Comparison of Utilization Trends between Biosimilars and Generics: Lessons from the Nationwide Claims Data in South Korea

BACKGROUND

South Korea is unique in that it leads global markets in R&D as well as production of biosimilar products and was the first market into which some biosimilar products were introduced. We analyzed the time trend of market penetration and simulated saved spending by biosimilars in South Korea.

METHODS

We pulled Korean National Health Insurance claims data from January 2012-December 2018 for second-generation biologics, including infliximab, rituximab, and trastuzumab, and examined the time trends of expenditure, utilization in defined daily dose, and price. We also assessed market penetration by biosimilars and simulated expenditure savings gained due to their introduction. We comparatively examined time trends and spending savings during the same period for selected small-molecule generic drugs to understand any specifics limited to biosimilars for time trends of market share and quantity-standardized prices.

RESULTS

The market share for infliximab biosimilar plateaued at over 30%, which is smaller than the market penetration of esomeprazole (over 60%), a small-molecule comparator. Despite a shorter observation period, rituximab and trastuzumab biosimilars also showed larger utilization rates (12.89% and 13.93%, respectively) than infliximab (9.05%) in their second year after market entry. Infliximab was associated with approximately US $82-114 million expenditure savings over 6 years after its biosimilar entry to the market. Rituximab and trastuzumab biosimilars each also resulted in reduction in total spending by approximately US $9-14 million, in less than 2 years.

CONCLUSION

Biosimilars captured the market rapidly, despite a heterogeneous uptake rate by product in South Korea. However, expansion of biosimilar use in the market and consequent expenditure savings need to be supported by pre-emptive policy measures to encourage price competition and boost utilization.

Comparable Efficacy and Safety of Generic Imatinib and Branded Imatinib in Patients With Newly Diagnosed Chronic Myeloid Leukemia With a Consideration of Socioeconomic Characteristics: A Retrospective Study From a Single Center

INTRODUCTION

To compare the efficacy and safety of generic and branded imatinib in adults with newly diagnosed chronic myeloid leukemia in the chronic phase (CML-CP), we retrospectively reviewed data from patients CML-CP who received generic or branded imatinib.

PATIENTS AND METHODS

A propensity score matching (PSM) study was performed. A Cox regression model was used to identify factors associated with responses and outcomes.

RESULTS

Four hundred forty-two adults receiving generic imatinib (n = 236) or Glivec (Novartis, Basel, Switzerland; n = 206) were included. There were more patients with rural household registration (P < .001), lower education level (P < .001), divorced or widowed status (P = .009), higher white blood cell counts (P = .019), splenomegaly (P < .001), and longer intervals from diagnosis to imatinib initiation (P = .033) in the generic cohort. During the follow-up, there was no significant difference between the 2 cohorts in the 4-year probabilities of achieving a complete cytogenetic response (97.0% vs. 97.3%; P = .736), major molecular response (87.8% vs. 90.1%; P = .113), and molecular response^4.5 (32.5% vs. 38.8%; P = .186), as well as failure-free survival (77.3% vs. 81.4%; P = .313), progression-free survival (94.4% vs. 95.8%; P = .489), and overall survival (96.8% vs. 98.3%; P = .088). Multivariate analyses showed that the drug type was not associated with responses and outcomes. After the PSM procedure, 177 pairs of patients with comparable baseline characteristics were reanalyzed. Multivariate analyses confirmed that generic or branded imatinib used as first-line therapy was not associated with either responses or outcomes.

CONCLUSION

Sociodemographic characteristics might influence the tyrosine kinase inhibitor that patients chose. Generic and branded imatinib as first-line therapy had comparable efficacy and safety in CML-CP patients.

