in large synapses near the lateral triangle. The effects of knockout of Sap47 or synapsin on olfactory associative learning/memory support the hypothesis that both proteins operate in the same molecular pathway. We therefore asked if this might also be true for other aspects of their function. We show that knockout of Sap47 but not synapsin reduces lifespan, whereas knockout of Sap47 and synapsin, either individually or together, affects climbing proficiency, as well as plasticity in circadian rhythms and sleep. Furthermore, electrophysiological assessment of synaptic properties at the larval neuromuscular junction (NMJ) reveals increased spontaneous synaptic vesicle fusion and reduced paired pulse facilitation in Sap47 and synapsin single and double mutants. Our results imply that Sap47 and synapsin cooperate non-uniformly in the control of synaptic properties in different behaviourally relevant neuronal networks of the fruitfly.

Correlation analysis framework for localization-based superresolution microscopy.

Superresolution images reconstructed from single-molecule localizations can reveal cellular structures close to the macromolecular scale and are now being used routinely in many biomedical research applications. However, because of their coordinate-based representation, a widely applicable and unified analysis platform that can extract a quantitative description and biophysical parameters from these images is yet to be established. Here, we propose a conceptual framework for correlation analysis of coordinate-based superresolution images using distance histograms. We demonstrate the application of this concept in multiple scenarios, including image alignment, tracking of diffusing molecules, as well as for quantification of colocalization, showing its superior performance over existing approaches.

TMEM16C facilitates Na(+)-activated K+ currents in rat sensory neurons and regulates pain processing.

TMEM16C belongs to the TMEM16 family, which includes the Ca(2+)-activated Cl(-) channels TMEM16A and TMEM16B and a small-conductance, Ca(2+)-activated, nonselective cation channel (SCAN), TMEM16F. We found that in rat dorsal root ganglia (DRG) TMEM16C was expressed mainly in the IB4-positive, non-peptidergic nociceptors that also express the sodium-activated potassium (K(Na)) channel Slack. Together these channel proteins promote K(Na) channel activity and dampen neuronal excitability. DRG from TMEM16C knockout rats had diminished Slack expression, broadened action potentials and increased excitability. Moreover, the TMEM16C knockout rats, as well as rats with Slack knockdown by intrathecal injection of short interfering RNA, exhibited increased thermal and mechanical sensitivity. Experiments involving heterologous expression in HEK293 cells further showed that TMEM16C modulated the single-channel activity of Slack channels and increased its sodium sensitivity. Our study thus reveals that TMEM16C enhances K(Na) channel activity in DRG neurons and regulates the processing of pain messages.

The Drosophila homologue of tubulin-specific chaperone E-like protein is required for synchronous sperm individualization and normal male fertility.

The tubulin-specific chaperone E-like protein (TBCEL or E-like) of vertebrates shows sequence homology to TBCE, a component of the multimolecular complex required for tubulin heterodimer formation in all eukaryotic cells. TBCEL apparently serves more specific functions, as it is found only in animals. At the cellular level, TBCEL plays a role as a regulator of tubulin stability. It is strongly expressed in human testes, but its systemic function is not known. The gene CG12214 codes for the Drosophila homologue of the vertebrate TBCEL protein. Here we show that disruption of the Drosophila Tbcel gene causes defects in spermatid individualixation, which leads to dispersed migration of F-actin-rich investment cones. Mutations affecting the Tbcel gene cause strong reduction in male, but not female, fertility. However, mature sperm function apparently is not impaired. We generated polyclonal antisera against TBCEL to study its localization and distribution in Drosophila tissues. Immunostainings of wild-type and null mutant testes demonstrated that TBCEL is localized in testes, presumably associated with axoneme bundles prior to spermatid individualization. Molecular analysis of the transposon insertion site in the mutant mulet (mlt), for which male sterility and sperm individualization defects have previously been described, demonstrates that the mlt P-element insertion resides in the Tbcel gene. Our results show that loss of TBCEL in Drosophila is compatible with viability and normal female fertility but causes reduced male fertility. We conclude that Drosophila TBCEL is strongly expressed in testes and plays an important role in sperm individualization during spermatogenesis. The high level of Tbcel mRNA in human testes suggests a general role of TBCEL in animal spermatogenesis. However, Western blots and courtship analysis suggest that TBCEL may have additional functions in the nervous system of Drosophila that could contribute to the observed reduced male fertility. These functions now have to be investigated.

Afadin, a Ras/Rap effector that controls cadherin function, promotes spine and excitatory synapse density in the hippocampus.

Many molecules regulate synaptogenesis, but intracellular signaling pathways required for their functions are poorly understood. Afadin is a Rap-regulated, actin-binding protein that promotes cadherin complex assembly as well as binding many other cell adhesion molecules and receptors. To examine its role in mediating synaptogenesis, we deleted afadin (mllt1), using a conditional allele, in postmitotic hippocampal neurons. Consistent with its role in promoting cadherin recruitment, afadin deletion resulted in 70% fewer and less intense N-cadherin puncta with similar reductions of ß-catenin and αN-catenin puncta densities and 35% reduction in EphB2 puncta density. Its absence also resulted in 40% decreases in spine and excitatory synapse densities in the stratum radiatum of CA1, as determined by morphology, apposition of presynaptic and postsynaptic markers, and synaptic transmission. The remaining synapses appeared to function normally. Thus, afadin is a key intracellular signaling molecule for cadherin recruitment and is necessary for spine and synapse formation in vivo.

Mass spectrometric analysis of synapsins in Drosophila melanogaster and identification of novel phosphorylation sites.

Synapsins are synaptic vesicle-associated phosphoproteins that play a major role in the fine regulation of neurotransmitter release. In Drosophila, synapsins are required for complex behavior including learning and memory. Synapsin isoforms were immunoprecipitated from homogenates of wild-type Drosophila heads using monoclonal antibody 3C11. Synapsin null mutants (Syn(97)) served as negative controls. The eluted proteins were separated by SDS-PAGE and visualized by silver staining. Gel pieces picked from five bands specific for wild type were analyzed by nano-LC-ESI-MS/MS following multienzyme digestion (trypsin, chymotrypsin, AspN, subtilisin, pepsin, and proteinase K). The protein was unambiguously identified with high sequence coverage (90.83%). A number of sequence conflicts were observed and the N-terminal amino acid was identified as methionine rather than leucine expected from the cDNA sequence. Several peptides from the larger isoform demonstrated that the in-frame UAG stop codon at position 582 which separates two large open reading frames is read through by tRNAs for lysine. Seven novel phosphorylation sites in Drosophila synapsin were identified at Thr-86, Ser-87, Ser-464, Thr-466, Ser-538, Ser-961, and Tyr-982 and verified by phosphatase treatment. No phosphorylation was observed at the conserved PKA/CaM kinase-I/IV site (RRFS, edited to RGFS) in domain A or a potential PKA site near domain E.