Neoadjuvant breast cancer treatment as a sensitive setting for trastuzumab biosimilar development and extrapolation

Systematic Review on the Use of Biosimilars of Trastuzumab in HER2+ Breast Cancer

Trastuzumab is a monoclonal antibody used in the treatment of breast cancer in cases where the tumor overexpresses the HER2 receptor, a cell membrane receptor activated by the epidermal growth factor. Intravenous and subcutaneous administration of trastuzumab have comparable clinical and pharmacological characteristics, but trastuzumab biosimilars are currently only available in intravenous form. Trastuzumab biosimilars are ultimately preferred by a proportion of patients, especially in cases where co-administration of other chemotherapeutic agents, such as trastuzumab and tucatinib, a small molecule of tyrosine kinase inhibitor, is required in patients with HER-positive metastatic breast cancer. Oncologists should be well-aware of the advantages of intravenously administered trastuzumab biosimilars over subcutaneous administration, certainly also taking into account the patient’s preferences. Further cost-effectiveness analyses will be very important, along with expectations regarding successful concomitant subcutaneous administration of trastuzumab with other anticancer drugs, such as pertuzumab. This systematic review describes and analyzes the so-far published studies concerning the use of the available trastuzumab biosimilars in HER-positive early and metastatic breast cancer in terms of efficacy, safety, and cost–benefit ratio. An attempt was also made to draw some conclusions and to comment on future needs and perspectives.

Extrapolation: Experience gained from original biologics

Biologicals undergo modifications throughout their commercial lifecycle. Major changes can unintentionally magnify their inherent physicochemical variability. Although trials comparing the pre- and the post-change versions have been requested occasionally, analytical comparison is the most sensitive approach to anticipating clinical equivalence. Therefore, it may be concluded, by means of 'extrapolation', that non-identical versions of a given biologic will behave equally in all indications. Despite the lessons learned with original biologics, there are still controversies around the approval of biosimilars through extrapolation. Here, a comprehensive analysis of scattered information allows for an account of cases of original biologic versions approved in some indications with no patient trials involved. Healthcare professionals can be reassured that inasmuch as extrapolation has proven valid for new versions of original biologics, the same holds for biosimilars.

Totality of Evidence Supporting the Use of ABP 980, a Trastuzumab Biosimilar: Practical Considerations

ABP 980 (KANJINTI™, Amgen, Thousand Oaks, CA, USA; Amgen Europe B.V., The Netherlands) is a biosimilar to trastuzumab (Herceptin^®), a monoclonal antibody that selectively binds human epidermal growth factor receptor-2 (HER2). Here we provide a brief overview of the totality of evidence (including analytical [structural and functional] characterization, nonclinical evaluation, and human pharmacokinetic [PK], pharmacodynamic, and clinical assessment comparing ABP 980 with trastuzumab reference product [RP]) that supported the approval of ABP 980, along with practical considerations on the reconstitution and use of the lyophilized product to ensure safe and effective administration. ABP 980 has been shown to be highly similar to the RP, with similar mechanism of action, binding, and potency. Key PK parameters, geometric means ratio (GMR [90% CI]) of C_max and AUC_inf, are comparable and within the equivalence margin of 0.80 to 1.25 (ABP 980: 1.04 [0.99–1.08] versus trastuzumab US: 1.06 [1.00–1.12]; ABP 980: 0.99 [0.95–1.03] versus trastuzumab EU: 1.00 [0.95–1.06]). No clinically meaningful differences were found between ABP 980 and RP in a comparative clinical trial in patients with HER2-positive early breast cancer. Pathological complete response—ABP 980: 48% versus RP: 41% (risk difference [RD], 90% CI: 7.3%, 1.2–13.4; relative risk [RR], 90% CI: 1.188, 1.033–1.366). Sensitivity analyses per central pathology review—ABP 980: 48%; RP: 42% (RD: 5.8%, −0.5 to 12.0; RR: 1.142, 0.993–1.312), with RD and RR falling within predefined equivalence margins. Similar to trastuzumab RP, KANJINTI™ is supplied as a sterile, lyophilized cake to be reconstituted with bacteriostatic water for injection (BWFI) for multiple-dose injection or sterile WFI for single use. Stability data support storage of reconstituted solution at 2–8°C (36–46°F), up to 28 days. Reconstituted solution can be diluted in infusion bags containing 0.9% saline and stored for up to 24 h prior to intravenous administration.

