Biosimilars and access to biologic therapy in immune-mediated diseases

BACKGROUND

The rise of biologic agents has been a major breakthrough in treating immune-mediated inflammatory diseases (IMIDs). However, their high cost underscores the need for strategies to optimize treatment efficiency. Biosimilars offer cost-effective alternatives to biologics. This study aimed to assess biosimilar drug availability's impact on biologic therapy access for IMIDs.

RESEARCH DESIGN AND METHODS

A retrospective observational study in 15 Spanish hospitals analyzed IMID patients (arthropathies, inflammatory bowel disease and psoriasis) initiating biologic therapy with originator or biosimilar drugs (infliximab, etanercept, adalimumab). Time to availability and initiation of biologic therapy were assessed.

RESULTS

267 patients were included, with 58.4% starting on biosimilars. The mean time to availability of the biologic drugs in the hospitals was 15.9 ± 6.7 months, (20.0 ± 12.4 for originator and 11.8 ± 5.2 for biosimilars). Mean time to biologic treatment was 7.7 ± 9.0 years (8.6 ± 8.9 for originators and 7.0 ± 9.0 for biosimilars). Showing statistically significant differences among conditions.

CONCLUSION

The emergence of biosimilar drugs has enhanced market competition and accelerated their adoption into hospitals' therapeutic regimens over original reference drugs. This has significantly improved access to biologic therapy for patients with IMIDs, evidenced by a notable 1.6-year reduction in access time for biosimilar drugs.

Comparative Effectiveness and Safety of Trastuzumab Biosimilars to Herceptin for Adjuvant Treatment of HER2+ Breast Cancer

Background: Ontario publicly funds reference trastuzumab (Herceptin) and four biosimilar trastuzumab products for adjuvant treatment of HER2+ breast cancer. We assessed the real-world safety and effectiveness of biosimilar trastuzumab compared to Herceptin for adjuvant treatment of patients with HER2+ breast cancer. Methods: This was a population-based, retrospective study comparing the safety and effectiveness of biosimilar trastuzumab and Herceptin for neoadjuvant/adjuvant treatment of HER2+ breast cancer from 2016 to 2021. Treatment patients started biosimilar trastuzumab from November 2019 to June 2021; historical comparator patients started Herceptin from June 2016 to October 2019. Safety outcomes death within 30 days of last dose of trastuzumab, direct hospitalization, emergency department visit leading to hospitalization, early treatment discontinuation, and in-patient admission for congestive heart failure were measured using logistic/negative binomial regression. Overall survival (OS) was measured using Kaplan-Meier methods and Cox proportional hazards regression. Propensity score matching was applied. Results: From June 2016 to 2021, 5071 patients with breast cancer were treated with neoadjuvant/adjuvant trastuzumab. The rate of direct hospitalization (RR: 0.85, 95% CI: 0.74-0.98, p-value: 0.032) was significantly lower in biosimilar compared to Herceptin patients. OS (log-rank test p = 0.98) and risk of mortality (HR: 1.29, 95% CI: 0.72-2.30, p-value = 0.39) did not significantly differ between treatment groups. Conclusions: Biosimilar trastuzumab demonstrated similar safety and effectiveness to Herceptin. The findings can help improve confidence in and use of biosimilars and demonstrate the value of real-world evidence generation for supporting biosimilar implementations and reassessments.

Biosimilars Would Reduce Health Care Costs But Are Yet Poorly Known - Patient Survey Study Among Biological Medicine Users

Background

From the beginning of the year 2024, gradually implemented amendment to the Medicines Act will enable interchange of biological medicines in pharmacies in Finland. The legislative change aims to reduce health care costs.

Methods

Opinions of the biological medicine users regarding substitution in pharmacies and knowledge about biological medicines were determined by a patient survey in community pharmacies and via patient organizations in Finland.

