Are we underdosing acne patients with generic isotretinoin?

With Roche's withdrawl of Accutane from the U.S. market in 2009, isotretinoin has only been available in its generic form. Many clinicians fail to realize that for approval by the U.S. Food and Drug Administration, a generic medication must have a bioequivalence between 80 percent and 125 percent of that of the innovator product. This potential variability in bioavailability between branded and generic medications is important to keep in mind with isotretinoin, given the implications for achieving a sustained remission in acne patients.

Thromboelastographic evaluation of blood coagulation in the presence of branded and generic enoxaparins

AIM

Enoxaparin is the most widely used low-molecular-weight heparin (LMWH) in the USA and has been approved for clinical use in multiple indications. Enoxaparin is a complex biological product with multiple known activities relevant to its antithrombotic effects, and variations in different forms of enoxaparin may have important clinical implications. This study aimed to compare the physiological anticoagulant activity of branded and a generic enoxaparin, using thromboelastography (TEG) to evaluate their effect on the dynamic formation of the blood clot as quantitated by interactions between coagulation factors and inhibitors, fibrinogen, platelets and the fibrinolytic system.

METHODS

Whole native (no preservative) blood was obtained from 7 healthy volunteers. Samples were immediately mixed with various concentrations of branded or generic enoxaparin and TEG was performed to assess anticoagulant activity. Five different batches of each enoxaparin (branded and generic) were tested.

RESULTS

Generic enoxaparin showed more variation in anticoagulation response with a less predictable concentration-dependent and linear response compared with branded enoxaparin. There was also an apparent batch-to-batch variation for generic enoxaparin. The results demonstrated a lower overall anticoagulant effect (P=0.05; no overlap of 95% confidence intervals) with a wider inter-individual variation for generic enoxaparin in comparison with branded enoxaparin. Some individuals responded with a higher than expected anticoagulant response to the given concentration of the generic enoxaparin.

CONCLUSION

The findings of this study suggest that other pre-clinical and clinical studies should be done to validate the clinical interchangeability between branded and generic enoxaparin.

Implementation of a reference-scaled average bioequivalence approach for highly variable generic drug products by the US Food and Drug Administration

Highly variable (HV) drugs are defined as those for which within-subject variability (%CV) in bioequivalence (BE) measures is 30% or greater. Because of this high variability, studies designed to show whether generic HV drugs are bioequivalent to their corresponding HV reference drugs may need to enroll large numbers of subjects even when the products have no significant mean differences. To avoid unnecessary human testing, the US Food and Drug Administration's Office of Generic Drugs developed a reference-scaled average bioequivalence (RSABE) approach, whereby the BE acceptance limits are scaled to the variability of the reference product. For an acceptable RSABE study, an HV generic drug product must meet the scaled BE limit and a point estimate constraint. The approach has been implemented successfully. To date, the RSABE approach has supported four full approvals and one tentative approval of HV generic drug products.

Quality of generic medicines in South Africa: perceptions versus reality - a qualitative study

BACKGROUND

Generic Medicines are an important policy option allowing for access to affordable, essential medicines. Quality of generic medicines must be guaranteed through the activities of national medicines regulatory authorities. Existing negative perceptions surrounding the quality of generic medicines must be addressed to ensure that people use them with confidence. Campaigns to increase the uptake of generic medicines by consumers and providers of healthcare need to be informed by local norms and practices. This study sought to compare South African consumers' and healthcare providers' perceptions of quality of generics to the actual quality of selected products.

METHODS

The study was conducted at the local level in three cities of South Africa: Johannesburg, Durban and Cape Town. Purposive sampling was used to recruit consumer participants (n = 73) and random sampling used to recruit healthcare providers from public and private sectors (n = 15). Data were obtained through twelve focus group discussions with consumers and semi-structured interviews (n = 15) with healthcare providers in order to gain familiarity with perceptions of quality. One hundred and thirty five products comprising paracetamol tablets (n = 47), amoxicillin capsules (n = 45) and hydrochlorothiazide tablets (n = 43) were sourced from public and private sector healthcare providers. These products were subjected to in vitro dissolution, uniformity of weight and identity (Fourier Transformed Infrared Spectroscopy) tests using prescribed methods from the British (2005) and United States Pharmacopeias (2006).

