Concepts and Challenges of Biosimilars in Breast Cancer: The Emergence of Trastuzumab Biosimilars

QL1701 (a proposed trastuzumab biosimilar) versus reference trastuzumab plus docetaxel as first-line therapy for HER2-positive metastatic breast cancer: a multicenter, randomized, double-blinded, parallel-controlled, phase III equivalence trial

BACKGROUND

QL1701 is a proposed biosimilar to the reference trastuzumab (Herceptin®). This trial compared the efficacy and safety of QL1701 with the reference trastuzumab in first-line treatment of human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer.

MATERIALS AND METHODS

This randomized, double-blinded, parallel-controlled, phase III equivalence trial was conducted in 73 centers in China. Eligible patients with histologically or cytologically diagnosed HER2-positive metastatic breast cancer were randomly assigned (1 : 1) to receive either QL1701 or reference trastuzumab in combination with docetaxel (every 3 weeks) for eight cycles as the first-line treatment. Then, in patients with objective responses or stable disease, the QL1701 or reference trastuzumab with or without docetaxel was maintained for totally up to 12 months if tolerated. The primary endpoint was 24-week objective response rate (ORR) assessed by an independent review committee (IRC). The equivalence margin was 0.80-1.25 with a 90% confidence interval (CI) for the ORR ratio (QL1701 to reference trastuzumab).

RESULTS

Between 29 April 2020 and 15 March 2022, 474 patients were randomized, and 473 received either QL1701 (n = 236) or reference trastuzumab (n = 237). The risk ratio for 24-week ORR was 1.07 (90% CI 0.94-1.21). The 90% CI fell within the pre-specified equivalence margin of 0.80-1.25. The 24-week ORR assessed by IRC was 59.7% (95% CI 53.2% to 66.1%) versus 56.1% (95% CI 49.5% to 62.5%) in QL1701 and the reference trastuzumab, respectively. As of 12 April 2023, there were no notable differences in progression-free survival (median: 8.3 versus 8.4 months) and overall survival (1-year rate: 95.1% versus 93.3%) between the two groups. Safety, pharmacokinetic (PK), and immunogenicity profiles were similar between the two groups.

CONCLUSION

QL1701 demonstrated equivalent efficacy and similar safety to the reference trastuzumab when combined with docetaxel in the first-line treatment of patients with HER2-positive metastatic breast cancer, with similar PK and immunogenicity profiles.

Efficacy and Safety of BP02 (Trastuzumab Biosimilar) in HER2-Positive Metastatic Breast Cancer: A Multicenter Phase III Study

BACKGROUND AND OBJECTIVE

Trastuzumab targets human epidermal growth factor receptor 2 (HER2) receptors and is indicated for treating HER2-positive metastatic breast cancer. BP02, a recombinant IgG1 kappa humanized monoclonal antibody, is being developed as a trastuzumab biosimilar. The objective of this study was to evaluate the equivalence of BP02 with reference trastuzumab (RT: Herceptin®-EU) in patients with HER2-positive metastatic breast cancer.

METHODS

This double-blinded, 1:1 randomized, parallel-group, active-controlled, phase III equivalence trial recruited women aged 18-75 years with histologically/cytologically confirmed HER2- positive, locally recurrent or metastatic breast cancer with systemic metastasis, from 59 sites in India. Patients were randomly allocated 1:1 stratified by estrogen receptor/progesterone receptor status to receive BP02/RT (8-mg/kg loading dose on day 1-cycle 1, 6 mg/kg on day 1-cycles 2-8, of each 3-week cycle) combined with docetaxel (75 mg/m2 on day 1-cycles 1-8) [induction phase]. Participants with complete or partial response, or stable disease at the end of the induction phase continued the study drug until disease progression/treatment discontinuation [maintenance phase]. The primary efficacy endpoint was the objective response rate per Response Evaluation Criteria in Solid Tumors (RECIST) 1.1.