Results

In total, 199 users of biological medicines responded to the survey. The respondents did not always know which product they were using, an originator or a biosimilar. This was more prominent among patients with biosimilars determined according to brand names. The more recently the biological medicine had been prescribed, the more likely a biosimilar was in use. Only about 40% of the respondents would enable pharmacies to substitute their biological medicine to a lower cost product. The most common obstacle to the idea of interchange in pharmacies was that the respondents wanted to keep the product the doctor had prescribed for them. In general, biosimilar users were more accepting towards possible interchange than originator users.

Conclusion

Although the most recent treatments appear to be initiated with biosimilars, interchange in pharmacies could enable an efficient way to lower health care costs. However, guidance and awareness regarding biosimilars and biological medicines in general would improve patients' willingness towards the change, but also help pharmacists and prescribing doctors in their meaningful role.

Etanercept originator versus etanercept biosimilar for the treatment of rheumatoid arthritis as a first biologic: results from the BSRBR-RA

OBJECTIVES

Etanercept biosimilars show comparable efficacy to their originators among biologic-naïve patients with RA in randomized controlled trials. Nationwide guidelines have obligated prescribing of etanercept biosimilars from 2016, resulting in significant cost savings. This analysis aimed to compare the effectiveness of etanercept originator vs etanercept biosimilar amongst biologic-naïve RA patients treated in routine clinical practice in the UK.

METHODS

Biologic-naïve RA patients starting etanercept in the British Society for Rheumatology Biologics Register in Rhematoid Arthritis (BSRBR-RA) cohort study from 2010 were included. Data collected at start of therapy includes patient demographics and disease activity. Follow-up data includes changes in disease activity and anti-rheumatic therapy. Six- and 12-month primary outcomes include DAS for 28-joints (DAS28) remission, EULAR response and minimal clinically important difference in function. Etanercept drug survival was assessed using Kaplan-Meier and Cox regression, including reasons for treatment withdrawal. Multiple imputation accounted for missing data. Propensity-decile adjustment was used to account for confounding by indication.

RESULTS

A total of 1806 biologic-naïve RA patients started etanercept: 1009 originator, 797 biosimilar. At 6 and 12 months, the proportion of patients achieving DAS28 remission and EULAR response were similar between treatments. During follow-up, 19% of originator patients switched onto etanercept biosimilar. Patients were censored at time of switch. Patients on originator were no more likely to stop therapy vs biosimilar; 71% of originator and 76% of biosimilar patients remained on therapy at 1 year.

CONCLUSIONS

In one of the largest analyses of patients with RA, biologic-naïve RA patients treated with etanercept originator showed similar outcomes vs biosimilar using real-world data. Drug survival, and disease activity after 6 and 12 months of therapy, was similar between cohorts.

Outcomes following switching from etanercept originator to etanercept biosimilar in 1024 RA patients: A matched-analysis of the BSRBR-RA

OBJECTIVES

Adults with RA are being switched from etanercept originator to biosimilar in non-medical/cost-saving switching. This analysis aims to investigate outcomes in these patients, including (a) drug survival and (b) disease activity at six and 12-month, compared with those who remain on originator.

METHODS

Using BSRBR-RA, those who switched directly from etanercept originator to biosimilar were identified and matched to patients receiving originator, based on gender, age, disease duration, originator start year. Drug survival was calculated; Cox-proportional hazard models assessed differences in drug persistence between those who switched versus remaining on originator. Change in DAS28 after six and 12-months was compared between cohorts. Multiple imputation was used.

RESULTS

1024 adults with RA switching from etanercept originator to biosimilar were included, with a matched cohort of patients remaining on originator. Patients who switched onto a biosimilar product were no more likely to discontinue etanercept treatment versus those who remained on originator; hazard ratio 1.06 (95%CI 0.89-1.26), with 65% of patients remaining on treatment at three years. Ninety-five (9%) patients switched back to originator within the first year. After six and 12-months, biosimilar patients were no more likely to have a worsening of DAS28 (>0.6units) compared with those who remained on originator.

CONCLUSIONS

This is the largest matched comparative effectiveness analysis showing patients switched from etanercept originator to biosimilar appear to do just as well with regards to disease activity and drug persistence compared with those who remained on originator. These data will be reassuring to clinicians and patients regarding non-medical switching.

