Concept: Generic drug
Introduction: Leishmaniasis is a parasitic disease transmitted by phlebotomine sandflies. Between 700,000 and 1.2 million cases of cutaneous leishmaniasis and between 200,000 and 400,000 cases of visceral leishmaniasis (VL), which is fatal if left untreated, occur annually worldwide. Liposomal amphotericin B (LAMB), alone or in combination with other drugs, has been extensively studied as VL treatment, but data on routine field use are limited, and several challenges to patients' access to this life-saving drug remain. Areas covered: This article provides a review of clinical studies on LAMB for VL and other forms of leishmaniasis. The current development of generic versions of LAMB and related challenges are also discussed. Expert opinion: LAMB proved to be highly efficacious and safe in over 8000 VL patients treated by MÉdecins Sans Frontières in South Asia, and its use was feasible even at primary healthcare level. Despite requiring higher doses, LAMB is the drug of choice to treat vulnerable groups (e.g., pregnant or HIV positive) and relapsing VL patients in East Africa. LAMB should be included in national VL guidelines and registered in all VL endemic countries. Its cost should be further reduced and regulatory pathways to prove bioequivalence for generic LAMB products should be implemented.
Gifts from pharmaceutical companies are believed to influence prescribing behavior, but few studies have addressed the association between industry gifts to physicians and drug costs, prescription volume, or preference for generic drugs. Even less research addresses the effect of gifts on the prescribing behavior of nurse practitioners (NPs), physician assistants (PAs), and podiatrists.
The Biopharmaceutics Classification system (BCS) classifies drug substances based on aqueous solubility and intestinal permeability. The objective of this study was to use the World Health Organization Model List of Essential Medicines to determine the distribution of BCS Class 1, 2, 3, and 4 drugs in Abbreviated New drug Applications (ANDA) submissions. To categorize solubility and intestinal permeability properties of generic drugs under development, we used a list of 61 drugs which were classified as BCS 1, 2, 3, and 4 drugs with certainty in the World Health Organization Model List of Essential Medicines. Applying this list to evaluation of 263 ANDA approvals of BCS drugs during the period of 2000 to 2011 indicated 110 approvals (41.8%) for Class 1 drugs (based on both biowaiver and in vivo bioequivalence studies), 55 (20.9%) approvals for Class 2 drugs, 98 (37.3%) approvals for Class 3 drugs, and no (0%) approvals for Class 4 drugs. The present data indicated a trend of more ANDA approvals of BCS Class 1 drugs than Class 3 or Class 2 drugs. Antiallergic drugs in Class 1, drugs for pain relief in Class 2 and antidiabetic drugs in Class 3 have received the largest number of approvals during this period.
PURPOSE: The objective of the study was to investigate the relative bioavailability between the generic tacrolimus products that are presently authorized in Spain by adjusted indirect comparison. This was based on demonstration of bioequivalence with the reference product (Prograf, Astellas Pharma), which makes these generic tacrolimus products prescribable, switchable and therapeutically equivalent to the reference product; yet, according to Spanish legislation, only prescribers can switch tacrolimus-containing products. METHODS: Data from independent bioequivalence studies that compare each generic product with the reference product were combined by adjusted indirect comparisons to investigate the relative bioavailability between generic drug products, since there is no direct bioequivalence study comparing generics to each other. RESULTS: Eight generic tacrolimus products in the form of capsules are presently authorized in Spain, but only five are marketed. These eight products represent only three different generic product developments. One product is authorized with four different names/companies, while another is authorized under three different names/companies. The adjusted indirect comparisons between generic products show bioequivalence within the conventional 80-125 % confidence interval acceptance criteria for area under the curve (AUC) and maximum concentration (Cmax). CONCLUSION: Not only are the generic products bioequivalent with the reference product, but also with each other.
Hydroxychloroquine (HCQ) is a racemic 4-aminoquinoline derivative that was first introduced as an antimalarial, and subsequently applied to the treatment of autoimmune diseases such as rheumatoid arthritis and systemic lupus erythematosus. Information on the pharmacokinetics of HCQ in healthy volunteers, especially in a Chinese population is limited, and this study was conducted to provide support for a generic product to obtain marketing authorization in China.The aim of the present study was to compare the pharmacokinetics and assess bioequivalence of a new generic test and the branded reference hydroxychloroquine sulfate tablets in healthy volunteers.This was a parallel, open-label, randomized, single-dose, 1-period fasting study. 54 healthy subjects were randomly assigned (1:1) to receive 200 mg hydroxychloroquine sulfate tablets of the test or the reference formulation. 15 blood samples were collected and whole blood concentrations of HCQ were determined by a validated liquid chromatography-isotopic dilution mass spectrometry method. Log-transformed Cmax and AUC0-24 values were used to test for bioequivalence. The 2 formulations were considered bioequivalent if 90% confidence intervals (CIs) for the log-transformed ratios of Cmax and AUC0-24 were within the predetermined bioequivalence range of 80-125%. Tolerability was evaluated throughout the study by vital signs, physical examinations, clinical laboratory tests, 12-lead electrocardiograms, and interviews with the subjects about adverse events.54 healthy subjects were enrolled and completed the study (mean [SD] age, height, body weight, and BMI were 23.9 [2.4] years, 168.9 [5.0] cm, 61.3 [5.4] kg, and 21.5 [1.7] kg/m2), 27 subjects per group. No formulation or sequence effects were observed. The mean values of Cmax and AUC0-24 for the test and reference formulations of HCQ (197.6 and 199.0 ng/mL, 2460.1 and 2468.3 ng/mL/h) were not significantly different. The 90% CIs of the ratios of Cmax and AUC0-24 were 99.3% (98.1-102.1%), 99.7% (98.9-101.4%), respectively. 4 subjects (7.41%) experienced a total of 4 mild AEs (headache and microscopic hematuria, 1 each; and increase in plasma triglycerides, 2).The results of this study suggest that the test and reference hydroxychloroquine sulfate tablets are bioequivalent. Both formulations were generally well tolerated.