RESULTS

Between 23 September, 2020 and 16 September, 2022, 690 patients were recruited (n = 345 each to BP02/RT). At the end of the induction phase (intent-to-treat population), a similar proportion of patients achieved an objective response rate with BP02 (n = 231 [67.0%], 95% confidence interval [CI] 62.0, 71.9) and RT (n = 238 [69.0%], 95% CI 64.1, 73.9). The 95% CI of risk difference (-2.03, 95% CI -9.15, 5.09) and 90% CI of risk ratio (0.97, 90% CI 0.89, 1.06) were within equivalence margins of ± 13% and (0.80, 1.25), respectively. Treatment-emergent adverse events leading to treatment withdrawal were reported in 2.9% and 3.2% patients with BP02 and RT, respectively.

CONCLUSIONS

BP02 showed an equivalent efficacy and similar safety profile to RT at the end of 24 weeks.

CLINICAL TRIAL REGISTRATION

CTRI Number: CTRI/2020/04/024456.

Monoclonal antibody biosimilars for cancer treatment

Monoclonal antibodies are important cancer medicines. The European Medicines Agency (EMA) approved 48 and the Food and Drug Administration (FDA) 56 anticancer monoclonal antibody-based therapies. Their high prices burden healthcare systems and hamper global drug access. Biosimilars could retain costs and expand the availability of monoclonal antibodies. In Europe, five rituximab biosimilars, six trastuzumab biosimilars, and eight bevacizumab biosimilars are available as anti-cancer drugs. To gain insight into the biosimilar landscape for cancer treatment, we performed a literature search and analysis. In this review, we summarize cancer monoclonal antibodies' properties crucial for the desired pharmacology and point out sources of variability. The analytical assessment of all EMA-approved bevacizumab biosimilars is highlighted to illustrate this variability. The global landscape of investigational and approved biosimilars is mapped, and the challenges for access to cancer biosimilars are identified.

Biosimilar in Breast Cancer: A Narrative Review

Breast cancer (BC) has been identified as a major public health cancer as it topped the list of most prevalent cancers among women in the last three years. Rigorous research has been conducted to improve the prognosis of cancer therapies since the time of inception. Recent advancements in cancer therapy have introduced monoclonal biosimilars as a promising treatment alternative. Monoclonal antibodies (mAbs), produced through cloning, have demonstrated effectiveness in targeting diverse antigens. Biosimilar, considered complex entities compared to small-molecule drugs, pose challenges in replication due to their biological nature. The manufacturing process involves rigorous comparability testing to ensure similarity in quality, safety, and efficacy with the reference product. Trastuzumab biosimilars, such as CT-P6, Ontruzant®, ABP 980, and PF-05280014, have shown efficacy in treating HER2-positive metastatic BCs, presenting a viable alternative to the reference product. The implications of monoclonal biosimilars extend beyond trastuzumab, with bevacizumab emerging as another significant biosimilar for BC treatment. The shift toward biosimilar aims to enhance accessibility to biologics by reducing costs. Health economic analyses indicate potential cost savings, contributing to the overall cost-effectiveness of biosimilar adoption. While concerns about switching between reference products and biosimilars exist, evidence suggests a lower risk of immunogenicity-related side effects with mAbs like trastuzumab. Monoclonal biosimilars present a promising avenue in BC therapy, demonstrating efficacy, safety, and potential cost savings. The integration of biosimilars into cancer treatment strategies offers a means to improve accessibility to effective care while addressing economic considerations in healthcare.

Establishing Analytical and Functional Comparability for Biosimilars

A biosimilar is a drug product that has been deemed to be highly similar to its off-patent reference product in terms of purity, molecular structure, and bioactivity. Approvals to such products are granted on the basis of unambiguous demonstration of “no clinically meaningful differences” between the reference and the intended biosimilar. For a successful biosimilar approval, establishing analytical and functional biosimilarity across all relevant critical quality attributes is an essential prerequisite. This critical activity is performed using a combination of orthogonal, high-resolution tools that can accurately quantitate the minor differences that exist. In this article, we review key findings from some of the recent biosimilarity assessments that we have published on biosimilars of granulocyte-colony-stimulating factor (G-CSF), insulin glargine, rituximab, and trastuzumab.

Biosimilars accessible in the market for the treatment of cancer

Biosimilars are the biological product clinically identical to a biologic reference standard regarding their strength, purity, and safety. A large segment of biosimilars has been developed for the treatment of cancer. This review aims to discuss various facets of biosimilars and explicates on biosimilars accessible in the market for cancer clinical intervention. It also illustrates the outcomes of recent clinical trial studies concerning biosimilars. Further, it also crosstalk the safety profiles, regulatory approval requirements, and allied challenges therein. The work will be of significant interest to researchers working in the field of biologics and biosimilars.