Biologic Drug Quality Assurance to Optimize HER2 + Breast Cancer Treatment: Insights from Development of the Trastuzumab Biosimilar SB3

SB3 is a biosimilar of trastuzumab that has been approved for use in the treatment of human epidermal growth factor 2-positive breast cancer and human epidermal growth factor 2-positive gastric cancer. Antibody-dependent cellular cytotoxicity is one of several critical quality attributes of trastuzumab. Data from the development of SB3 support the hypothesis of a relationship between antibody-dependent cellular cytotoxicity activity and clinical outcomes in terms of the response rate and long-term survival. Current analytic methods utilizing advanced technology allow the detection of small changes in other quality attributes that influence antibody-dependent cellular cytotoxicity, such as glycosylation and FcγRIIIa binding. Use of such methods to monitor batch-to-batch consistency enables production of trastuzumab biosimilars with consistent quality. Trastuzumab biosimilars such as SB3 therefore have the potential to increase accessibility to trastuzumab-based therapy without compromising efficacy or safety.

Totality of Scientific Evidence in the Development of ABP 980, a Biosimilar to Trastuzumab

ABP 980 was developed as a biosimilar to trastuzumab, a monoclonal antibody targeting human epidermal growth factor receptor 2 (HER2), that is indicated for the treatment of HER2-positive metastatic breast cancer, early breast cancer (EBC), and metastatic gastric cancer. ABP 980 is approved in the United States, European Union, and Japan for all the indications of trastuzumab, based on the totality of evidence (TOE) gathered by the systematic step-wise accumulation of comparative analytical, preclinical, and clinical (pharmacokinetics [PK], efficacy, safety and immunogenicity) data for ABP 980 and trastuzumab reference product (RP). As a key first step of the ABP 980 biosimilar program, comprehensive analytical characterization of critical quality attributes established that ABP 980 is structurally and functionally similar to trastuzumab RP. Complementing these data, results of non-clinical pharmacology, toxicology, and toxicokinetic studies supported similarity between ABP 980 and trastuzumab RP. A randomized study in healthy subjects demonstrated clinical PK equivalence of ABP 980 relative to trastuzumab RP in these subjects. In the final clinical evaluation step, a randomized comparative study (LILAC) confirmed the lack of clinically meaningful differences between ABP 980 and trastuzumab RP in efficacy, safety, and immunogenicity in women with HER2-positive EBC in the neoadjuvant–adjuvant setting. Neoadjuvant EBC represented a sensitive homogenous population for biosimilar demonstrations, and the primary endpoint of pathologic complete response served as a sensitive surrogate endpoint. An important aspect of the LILAC study design is that it is the only study that evaluated the effect of switching from the trastuzumab RP to a trastuzumab biosimilar during the adjuvant phase. No new or unexpected safety signals emerged in the clinical evaluations, with the safety profile of ABP 980 consistent with that previously described for trastuzumab. Overall, the TOE data generated for ABP 980 support the conclusion that it is highly similar to trastuzumab RP, thus providing the scientific justification for extrapolation to all the approved indications of trastuzumab.

Biosimilars in oncology: key role of nurses in patient education

Biosimilars have the potential to lower costs and increase patient access to life-saving cancer therapies. However, lack of familiarity with biosimilars can be a barrier to their adoption, limiting their health and economic benefits. As highly trusted healthcare providers, nurses play integral roles in patient education. This review aims to help prepare nurses to respond to potential questions from patients on biosimilars. The regulation, use and potential benefits of biosimilars are discussed, with a focus on biosimilars in oncology. Overall, biosimilars are highly regulated medicines that provide comparable benefits to available biologics. Nurses can influence the adoption of biosimilars through patient education and can impact the future of the field in their expanding roles within health care systems.