Efficacy of Biosimilar Infliximab-Dyyb in Non-Infectious Uveitis

PURPOSE

To describe the frequency of uveitis recurrences in patients with non-infectious uveitis treated with the biosimilar infliximab-dyyb.

DESIGN

Retrospective case series.

METHODS

Records of uveitis patients treated with the biosimilar infliximab-dyyb between 2016 and 2022 at two institutions were reviewed. Data extracted included patient demographics, diagnosis, previous originator infliximab use, additional immunosuppression medications, infliximab-dyyb use, reason for switch, disease activity, and follow-up time.

RESULTS

A total of 14 patients were identified. Seven patients were switched from originator infliximab to a biosimilar for nonmedical/non-ocular reasons (insurance prompted the switch). One patient was started directly on infliximab-dyyb due to active joint disease despite well-controlled uveitis. None of these eight patients developed inflammation after the switch. Six patients were started directly on infliximab-dyyb due to poorly controlled uveitis. Of these, five patients achieved disease quiescence during follow-up. The mean dose of originator was 1.79 mg/kg/week, with a median dosing schedule of 4 weeks prior to therapy with infliximab-dyyb. The mean final infliximab-dyyb dosage was 1.81 mg/kg/week, with a median dosing schedule of 4 weeks.

CONCLUSION

Infliximab-dyyb appears to be efficacious in achieving and maintaining uveitis control.

Clinical Outcome and Medical Cost of Originator and Generic Antihypertensive Drugs: A Population-Based Study in Yinzhou, China

Background: The substitution of generic drugs can effectively alleviate the rapid growth of drug costs; however, the clinical effectiveness and medical costs of originator products and generics were barely studied in China.

Objectives: To compare the effectiveness of antihypertensive drugs and hypertension-related medical costs between originator and generic initiators in Yinzhou, China.

Methods: We conducted a population-based retrospective cohort study using the Chinese Electronic Health Records Research in Yinzhou (CHERRY), from July 1, 2011, to December 31, 2018. Hypertension patients initiating with originator products were compared with patients initiating with generic counterparts. We used 1:1 propensity score matching to pair the two groups based on sociodemographic, clinical, and health service utilization variables. Cox proportional regression was adopted to compare the rate of hospitalization for hypertension-related cardiovascular disease between matched originator and generic initiators. Wilcoxon matched-pairs signed-rank test was used to compare annual hypertension-related medical costs.

Results: Matched pairs (10,535) of patients were included in the comparative study of originator products and generics, corresponding to seven antihypertensive drugs including amlodipine, felodipine, nifedipine, irbesartan, losartan, valsartan, and metoprolol. The average age of patients included in the analysis was around 60 years (originator vs. generics initiators: from 59.0 vs. 59.1 years in losartan to 62.9 vs. 63.6 years in nifedipine). Higher hospitalization rates among originator initiators were observed for three calcium channel blockers (hazard ratio[95% CI]: amlodipine, 3.18[1.43, 7.11]; felodipine, 3.60[1.63, 7.98]; and nifedipine, 3.86[1.26, 11.81]; respectively). The remaining four out of seven drugs of the clinical endpoint estimates showed comparable outcomes between originator products and generics (hazard ratio[95% CI]: irbesartan, 1.19[0.50, 2.84]; losartan, 1.84[0.84, 4.07]; valsartan, 2.04[0.72, 5.78]; and metoprolol, 1.25[0.56, 2.80]; respectively). Higher median annual hypertension-related medical costs were observed in originator initiators (all p < 0.001), except for metoprolol (p = 0.646).

Conclusion: We observed comparable or even better clinical outcomes and less medical cost associated with the use of antihypertensive generics compared to originator counterparts. This could help increase patient and provider confidence in the efficacy of generic medicines to manage hypertension diseases.