Current and future roles of biosimilars in oncology practice

Biologics have been used increasingly in the treatment and supportive care of cancer; however, their high cost places a significant burden on healthcare systems. The expiration of patents for biologics has led to the development of biosimilars, with the aim of reducing cost and increasing accessibility to novel treatments, which are affordable for a greater number of patients. Biosimilars are highly similar but not identical to the reference products; therefore, strict regulatory requirements have been formed for their approval. This ensures that there are no clinically meaningful differences compared with respective biologics, with regard to purity, safety and efficacy. In 2003, a regulatory framework for the approval of biosimilars was established in Europe, whereas the USA did not implement a framework until 2009, when the Biologics Price Competition and Innovation Act was formed. A number of biosimilars have currently been approved in oncology and the number is expected to rise in the near future. More than 10 years of evidence has revealed that biosimilars are safe and effective; however healthcare professionals need to be further educated to eliminate potential misconceptions and integrate biosimilars into routine clinical practice. The present review aims to provide an overview of the biosimilars used in Europe and the USA, present their main benefits and challenges, and discuss their current and future roles in medical oncology.

Antibody therapeutics and immunoregulation in cancer and autoimmune disease

Cancer and autoimmune disease are closely related, and many therapeutic antibodies are widely used in clinics for the treatment of both diseases. Among them, the anti-CD20 antibody has proven to be effective against both lymphoid malignancy and autoimmune disease. Moreover, immune checkpoint blockade using the anti-PD1/PD-L1/CTLA4 antibody has improved the prognosis of patients with refractory solid tumors. At the same time, however, over-enhancement of immunoreaction can induce autoimmune reaction. Although anti-TNF antibody therapies represent a breakthrough in the treatment of autoimmune diseases, optimal management is required to control the serious associated issues, including development and progression of cancer, and it is becoming more and more important to control the immunoreaction. In addition, next-generation antibody therapeutics such as antibody-drug conjugates and bispecific antibodies, are anticipated to treat uncontrolled cancer and autoimmune disease. IL-7R signaling plays an important role in the development and progression of both lymphoid malignancy and autoimmune disease. In addition, abnormal homing activity and steroid resistance caused by IL-7R signaling may worsen prognosis. Therefore, anti-IL-7R targeting antibody therapies that enable suppression of such pathophysiological status have the potential to be beneficial for the treatment of both diseases. In this review, we discuss current antibody therapeutics in cancer and autoimmune disease, and describe a new therapeutic strategy for immunoregulation including IL-7R targeting antibodies.

Access to high-cost drugs for advanced breast cancer in Latin America, particularly trastuzumab

Provision of high-level healthcare is a challenge for all low- to middle-income countries (LMICs) since healthcare systems are heterogeneous, face many challenges such as inadequate funding, inequitable distribution of resources and services and usually are not adequately equipped to deal with a huge problem such as breast cancer. The development of anti-HER2 therapies can be considered one of the most important examples of the translation of molecular biology knowledge into clinical benefits for cancer patients. While a variety of novel therapeutic strategies are emerging, current treatment regimens remain focussed on targeted therapy with monoclonal antibodies, mainly trastuzumab, the first agent developed in this field. While these results have revolutionised the outcome of HER2+ patients in clinical trials and in high-income countries where they are widely available, results have not impacted the natural history of this aggressive disease in most of the world. Unfortunately, the availability of these drugs is far from universal in many LMICs, and in Latin America, in particular, patients with HER2+ breast cancer are treated exclusively with standard chemotherapy, a more toxic and less efficient therapy. While the complexity of the situation and the multiple factors that have an impact in this scenario are recognised, we need to map the future and develop feasible strategies to address possible solutions to the problem of drug access. A clear and unbiased diagnosis of the situation is a good starting point. Defining healthcare priorities and a clear strategy for the allocation of resources is difficult but mandatory. In this article, we will discuss current and future challenges regarding access (and lack of access) to high-cost cancer drugs in Latin America, with a focus on anti-HER2 therapies.