[Comparison of the efficacy and safety of Chinese generic imatinib and branded imatinib in patients with chronic myeloid leukemia in consideration of demographic characteristics]

目的

比较国产和原研伊马替尼一线治疗慢性髓性白血病慢性期（CML-CP）患者的有效性和安全性；探索服用原研伊马替尼获得完全细胞遗传学反应（CCyR）后转换为国产伊马替尼的患者疾病的稳定性和不良反应的变化。

方法

①一线治疗组：回顾性收集和分析2013年10月至2018年8月期间，接受国产仿制伊马替尼（商品名昕维®）或进口原研伊马替尼（商品名格列卫®）作为一线治疗并定期随访、监测的CML-CP连续病例。②转换组：回顾性收集和分析2006年12月至2016年9月期间，接受原研伊马替尼至少获得CCyR后转换为国产仿制伊马替尼治疗的CML-CP连续病例。

结果

①一线治疗组：共409例（国产伊马替尼201例，原研伊马替尼208例）患者入组，中位年龄42（18~83）岁。国产和原研组患者人口学特征差异具有统计学意义：国产伊马替尼组患者中受教育水平更低（P<0.001）、离异或丧偶者比例更高（P=0.004）、农村户籍者比例更高（P<0.001）。两组年龄、性别、Sokal危险度评分、WBC和HGB水平的差异无统计学意义。中位随访25（3~62）个月，国产伊马替尼组和原研伊马替尼组的3年CCyR、主要分子学反应（MMR）、分子学反应4.0（MR4.0）和分子学反应4.5（MR4.5）的累积获得率差异均无统计学意义（97.5%对94.5%，P=0.592；84.3%对93.1%，P=0.208；42.7%对41.7%，P=0.277；25.4%对33.0%，P=0.306），3年无失败生存（FFS）率、无进展生存（PFS）率和总生存（OS）率差异亦无统计学意义（76.7%对81.0%，P=0.448；91.8%对96.3%，P=0.325；95.8%对98.5%，P=0.167）。多因素分析显示，TKI类型不影响患者的治疗反应（CCyR、MMR、MR4.0和MR4.5累积获得率）及结局（FFS、PFS和OS）。两组不良反应发生率也相似。②转换组：共39例患者入组，中位年龄42（23~80）岁，于原研伊马替尼中位治疗38（8~114）个月后换为国产伊马替尼，换药后中位随访39（6~63）个月，23例（58.9%）患者分子学反应维持原来水平，12例（30.8%）分子学反应改善。新发药物不良反应均可耐受。

结论

人口学特征影响CML-CP患者的用药选择。在规范的监测和管理下，国产与原研伊马替尼一线治疗CML-CP患者的有效性和安全性相当。对于接受原研伊马替尼后获得稳定治疗反应的患者，可有效、安全地转换为国产伊马替尼。

Efficacy and safety of generic imatinib after switching from original imatinib in patients treated for chronic myeloid leukemia in the United States

Introduction

Imatinib is standard therapy for patients with chronic myeloid leukemia (CML). In February 2016, a generic formulation entered the US market. Physicians and patients are frequently concerned about whether switching from original to generic drugs may affect the efficacy and/or safety.

Materials and methods

This is an observational retrospective study using medical charts of patients diagnosed with CML in the chronic phase who were treated with original imatinib from the year 2000 to 2017 and who were subsequently switched to generic imatinib.

Results

In this study, 38 patients have switched to generic imatinib. Before the switch, responses were assessed on all patients, all of them were in CCyR and 36 (95%) were in MMR, including 28 (74%) with MR4.5. Patients have received generic imatinib for a median of 19.4 (range, 3.4‐46.3) months. Molecular responses after switching were stable in 89%, improved in 8%, and worsened in 3% of patients. After switching, 15 (39%) patients reported new or worsening adverse events, including 5 (13%) patients with edema, 8 (21%) muscle cramps, 7 (18%) nausea, 6 (16%) diarrhea, and 5 (13%) fatigue.

Discussion

Bioequivalence studies demonstrated the same rate and extent of absorption of generic imatinib compared to the original form, which led to the FDA approval. In our observational series, most of the patients maintained their responses and none lost MMR. Adverse events noted were mild and well tolerated.

Conclusion

A change from original to generic imatinib appears to maintain efficacy and be generally safe. More patients and longer follow‐up are required to confirm these observations.

