Comparison of subcutaneous versus intravenous administration of rituximab as maintenance treatment for follicular lymphoma: results from a two-stage, phase IB study

Predicting Human Subcutaneous Bioavailability of Therapeutic Monoclonal Antibodies from Systemic Clearance and Volume of Distribution

Subcutaneous delivery of monoclonal antibody therapeutics is often preferred to intravenous delivery due to better patient compliance and overall lower cost to the healthcare system. However, the systemic absorption of biologics dosed subcutaneously is often incomplete. The aim of this work was to describe a human bioavailability prediction method for monoclonal antibodies delivered subcutaneously that utilizes intravenous pharmacokinetic parameters as input. A two-compartment pharmacokinetic model featuring a parallel-competitive absorption pathway and a presystemic metabolism pathway was employed. A training data set comprised 19 monoclonal antibodies (geometric mean bioavailability of 68%), with previously reported human pharmacokinetic parameters, while a validation set included data compiled from 5 commercial drug products (geometric mean bioavailability of 69%). A single fitted absorption rate constant, paired with compound-specific estimates of presystemic metabolism rate proportional to compound-specific systemic clearance parameters, resulted in calculations of human subcutaneous bioavailability closely mimicking clinical data in the training data set with a root-mean-square error of 5.5%. Application of the same approach to the validation data set resulted in predictions characterized by 12.6% root-mean-square error. Factors that may have impacted the prediction accuracy include a limited number of validation data set compounds and an uncertainty in the absorption rate, which were subsequently discussed. The predictive method described herein provides an initial estimate of the subcutaneous bioavailability based exclusively on pharmacokinetic parameters available from intravenous dosing.

Advancing Subcutaneous Dosing Regimens for Biotherapeutics: Clinical Strategies for Expedited Market Access

In recent years, subcutaneous administration of biotherapeutics has made significant progress. The self-administration market for rheumatoid arthritis has witnessed the introduction of additional follow-on biologics, while the first subcutaneous dosing options for monoclonal antibodies have become available for multiple sclerosis. Oncology has also seen advancements with the authorization of high-volume subcutaneous formulations, facilitated by the development of high-concentration formulations and innovative delivery systems. Regulatory and Health Technology Assessment bodies increasingly consider preference data in filing dossiers, particularly in evaluating novel drug delivery methods. The adoption of a pharmacokinetic-based clinical bridging approach has become standard for transitioning from intravenous to subcutaneous administration. Non-inferiority studies with pharmacokinetics as the only primary endpoint have started deviating from traditional randomization schemes, favoring the subcutaneous route and comparing with historical intravenous data. While nonclinical and computational models made progress in predicting safety and immunogenicity for subcutaneously dosed antibodies, clinical trial evidence remains essential due to inter-individual variations and the impact of formulation parameters on anti-drug antibody formation. Ongoing technological advancements and the expanding knowledge base on pharmacokinetic-pharmacodynamic correlation across specialty areas are expected to further accelerate clinical development of subcutaneous biologics.

Clinical efficacy and safety of subcutaneous rituximab in non-Hodgkin lymphoma: a systematic literature review and meta-analysis

OBJECTIVES

The role of subcutaneous (SC) rituximab in the efficacy and safety to non-Hodgkin lymphoma (NHL) is not clear enough. The purpose of this study was to conduct a systematic review and meta-analysis, to assess the efficacy and safety of subcutaneous rituximab to NHL.

METHOD

A full-scale search was carried out based on the set search terms in PubMed, Web of Science, Embase and Cochrane CENTRAL until 12 October 2022 to identify relevant studies of subcutaneous rituximab for NHL. The efficacy and safety outcomes included complete response (CR) plus unconfirmed complete response (CRu), adverse events (AEs), grade ≥3 AEs, serious adverse events (SAEs), administration-related reactions (ARRs), adverse reaction rates.

RESULTS

From a total of 758 studies, 9 trials were eligible. The CR/CRu of patients with NHL receiving SC rituximab was 57%, 55% for Diffuse large B-cell lymphoma (DLBCL) and 54% for Follicular lymphoma (FL). The meta-analysis performed on safety demonstrated that AEs of NHL patients with SC rituximab was 85%, grade ≥3 AEs was 38%, SAE was 27% and ARR was 33%. The result also showed that SC rituximab had a high risk of neutropenia and nausea.

CONCLUSION

For NHL patients, there is no significant difference in the efficacy between subcutaneous rituximab and conventional therapy, while subcutaneous injection can shorten exposure time in the hospital and reduce the risk of infection.

Ultrafast 30-min infusion of a rituximab biosimilar (Truxima)

In this clinical trial, we demonstrate that ultrarapid fast infusion of rituximab (Truxima) in 30 min with oral premedication is feasible and secure for patients, and reduce the day-care hospital stays.

Rituximab induced cytokine release with high serum IP-10 (CXCL10) concentrations is associated with infusion reactions

Monoclonal antibody induced infusion reactions (IRs) can be serious and even fatal. We used clinical data and blood samples from 37 treatment naïve patients with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL) initiating therapy for progressive disease with a single 50 mg dose of intravenous (IV) rituximab at 25 mg/h. Twenty-four (65 %) patients had IRs at a median of 78 min (range 35-128) and rituximab dose of 32 mg (range 15-50). IR risk did not correlate with patient or CLL characteristics, CLL counts or CD20 levels, or serum rituximab or complement concentrations. Thirty-five (95 %) patients had cytokine release response with a ≥ 4-fold increase in serum concentration of ≥ 1 inflammatory cytokine. IRs were associated with significantly higher post-infusion serum concentrations of gamma interferon induced cytokines IP-10, IL-6 and IL-8. IP-10 concentrations increased ≥ 4-fold in all patients with an IR and were above the upper limit of detection (40,000 pg/ml) in 17 (71 %). In contrast, to only three (23 %) patients without an IR had an ≥ 4-fold increase in serum concentrations of IP-10 (highest 22,013 pg/ml). Our data suggest that cytokine release could be initiated by activation of effector cells responsible for clearance of circulating CLL cells with IRs occurring in those with higher levels of gamma interferon induced cytokines. These novel insights could inform future research to better understand and manage IRs and understand the role of cytokines in the control of cytotoxic immune responses to mAb.