Effectiveness of SB4 Transition from Originator Etanercept in Rheumatoid Arthritis and Axial Spondyloarthritis: A Subgroup Analysis from the BENEFIT Study

OBJECTIVES

The pan-European BENEFIT study of patients with stable rheumatoid arthritis (RA) or axial spondyloarthritis (axSpA) who transitioned from reference etanercept to SB4 found no clinically meaningful changes in disease control after transition. The analysis aims to illustrate the peculiarities of the Italian cohort of patients compared with the whole population to provide a more real-life approach to the data for the Italian rheumatologists, ruling out possible local confounding factors.

METHODS

A prospective study for up to 6 months following transition was conducted. Outcome measures of interest include clinical characteristics at time of transition and disease activity scores (Disease Activity Score-28 [DAS28] for RA, Bath Ankylosing Spondylitis Disease Activity Index [BASDAI] for axSpA) over time and safety.

RESULTS

One-hundred and eleven subjects (out of the 557 in total enrolled in the study) were derived from 8 Italian sites, including 79 with RA and 32 with axSpA. In both cohorts, the efficacy was maintained at 3 months and 6 months from the transition to the biosimilar with no significant change in mean DAS28 and BASDAI scores: at the end of the 6 months of observation the mean DAS28 and BASDAI was similar to baseline (confidence interval [CI] -0.22, 0.22), while the mean variation of the BASDAI was -0.14. Of note, 100.0% (95% CI 89.1, 100.0) in the axSpA and 90.8% (95% CI 81.5, 95.5) in the RA cohort of patients continued to receive SB4 at month 6 (binary variable with 95% Clopper-Pearson CI).

CONCLUSIONS

Italian patients with stable RA or axSpA who transitioned from originator Etanercept to SB4 maintained clinical response at 6 months post-transition. Both the cohorts are representative of typical patients with long-standing established diagnoses. Most of the patients transitioned to the same dose regimen of biosimilar as that received for the originator, and the regimen remained unchanged at 6 months, supporting the effectiveness of the transition.

Viability of a Serum Infliximab Concentration-Detecting Reagent as a Qualitative Assay for an Infliximab Biosimilar

The efficacy of infliximab in treating rheumatoid arthritis depends on its serum trough concentration, which must be maintained at a minimum of 1 µg/mL to achieve the desired effects. However, Japan's National Health Insurance system does not cover tests for rheumatoid arthritis patients undergoing treatment with biosimilar infliximab because its performance as a biosimilar remains unclear. This study aimed to investigate whether the Remi-check Q qualitative assay yields comparable results for biosimilar infliximab and the originator product. Infliximab BS 100 "NK" and Remicade 100^® were separately diluted in pooled human serum to yield test samples at the following concentrations: 0.30, 0.70, 1.20, and 3.00 µg/mL. Prepared samples were quantitatively assessed using an enzyme-linked immunosorbent assay (ELISA) and qualitatively using Remi-check Q, and the results obtained for the originator and biosimilar product were compared. For both originator and biosimilar infliximab, Remi-check Q yielded a negative result for all 0.30 and 0.70 µg/mL samples and a positive result for all 3.00 µg/mL samples. However, negative results were obtained with a fraction of the 1.20 µg/mL samples (biosimilar, 4/15; originator, 3/15). Concurrence rates between the results of quantitative ELISA and qualitative Remi-check Q analyses were comparable between originator and biosimilar infliximab at all tested concentrations. These results indicate that Remi-check Q yields comparable results for biosimilar infliximab and the originator product on being used as a qualitative assay for trough serum levels.

Switching from Biosimilar to Biosimilar Adalimumab, Including Multiple Switching, in Crohn's Disease: A Prospective Study

