A phase III, randomized, non-inferiority study comparing the efficacy and safety of biosimilar filgrastim versus originator filgrastim for chemotherapy-induced neutropenia in breast cancer patients

Comparative Safety Profiles of Oncology Biosimilars: A Systematic Review and Network Meta-analysis

BACKGROUND

It is crucial that the safety profiles of biosimilars are similar to those of the original biologics. A better understanding of biosimilars and their relative safety and immunogenicity profiles are required for healthcare providers to prescribe them to patients with life-threatening cancer diseases who receive chemotherapies with potentially serious adverse events (AEs).

OBJECTIVES

The purpose of this study was to collate and analyze currently available safety and immunogenicity outcomes of biosimilars used in oncology and compare their safety information with those of the original biologics.

METHODS

The MEDLINE and Cochrane Library databases were searched as at 28 February 2022. Four anti-cancer biosimilar molecules were considered: bevacizumab, trastuzumab, rituximab, and (peg)filgrastim. Through a systematic review, we selected the randomized controlled trials (RCTs) comparing safety outcomes between the biosimilars and original biologics of the four molecules. As safety outcomes, various treatment-emergent adverse events (TEAEs) were collated, such as any TEAE, serious AE, and TEAE higher than grade 3. A risk ratio (RR) per category of TEAE was estimated through a meta-analysis. A network meta-analysis (NMA) was also conducted to compare the safety among the biosimilar brands for TEAEs over 25% with higher variability in addition to the serious AE cases.

RESULTS

Forty-nine RCTs were identified. The results from the meta-analysis showed that the safety and immunogenicity profiles of all four biosimilar molecules are comparable with that of the original biologics at the TEAE level without statistically significant differences, except for diarrhea for (peg)filgrastim. The incidence of diarrhea with (peg)filgrastim was less than that with the original biologic (RR 0.66, 95% confidence interval 0.50-0.89). The NMA results showed similar safety profiles among the biosimilar brands for all four biosimilar molecules, except for the serious adverse event of a trastuzumab biosimilar (RR 0.296, 95% credible interval 0.109-0.840).

CONCLUSION

The meta-analysis and NMA for all four biosimilars showed that the safety and immunogenicity profiles of biosimilar products in oncology are generally comparable with that of the original biologics at the TEAE level. However, additional evidence needs to be collected since several TEAEs of specific biosimilars were out of the equivalent range. The results of this study provide comparative safety information and a better understanding of oncology biosimilars for healthcare providers to prescribe them to patients.

Biosimilar Versus Originator Pegfilgrastim for Preventing Chemotherapy-Induced Neutropenia: A Phase III Randomized, Multicenter, Evaluator-Blinded, Noninferiority Study

PURPOSE

This study evaluated the efficacy, safety, and immunogenicity of biosimilar pegfilgrastim (PegFilBS) and originator pegfilgrastim (PegFilOR) in patients with stage 2-4 breast cancer.

METHODS

This phase III randomized, multicenter, evaluator-blinded, noninferiority study recruited women with stage 2-4 breast cancer in Argentina who were scheduled to receive chemotherapy. Stratification was based on the breast cancer stage. The primary end point was the duration of severe neutropenia (DSN, noninferiority margin: 1 day) in the first chemotherapy cycle. Secondary end points assessed were incidence of severe neutropenia, grade 3 neutropenia, febrile neutropenia, infections, postchemotherapy hospitalization and duration, and the incidence of adverse drug reactions (ADRs).

RESULTS

A total of 120 patients were randomly assigned to receive PegFilBS (58 patients) or PegFilOR (62 patients). Severe neutropenia occurred in 52 of 283 cycles (18.4%) for 27 patients who received PegFilBS and in 48 of 297 cycles (16.2%) for 20 patients who received PegFilOR (P = .48). During the first cycle, severe neutropenia occurred in 16 patients who received PegFilBS (DSN: 0.78 ± 1.53 days) and in 11 patients who received PegFilOR (DSN: 0.53 ± 1.25 days; 95% CI, -0.26 to 0.76 days). In the intention-to-treat analysis, the mean DSN values were 0.90 ± 1.79 days for the PegFilBS group and 0.50 ± 1.21 for the PegFilOR group (95% CI, -0.15 to 0.95 days). No significant differences were observed for the secondary efficacy end points. Three patients experienced seven ADRs in the PegFilBS group while 10 patients experienced 31 ADRs in the PegFilOR group. The most common ADR was myalgia.

CONCLUSION

Relative to PegFilOR, PegFilBS provided noninferior efficacy outcomes in Argentinian women with stage 2-4 breast cancer who were treated using myelosuppressive chemotherapy.