Understanding the Role of Comparative Clinical Studies in the Development of Oncology Biosimilars

Biosimilars have the potential to broaden patient access to biologics and provide cost savings for health care systems. During the development of a biosimilar, data that directly compare the proposed biosimilar with the reference product are required. Such comparative data are generated in a stepwise hierarchical process that begins with extensive laboratory-based structural analyses and functional assays. This initial analytical phase serves as the foundation for the demonstration of biosimilarity and is followed by nonclinical in vivo testing (if required) and then clinical evaluation, including a comparative pharmacokinetics/pharmacodynamics study that is usually conducted in healthy volunteers. The development program typically culminates with a comparative clinical efficacy study. The aim of this study is to confirm clinical equivalence of the potential biosimilar and reference product on the basis of prespecified margins, using a study population and efficacy end point that are sufficiently sensitive for detecting potential product-related differences. Such studies also include detailed analyses of safety as well as evaluation of immunogenicity. As biosimilars become more widely available in oncology, especially with recent regulatory approvals of rituximab, trastuzumab, and bevacizumab biosimilars, it is critically important that clinicians understand how the comparative clinical study differs from a traditional phase III efficacy and safety study in the development of a novel biologic originator product. Here, we review the role of comparative clinical studies in biosimilar development, with a focus on trials conducted to support approved trastuzumab biosimilars. We discuss the study populations and end points used, extrapolation of indications, and the confirmatory nature of these studies within the totality of evidence supporting biosimilarity.

The rise of oncology biosimilars: from process to promise

Biosimilars are biologic products that are highly similar to, and have no clinically meaningful differences from, the approved originator molecule. They are poised to play an increasingly central role in cancer treatment, helping to improve access by driving down costs. Regulatory bodies have set out robust mechanisms for the approval of biosimilars, based on comprehensive and rigorous analytical and nonclinical comparisons with the originator. Product attributes (e.g., post-translational modifications) that are important to the function of the molecule must be similar between biosimilar and originator. This should be followed by a robust clinical development program, assessing pharmacokinetics, pharmacodynamics, efficacy, safety and immunogenicity. Equivalence in one indication might allow extrapolation across all the indications of the originator biologic. The recent approval of several trastuzumab biosimilars provides an example of how this process can work in practice for the benefit of patients, clinicians and payers.

The arrival of biosimilar monoclonal antibodies in oncology: clinical studies for trastuzumab biosimilars

The monoclonal antibody trastuzumab (Herceptin®), which targets the human epidermal growth factor receptor 2 (HER2), is approved for the treatment of early breast and advanced breast and gastric cancer in which HER2 is overexpressed. Several biosimilar versions of trastuzumab are expected to enter the European market over the course of 2018 and 2019. The biosimilar development pathway consists of a comprehensive comparability exercise between the biosimilar candidate and the reference product, primarily focussing on data from analytical studies. Clinical studies for biosimilar candidates follow a different design to those for a new biological, as the aim is not to independently establish clinical benefit, but to confirm biosimilarity between the two agents. The different trastuzumab biosimilar candidates have followed diverse pathways in their clinical development, with differences in clinical trial design (equivalence or non-inferiority design), patient population (those with metastatic or early breast cancer) and endpoint (overall response rate or pathological complete response). These differences in approach in phase 3 testing must be viewed in the totality of evidence demonstrating biosimilarity. Adequate information on the biosimilar approval pathway, the nature of the biosimilarity exercise and how the clinical development of a biosimilar is tailored to meet the licensing requirements can help informed decision making in clinical practice.

Randomised clinical endpoint studies for trastuzumab biosimilars: a systematic review

PURPOSE

Uptake of biosimilars depends on clinicians and patients having confidence in the evidential basis of marketing approval. The aim of this systematic review was to assess the evidential role of randomised clinical endpoint studies in the marketing approval of trastuzumab biosimilars.

METHODS

We searched PubMed for any published reports of randomised studies associated with the five trastuzumab biosimilars approved by the EMA, as on 31 January 2019. We also searched ClinicalTrials.gov for any ongoing studies for other trastuzumab biosimilars.