No data are available regarding the safety and effectiveness of the biosimilar-to-biosimilar switch of adalimumab in any disease, and in particular in Crohn’s disease (CD). The aim of our study was to provide real world data on switching from biosimilar adalimumab to another biosimilar, including multiple switching. We conducted a prospective, single-centre observational study in which we consecutively recruited all CD patients who switched from adalimumab biosimilar ABP 501 to biosimilar SB5 from January to July 2021. Sixty-one patients were included in the final analysis, of whom 43/61 (70.5%) were multiple switches (Humira^® → ABP 501 → SB5). After 6 months of follow up, 88.5% (54/61) of patients maintained SB5 on therapy. The success of the switch (defined as no systemic corticosteroids within 6 months, non-discontinuation of SB5, no dose escalation) was achieved by 82.0% (50/61) of patients. At multivariate analysis, C-reactive protein > 5 mg/L predicted switch failure (p = 0.03). Seven patients (11.5%) experienced side effects, compared to one patient (1.6%) in the 6 pre-switch months (p = 0.03). In conclusion, switching from biosimilar to biosimilar of adalimumab did not lead to signs of safety or loss of efficacy other than those already known in the literature for the class of drugs.

Physicians' Knowledge, Attitude and Practice of Generic Substitution in China: A Cross-Sectional Online Survey

The purpose of this study is to investigate physicians’ knowledge, attitudes and practice of generic medicine substitutions in China. We conducted a cross-sectional online questionnaire survey on physicians from secondary or tertiary hospitals in China from 2020 December to 2021 April. Descriptive statistical and ordered logistic regression were used for analysis. A total of 1225 physicians were included in the final analysis, and only 330 (26.94%) of them scored 4 or above in the knowledge part, which means that the physicians have a good knowledge of generic substitutions. Of the total, 586 (47.83%) agreed or strongly agreed that generic drugs could be substituted for originator drugs and 585 (47.75%) always or often prescribed generic medicines. The percentage of physicians with a positive attitude toward or that practice prescribing generic medicine is below 50%, which needs to be improved in China. Physicians’ knowledge, their attitude toward generic substitution, if familiar with the policy of generic substitution, and incentives for prescribing generic medicines are influencing factors for the practice of generic substitution. Our studies show that the practice of generic substitution by physicians could be improved by several measures in China. We suggested that the physicians should be taught more about the bulk-buy policy and the generic-originator equivalence evaluation policy. Moreover, government incentives to promote generic substitution should be established. Our study also suggested that physicians with less working experience and female physicians should learn more about generic substitution.

Dose equivalency and efficacy of biosimilar erythropoietin stimulating agents: Data from real clinical practice

Recently, biosimilar erythropoietin stimulating agents become available in Kazakhstan. Important properties of the biosimilar such as dose equivalency to the original medicine (originator) and the ability to maintain hemoglobin target levels remain insufficiently described in many clinical settings. Thus, the current study aims to determine dose equivalency and hemoglobin target levels in a cohort of dialysis patients who were switched from the originator to biosimilar. Retrospective data of 74 patients from different dialysis centers who received at least 6 months of originator and switched to biosimilar and had at least 6 months follow‐up were analyzed. The clinical data of 32 male and 42 female patients were collected. The mean age was 52.5 ± 13.5 years. There is no significant difference in mean levels of hemoglobin during pre‐switching from originator to biosimilar (6 months prior) and post switching period (9 months after). Additionally, a subgroup analysis of 59 patients who received originator (epoetin beta), 6 months before the switch, showed similar level of hemoglobin (110.7 ± 14 vs 113.2 ± 10 g/L, P = .05) 6 months after the switch to biosimilar (epoetin zeta) at the equivalent dose regimen (69.5 ± 29 vs 68.1 ± 30 IU/kg/wk, P = .55). However, after 9 months of switching, patients using lower doses of biosimilar (69.5 ± 29 vs 63.3 ± 30 IU/kg/wk, P < .01), showed significantly higher levels of hemoglobin (110.7 ± 14 vs 114.7 ± 8 g/L, P = .01) compared to preswitching period. In conclusion, long‐term use of lower doses of biosimilar managed to maintain hemoglobin within the target levels.