Efficacy and Safety of Filgrastim and Its Biosimilars to Prevent Febrile Neutropenia in Cancer Patients: A Prospective Study and Meta-Analysis

Simple Summary

Febrile neutropenia is the serious side-effect associated with myelosuppressive chemotherapy. Filgrastim, the first granulocyte colony-stimulating factor (G-CSF) was approved by the Food and Drug Administration for the treatment of neutropenia. Subsequently, pegfilgrastim (long-acting G-CSF) and filgrastim biosimilars were developed to have comparable efficacy to filgrastim. Therefore, it is necessary to produce a systematic review and meta-analysis that provides evidence that filgrastim is more efficacious than placebo/no-treatment, as it provides evidence on the comparable efficacy of filgrastim versus pegfilgrastim and biosimilar filgrastim.

Abstract

Background: The aim of this review and meta-analysis was to identify, assess, meta-analyze and summarize the comparative effectiveness and safety of filgrastim in head-to-head trials with placebo/no treatment, pegfilgrastim (and biosimilar filgrastim to update advances in the field. Methods: The preferred reporting items for systematic reviews and meta-analyses PRISMA statement were applied, and a random-effect model was used. Primary endpoints were the rate and duration of grade 3 or 4 neutropenia, and an incidence rate of febrile neutropenia. Secondary endpoints were time to absolute neutrophil count ANC recovery, depth of ANC nadir (lowest ANC), neutropenia-related hospitalization and other neutropenia-related complications. For filgrastim versus biosimilar filgrastim comparison, the primary efficacy endpoint was the mean difference in duration of severe neutropenia DSN. Results: A total of 56 studies were considered that included data from 13,058 cancer patients. The risk of febrile neutropenia in filgrastim versus placebo/no treatment was not statistically different. The risk ratio for febrile neutropenia was 0.58, a 42% reduction in favor of filgrastim. The most reported adverse event with FIL was bone pain. For pegfilgrastim versus filgrastim, no statistically significant difference was noted. The risk ratio was 0.90 (95% CI 0.67 to 1.12). The overall difference in duration of severe neutropenia between filgrastim and biosimilar filgrastim was not statistically significant. The risk ratio was 1.03 (95% CI 0.93 to 1.13). Conclusions: Filgrastim was effective and safe in reducing febrile neutropenia and related complications, compared to placebo/no treatment. No notable differences were found between pegfilgrastim and filgrastim in terms of efficacy and safety. However, a similar efficacy profile was observed with FIL and its biosimilars.

The underreporting of phase III chemo-therapeutic clinical trial data of older patients with cancer: A systematic review

PURPOSE

Inspired by the American Society of Clinical Oncology's recommendations to strengthen the evidence base for older adults with cancer, the purpose of this systematic review is to identify the reporting of treatment efficacy and adverse events specific to older adults with cancer in Phase III chemo-therapeutic clinical trials. This review also investigates the frequency with which these data points were reported in the literature to identify gaps in reporting and opportunities to expand the knowledge base on clinical outcomes for older adults with cancer.

METHODS

Chemo-therapeutic clinical trial data published from July 1, 2016 to June 30, 2017 was reviewed. Manuscripts (n = 929) were identified based on keyword searches of EMBASE and PubMed. After removal of duplicates (n = 116) and articles that did not meet this study's inclusion criteria (n = 654), 159 articles were identified for review.

RESULTS

Reviewed papers were published in 36 different scientific journals and included twenty-five different cancer types. Of the 159 articles, 117 (73.6%) reported age-specific medians and 75 (47.2%) included stratifications of data by age. Treatment efficacy was reported in 96.2% of the articles with 39.9% reporting effectiveness of treatment by age. Reporting of adverse events was included in 84.9% of the articles with only 8.9% reporting these events stratified by age.

CONCLUSION

Results suggest inadequate reporting of treatment efficacy and adverse events as well as basic descriptive statistics about the age distribution of study subjects. Conscious efforts are needed to address these deficiencies at every level of planning and conducting clinical trials as wells as reporting outcomes stratified by age. Ultimately, standardized reporting could lead to improved treatment decisions and outcomes for older adults with cancer.

Efficacy and Safety of Supportive Care Biosimilars Among Cancer Patients: A Systematic Review and Meta-Analysis

BACKGROUND

Biologics are widely used to manage the side effects of cancer treatment (e.g., epoetin alfa is used to treat chemotherapy-induced anemia [CIA] and granulocyte colony-stimulating factors [G-CSFs] are used to treat chemotherapy-induced neutropenia [CIN]). As several patents for biologics used in cancer treatment have expired, a number of companies have developed supportive care biosimilars (e.g., epoetin alfa biosimilar, filgrastim biosimilar, pegfilgrastim biosimilar).