Pharmacokinetic characterization, benefits and barriers of subcutaneous administration of monoclonal antibodies in oncology

OBJECTIVE

Therapeutic monoclonal antibodies in oncology are slowly becoming the dominant treatment option for many different cancer types. The main route of administration, infusion, requires extensive product preparations, patient hospitalization and close monitoring. Patient comfort improvement, staff workload reduction and cost savings dictated the development of subcutaneous formulations. The aim of this review is to present pharmacokinetic characteristics of subcutaneous products, discuss the differences between intravenous and subcutaneous routes and to point out the advantages as well as challenges of administration route shift from the formulation development and pharmacometric angle.

DATA SOURCES

Food and Drug administration's Purple book database and electronic medicines compendium were used to identify monoclonal antibodies in oncology approved as subcutaneous forms. Using keywords subcutaneous, monoclonal antibodies, pharmacokinetics, model, as well as specific drugs previously identified, both PubMed and ScienceDirect databases were researched.

DATA SUMMARY

There are currently six approved subcutaneous onco-monoclonal antibodies on the market. For each of them, exposure to the drug was similar in relation to infusion, treatment effectiveness was the same, administration was well tolerated by the patients and costs of the medical service were reduced.

CONCLUSION

Development of subcutaneous forms for existing and emerging new monoclonal antibodies for cancer treatment as well as shifting from administration via infusion should be encouraged due to patient preference, lower costs and overall lack of substantial differences in efficacy and safety between the two routes.

Customer-centric product presentations for monoclonal antibodies

Delivering customer-centric product presentations for biotherapeutics, such as monoclonal antibodies (mAbs), represents a long-standing and paramount area of engagement for pharmaceutical scientists. Activities include improving experience with the dosing procedure, reducing drug administration-related expenditures, and ultimately shifting parenteral treatments outside of a controlled healthcare institutional setting. In times of increasingly cost-constrained markets and reinforced with the coronavirus pandemic, this discipline of "Product Optimization" in healthcare has gained momentum and changed from a nice-to-have into a must. This review summarizes latest trends in the healthcare ecosystem that inform key strategies for developing customer-centric products, including the availability of a wider array of sustainable drug delivery options and treatment management plans that support dosing in a flexible care setting. Three disease area archetypes with varying degree of implementation of customer-centric concepts are introduced to highlight relevant market differences and similarities. Namely, rheumatoid arthritis and inflammatory bowel disease, multiple sclerosis, and oncology have been chosen due to differences in the availability of subcutaneously dosed and ready-to-use self-administration products for mAb medicines and their follow-on biologics. Different launch scenarios are described from a manufacturer's perspective highlighting the necessity of platform approaches. To unfold the full potential of customer-centric care, value-based healthcare provider reimbursement schemes that incentivize the efficiency of care need to be broadly implemented.

Development of Therapeutic Proteins for a New Subcutaneous Route of Administration after the Establishment of Intravenous Dosages: A Systematic Review

Therapeutic proteins may first be developed as intravenous (i.v.) therapies with new subcutaneous (s.c.) dosage forms being subsequently developed to provide an alternative route of administration. As of August 2022, there have been 9 therapeutic proteins which were developed as a new s.c. dosage form after the approval of the corresponding i.v. product. This article provides a systematic review of prior experiences in the i.v. to s.c. switch development programs. We describe what types of clinical studies were conducted to support the i.v. to s.c. switch for these nine therapeutic proteins. Publicly available scientific advice from health authorities is summarized, particularly regarding recommendations on overall development strategy, dose selection, immunogenicity assessment, and indication extrapolation. The clinical data from these i.v. to s.c. development programs demonstrate that: (1) when switching from i.v. dosing to s.c. dosing, trough drug concentration (C_trough ) from s.c. dosing should not be inferior to i.v. dosing with average drug concentration (C_avg ; equivalent to AUC, area under the curve after correcting for dosing intervals between i.v. and s.c. administration) being matched or non-inferior to i.v. dosing; and (2) with appropriate s.c. dose regimens, treatment with s.c. therapeutic proteins can generally achieve similar efficacy and safety as the corresponding i.v. products, suggesting that the much higher maximum concentration (C_max ) after i.v. infusion as compared with that from s.c. injection is often not relevant to the treatment effect.

Safety and tolerability of a 90-minute rapid infusion of Sandoz biosimilar rituximab in B-cell lymphoproliferative disorders in a real-world setting

Although rituximab is generally well-tolerated, infusion-related reactions (IRRs) are common with the initial dose when administered intravenously according to standard recommendations. To prevent IRRs, premedication and low-speed infusion rates have been recommended. Consequently, intravenous (i.v.) infusion of rituximab can become a labor-intensive process. Rapid i.v. rituximab infusion over 90 min has demonstrated a favorable safety profile for the second and subsequent infusions during the course of therapy. The aim of this study was to investigate the safety and tolerability of 90-min rapid infusion of Sandoz rituximab biosimilar (SDZ-RTX) for patients with CD20+ lymphoma or chronic lymphocytic leukemia (CLL). We retrospectively reviewed all patients with CD20+ lymphoma or CLL who received SDZ-RTX infusions in 90 min from July 2019 to July 2021 at seven Spanish hospitals. The primary end point was the incidence of IRRs. We identified 124 patients and 576 rapid administrations of SDZ-RTX, with an average of five rapid infusions per patient. Most rapid infusions of SDZ-RTX were in combination with CHOP/CHOP-like therapy (48.4%), followed by SDZ-RTX alone (15.1%), in combination with bendamustine (14.5%), or with other regimens (22%). The 90-min SDZ-RTX infusion schedule was well-tolerated with no grade 3/4 IRRs. The incidence of any grade IRR during the first rapid infusion was 1% (5 grade 1 IRRs and 1 grade 2 IRR). In conclusion, rapid 90-min i.v. administration of SDZ-RTX for the second and subsequent infusions during the course of therapy is well-tolerated in patients with CD20+ lymphoma or CLL.