Switching from originator infliximab to biosimilar infliximab in Japanese patients with rheumatoid arthritis achieving clinical remission (the IFX-SIRIUS study I): Study protocol for an interventional, multicenter, open-label, single-arm and noninferiority clinical trial with clinical, ultrasound, and biomarker assessments

BACKGROUND

The introduction of biological disease-modifying anti-rheumatic drugs (bDMARDs) into clinical practice has dramatically improve the clinical outcomes of individuals with rheumatoid arthritis (RA). However, bDMARDs are associated with high costs, which has resulted in restricted treatment access and a burden on medical insurance finances. Although biosimilars offer cost-saving, their effectiveness and safety must be established in Post-Marketing Surveillance (PMS). Infliximab (IFX), a chimeric monoclonal antibody to TNF-alpha, is the first bDMARD; its biosimilar, CT-P13, is the first biosimilar DMARD approved for RA treatment in Japan. We will evaluate whether switching from originator IFX to CT-P13 is not inferior for maintaining non-clinical relapse to continued treatment with originator IFX in RA patients achieving clinical remission.

METHODS/DESIGN

This study is an interventional, multicenter, open-label, single-arm against historical control and noninferiority clinical trial with a 24-week follow-up. Eighty RA patients who are treated by originator IFX for ≥24 weeks and are achieving clinical remission will be included. Patients will be switched to CT-P13 with the unchanged dosing regimen. We will evaluate disease activity by measuring clinical disease activity indices and by using musculoskeletal ultrasound (MSUS). The primary endpoint is the ratio of patients who experience a nonclinical relapse during the study period. Important secondary endpoints are the changes from the baseline of the MSUS scores. We will also comprehensively analyze the serum levels of many biomarkers such as cytokines and chemokines.

DISCUSSION

The study results are expected to show the noninferiority of switching to CT-P13 over the continuation of originator IFX. The strength of this study is its prospective evaluation of therapeutic efficacy using not only clinical disease activity indices but also MSUS to accurately and objectively evaluate disease activity at the joint level among patients drawn from multiple centers with a standardized evaluation by MSUS. We will explore whether parameters at baseline can predict a nonclinical relapse after switching from originator IFX to CT-P13 by integrating multilateral assessments, i.e., clinical disease activity indices, MSUS findings, and serum biomarkers.

TRIAL REGISTRATION

This study was registered in the Japan Registry of Clinical Trials (https://jrct.niph.go.jp) on October 11, 2019 as jRCTs071190030.

The Role of Biosimilars in Uveitis: Long-Term Real-World Outcomes of the Switch From Original to Biosimilar TNF-Alpha Inhibitors

Background: Recent expiry of patents for tumor necrosis factor (TNF)-α inhibitors has led to the employment of biosimilars in clinical practice. The aim of the study was to identify any change in the control of ocular inflammatory manifestations among patients with non-infectious uveitis switching from an originator to a corresponding anti-TNF-α biosimilar.

Methods: Thirty-seven consecutive patients (62 eyes involved) with non-infectious uveitis undergoing the switch from anti-TNF-α originators to biosimilars were retrospectively enrolled; the frequency of ocular flares before and after the switch as well as best corrected visual acuity (BCVA), central macular thickness (CMT), daily systemic corticosteroid intake, and frequency of uveitic macular edema (UME) at the switch and at the following assessments were statistically analysed.

Results: The number of ocular flares during the 12 months preceding the switch was 16, corresponding to 3.6 flares/100 patients/12 months; the number of flares after the switch was 14, corresponding to 2.0 flares/100 patients/12 months. No statistically significant differences were identified in the frequency of flares (p = 0.84) and in the number of patients experiencing ocular flares (p = 0.39) between the twelve months preceding the switch and the period thereafter. No statistically significant changes were observed in the BCVA (p = 0.27), CMT (p = 0.50), frequency of UME (p = 0.57) and daily corticosteroid intake (p = 0.42) between the time of the switch and the last follow-up visit.

Conclusions: The switch to biosimilars represents a feasible treatment choice associated with the maintenance of clinical efficacy in patients with non-infectious uveitis previously treated with the corresponding originator anti-TNF-α biologic agents.

Clinical and pharmacokinetics equivalence of multiple doses of levodopa benserazide generic formulation vs the originator (Madopar)

AIMS

While several generic preparations of levodopa/carbidopa and levodopa/benserazide (LBD) are currently available, pharmacokinetic (PK) equivalence and therapeutic equivalence studies with levodopa generics are not available in Italy. Lack of data on generic formulations is a critical factor for their limited use in this country and often lead patients to refuse the generic version of the branded drug.