Generic Substitution of Orphan Drugs for the Treatment of Rare Diseases: Exploring the Potential Challenges

Generic drugs are important components of measures introduced by healthcare regulatory authorities to reduce treatment costs. In most patients and conditions the switch from a branded drug to its generic counterpart is performed with no major complications. However, evidence from complex diseases suggests that generic substitution requires careful evaluation in some settings and that current bioequivalence criteria may not always be adequate for establishing the interchangeability of branded and generic products. Rare diseases, also called orphan diseases, are a group of heterogeneous diseases that share important characteristics: in addition to their scarcity, most are severe, chronic, highly debilitating, and often present in early childhood. Finding a treatment for a rare disease is challenging. Thanks to incentives that encourage research and development programs in rare diseases, several orphan drugs are currently available. The elevated cost of orphan drugs is a highly debated issue and a cause of limited access to treatment for many patients. As patent protection and the exclusivity period of several orphan drugs will expire soon, generic versions of orphan drugs should reach the market shortly, with great expectations about their impact on the economic burden of rare diseases. However, consistent with other complex diseases, generic substitution may require thoughtful considerations and may be even contraindicated in some rare conditions. This article provides an overview of rare disease characteristics, reviews reports of problematic generic substitution, and discusses why generic substitution of orphan drugs may be challenging and should be undertaken carefully in rare disease patients.

Tyrosine Kinase Inhibitors in the Treatment of Chronic-Phase CML: Strategies for Frontline Decision-making

PURPOSE OF REVIEW

Over the past two decades, the introduction of tyrosine kinase inhibitors (TKIs) has transformed the treatment of chronic myeloid leukemia (CML). With four agents currently approved for frontline use in chronic-phase (CP) disease, it follows that treatment decision-making has been rendered more challenging. Here we will review recent advances that help inform the selection of a first-line TKI.

RECENT FINDINGS

Extended follow-up of the seminal CML trials has demonstrated the long-term efficacy of TKIs, while also highlighting significant differences in their respective toxicity profiles and potency. Dasatinib and nilotinib generate deeper molecular responses than imatinib, particularly among patients with higher risk disease, but this has not translated into a significant survival advantage. Similar results have been obtained at 1 year with bosutinib; its efficacy and toxicity were well balanced at a dose of 400 mg daily, prompting its recent approval for this indication. Lastly, multiple studies have demonstrated that TKIs can be safely discontinued in select individuals who have maintained deep responses for extended periods, establishing treatment-free remission as a novel goal in CP CML. The careful consideration of parameters such as disease risk, the potency, and toxicity profile of each TKI, as well as each patient's unique comorbidities and preferences, enables truly individualized therapeutic decision-making in CP CML, with the goal of ensuring that a high quality of life accompanies the survival advantage conferred by these agents.

Generic formulations of imatinib for treatment of Philadelphia chromosome-positive leukemia in pediatric patients

Since the patent for imatinib has expired, the role of generic imatinib (GI) in the management of Philadelphia chromosome-positive (Ph+) leukemia in pediatric patients has had ongoing discussion. Some studies in adults demonstrated that equivalent doses of GI and branded imatinib (BI) result in comparable plasma concentrations and clinical efficacy. However, other studies found that GI users are more likely to stop imatinib, with intolerance and decreased persistence as the main causes. Economic factors also heavily influence GI selection. This article aims to review the present knowledge to support further discussion on the role of GI in the management of pediatric Ph+ leukemia.

Treating the chronic-phase chronic myeloid leukemia patient: which TKI, when to switch and when to stop?

INTRODUCTION

With the discovery of imatinib mesylate nearly 20 years ago, tyrosine kinase inhibitors (TKIs) were found to be effective in chronic myeloid leukemia (CML). TKI therapy has since revolutionized the treatment of CML and has served as a paradigm of success for targeted drug therapy in cancer. Several new TKIs for CML have been approved over the last two decades that exhibit improved potency over imatinib and have different off-target profiles, providing options for individualized therapy selection. Areas covered: Current management of chronic phase CML, including guidance on the sequential use of imatinib and newer-generation TKIs and evolving treatment strategies such as TKI discontinuation. Relevant literature was identified by searching biomedical databases (i.e. PubMed) for primary research material. Expert commentary: Although survival outcomes have drastically improved for CML patients, treatment for CML has grown more complex with the introduction of next-generation TKIs and the advent of treatment-free remissions (TFR). Goals of therapy have shifted accordingly, with increased focus on improving quality of life, managing patient expectations and optimizing patient adherence.

