Over the last three decades many first-generation nanomedicines have successfully entered routine clinical use and it is now important for medicines regulatory agencies to consider the mechanisms needed to ensure safe introduction of 'follow-on' nanomedicine products, 'nanosimilars'. Moreover, drug regulators need to ensure that 'next'-generation nanomedicines enter clinical development and consequently the market in a safe and timely way for the benefit of public health. Here we review recent European Medicines Agency activities that relate to the effective development and evaluation of nanomedicine products while keeping patient and consumer safety at the forefront.

Bioequivalence studies are performed to demonstrate in vivo that two pharmaceutically equivalent products (in the US) or alternative pharmaceutical products (in the EU) are comparable in their rate and extent of absorption. By definition, for highly variable drugs (HVDs), the estimated within-subject variability is >30%. HVDs often fail to meet current regulatory acceptance criteria for average bioequivalence (ABE). The determination of the bioequivalence of HVDs has been a vexing problem since the inception of the current regulations. It is of concern not only to the generic industry but also to the innovator industry. This article reviews the definition of HVDs, the present regulatory recommendations and the approaches proposed in the literature to deal with the bioequivalence problems of HVDs. The approach of scaled ABE (SABE) is proposed as the most adequate procedure to solve the problem. It is demonstrated that SABE has firm theoretical foundations. In fact, statistical tests similar to SABE are used in various fields, such as psychology and quality control. Algorithms and numerical examples are presented to calculate SABE from the data in conventional two-period and replicate-design studies. The most important feature of SABE is that a fixed sample size is adequate to demonstrate bioequivalence regardless of within-subject variability. The conditions for reaching consistent regulatory decisions with SABE are discussed. The required sample size, for a given statistical power, depends on the regulatory criteria. Sample sizes with different criteria are demonstrated and compared with those arising from a recent informal US FDA proposal. Pragmatic considerations lead to modifications of the theoretical concept of SABE. Several modifications are proposed, including reference scaling, restriction on the estimated geometric mean ratios and possibly limiting SABE to only secondary bioequivalence metrics such as the maximum concentration. Each proposal has its own merit but is also a source of new controversy. Overall, the statistical evaluation of SABE is more complex than that of ABE, which means higher regulatory burden. Standardized open software could be very useful in this regard. A small program script is presented to calculate SABE confidence limits.

Objective. To analyze enzymes involved in joint damage by simultaneous investigation of glycosidases and matrix metalloproteinases (MMPs) in patients with various joint diseases. In joint diseases, the major clinical symptoms and disability of patients are caused by an irreversible destruction of hyaline cartilage. Enzymes capable of degrading extracellular matrix components (collagen and aggrecan) and concomitantly exposing chondrocytes to a variety of cytotoxic and/or apoptosis-inducing factors are considered to be the major effector molecules in cartilage degradation. Methods. Activities of glycosidases (␤-DRecently, significant advances have been made in our understanding of joint destruction and the mechanism of proteolytic cleavage of cartilage. Active proteases are currently implicated in the destructive processes and include matrix metalloproteinases (MMPs), the ADAM family (1), the ADAM-TS family (2), and serine proteases (elastase, cathepsins, and granzymes) (3-5). Of the 4 groups of MMPs, collagenase (MMP-1 in particular) appears to be responsible for the degradation of interstitial collagens. The gelatinases (including MMP-2 and MMP-9) degrade the denatured form of collagens, thus acting in synergy with MMP-1. The stromelysins (including MMP-3) have a broader substrate specificity for non-connective tissue components.

Abstract. Reference-scaled average bioequivalence (RSABE) has been recommended by Food and Drug Administration (FDA), and in its closely related form by European Medicines Agency (EMA), for the determination of bioequivalence (BE) of highly variable (HV) and narrow therapeutic index (NTI) drug products. FDA suggested that RSABE be evaluated by an approximating procedure. Development of an alternative, numerically exact approach was sought. A new algorithm, called Exact, was derived for the assessment of RSABE. It is based upon the observation that the statistical model of RSABE follows a noncentral t distribution. The parameters of the distribution were derived for crossover and parallelgroup study designs. Simulated BE studies of HV and NTI drugs compared the power and consumer risk of the proposed Exact method with those recommended by FDA and EMA. The Exact method had generally slightly higher power than the FDA approach. The consumer risks of the Exact and FDA procedures were generally below the nominal error risk with both methods except for the partial replicate design under certain heteroscedastic conditions. The estimator of RSABE was biased; simulations demonstrated the appropriateness of Hedges' correction. The FDA approach had another, small but meaningful bias. The confidence intervals of RSABE, based on the derived exact, analytical formulas, are uniformly most powerful. Their computation requires in standard cases only a single-line program script. The algorithm assumes that the estimates of the within-subject variances of both formulations are available. With each algorithm, the consumer risk is higher than 5% when the partial replicate design is applied.KEY WORDS: bioequivalence; exact method; highly variable drugs; narrow therapeutic index; reference-scaled average bioequivalence.

Serotonin-1A (5-HT(1A)) receptors are known to play a role in impulsivity-related behavior. The C(-1019)G functional polymorphism (rs6295) has been suggested to regulate the 5-HT(1A) receptor gene (HTR(1A)) expression in presynaptic raphe neurons, namely, increased receptor concentration and reduced neuronal firing could be associated with the G allele. Previous studies indicate that this polymorphism is associated with aggression, suicide, and several psychiatric disorders, yet its association with impulsivity has rarely been investigated. We studied the relationship between impulsivity and the C(-1019)G polymorphism of the HTR(1A) in a population sample of 725 volunteers using the Impulsiveness subscale (IVE-I) of the Eysenck Impulsiveness, Venturesomeness, and Empathy scale and also the Barratt Impulsiveness Scale (BIS-11). Data were analyzed using analysis of variance with age and gender as covariates and Tukey's HSD post-hoc test. Post-hoc analysis revealed that the study had 0.958 power to detect 0.15 effect size. Significant differences between the C(-1019)G genotype groups (GG vs. GC vs. CC) were found. Subjects carrying GG genotype showed significantly higher impulsiveness scores compared to GC or CC carriers for the IVE-I scale (P = 0.014), for the Motor (P = 0.021), Cognitive Impulsiveness (P = 0.002), and for the BIS total score (P = 0.008) but not for the Nonplanning Impulsiveness (P = 0.520) subscale of the BIS-11. Our results suggest the involvement of the HTR(1A) in the continuum phenotype of impulsivity.