Trajectories of symptom severity predicts quality of life change in newly diagnosis lymphoma survivors: An initial study

OBJECTIVE

This study aimed to explore the subgroups of symptom severity and impact of their trajectories on quality of life in lymphoma survivors.

METHODS

Secondary data were analysed from a prospective study with four-time measures: before treatment (T1), during treatment (T2), treatment completion (T3) and 10 weeks after treatment (T4). Data were analysed using descriptive statistics, group-based trajectory model and generalised estimation equation.

RESULTS

Fifty nine of 61 participants completed three-time measure (mean age = 60.43 years, male-predominant). The changes in symptom severity over time were divided into two subgroups: slight-stable group (n = 54, 89%) and mild-fickle group (n = 7, 11%). Pain, tiredness and sleeping trouble were the predominant symptoms. The quality of life change in the slight-stable group was significantly better than that of the mild-fickle group (B = 13.35, SE = 3.53, p < 0.001). The overall quality of life at T2, T3 and T4 was better than it was at T1.

CONCLUSION

The different trajectories of symptom severity significantly influenced quality of life changes in lymphoma survivors. Healthcare providers must be aware that there is a group of lymphoma survivors with relatively severe symptoms when newly diagnosed, compared to the opposite. More attention must be paid to this group, in addition to providing in-time symptom management.

Enabling faster subcutaneous delivery of larger volume, high viscosity fluids

OBJECTIVES

Many current subcutaneous (SC) biologic therapies may require >1 mL volume or have increased viscosity, necessitating new delivery system approaches. This study evaluated 2-mL large-volume autoinjector (LVAI) delivery performance across varying solution viscosities and design inputs to assess the design space and identify configurations that produce practical injection times.

METHODS

Investigational LVAI delivery duration and volume, depot location, and tissue effects were examined in both air and in vivo models across various pre-filled syringe (PFS) cannula types (27 G Ultra-thin wall [UTW], 27 G special thin wall [STW], or 29 G thin-wall [TW]), drive spring forces (SF_LOW or SF_HIGH), and Newtonian solutions (2.3-50 centipoise [cP]).

RESULTS

Within each design configuration, increasing PFS internal diameters and spring forces reduced delivery times, while increasing viscosity increased times. The 27 G UTW PFS/SF_HIGH combination achieved shorter delivery times across all injection conditions, with 2 mL in vivo durations <15 seconds at ≤31 cP and routinely <20 seconds at 39 and 51 cP, with nominal and transitory tissue effects.

CONCLUSION

PFS cannula and spring force combinations can be tailored to achieve various injection durations across viscosities, while UTW PFS enables faster rates to potentially better accommodate human factors during LVAI injection, especially at high viscosity.

Subcutaneous rituximab in patients with diffuse large B cell lymphoma and follicular lymphoma: Final results of the non-interventional study MabSCale

BACKGROUND

Rituximab has become a standard treatment for non-Hodgkin lymphoma. Clinical studies have demonstrated the efficacy of rituximab in combination with standard chemotherapies in the treatment of follicular lymphoma (FL) and diffuse large B cell lymphoma (DLBCL) patients. This non-interventional study aimed to evaluate the effectiveness and safety of subcutaneous (SC) rituximab in routine clinical practice.

METHODS

Adult patients with previously untreated CD20 positive DLBCL or FL who received rituximab SC and chemotherapy as first-line treatment were observed between 07/2014 and 07/2019 at 99 institutions in Germany. Primary endpoint was the (unconfirmed) complete remission (CR/CRu) rate. Primary outcome was analyzed inferentially; other variables were evaluated descriptively.

RESULTS

Overall 583 patients (247 FL; 336 DLBCL) were evaluated. CR/CRu rates were 51.4% (95% CI: 45.2; 57.6) in the FL set and 48.5% (95% CI: 43.2; 53.8) in the DLBCL set. Regarding progression-free survival in the FL group, the probability of being event-free was 94.2% in the first year and 86.2% in the second year. An overall response was achieved in 85.8% (FL) and 85.4% patients (DLBCL). Patient satisfaction at the end of study with the time saving simplification of the SC vs. intravenous route was 98% for FL and 97% for DLBCL. 45.3% of FL and 47.0% of DLBCL patients experienced an adverse event of grade ≥3. Serious adverse events of grade ≥3 occurred in 27.9% FL and 32.4% DLBCL patients, with the highest incidences for leucopenia, anemia, nausea, and fatigue. No new safety signals were detected.

CONCLUSIONS

The results confirmed the effectiveness and safety of rituximab SC in both the FL and the DLBCL group. Satisfaction of patients and nurses with SC administration was high.