Association between insurance status at diagnosis and overall survival in chronic myeloid leukemia: A population-based study

BACKGROUND

Chronic myeloid leukemia (CML) can be treated effectively with tyrosine kinase inhibitor therapy directed at BCR-ABL, but access to care, medication cost, and adherence may be barriers to treatment. This study was designed to determine whether the insurance status at diagnosis influences CML patient outcomes.

METHODS

The Surveillance, Epidemiology, and End Results database was used to identify 5784 patients, aged 15 years or older, who were diagnosed with CML between 2007 and 2012 and whose insurance status was documented at diagnosis. The primary outcome was 5-year overall survival (OS). Covariates of interest included the age at diagnosis, race, ethnicity, sex, county-level socioeconomic status, and marital status. OS was evaluated with a log-rank test and Kaplan-Meier estimates.

RESULTS

Among patients aged 15 to 64 years, insurance status was associated with OS (P < .001): being uninsured or having Medicaid was associated with worse 5-year OS in comparison with being insured (uninsured patients, 72.7%; Medicaid patients, 73.1%; insured patients, 86.6%). For patients who were 65 years old or older, insurance had less of an impact on OS (P = .07), with similar 5-year OS rates for patients with Medicaid and those with other insurance (40.2% vs 43.4%). In a multivariate analysis of patients aged 15 to 64 years, both uninsured patients (hazard ratio [HR], 1.93; P < .001) and Medicaid patients (HR, 1.83; P < .001) had an increased hazard of death in comparison with insured patients; patients younger than 40 years, female patients, and married patients also had a lower hazard of death.

CONCLUSION

These findings suggest that CML patients under the age of 65 years who are uninsured or have Medicaid have significantly worse survival than patients with other insurance coverage. Cancer 2017;123:2561-69. © 2017 American Cancer Society.

The Efficacy of Generic Imatinib as First- and Second-line Therapy: 3-Year Follow-up of Patients With Chronic Myeloid Leukemia

INTRODUCTION

Generics of imatinib mesylate, the first tyrosine kinase inhibitor targeting the BCR-ABL1 fusion protein, have recently been approved in many countries as the alternative, low-cost forms for the treatment of patients with chronic myeloid leukemia (CML). The aim of this study was to evaluate the long-term clinical outcomes of patients with CML receiving first-line and second-line generic imatinib in Bosnia and Herzegovina.

PATIENTS AND METHODS

This was a multicenter retrospective cohort study of patients (n = 41) treated with generic imatinib in Bosnia between September 1, 2013 and August 5, 2016. Patients were categorized into 2 study groups: Group 1 (n = 27) included newly diagnosed patients with CML receiving front-line generic imatinib, and Group 2 (n = 14) consisted of patients who started with front-line Glivec and were mandated to switch to the second-line generic imatinib.

RESULTS

The median follow-up for Group 1 (first-line generic imatinib) and Group 2 (second-line generic imatinib) was 16 and 36 months, respectively. At 36 months, the overall survival for patients in Group 1 was 85%, and the achievement of complete cytogenetic response was 81%. At 24 months, the major molecular response rate was 48%. Overall, 52% of patients switched from first-line generic imatinib to nilotinib owing to treatment failure and side-effects. In Group 2, 93% of patients sustained cytogenetic and molecular response at 3 years after the switch from branded to generic imatinib.

CONCLUSION

Our results lead us to conclude that generic imatinib as second-line therapy does not have deleterious effects on patient outcomes. However, first-line generic imatinib showed suboptimal efficacy compared with branded imatinib.

Cost-effectiveness of Tyrosine Kinase Inhibitor Treatment Strategies for Chronic Myeloid Leukemia in Chronic Phase After Generic Entry of Imatinib in the United States

Background:

We analyzed the cost-effectiveness of treating incident chronic myeloid leukemia in chronic phase (CML-CP) with generic imatinib when it becomes available in United States in 2016. In the year following generic entry, imatinib’s price is expected to drop 70% to 90%. We hypothesized that initiating treatment with generic imatinib in these patients and then switching to the other tyrosine-kinase inhibitors (TKIs), dasatinib or nilotinib, because of intolerance or lack of effectiveness (“imatinib-first”) would be cost-effective compared with the current standard of care: “physicians’ choice” of initiating treatment with any one of the three TKIs.