OBJECTIVE

The objective of this study was to synthesize current evidence on the efficacy and safety of supportive care biosimilars compared with their reference biologics in oncology.

METHODS

We searched PubMed, Embase, the Cochrane library, ClinicalTrials.gov, ISI Web of Science and several Chinese databases from their inception dates to December 31, 2018 for randomized controlled trials (RCTs) or comparative observational studies that compared the efficacy and safety of supportive care biosimilars and their reference biologics in oncology. We pooled results separately for RCTs and observational studies, as such studies involve different patient populations and are designed differently. We pooled binary outcomes using risk ratios (RR) with confidence intervals (CIs) and continuous outcomes using weighted mean differences (WMD) with 95% CIs, then conducted subgroup and sensitivity analyses. We used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to rate the quality of evidence.

RESULTS

We identified 28 studies that compared biosimilars of G-CSF or epoetin alfa: one RCT and five cohort studies (total N = 2816) of epoetin alfa biosimilars, and 13 RCTs and 9 cohort studies (total N = 23,043) of G-CSF biosimilars [corrected]. Despite involving different populations, RCTs and observational studies comparing biosimilars and reference biologics indicated similar efficacy and safety results. Overall, there was no statistically significant difference in any efficacy or safety outcomes between any biosimilars and their corresponding original biologics (all p > 0.05). The quality of GRADE evidence of efficacy and safety outcomes was moderate or low. Findings were robust for all prespecified subgroup and sensitivity analyses.

CONCLUSION

Existing evidence suggests highly comparable efficacy and safety profiles for supportive care biosimilars and their reference biologics in oncology.

Efficacy and tolerability of granulocyte colony-stimulating factors in cancer patients after chemotherapy: A systematic review and Bayesian network meta-analysis

The optimum granulocyte colony-stimulating factor (G-CSF) treatment for cancer patients after being treated with cytotoxic chemotherapy remains unknown. Therefore, a systematic review and Bayesian network meta-analysis were performed to assess the efficacy and tolerability of 11 G-CSF drugs on patients after chemotherapy. A total of 73 randomized controlled trials (RCTs) containing 15,124 cancer patients were included for the final network meta-analysis. Compared with pegfilgrastim, there were a higher risk with filgrastim for incidence of febrile neutropenia (FN) (OR [95% CI]: 1.63 [1.07, 2.46]), and a higher risk with short-acting G-CSF (S-G-CSF) biosimilar and lenograstim for incidence of bone pain (BP) (OR [95% CI]: 6.45 [1.10, 65.73], 5.12 [1.14, 26.12], respectively). Mecapegfilgrastim, lipegfilgrastim and balugrastim were best G-CSF drugs in reducing FN (cumulative probabilities: 58%, 15%, 11%, respectively). S-G-CSF biosimilar, empegfilgrastim, and long-acting G-CSF (L-G-CSF) biosimilar were best G-CSF drugs in reducing severe neutropenia (SN) (cumulative probabilities: 21%, 20%, 15%, respectively). Mecapegfilgrastim, balugrastim, lipegfilgrastim and L-G-CSF biosimilar were best G-CSF drugs in reducing BP (cumulative probabilities: 20%, 14%, 8%, 8%, respectively). Mecapegfilgrastim, lipegfilgrastim and balugrastim might be the most appreciate G-CSF drugs with both good efficacy and tolerability when treating cancer patients after cytotoxic chemotherapy.

A Comparison of Brand and Biosimilar Granulocyte-Colony Stimulating Factors for Prophylaxis of Chemotherapy-Induced Febrile Neutropenia

BACKGROUND

Filgrastim-sndz, a granulocyte-colony stimulating factor (G-CSF), was introduced as a biosimilar to filgrastim in 2015, but real-world comparative effectiveness for filgrastim versus filgrastim-sndz has not been reported to date.

OBJECTIVES

To (a) compare the incidence of febrile neutropenia for patients taking filgrastim versus those taking filgrastim-sndz and (b) compare the incidence of a potential serious adverse event for filgrastim versus filgrastim-sndz.