Safety and Efficacy of Subcutaneous Rituximab in Previously Untreated Patients with CD20+ Diffuse Large B-Cell Lymphoma or Follicular Lymphoma: Results from an Italian Phase IIIb Study

Subcutaneous (SC) rituximab may be beneficial in terms of convenience and tolerability, with potentially fewer and less severe administration-related reactions (ARRs) compared to the intravenous (IV) form. This report presents the results of a phase IIIb study conducted in Italy. The study included adult patients with CD20+ DLBCL or FL having received at least one full dose of IV RTX 375 mg/m² during induction or maintenance. Patients on induction received ≥4 cycles of RTX SC 1400 mg plus standard chemotherapy and FL patients on maintenance received ≥6 cycles of RTX SC. Overall, 159 patients (73 DLBCL, 86 FL) were enrolled: 103 (54 DLBCL, 49 FL) completed induction and 42 patients with FL completed 12 maintenance cycles. ARRs were reported in 10 patients (6.3%), 3 (4.2%) with DLBCL and 7 (8.1%) with FL, all of mild severity, and resolved without dose delay/discontinuation. Treatment-emergent adverse events (TEAEs) and serious adverse events occurred in 41 (25.9%) and 14 patients (8.9%), respectively. Two patients with DLBCL had fatal events: Klebsiella infection (related to rituximab) and septic shock (related to chemotherapy). Neutropenia (14 patients, 8.9%) was the most common treatment-related TEAE. Two patients with DLBCL (2.8%) and 6 with FL (7.0%) discontinued rituximab due to TEAEs. 65.2% and 69.7% of patients with DLBCL and 67.9% and 73.6% of patients with FL had complete response (CR) and CR unconfirmed, respectively. The median time to events (EFS, PFS, and OS) was not estimable due to the low rate of events. At a median follow-up of 29.5 and 47.8 months in patients with DLBCL and FL, respectively, EFS, PFS, and OS were 70.8%, 70.8%, and 80.6% in patients with DLBCL and 77.9%, 77.9%, and 95.3% in patients with FL, respectively. The switch from IV to SC rituximab in patients with DLBCL and FL was associated with low risk of ARRs and satisfactory response in both groups. This trial was registered with NCT01987505.

Ibrutinib plus rituximab for the treatment of adult patients with Waldenström's macroglobulinemia: a safety evaluation

Introduction: Waldenström's macroglobulinemia (WM), an orphan disease, is a rare low-grade B-cell lymphoplasmacytic lymphoma with unique clinical features and monoclonal IgM production. Rituximab remains to this date the backbone of most commonly used treatment combinations. The FDA/EMA approval of Ibrutinib, the first-in-class BTK inhibitor, either as monotherapy or in combination with rituximab, changed the treatment landscape of the disease.Areas covered: Clinical trial data that demonstrate mode of action, efficacy, and the safety profile of each agent will be covered. A safety analysis of the combination treatment will also be performed to point out its high efficacy and overall favorable toxicity profile. The disadvantages and treatment gaps that still exist in the treatment of WM which relate to the need for long-term ibrutinib administration and the lack of deep remissions and subsequent disease relapse, will also be reviewed.Expert opinion: The ibrutinib-rituximab combination is both effective and safe, in the newly-diagnosed and relapsed-refractory disease setting. The optimal therapeutic approach for WM patients remains however to be established. The question of which combinatory (or synergistic) regimen can allow for a fixed-treatment duration, deep and durable responses with a safe toxicity profile is being addressed in ongoing clinical trials.

Importance and Considerations of Antibody Engineering in Antibody-Drug Conjugates Development from a Clinical Pharmacologist's Perspective

Antibody-drug conjugates (ADCs) appear to be in a developmental boom, with five FDA approvals in the last two years and a projected market value of over $4 billion by 2024. Major advancements in the engineering of these novel cytotoxic drug carriers have provided a few early success stories. Although the use of these immunoconjugate agents are still in their infancy, valuable lessons in the engineering of these agents have been learned from both preclinical and clinical failures. It is essential to appreciate how the various mechanisms used to engineer changes in ADCs can alter the complex pharmacology of these agents and allow the ADCs to navigate the modern-day therapeutic challenges within oncology. This review provides a global overview of ADC characteristics which can be engineered to alter the interaction with the immune system, pharmacokinetic and pharmacodynamic profiles, and therapeutic index of ADCs. In addition, this review will highlight some of the engineering approaches being explored in the creation of the next generation of ADCs.

Efficacy and safety assessment of prolonged maintenance with subcutaneous rituximab in patients with relapsed or refractory indolent non-Hodgkin lymphoma: results of the Phase III MabCute study

Rituximab plus chemotherapy induction followed by rituximab maintenance for up to 2 years confers a long-term benefit in terms of progression-free survival in patients with indolent non-Hodgkin lymphoma. It is not known whether further prolonged maintenance with rituximab provides additional benefit. The phase III MabCute study enrolled 692 patients with relapsed or refractory indolent non-Hodgkin lymphoma. Patients who responded to induction with rituximab plus chemotherapy and were still responding after up to 2 years’ initial maintenance with subcutaneous rituximab were randomized to extended maintenance with subcutaneous rituximab (n=138) or observation only (n=138). The primary endpoint of investigator-assessed progression-free survival in the randomized population was un-addressed by the end of study because of an insufficient number of events (129 events were needed for 80% power at 5% significance if approximately 330 patients were randomized). In total, there were 46 progression-free survival events, 19 and 27 in the rituximab and observation arms, respectively (P=0.410 by stratified log-rank test; hazard ratio 0.76 [95% confidence interval: 0.37– 1.53]). The median progression-free survival was not reached in either randomized arm. There were no new safety signals; however, adverse events were seen slightly more frequently with rituximab than with observation during extended maintenance. Maintenance for up to 2 years with rituximab after response to initial induction therefore remains the standard of care in patients with relapsed or refractory indolent non- Hodgkin lymphoma. (Clinicaltrials.gov identifier: NCT01461928)

Quantitative Clinical Pharmacology Supports the Bridging from i.v. Dosing and Approval of s.c. Rituximab in B-Cell Hematological Malignancies

