Generic and branded drugs for the treatment of people living with HIV/AIDS

Bioequivalence of indinavir capsules in healthy volunteers

Background: Indinavir, one component in the HAART regimen, plays an important role in the current treatment of HIV-infection and AIDS. Availability and accessibility of qualified generic indinavir to patients may be the keys for the success of treatment. Objective: Compare the rate and extent of absorption of a generic indinavir formulation with those of an original formulation in healthy Thai volunteers. Method: A randomized, two-period, two-treatment, two-sequence, crossover study with a two-week washout period was performed. A single dose of 2×400 mg indinavir capsules of each formulation was administered to 24 volunteers after an overnight fast. Indinavir plasma concentrations up to 10 hours postdose were determined using high-performance liquid chromatography. Relevant pharmacokinetic parameters were derived and tested for statistically significant differences using ANOVA and criteria of bioequivalence determination were applied. Results: No statistically significant differences were demonstrated for pharmacokinetic parameters including Cmax, Tmax, AUC0-t, and AUC0-∞ derived from the two formulations (n=23, p>0.05). The criteria of bioequivalence determination i.e., the 90% confidence intervals on the mean ratio (generic/original formulation) of natural logarithmtransformed values of Cmax, AUC0-t and AUC0-∞ were 86.3-106.5%, 94.0-108.5%, and 93.9-108.5%, respectively. Conclusion: As the mean ratios of Cmax, AUC0-t and AUC0-∞ of the generic and original formulations were entirely within the guideline range of bioequivalence (80.0-125.0%), the two formulations were considered bioequivalent in terms of rate and extent of absorption.

Chronic Hepatitis C: Do Generics Work as Well as Branded Drugs?

India has a large share of the hepatitis C virus (HCV) burden of the world. Unsafe medical practices and blood transfusions are the leading modes of transmission of HCV in India. The commonest HCV genotype in India is genotype 3 followed by genotype 1. While directly acting antivirals (DAAs) agents have become available at reasonable rates in India, cost of therapy remains a major barrier for control of HCV in India. Generic DAAs have been proven to be cost-saving in prior studies. We examined data from various studies in India and elsewhere using generic DAAs, and evaluated whether they are equally efficacious as the branded drugs. Since the availability of generic DAAs in the Indian market, there is a lot of real life data as well as prospective studies in special patient populations such as hematological disorders (thalassemia and hemophilia), chronic kidney disease, hemodialysis patients, post liver and renal transplant patients on immunosuppression, intravenous drug users, confections and other high risk groups. Control of HCV infection in India requires multi pronged approach. There is a need to formulate a health educational curriculum targeting not only the high-risk population but also the general population regarding the transmission of HCV. Adopting the dual approach of treating the old cases (decreasing the reservoir pool of HCV) and decreasing the incidence of new ones would help curtail the disease and decrease liver related mortality. In this scenario, the role of efficacious low cost generic medications is essential.

Efficacy and safety of switching from branded to generic antiretrovirals in virologically suppressed HIV-infected patients

Background

Aim of this study was to evaluate the efficacy and the safety of switching from branded to generic antiretrovirals in patients with HIV-RNA <50 copies/mL.

Methods

Matched-cohort study of patients followed at a single clinical center. Since September 2014, all patients with HIV-RNA <50 copies/mL who were receiving branded lamivudine or zidovudine/lamivudine or efavirenz were switched to the generic compound (switchers) and matched, in a ratio 1:1, for age (±5 years), gender, anti-HCV antibodies, nadir and (±50 cells/μL) baseline CD4+ count (±100 cells/μL), duration of antiretroviral therapy (±1 year), with patients with HIV-RNA <50 copies/mL, on treatment with unavailable generic compounds (non-switchers). Incidence rates (IR) of different outcomes were calculated and compared by Poisson regression model. A confirmed HIV-RNA ≥50 copies/mL defined virological failure; any change in the antiretroviral regimen was defined as treatment discontinuation.