RESULTS

We identified eight published papers or abstracts for seven randomised clinical endpoint studies for five trastuzumab biosimilars approved by the EMA: four studies in the neoadjuvant setting and three in the first-line metastatic setting. Another six unpublished or ongoing studies for other trastuzumab biosimilars were identified via ClinicalTrials.gov. According to GRADE, and considered in isolation, the randomised studies would be categorised as low-quality evidence because of the use of surrogate endpoints and the small sample size. However, according to GRADE, the totality-of-evidence for each of the five approved trastuzumab biosimilars would be categorised as high quality in that further data would be unlikely to change the conclusion that each biosimilar was not different from Herceptin in any clinically important way.

CONCLUSION

The pivotal data for each marketing approval was not the randomised clinical endpoint study, but the in vitro analytic characterisation. Regulatory confidence in in vitro analytic characterisation stems from years of experience with manufacturing changes for originator biological medicines. This emphasis on in vitro data, as the most sensitive way to detect clinically important differences, will be a new way of thinking for many oncologists.

Biosimilar Trastuzumab in Clinical Trials: Differences or Not?

In the last decade, cancer therapies have increasingly taken the form of combination treatments in which biologic agents play a crucial role. In breast cancer, the treatment strategy is adjusted to intrinsic subtypes such as human epidermal growth factor receptor-2(HER2)-positive. With the introduction of trastuzumab, a monoclonal antibody against HER2, survival has significantly improved in early and metastatic breast cancer. Trastuzumab's patent has now expired and biosimilars are moving into the market. Several clinical trials have led to the approval of 5 different biosimilar trastuzumabs. Results proved similarity between the proposed biosimilar and the reference product without significant differences in efficacy and safety, although follow-up has been short. However, the shorter drug development process with its goal of showing similarity rather than patient benefit uses surrogate endpoints such as pathologic complete response and overall response rate, not survival endpoints in terms of the 'gold standarD' in evaluating cancer therapies. The aim of this article is to give insight into how to plan and perform a clinical trial to prove equivalence between a biosimilar trastuzumab and its reference product and to elucidate the setup and outcome of published clinical trials.

Biosimilars: what the oncologist should know

As originator biologic medicines lose patent protection, some biopharmaceutical companies are focusing on developing similar versions of these costly and complex therapies with a goal of providing more affordable treatment options. Many of these molecules, known as biosimilars, are now approved worldwide and several more are expected to be introduced in the near future. As more biosimilars become available, it is important for clinicians to become familiar with this new category of products and understand how biosimilars are developed, how their development differs from that of originator biologics and how they differ from generics. This review aims to provide the practicing clinician with the knowledge needed to understand biosimilars, along with some guidance on their use in treating oncologic diseases.

The biosimilars journey: current status and ongoing challenges

Biosimilar products are already approved and marketed in several countries. The Food and Drug Administration has approved ten different biosimilars, and the European Medicines Agency has approved 40. Even though this scenario has provided important experience with biosimilar products, there are still challenges and unanswered questions. Up to now, a good amount of knowledge has been gathered in order to support the importance of the totality of evidence and the construction of a biosimilarity exercise for regulatory approval. In addition, the extrapolation of indications has been proved viable when a careful analysis is performed. The models for clinical trials and the use of the most sensible populations have been extensively discussed, and there is apparent homogeneity in manufacturer choices for study designs. However, some challenges remain. The lack of regulatory harmony, especially concerning naming, the marketed intended copies, the interchangeability, and the biosimilars in orphan diseases are some of those and are the focus of discussion in this review.