A fixed-dose subcutaneous (s.c.) formulation of the anti-CD20 antibody, rituximab, has been developed to address safety, infusion time, and patient comfort concerns relating to intravenous (i.v.) dosing, and has been approved based upon a pharmacokinetic (PK)-clinical bridging strategy, which demonstrated noninferiority of s.c. vs. i.v. dosing in malignancies, including follicular lymphoma (FL) and chronic lymphocytic leukemia (CLL). A clinical development plan was undertaken to identify rituximab s.c. doses achieving noninferior exposure to rituximab i.v., and to confirm PK-clinical bridging, with the same efficacy and similar safety. This drew upon data from 1,579 patients with FL, CLL, or diffuse large B-cell lymphoma in 5 clinical studies, and showed minimum steady-state serum concentration (C_trough ) as the most appropriate exposure bridging measure. Population PK models were developed, simulations were run using covariates and PK parameters from clinical studies, and exposure-efficacy and -safety analyses performed. Population PKs showed a two-compartment model with time-dependent and -independent clearances. Clearance and volume were predominantly influenced by body surface area; disposition and elimination were similar for the s.c. and i.v. formulations. After s.c. administration, patients with FL and CLL achieved noninferior exposures to i.v. dosing. Overall, rituximab exposure and route of administration did not influence clinical responses in patients with FL or CLL, and there was no association between exposure and safety events. C_trough was shown to be an effective pharmacologic-clinical bridging parameter for rituximab in patients with FL or CLL. Clinically effective exposures are achieved with either s.c. or i.v. dosing.

Impact of the subcutaneous formulations of trastuzumab and rituximab on efficiency and resource optimization in Spanish hospitals: H-Excelencia study

Background

Subcutaneous (SC) versus intravenous (IV) administration is advantageous in terms of patient convenience and hospital efficiency. This study aimed to compare the effect of optimizing the processes involved in SC versus IV administration of rituximab and trastuzumab on hospital capacity and service quality.

Methods

This cross-sectional resource utilization study interviewed oncologists, hematologists, nurses, and pharmacists from 10 hospitals in Spain to estimate changes in processes associated with conversion from IV to SC rituximab and trastuzumab, based on clinical experience and healthcare use from administrative databases.

Results

Efficient use of SC formulations increased the monthly capacity for parenteral administration by 3.35% (potentially increasable by 5.75% with maximum possible conversion according to the product label). The weekly capacity for hospital pharmacy treatment preparation increased by 7.13% due to conversion to SC formulation and by 9.33% due to transferring SC preparation to the cancer treatment unit (potentially increasable by 12.16 and 14.10%, respectively). Monthly hospital time decreased by 33% with trastuzumab and 47% with rituximab. In a hypothetical hospital, in which all processes for efficient use of SC rituximab and/or trastuzumab were implemented and all eligible patients received SC formulations, the estimated monthly capacity for preparation and administration increased by 23.1% and estimated hospital times were reduced by 60–66%.

Conclusions

Conversion of trastuzumab and rituximab to SC administration could improve the efficiency of hospitals and optimize internal resource management processes, potentially increasing care capacity and improving the quality of care by reducing time spent by patients at hospitals.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-021-06277-8.

Recombinant human hyaluronidase PH20-mediated dermal spreading activity in mice is not altered by steroids, antihistamines, or salicylic acid

OBJECTIVES

Drug-drug interaction studies for hyaluronidase safety assessments have evaluated only animal-derived enzyme preparations. We therefore set out to evaluate whether high-dose administration of two antihistamines, a potent corticosteroid, steroid hormone, adrenocorticotropic hormone (ACTH), or salicylic acid would alter the dispersive activity of recombinant human hyaluronidase PH20 (rHuPH20).

METHODS

NCr nu/nu mice were pretreated with diphenhydramine, cetirizine, dexamethasone, estrogen, ACTH, salicylic acid, and/or neutral-buffered saline (NBS). An hour following final pretreatment, dosed mice were anesthetized with ketamine/xylazine and placed in an imaging chamber. A 120 mg/mL immunoglobulin G (IgG) solution with 0.3 μg/mL IgGDL755 (labeled IgG) was injected intradermally, with/without 2,000 U/mL rHuPH20. Fluorescent images of labeled IgG dispersion were acquired ≤20 min post injection.

RESULTS

Dispersion of high-concentration labeled IgG combined with rHuPH20 was greater at all time points vs. antibody alone. At 20 min post injection (last time point), the antibody dispersion area was significantly increased with rHuPH20 vs. without rHuPH20 (p≤0.005). The relative percent increase in antibody dispersion with rHuPH20 ranged from 22.8‒106.6% over the 20-min time course, compared with the corresponding non-rHuPH20 treated groups. The area of labeled IgG dispersion was statistically similar between rHuPH20 groups pretreated with an active compound and their paired NBS pretreated controls.

CONCLUSIONS

The addition of 2,000 U/mL rHuPH20 to a high-concentration antibody solution reproducibly incre-ased local antibody dispersion. Systemic pretreatment with diphenhydramine, cetirizine, dexamethasone, estrogen, ACTH, or salicylic acid did not affect the enzymatic spreading activity of rHuPH20, as measured by intradermal dispersion of labeled IgG in mice.

rHuPH20-facilitated subcutaneous administration of monoclonal antibodies in cancer therapy

Aim: This meta-analysis aimed to evaluate the pharmacokinetics, efficacy, safety and immunogenicity of rHuPH20-facilitated subcutaneous (SC) administration of monoclonal antibody compared with intravenous (IV) administration for patients with cancer. Materials & methods: Outcomes included trough concentrations (C_trough), overall response rate, adverse events, serious adverse events and antidrug antibody positivity rate. Subgroup analysis was also performed. Results: Five studies involving 1575 participants (788/787) were included. All studies met the non-inferiority criterion in C_trough. No significant differences were observed in overall response rate (p = 0.12), adverse events (p = 0.05), and severe adverse events (p = 0.73) between SC and IV groups. The SC group also had lower immunogenicity than the IV group. Conclusion: rHuPH20-facilitated subcutaneous administration of monoclonal antibody is highly similar to IV administration in terms of pharmacokinetics, efficacy, and safety, but with lower immunogenicity.