Methods:

We constructed Markov models to compare the five-year cost-effectiveness of imatinib-first vs physician’s choice from a US commercial payer perspective, assuming 3% annual discounting ($US 2013). The models’ clinical endpoint was five-year overall survival taken from a systematic review of clinical trial results. Per-person spending on incident CML-CP treatment overall care components was estimated using Truven’s MarketScan claims data. The main outcome of the models was cost per quality-adjusted life-year (QALY). We interpreted outcomes based on a willingness-to-pay threshold of $100 000/QALY. A panel of European LeukemiaNet experts oversaw the study’s conduct.

Results:

Both strategies met the threshold. Imatinib-first ($277 401, 3.87 QALYs) offered patients a 0.10 decrement in QALYs at a savings of $88 343 over five years to payers compared with physician’s choice ($365 744, 3.97 QALYs). The imatinib-first incremental cost-effectiveness ratio was approximately $883 730/QALY. The results were robust to multiple sensitivity analyses.

Conclusion:

When imatinib loses patent protection and its price declines, its use will be the cost-effective initial treatment strategy for CML-CP.

Formulation and in vitro, in vivo evaluation of effervescent floating sustained-release imatinib mesylate tablet

Introduction

Imatinib mesylate is an antineoplastic agent which has high absorption in the upper part of the gastrointestinal tract (GIT). Conventional imatinib mesylate (Gleevec) tablets produce rapid and relatively high peak blood levels and requires frequent administration to keep the plasma drug level at an effective range. This might cause side effects, reduced effectiveness and poor therapeutic management. Therefore, floating sustained-release Imatinib tablets were developed to allow the tablets to be released in the upper part of the GIT and overcome the inadequacy of conventional tablets.

Methodology

Floating sustained-release Imatinib mesylate tablets were prepared using the wet granulation method. Tablets were formulated using Hydroxypropyl Methylcellulose (HPMC K4M), with Sodium alginate (SA) and Carbomer 934P (CP) as release-retarding polymers, sodium bicarbonate (NaHCO₃) as the effervescent agent and lactose as a filler. Floating behavior, in vitro drug release, and swelling index studies were conducted. Initial and total drug release duration was compared with a commercial tablet (Gleevec) in 0.1 N HCl (pH 1.2) at 37 ± 0.5°C for 24 hours. Tablets were then evaluated for various physical parameters, including weight variation, thickness, hardness, friability, and drug content. Consequently, 6 months of physical stability studies and in vitro gastro-retentive studies were conducted.

Results and Discussion

Statistical data analysis revealed that tablets containing a composition of 14.67% w/w HPMC K4M, 10.67%, w/w Na alginate, 1.33%, w/w Carbomer 934P and 9.33%, w/w NaHCO₃ produced the most favorable formulation to develop 24-hour sustained-release tablets with optimum floating behavior and satisfactory physicochemical characteristics. Furthermore, in vitro release study revealed that the formulated SR tablet had significantly lower C_max and higher T_max compared to the conventional tablet (Gleevec). Thus, formulated SR tablets preserved persistent concentration of plasma up to 24 hours.

Conclusion

In conclusion, in order to suggest a better drug delivery system with constant favorable release, resulting in optimized absorption and less side effects, formulated CP-HPMC-SA based imatinib mesylate floating sustained-release tablets can be a promising candidate for cancer chemotherapy.

Generic imatinib in the treatment of chronic myeloid leukemia: Cerrahpaşa experience

As the first tyrosine kinase inhibitor (TKI), imatinib (Gleevec or Glivec, Novartis Pharmaceuticals) was introduced, the treatment of chronic myeloid leukemia (CML) has changed radically, and the TKIs are now the mainstay of CML treatment. The substantially high treatment cost has unfortunately been a major issue, which puts a strain on health-care budgets even in developed countries. So reimbursement policies encourage generic drug (i.e. generic imatinib) use to lower the expenses, and it is true that generics would lead to considerable cost savings, but they also give rise to questions associated with their efficacy, safety and quality. In this commentary, we discuss the current evidence on generic imatinib based mainly on our "Cerrahpaşa" experience along with other data available in the literature together with the data discussed by de Lemos and colleagues.