METHODS

An experimental, 2-centre, randomized, double-blind, 2-sequence, noninferiority cross-over study was designed to evaluate both the PK equivalence and clinical equivalence of multiple doses of the generic preparation of LDB, Teva Italia, compared to the originator (Madopar). Forty-three out-patients with a diagnosis of idiopathic Parkinson's disease on LDB, were recruited and randomly assigned to 1 of 2 study sequences: generic-originator or originator-generic. Clinical evaluations were performed at the end of each study period. A PK study with an LDB fixed dose (100 + 25 mg) was performed in a subpopulation of 14 subjects.

RESULTS

Clinical data showed a reduction of 0.49 and 1.54 in the mean UPDRS III scores for the LDB and the originator, respectively. The 95% CIs [-2.21: 0.11] of the mean difference original vs LDB are smaller than the clinically significant difference of 3 UPDRS III points, supporting the conclusion that the treatment with LDB is not inferior to the originator. No statistically significant differences were found with respect to area under the curve to last dose, half-life, maximum concentration, time to maximum concentration and last observed concentration.

CONCLUSION

These findings prove the therapeutic clinical equivalence as well the PK equivalence of the generic LDB and the originator (Madopar).

Market Exclusivity Time for Top Selling Originator Drugs in Canada: A Cohort Study

OBJECTIVES

This study looks at market exclusivity time for the top selling originator drugs in Canada. Total sales for drugs without competition were also calculated.

METHODS

A list of the top selling originator drugs by dollar sales from 2009 to 2015 inclusive, except for 2010, was compiled along with their annual sales. Health Canada databases were used to extract the following information: generic name, date of Notice of Compliance (NOC, date of marketing authorization), whether the product was a small molecule drug or a biologic, and date of NOC for a generic or biosimilar. Market exclusivity time was calculated in days for drugs.

RESULTS

A total of 121 drugs were identified. There were 96 small molecule drugs (63 with a generic competitor and 33 with no generic competitor) and 25 biologics (none with a biosimilar competitor). The 63 drugs with a competitor had a mean market exclusivity time of 4478 days (12.3 years) (95% CI 4159-4798). The 58 drugs without competition had total annual sales of Can$8.59 billion and were on the market for a median of 5357 days (14.7 years) (interquartile range 3291-6679) as of January 31, 2017.

CONCLUSIONS

Top selling originator drugs in Canada have a considerably longer period of market exclusivity than the 8 to 10 years that the research-based pharmaceutical industry claims.

Patents and profits: A disparity of manufacturing margins in the tenofovir value chain

Registered in 2001, tenofovir disoproxil fumarate (TDF) has quickly become a mainstay of first line regimens for the treatment of HIV. Initially only available in developed countries at a cost of US$5 000 per person per year (ppy), Gilead's Access Programme (GAP) has extended the use of the product to 2.4 million patients in low and middle income countries. The programme has two components: distribution of the branded product at reduced prices and licensing partnerships with generic manufacturers. The licensing partnerships now supply 75% of the market by volume, at a treatment cost of US$57 ppy (1% of the branded cost). From Gilead's perspective, GAP must be considered a huge success. It has enabled the company to maintain high prices in developed countries whilst reducing its input costs and deflecting criticism of its failure to provide essential medicines for the poor, hence risking the possibility of compulsory licensing. Over the period 2001 to 2011, TDF in its various forms has generated for Gilead more than US$31 billion revenue at a gross margin of 80%, equivalent to a gross profit of US$25 billion. Analysis of the TDF value chain, from preparation of the active pharmaceutical ingredient (API) to sale of the formulated product, shows that manufacturing margins are highly skewed in favour of the originator, with the latter's profit being US$3.2 billion vs. US$4 million for API manufacturers and US$39 million for formulators (2011). The data argues for a more rational approach to drug pricing including possible regulation in developed countries and more sustainable margins for the generic producers.