METHODS

This retrospective cohort study identified patients receiving a G-CSF following chemotherapy, using administrative claims from the Humana Research Database. Patients enrolled in a Medicare Advantage Prescription Drug plan with a claim for a G-CSF from October 1, 2015, through September 30, 2016, were identified. G-CSF use had to occur within 6 days of exposure to chemotherapy and without any subsequent chemotherapy within 14 days after G-CSF use. Febrile neutropenia requiring hospitalization was defined as hospitalization within 14 days after G-CSF use with (a) diagnosis of infection and/or neutropenia (broad definition) or (b) infection and neutropenia diagnoses (narrow definition). Serious adverse drug events (spleen rupture, acute respiratory syndrome, serious allergic reactions, capillary leak syndrome, thrombocytopenia, leukocytosis, cutaneous vasculitis, or bones and muscle ache) were also identified within 14 days after G-CSF use. An incidence difference of < 1% with 90% CI crossing zero qualified as support for noninferiority. Two-tailed chi-square tests were also used to investigate differences.

RESULTS

A total of 88 filgrastim and 101 filgrastim-sndz patients were identified. Filgrastim and filgrastim-sndz met the criteria for noninferiority based on an incidence difference of -0.6% (90% CI = -5.1%-4.0%; P = 0.84) for the broad definition of febrile neutropenia and a difference of -0.8% (90% CI = -3.8%-2.1%; P = 0.64) for the narrow definition. For the analysis of serious adverse events, an incidence difference of -2.5% (90% CI = -7.5%-2.5%; P = 0.42) for filgrastim compared with filgrastim-sndz was not sufficient to establish noninferiority.

CONCLUSIONS

This study is one of the first analyses of real-world evidence regarding the noninferiority of filgrastim and filgrastim-sndz. The study results support noninferiority of filgrastim and filgrastim-sndz for prevention of febrile neutropenia requiring hospitalization. While noninferiority for serious adverse events was not supported, there was also no statistically significant difference between filgrastim and filgrastim-sndz. The study's small sample size could have limited the analysis of the relatively rare outcomes of febrile neutropenia requiring hospitalization and serious adverse events. A study including a larger numbers of patients taking filgrastim or filgrastim-sndz could provide additional insights.

DISCLOSURES

This study received no outside funding. Douglas, Kennedy, and Slabaugh were employees of Humana Pharmacy Solutions at the time the study was conducted. Bowe, Schwab, and Lane were employees of Comprehensive Health Insights, a wholly owned subsidiary of Humana, at the time the study was conducted. Study concept and design were contributed by Douglas, Kennedy, Schwab, and Lane, along with Slabaugh and Bowe. Bowe took the lead in data collection, assisted by Schwab, and data interpretation was performed by Schwab, along with the other authors. The manuscript was written by Schwab, Lane, and Douglas and revised by Kennedy, Slabaugh, and Bowe, along with Schwab, Lane, and Douglas.

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.

Adequate Neutrophil Responses and Non-Inferior Clinical Outcomes Can Be Achieved by a Two-Day Course of Low-Dose Filgrastim: A Retrospective Single Institution Experience

Background

Filgrastim is used in the setting of chemotherapy-induced neutropenia to stimulate recovery of bone marrow, which allows for further chemotherapy administration without delay. The recommended dose is 5 ug/kg. The commercially available vials of the drug come in two strengths; 300 ug and 480 ug. Due to these limitations in dosage formulations, it is a frequent occurrence to administer a lower dosage to patients weighing more than 60 kg, in whom the ideal dose would have been more than 300 ug but less than 480 ug. It is also a frequent practice to administer the drug for two consecutive days as it often leads to adequate response that will render patients eligible for their next cycle administration.

Objective

To determine whether a course of 300 ug of filgrastim administered daily for two consecutive days was as successful at reducing chemotherapy-induced neutropenia-related complications in patients with a higher weight (>60 kg) and hence receiving suboptimal dose as compared to those with weight less than 60 kg who are receiving the recommended dose.

Methods

We identified 91 patients from our facility with chemotherapy-induced neutropenia treated with 300 ug of filgrastim daily for two consecutive days, and we separated them into low, medium, and high weight groups. Multivariate logistic regression models examined correlations between outcomes (e.g., increases in absolute neutrophil count) and predictors (e.g., weight groups).

Results

The vast majority of encounters demonstrated rises in white blood cell (WBC) and absolute neutrophil count (ANC). Infection rates were not significantly different between low and medium weight groups (5% vs 0%; p = 0.1658), but the high weight group’s infection rate was significantly higher than the medium weight group (5% vs 33%; p = 0.001). The high weight group did have an increased rate of febrile neutropenia as compared to medium and low weight groups, but these differences were not significant. Incidences of chemotherapy delay and dose reduction were comparable across the three weight groups.

Limitations

Retrospective study, small sample size, heterogeneous cancer sites and different chemotherapy regimens administered limit generalizability of findings.

Conclusion

Patients with weights <85 kg receiving a two-day course of 300 ug of filgrastim have similar neutropenia-related complication rates with a potential percent cost-savings of roughly 43%.