Anti-CD20 treatment for B-cell malignancies: current status and future directions

INTRODUCTION

The introduction of anti-CD20 monoclonal antibody therapy with rituximab in the 1990s greatly improved outcomes for patients with B-cell malignancies. Disease resistance or relapse after successful initial therapy and declining efficacy of subsequent rounds of treatment were the basis for the development of alternative anti-CD20-based antibody therapies.

AREAS COVERED

The novel anti-CD20 antibodies of atumumab, ublituximab, and obinutuzumab were developed to be differentiated via structural and mechanistic features over rituximab. We provide an overview of preclinical and clinical data, and demonstrate ways in which the pharmacodynamic properties of these novel agents translate into clinical benefit for patients.

EXPERT OPINION

Of the novel anti-CD20 antibodies, only obinutuzumab has shown consistently improved efficacy over rituximab in randomized pivotal trials in indolent non-Hodgkin lymphoma and chronic lymphocytic leukemia. The Phase 3 GALLIUM trial demonstrated significant improvements in progression-free survival with obinutuzumab-based immunochemotherapy over rituximab-based immunochemotherapy. Novel combinations of obinutuzumab, including with chemotherapy-free options are being explored, such as with the newly approved combinations of obinutuzumab with venetoclax, ibrutinib, or acalabrutinib. The biggest unmet need remains in the treatment of diffuse large B-cell lymphoma; emerging options in this field include the use of CAR-T cells and T-cell bispecific antibodies.

The Influence of Different Disease States on Rituximab Pharmacokinetics

BACKGROUND

The anti-CD20 antibody rituximab, which promotes the selective depletion of CD20 positive B cells, was the first targeted therapy that was approved for the treatment of B-cell malignancies, and it is now widely prescribed in both malignant and non-malignant, immune-related diseases. However, the cause of its various clinical responses in certain diseases, have not been clearly elucidated. The variabilities in inter-individual pharmacokinetic and the emerging evidence of the relationships between pharmacokinetic and pharmacodynamic may provide a better understanding of this drug.

METHODS

We searched and summarized the latest published articles on rituximab pharmacokinetic profiles and the pharmacokinetic/pharmacodynamic models in different patient populations, including B-cell malignancies, rheumatoid arthritis, ANCA-associated vasculitis, and glomerular kidney diseases.

RESULTS

Most pharmacokinetic data are drawn from clinical studies in oncology clinical practice. Body weight, gender, and antigen-related factors are proven to be the key factors affecting rituximab pharmacokinetics. In addition, the positive exposure-response relations were reported, which provide encouraging evidence for individualized therapies. While in immune disorders, especially in the off-labeled indications, pharmacokinetic studies are quite limited. Compared with that in B-cell malignancies, the differences in the pharmacokinetic parameters may be attributed to the different pathogeneses of diseases, mechanisms of action and dosing strategies. However, the correlation between drug exposure and clinical outcomes remains unclear.

CONCLUSION

Here, we provide an overview of the complexities associated with rituximab pharmacokinetics and pharmacodynamics in different diseases. Although many influencing factors need to be verified in future studies, a better understanding of the relationships between pharmacokinetic and pharmacodynamic may assist in optimizing rituximab clinical practice.

Antibody Therapy Maintenance in Follicular Lymphoma

Because patients with follicular lymphoma (FL) usually experience repeated disease recurrences, maintenance treatment is an attractive option to prolong remission after induction therapy. Rituximab maintenance therapy has been shown in multiple randomized studies to significantly improve progression-free survival in FL with both low and high tumor burden after induction therapy, independently of patient and disease characteristics. Several questions regarding the use of antibody directed against CD20 (anti-CD20) maintenance remain open, including the optimal antibody administration schedule and duration, the risk/benefit ratio of maintenance in the context of previous bendamustine administration, and its cost-effectiveness.

Update on the subcutaneous administration of rituximab in Canadian cancer centres

Results of studies comparing subcutaneous (sc) with intravenous (iv) rituximab indicate that the two formulations are comparable in efficacy, but most patients and health care professionals prefer the sc route, commonly because of shorter chair time and reduced risk of infusion-related reactions. Recent Canadian data, including those from the scuba study reported here, support the results of earlier international studies showing a reduction in preparation and administration time with the sc formulation, lower cost of administration, and reduced drug wastage because of the fixed sc dosing. Given the significant time and cost savings of the sc formulation, that formulation is generally preferred over the iv formulation for the treatment of follicular lymphoma, diffuse large B cell lymphoma, and chronic lymphocytic leukemia.

Battle of Thermopylae: 300 Spartans (natural killer cells plus obinutuzumab) versus the immortal warriors (chronic lymphocytic leukemia cells) of Xerxes' army

Aim:

To analyze the effects of subcutaneous or intravenous rituximab + lymphokine-activated killer cells, obinutuzumab or ibrutinib on natural killer (NK) cell levels in chronic lymphocytic leukemia and follicular lymphoma patients.

Patients & methods:

The distribution of peripheral blood NK cells of 31 patients was analyzed by flow cytometry.

Results:

We detected a decrease of NK cells in peripheral blood below normal range after obinutuzumab treatment. During maintenance treatment with subcutaneous rituximab, an NK cell reduction was less pronounced than after intravenous rituximab treatment, despite lymphokine-activated killer cell infusions.

Conclusion:

After one dose of obinutuzumab, each NK cell in peripheral blood destroys 25 leukemic cells.

The standard treatment of chronic lymphocytic leukemia and follicular lymphoma is chemotherapy in combination with anti-CD20 monoclonal antibodies, resulting in the destruction of the immune system, or a ‘Kamikaze effect’. Unfortunately, immunotherapy with rituximab or obinutuzumab may be of limited efficacy when the immunological system is overwhelmed by abundant tumor cells or is diminished by chemotherapy, which eliminates effector immune cells such as natural killer cells before they would be able to kill the whole tumor. Hence, it is important to measure the number of immune cells to ensure that during the encounter of effector cells with tumor cells, sufficient ‘warriors’ can win the battle against the tumor. Otherwise, something akin to the Battle of Thermopylae can happen where a limited number of Spartan warriors faced a huge army and were defeated in the end.