Development of New Formulations of Biologics: Expectations, Immunogenicity, and Safety for Subcutaneous Trastuzumab

Subcutaneous (SC) trastuzumab has long been approved as a cancer treatment for early and advanced HER2-positive (HER2+) breast cancer by both the European Medicines Agency (EMA) and Agência Nacional de Vigilância Sanitária (ANVISA), the Brazilian National Health Surveillance Agency. A pivotal non-inferiority phase III trial, which aimed to provide a more convenient and cost-effective treatment in the HER2+ breast cancer neoadjuvant setting, showed that the SC group met prespecified efficacy endpoints and the SC formulation was considered as safe as the intravenous (IV) formulation. Considering the recent approval of several biosimilars, new SC formulations are also an interesting manufacturer strategy as these drugs can obtain patent protection. Despite being considered non-inferior to the IV formulation of trastuzumab, in clinical development, the SC formulation elicited higher immunogenicity, mainly related to overall anti-drug antibodies (ADAs); however, this finding was classified as clinically non-significant. In this article, we explore different aspects of the benefits and risks of the SC trastuzumab formulation according to published data.

The evolution of biosimilars in oncology, with a focus on trastuzumab

Cancer therapy has evolved significantly with increased adoption of biologic agents ("biologics"). That evolution is especially true for her2 (human epidermal growth factor receptor-2)-positive breast cancer with the introduction of trastuzumab, a monoclonal antibody against the her2 receptor, which, in combination with chemotherapy, significantly improves survival in both metastatic and early disease. Although the efficacy of biologics is undeniable, their expense is a significant contributor to the increasing cost of cancer care. Across disease sites and indications, biosimilar agents are rapidly being developed with the goal of offering cost-effective alternatives to biologics. Biosimilars are pharmaceuticals whose molecular shape, efficacy, and safety are similar, but not identical, to those of the original product. Although these agents hold the potential to improve patient access, complexities in their production, evaluation, cost, and clinical application have raised questions among experts. Here, we review the landscape of biosimilar agents in oncology, with a focus on trastuzumab biosimilars. We discuss important considerations that must be made as these agents are introduced into routine cancer care.

Developing the Totality of Evidence for Biosimilars: Regulatory Considerations and Building Confidence for the Healthcare Community

Biosimilars are highly similar versions of approved branded biologics. Unlike generics, they are not exact replicas of reference products. Minor differences between biosimilars and reference products in some aspects are expected; likewise, biosimilar products will differ from each other. The objective of this review is to discuss the challenges associated with the development and approval of biosimilar products that are unique because of their complex structure and specialized manufacturing processes, which can impact not only efficacy but also immunogenicity and safety. Regulatory guidelines recommend a totality-of-evidence approach focused on stepwise development that involves demonstration of structural similarity and functional equivalence. Structural and functional characteristics of the proposed biosimilar are compared with the reference product; similarity of these functions forms the foundation of the biosimilar development program, including potential animal studies, a human pharmacokinetics/pharmacodynamics equivalence study, and a clinical study to confirm similar efficacy, safety, and immunogenicity. The clinical study should be performed in a sensitive population using appropriate endpoints to allow detection of any clinically meaningful differences between the biosimilar and the reference product if such differences exist. In conclusion, development of biosimilars is focused on the minimization of potential differences between the proposed biosimilar and reference product and the establishment of a robust manufacturing process to consistently produce a high-quality biosimilar product.

Quantitative evaluation of redox ratio and collagen characteristics during breast cancer chemotherapy using two-photon intrinsic imaging

Preoperative neoadjuvant treatment in locally advanced breast cancer is recognized as an effective adjuvant therapy, as it improves treatment outcomes. However, the potential complications remain a threat, so there is an urgent clinical need to assess both the tumor response and changes in its microenvironment using non-invasive and precise identification techniques. Here, two-photon microscopy was employed to detect morphological alterations in breast cancer progression and recession throughout chemotherapy. The changes in structure were analyzed based on the autofluorescence and collagen of differing statuses. Parameters, including optical redox ratio, the ratio of second harmonic generation and auto-fluorescence signal, collagen density, and collagen shape orientation, were studied. Results indicate that these parameters are potential indicators for evaluating breast tumors and their microenvironment changes during progression and chemotherapy. Combined analyses of these parameters could provide a quantitative, novel method for monitoring tumor therapy.