The purpose of this review is to discuss the process of genericisation of medications in the US and Europe with a focus on ophthalmic drugs. Regulatory guidelines of the US Food and Drug Administration and the European Medicines Agency will be discussed, and the advantages and concerns of genericisation will be explored. We will look at various studies concerning the safety and efficacy of generic drugs compared to their branded counterparts. In particular, the challenges of assuring bioequivalence and therapeutic equivalence in topical ophthalmic drugs will be examined.
Abstract Objective To provide evidence on recent trends in: (1) market exclusivity periods (MEPs, the time between launch of a brand-name drug and its first generic competitor) for new molecular entities (NMEs); (2) the likelihood and timing of patent challenges under Paragraph IV of the Hatch-Waxman Act; and (3) generic drug penetration. Methods We used IMS Health National Sales Perspectives™ data to calculate MEPs for the 257 NMEs experiencing initial generic entry between January 1995 and September 2012 and the number of generic competitors for twelve months afterwards, by level of annual sales prior to generic entry and time period. We calculated the likelihood and timing of Paragraph IV challenge using data from Abbreviated New Drug Approval (ANDA) approval letters, the FDA website, and public information searches to identify drugs experiencing Paragraph IV filings, and the first filing date. Results For drugs experiencing initial generic entry in 2011-12, the MEP was 12.6 years for drugs with sales greater than $100 million (in 2008 dollars) in the year prior to generic entry, 12.9 years overall. After generic entry, the brand rapidly lost sales, with average brand unit share of 16 percent at one year; 11 percent for NMEs with pre-generic entry sales at least $250 million (in 2008 dollars). Over 80 percent of NMEs experiencing 2011-12 initial generic entry had faced at least one Paragraph IV challenge from a generic manufacturer. These challenges were filed relatively early in the brand-name drug life cycle, within seven years after brand launch on average. Limitations Analyses, including Paragraph IV calculations, were restricted to NMEs where generic entry had occurred. Conclusion Pharmaceutical competition continues to evolve; while the average MEP below 13 years for 2011-12 remains consistent with prior research, Paragraph IV challenges are increasingly frequent and occur earlier, and generic share erosion has intensified.
The objective of this article is to discuss the similarities and differences among bioequivalence approaches used by international regulatory authorities when reviewing applications for marketing new generic drug products which are systemically active and intended for oral administration. We focused on the 13 jurisdictions and organizations participating in the International Generic Drug Regulators Pilot. These are Australia, Brazil, Canada, China, Chinese Taipei, the European Medicines Association, Japan, Mexico, Singapore, South Korea, Switzerland, the USA, and the World Health Organization. We began with a comparison of how the various jurisdictions and organizations define a generic product and its corresponding reference product. We then compared the following bioequivalence approaches: recommended bioequivalence study designs, method of pharmacokinetic calculations and bioequivalence acceptance limits, recommendations for modifying bioequivalence study designs and limits for highly variable drugs and narrow therapeutic index drugs, provisions for waiving bioequivalence study requirements (granting biowaivers), and implementation of the Biopharmaceutics Classification System. We observed that, overall, there are more similarities than differences in bioequivalence approaches among the regulatory authorities surveyed.
Many antihypertensive drugs are now available in generic formulations at fractions of the cost of their branded counterparts. In the United States, marketing approval for generic medications is usually granted by the Food and Drug Administration on the basis of two simple studies involving dissolution rates and bioavailability in 24 - 36 healthy people, without data regarding antihypertensive efficacy, safety, or long-term outcomes. This process leaves many true disciples of “Evidence-Based Medicine” in a quandary: prescribe only brand-name medications that have been demonstrated in clinical trials to both lower blood pressure and prevent cardiovascular events, or instead recommend lower-priced generic agents that are usually supported by no such data. This review summarizes the current evidence that generic antihypertensive drugs are likely to be safe and effective, may increase the probability of medication availability and adherence for many patients, but, by law, must have a different physical appearance than the original product.
In 2010, the US Food and Drug Administration (FDA) approved a generic low-molecular-weight heparin without clinical safety or efficacy data under the Abbreviated New Drug Application (ANDA) pathway. To enable a determination of active ingredient sameness of generic and innovator enoxaparin products, the FDA developed a scientifically rigorous approach based on five criteria: first, equivalence of physicochemical properties; second, equivalence of heparin source material and mode of depolymerization; third, equivalence in disaccharide building blocks, fragment mapping and sequence of oligosaccharide species; fourth, equivalence in biological and biochemical assays; and finally, equivalence of in vivo pharmacodynamic profile. In addition to fulfillment of these criteria, FDA also used in vitro, ex vivo and model animal data to ensure there was no increased immunogenicity risk of the generic enoxaparin product relative to the brand name product. The approval of the highly complex enoxaparin product using this framework under the ANDA pathway represents a major development. It also suggests that analytical and scientific advancements may in certain cases allow the elimination of unnecessary in vivo testing in animals and humans.