RESULTS

Respondents described drug quality in relation to the effect on symptoms. Procurement and use behavior of healthcare providers was influenced by prior experience, manufacturers' names and consumers' ability to pay. All formulations passed the in vitro tests for quality.

CONCLUSIONS

This study showed clear differences between perceptions of quality and actual quality of medicines suggesting deficiencies in public engagement by government regarding the implementation of generic medicines policy. Implementation of generic medicines policy requires the involvement of consumers and healthcare providers to specifically address their information gaps and needs.

[Generic drugs: we must cut pharmaceutical spending but undertaking drug quality]

The World Health Organization and all drug regulatory agencies (DRA) support the commercialization of generic medicines because they control costs and are irreplaceable therapeutic options in countries lacking the innovator product. Generic drugs are widely considered to be cost-efficient substitutes for brand-name medications. They make up about 20% of the total number of prescriptions in Spain, a figure that is still far from the use of generic drugs in USA and other European countries. Despite economical interest in this issue, in this article we review the interest of generic drugs from a pharmacological and clinical perspective that must undertake drug quality to ensure drug efficacy and safety of the patients. A generic drug (generic drugs, short: generics) is defined as "a drug product that is comparable to brand/reference listed drug product in dosage form, strength, route of administration, quality and performance characteristics, and intended use". Both the reference drug and the generic drug have to demonstrate previously they are therapeutically equivalent. With the exception of parenteral drugs, two products have demonstrated to be therapeutically equivalent if after administration in the same molar dose, their effects with respect to both efficacy and safety are essentially the same, as determined from bioequivalence studies in terms of comparison of appropriate pharmacokinetic parameters and bioavailability. Parenteral formulations, however, are not required to demonstrate therapeutic equivalence because it may be considered self-evident. Such assumptions have never been challenged, but there are reasons to do so for parenteral antimicrobials. It is interesting to highlight that although brand-name drugs and generic drugs are both approved by DRA and may be interchangeable with respect to their clinical effects, they can differ substantially in their appearance. Consumers of brand-name medications receive identical-appearing batches of pills with each refill, whereas consumers of generic drugs must be prepared to receive pills of a different size, color, and shape, depending on which manufacturer is supplying their pharmacies.

[Trends in the quality evaluation of generic products and bioequivalence guidelines]

Recent activities on the generic products such as the revision of bioequivalence guidelines, the accomplish of the reevaluation of the oral dosage forms approved before 1995, and the action program for promoting comfortable use of generics issued by MHLW in 2007, were summarized in this review. The bioequivalence guidelines established in 1997 were revised in 2012 based on the discussion in a dissolution working group (WG). The WG were consists of the members from pharmaceutical companies, academia and regulators belonging to MHLW, PMDA and NIHS. In the revision, some flexibility in the dissolution test conditions was achieved considering the many experiences. And also the special Q&A for the combination products was published at the same time. The reevaluation of the oral products since 1997 was completed in 2010, and 1361 dissolution specifications for 4133 oral products were noticed. Through the reevaluation the sufficient similarity in the dissolution profiles between the standards product and the generic products was achieved in the Japanese pharmaceutical market. In the action program to promote the share of generics, the special committee was established in the NIHS to assess the scientific papers that reported the quality concern of the commercial generic products and to confirm the target quality of the products by testing. Many generic products were checked their dissolution profile similarities to the reference products in multimedia dissolution tests and the appropriate similarities were shown in most products. In some preparations, the purity tests were performed and the content of the impurity is confirmed to be in the acceptance range.