Clinical equivalence with G-CSF biosimilars: methodologic approach in a (neo)adjuvant setting in non-metastatic breast cancer

Biosimilars are biological medicines that have been shown to be similar to a reference biological medicine that has already been approved for use. Development of biosimilars is based on a "totality of evidence" approach that involves a series of steps by which biosimilars must demonstrate similarity to a reference product in all aspects of the drug and eliminate any remaining uncertainties. Clinical studies are then considered confirmatory and are performed to show that there are no clinically meaningful differences compared with the reference product in a sensitive patient population. The recombinant human granulocyte colony-stimulating factor (G-CSF) biosimilar EP2006/Zarxio® (filgrastim-sdnz) became the first FDA-approved biosimilar in 2015. This review evaluates how clinical equivalence can be demonstrated with G-CSF biosimilars through the identification of "sensitive" study populations and endpoints. Patients with non-metastatic breast cancer treated in the (neo)adjuvant setting represent a potentially homogenous population, making this a suitable sensitive indication for assessing filgrastim and pegfilgrastim biosimilars compared with reference products. This review includes clinical trials of G-CSF biosimilars in breast cancer, focusing on key aspects of the trials that were necessary to accurately demonstrate clinical equivalence and enable extrapolation to relevant indications, based on guidelines and biostatistical principles.

Regulatory considerations in oncologic biosimilar drug development

Biosimilar monoclonal antibodies are being developed globally for patients with different types of solid tumors and hematologic malignancies. Applications for proposed biosimilar monoclonal antibodies are being submitted to the regulatory authorities around the world and may increase patient access to key treatment options upon approval. An understanding among stakeholders (e.g., physicians, patients and their caregivers, pharmacists, payers) of the approval criteria, as well as the similarities and differences in regulatory pathways involved in biosimilar approval in different countries, as presented in this review, will facilitate identification of high-quality, safe, monoclonal antibodies that have been developed according to strict, biosimilar regulatory standards. Further guidance and resolution of the ongoing discussions on biosimilar labeling, naming, automatic substitution, and indication extrapolation may ensure, in the future, an effective and appropriate use of biosimilar monoclonal antibodies by oncologists and other stakeholders in daily clinical practice.

The evolving role of biosimilars in haematology-oncology: a practical perspective

The loss of patents covering many biopharmaceutical/biological agents in the mid 1990s led to the introduction of a new generation of drugs: biosimilars. These new agents, produced by living cells just as the originator drugs, are chemically highly similar to endogenous human proteins; characterized by three-dimensionally complex, high molecular weight compounds. Among the first biosimilars used in haematology-oncology were erythropoietin and granulocyte colony-stimulating factor. After five years of use in clinical practice, the efficacy and safety profile of biosimilars approved by the European Medicines Agency is excellent. Over the next year or two, biosimilar monoclonal antibodies (MoAbs) will become available; the first will be rituximab and trastuzumab. Not only are MoAbs more complex in terms of molecular weight and number of amino acids than the first biosimilars, but they are also anticancer drugs, not merely supportive treatments like their predecessors. This opens up important questions. How are regulatory agencies to assess their clinical efficacy, immunogenicity and safety? Is the neoadjuvant clinical setting the best to evaluate them? What will regulatory agencies decide in terms of switching an originator molecule for a biosimilar or extrapolating efficacy results from one pathology to another? Once biosimilars of rituximab and trastuzumab are approved, several challenging issues will need to be addressed such as how to maintain appropriate pharmacovigilance, how to extrapolate across indications, and issues concerning automatic substitution. There is currently no consensus in any of these areas. This review addresses all these issues: new challenges that the oncology community will face in the near future.

Nanomaterials-Tools, Technology and Methodology of Nanotechnology Based Biomedical Systems for Diagnostics and Therapy

Nanomedicine helps to fight diseases at the cellular and molecular level by utilizing unique properties of quasi-atomic particles at a size scale ranging from 1 to 100 nm. Nanoparticles are used in therapeutic and diagnostic approaches, referred to as theranostics. The aim of this review is to illustrate the application of general principles of nanotechnology to select examples of life sciences, molecular medicine and bio-assays. Critical aspects relating to those examples are discussed.