Results

Four hundred forty patients were switched to generic compounds (268 [61%] on lamivudine, 65 [15%] on zidovudine/lamivudine, 87 [20%] on efavirenz and 20 [4%] on efavirenz and either lamivudine or zidovudine/lamivudine). Over a median follow-up of 15.0 (12.1–15.7) months, virological failure occurred in four switchers (IR: 0.07 [0.02–0.18]/100-person months of follow-up [PMFU]) and in ten non-switchers (IR: 0.20 [0.10–0.35]/100-PMFU) (p = 0.0003), while treatment discontinuation occurred in 118 switchers (IR: 2.05 [1.70–2.44]/100-PMFU) and in 128 non-switchers (IR: 2.37 [1.99–2.81]/100-PMFU) (p = 0.699).

Conclusions

After more than one year of follow-up, we found no evidence of increased risk of reduced efficacy or increased toxicity after switching from branded to generic lamivudine or zidovudine/lamivudine or efavirenz.

Quality Attributes and In Vitro Bioequivalence of Different Brands of Amoxicillin Trihydrate Tablets

Bacterial resistance and antibiotic drug effectiveness can be related to administering generic products with a subtherapeutic dose or poor in vivo drug release. The aim of this study was to investigate whether locally marketed amoxicillin tablets have the required chemical and physical attributes, including in vitro bioequivalence performance. Five generic products (T1, T2, T3, T4, and T5) containing combination of amoxicillin trihydrate and potassium clavulanate as 1 g strength present in immediate release tablets were compared to the reference listed drug product Augmentin® (R) for weight variation, friability, resistance to crushing, and chemical content of amoxicillin. Difference (ƒ1) and similarity (ƒ2) factors were calculated to assess in vitro bioequivalence requirements. The tablets from different products have shown compliance with the pharmacopeial requirements of the performed tests. The measured resistance to crushing of tablets did not influence the dissolution time. Three generic products released more than 85% of amoxicillin by the first 15 min as did the reference product and were considered as bioequivalent products. T1 and T4 had ƒ1 values of 16.5% and 25.4% respectively and their ƒ2 values were 44.5 and 34.6 respectively, indicating failure to meet in vitro bioequivalence requirements. Tablet formulations can play an important role in achieving bioequivalence. Independent investigations such as this study serve as an important tool to reveal possible inferior or noncompliant products that may find their way to the market.

[Prostaglandin analogues in glaucoma treatment]

AIM

to evaluate the effectiveness of prolatan (latanoprost 0.005%) in the treatment of primary open-angle glaucoma (POAG).

MATERIAL AND METHODS

The study included 35 POAG patients (41 eyes) aged 55-72 years, of them 20 men and 15 women. The patients were randomized into two groups followed up for 3 months. Group 1 consisted of 17 patients (19 eyes) who received prolatan once daily in the evening. Group 2 consisted of 18 patients (22 eyes) under Xalatan 0.005% once daily in the evening.

RESULTS

The true intraocular pressure (IOP) decreased by the average of 28.6%. Analysis of perimetry results showed a statistically reliable increase in the MD - by 17.4% in the study group and by 20% in the control group, and PSD indices - by 10.7% and 11.9%, respectively. Optical coherence tomography revealed an improvement of optic disc parameters in both groups. In particular, the cup volume decreased reliably by 8.4% and 6.3% and cup area - by 24.4% and 28.5%, respectively, while the rim area increased by 20.8% and 17.9%, respectively. The patients complained of neither burning, nor discomfort, nor foreign body sensation after prolatan instillations. We also report the absence of side effects.

CONCLUSION

The study has proved high antihypertensive effectiveness of prolatan. Improved morphometric parameters of the optic disc (decreased cup volume and area, increased rim area) indirectly indicate the neuroprotective potential of the drug. Being well-tolerated by the patients, prolatan can be recommended as the first choice treatment of glaucoma.