Safety of switching from intravenous to subcutaneous rituximab during first-line treatment of patients with non-Hodgkin lymphoma: the Spanish population of the MabRella study

Rituximab is a standard treatment for non‐Hodgkin diffuse large B‐cell (DLBCL) and follicular (FL) lymphomas. A subcutaneous formulation was developed to improve the resource use of intravenous rituximab, with comparable efficacy and safety profiles except for increased administration‐related reactions (ARRs). MabRella was a phase IIIb trial to assess the safety of switching from intravenous to subcutaneous administration of rituximab during first‐line induction/maintenance for DLBCL or FL, focusing on ARRs. Efficacy, satisfaction and quality of life were also assessed. Patients received subcutaneous rituximab plus standard induction chemotherapy for DLBCL or FL for 4–7 cycles, and/or every 2 months maintenance monotherapy for FL for 6–12 cycles. The study included 140 patients: DLBCL, n = 29; FL, n = 111. Ninety‐five percent of patients experienced adverse events, reaching grade ≥3 in 38·6% and were serious in 30·0%. AARs occurred in 48·6%, mostly (84·9%) at the injection site, with only 2·1% of patients reaching grade 3. The end‐of‐induction complete/unconfirmed complete response rate was 69·6%. After a median follow‐up of 33·5 months, median disease‐/event‐/progression‐free and overall survivals were not attained. The Rituximab Administration Satisfaction Questionnaire showed improvements in overall satisfaction and the EuroQoL‐5D a good quality‐of‐life perception at induction/maintenance end. Therefore, switching to subcutaneous rituximab showed no new safety issues and maintained efficacy with improved satisfaction and quality of life.

ENHANZE® drug delivery technology: a novel approach to subcutaneous administration using recombinant human hyaluronidase PH20

ENHANZE^® drug delivery technology is based on the proprietary recombinant human hyaluronidase PH20 enzyme (rHuPH20; Halozyme Therapeutics, Inc.) that facilitates the subcutaneous (SC) delivery of co‐administered therapeutics. rHuPH20 works by degrading the glycosaminoglycan hyaluronan (HA), which plays a role in resistance to bulk fluid flow in the SC space, limiting large volume SC drug delivery, dispersion, and absorption. Co-administration of rHuPH20 with partner therapies can overcome administration time and volume barriers associated with existing SC therapeutic formulations, and has been shown to reduce the burden on patients and healthcare providers compared with intravenous formulations. rHuPH20 (as HYLENEX^® recombinant) is currently FDA-approved for subcutaneous fluid administration for achieving hydration, to increase the dispersion and absorption of other injected drugs, and in subcutaneous urography for improving resorption of radiopaque agents. rHuPH20 is also co-formulated with two anticancer therapies, trastuzumab (i.e. Herceptin^® SC) and rituximab (i.e. RITUXAN HYCELA^®/RITUXAN^® SC/MabThera^® SC) and dosed sequentially with human immunoglobin to treat primary immunodeficiency (i.e. HyQvia^®/HYQVIA^®). This article reviews pharmaceutical properties of rHuPH20, its current applications with approved therapeutics, and the potential for future developments.

Rituximab Serum Concentrations and Anti-Rituximab Antibodies During B-Cell Depletion Therapy for Myalgic Encephalopathy/Chronic Fatigue Syndrome

PURPOSE

Previous Phase II trials indicated clinical benefit from B-cell depletion using the monoclonal anti-CD20 antibody rituximab in patients with myalgic encephalopathy/chronic fatigue syndrome (ME/CFS). The association between rituximab serum concentrations and the effect and clinical relevance of antidrug antibodies (ADAs) against rituximab in ME/CFS is unknown. We retrospectively measured rituximab concentrations and ADAs in serum samples from patients included in an open-label Phase II trial with maintenance rituximab treatment (KTS-2-2010) to investigate possible associations with clinical improvement and clinical and biochemical data.

METHODS

Patients with ME/CFS fulfilling the Canadian criteria received rituximab (500 mg/m²) infusions: 2 infusions 2 weeks apart (induction), followed by maintenance treatment at 3, 6, 10, and 15 months. The measured rituximab concentrations and ADAs in serum samples included 23 of 28 patients from the trial.

FINDINGS

There were no significant differences in mean serum rituximab concentrations between 14 patients experiencing clinical improvement versus 9 patients with no improvement. Female patients had higher mean serum rituximab concentrations than male patients at 3 months (P = 0.05). There was a significant negative correlation between B-cell numbers in peripheral blood at baseline and rituximab serum concentration at 3 months (r = -0.47; P = 0.03). None of the patients had ADAs at any time point.

IMPLICATIONS

Clinical improvement of patients with ME/CFS in the KTS-2-2010 trial was not related to rituximab serum concentrations or ADAs. This finding is also in line with a recent randomized trial questioning the efficacy of rituximab in ME/CFS. Rituximab concentrations and ADAs still offer supplemental information when interpreting the results of these trials.

Evaluation of subcutaneous rituximab administration on Canadian systemic therapy suites

Background

Non-Hodgkin lymphoma (nhl) is the most common hematologic malignancy. Diffuse large B-cell lymphoma (dlbcl) and follicular lymphoma (fl) constitute 55% of new nhl cases and are initially treated with rituximab-based chemoimmunotherapy. Relative to intravenous (IV) rituximab, a subcutaneous (sc) formulation approved in 2016 has comparable pharmacokinetics, efficacy, and safety, and a greatly reduced administration time; it is also preferred by patients. The objective of the present study was to estimate the effect (on systemic therapy suite time and on the costs of drug acquisition and administration) of implementing sc rituximab in the initial chemoimmunotherapy for fl and dlbcl over 3 years in the Canadian market.