Legal, ethical, and economic implications of breaking down once-daily fixed-dose antiretroviral combinations into their single components for cost reduction

The availability of generic lamivudine in the context of the current economic crisis has raised a new issue in some European countries: breaking up the once-daily fixed-dose antiretroviral combinations (FDAC) of efavirenz/tenofovir/emtricitabine, tenofovir/emtricitabine, or abacavir/lamivudine, in order to administer their components separately, thereby allowing the use of generic lamivudine instead of branded emtricitabine or lamivudine. The legal, ethical, and economic implications of this potential strategy are reviewed, particularly in those patients receiving a once-daily single-tablet regimen. An unfamiliar change in antiretroviral treatment from a successful patient-friendly FDAC into a more complex regimen including separately the components to allow the substitution of one (or some) of them for generic surrogates (in the absence of a generic bioequivalent FDAC) could be discriminatory because it does not guarantee access to equal excellence in healthcare to all citizens. Furthermore, it could violate the principle of non-maleficence by potentially causing harm both at the individual level (hindering adherence and favouring treatment failure and resistance), and at the community level (hampering control of disease transmission and transmission of HIV-1 resistance). Replacing a FDAC with the individual components of that combination should only be permitted when the substituting medication has the same qualitative and quantitative composition of active ingredients, pharmaceutical form, method of administration, dosage and presentation as the medication being replaced, and a randomized study has demonstrated its non-inferiority. Finally, a strict pharma-economic study supporting this change, comparing the effectiveness and the cost of a specific intervention with the best available alternative, should be undertaken before its potential implementation.

Low-cost generic drugs under the President's Emergency Plan for AIDS Relief drove down treatment cost; more are needed

The President's Emergency Plan for AIDS Relief (PEPFAR) was originally authorized in 2003 with the goal of supporting HIV prevention, treatment, and care within fifteen focus countries in the developing world. By September 2011 nearly 13 million people around the world were receiving HIV/AIDS-related care through PEPFAR, and 3.9 million were receiving antiretroviral treatment. However, in the early years of the program, access to antiretroviral drugs was hampered by the lack of a licensing process that the US government recognized for generic versions of these medications. Ultimately, the obstacle to approval of generic antiretroviral drugs was removed, which led to PEPFAR's considerable success at making these treatments widely available. This article outlines PEPFAR's evolving use of generic antiretroviral drugs to treat HIV in the developing world, highlights ongoing initiatives to increase access to generic antiretrovirals, and points to the need for mechanisms that will speed up the approval of new generic drugs. The striking decline in antiretroviral treatment costs, from $1,100 per person annually in 2004 to $335 per person annually in 2012, is due to the availability of effective generic antiretrovirals. Given growing resistance to existing drugs and the planned expansion of treatment to millions more people, access to newer generations of generic antiretrovirals will have to be expedited.

Effectiveness of generic and proprietary first-line anti-retroviral regimens in a primary health care setting in Lusaka, Zambia: a cohort study

Background Although generic anti-retroviral drugs are in common use throughout the developing world, studies comparing their clinical effectiveness with that of proprietary formulations are lacking.

Methods We analysed observational data from a large cohort of adults on anti-retroviral therapy (ART) to assess potential differences between generic and proprietary zidovudine (ZDV) formulations in post-90-day mortality, ‘programme failure’ (a composite of death, follow-up losses and withdrawals) and other clinical outcomes. We accounted for drug exposure in three ways: an ‘initial dispensation’ approach that categorized patients according to the first prescription; ‘time-varying’ approach that attributed an outcome to the formulation taken at the time of event; and ‘predominant exposure’ approach that considered only those with >75% exposure to either brand or generic ZDV. Proprietary formulations were used as the reference group in all adjusted Cox proportional hazard regressions.

Results Among 14 736 patients eligible for analysis, 7277 (49%) initiated a generic formulation of ZDV and 7459 (51%) initiated a proprietary formulation. When categorized according to initial dispensation, no difference in post-90-day mortality was observed between the two groups [adjusted hazard ratio (AHR): 0.93, 95% confidence interval (CI): 0.77–1.12]. Similar findings were noted when drug formulation was treated as a time-varying exposure (AHR: 1.15, 95% CI: 0.89–1.48) when analysis was limited to those with a predominant exposure to one formulation or the other (AHR: 0.59, 95% CI: 0.24–1.49). Results were consistent across all approaches when programme failure was considered as an outcome. No longitudinal differences were detected between formulations for CD4 response, weight change and haemoglobin concentration. Generic ZDV formulations were associated with slight decreases in single-drug substitution.

Conclusions In this large programmatic cohort of adults starting ZDV-based first-line therapy, clinical outcomes appeared similar among patients on generic or proprietary formulations. These findings support continued use of generic anti-retroviral drug formulations in resource-constrained settings.