Methods

An Excel (Microsoft Corporation, Redmond, WA, U.S.A.)-based model was created with a population size based on epidemiologic data and current rituximab use, duration of use considering initial therapy, time savings for sc rituximab administration from published studies, costs from standard Canadian sources, and assumed uptake in implementing provinces of 65%, 75%, and 80% over 3 years. Key parameters and sensitivity analysis values were validated by clinical experts located in various Canadian jurisdictions. Costs are reported in 2017 Canadian dollars from the perspective of the health care system.

Results

More than 3 years after implementation of sc rituximab, we estimated that 5762 Canadians would be receiving sc rituximab, resulting in savings of 128,715 hours in systemic therapy suite time and approximately $40 million in drug and administration costs. Sensitivity analyses suggest that the model is most sensitive to sc market uptake, number of induction therapy cycles, and eligible patients.

Conclusions

Subcutaneous administration of rituximab can significantly reduce systemic therapy suite time and achieve substantial savings in drug and administration costs.

Anti-CD20 monoclonal antibodies: reviewing a revolution

Since the inception of rituximab in the 1990s, anti-CD20 monoclonal antibodies have revolutionised the treatment of B cell hematological malignancies and have become a cornerstone of modern gold-standard practice. Additionally, the potent efficacy of these agents in depleting the B cell compartment has been used in the management of a broad array of autoimmune diseases. Multiple iterations of these agents have been investigated and are routinely used in clinical practice. In this review, we will discuss the physiology of CD20 and its attractiveness as a therapeutic target, as well as the pharmacology, pre-clinical and clinical data for the major anti-CD20 monoclonal antibodies: rituximab, obinutuzumab and ofatumumab.

The use of intravenous versus subcutaneous monoclonal antibodies in the treatment of severe asthma: a review

BACKGROUND

Monoclonal antibodies (mAbs) approved for use as add-on therapy in patients with severe asthma target the underlying pathogenesis of asthma.

MAIN BODY

Omalizumab binds immunoglobulin E (IgE), thereby inhibiting its interaction with the high-affinity IgE receptor and reducing the quantity of free IgE available to trigger the allergic cascade. Anti-interleukin (IL)-5 mAbs mepolizumab, benralizumab and reslizumab block the interaction between IL-5 and its receptor on eosinophils, thus targeting the eosinophilic pathway in asthma. Most mAbs are available as intravenous (IV) or subcutaneous (SC) formulations, as their high molecular weight and gastric degradation preclude oral administration. This review compares the pharmacology, efficacy, immunogenicity, injection- and infusion-related adverse drug reactions of subcutaneously administered omalizumab and mepolizumab with the intravenously administered reslizumab. In terms of pharmacokinetics, IV route of administration appears to be superior to the SC route due to quicker absorption, greater bioavailability, shorter time to maximum serum concentration and similar elimination half-life. Route of administration does not appear to translate into striking differences in efficacy and safety of mAbs used for the treatment of severe asthma, as all are generally considered to be effective and well tolerated. Hypersensitivity and administration-related reactions have been described with both IV and SC mAbs.

CONCLUSION

mABs are effective and have low immunogenicity due to their nature as humanised antibodies. Evidence on the use of mAbs in indications other than severe asthma suggest that both the SC and the IV routes of administrations have their respective advantages and disadvantages; but their full utility remains to be elucidated.

Cellular Cytotoxicity of Next-Generation CD20 Monoclonal Antibodies

CD20 monoclonal antibodies (CD20 mAb) induce cellular cytotoxicity, which is traditionally measured by antibody-dependent cellular cytotoxicity (ADCC) assays. However, data suggest that antibody-dependent cellular phagocytosis (ADCP) is the primary cytotoxic mechanism. We directly compared in vitro ADCP versus ADCC using primary human cells. After establishing the primacy of ADCP, we examined next-generation CD20 mAbs, including clinically relevant drug combinations for their effects on ADCP. ADCP and ADCC induction by rituximab, ofatumumab, obinutuzumab, or ocaratuzumab was measured using treatment-naïve chronic lymphocytic leukemia (CLL) target cells and either human monocyte-derived macrophages (for ADCP) or natural killer (NK) cells (for ADCC). Specific effects on ADCP were evaluated for clinically relevant drug combinations using BTK inhibitors (ibrutinib and acalabrutinib), PI3Kδ inhibitors (idelalisib, ACP-319, and umbralisib), and the BCL2 inhibitor venetoclax. ADCP (∼0.5-3 targets/macrophage) was >10-fold more cytotoxic than ADCC (∼0.04-0.1 targets/NK cell). ADCC did not correlate with ADCP. Next-generation mAbs ocaratuzumab and ofatumumab induced ADCP at 10-fold lower concentrations than rituximab. Ofatumumab, selected for enhanced complement activation, significantly increased ADCP in the presence of complement. CD20 mAb-induced ADCP was not inhibited by venetoclax and was less inhibited by acalabrutinib versus ibrutinib and umbralisib versus idelalisib. Overall, ADCP was a better measure of clinically relevant mAb-induced cellular cytotoxicity, and next-generation mAbs could activate ADCP at significantly lower concentrations, suggesting the need to test a wide range of dose sizes and intervals to establish optimal therapeutic regimens. Complement activation by mAbs can contribute to ADCP, and venetoclax, acalabrutinib, and umbralisib are preferred candidates for multidrug therapeutic regimens. Cancer Immunol Res; 6(10); 1150-60. ©2018 AACR.

Challenges and Opportunities for the Subcutaneous Delivery of Therapeutic Proteins

Biotherapeutics is a rapidly growing drug class, and over 200 biotherapeutics have already obtained approval, with about 50 of these being approved in 2015 and 2016 alone. Several hundred protein therapeutic products are still in the pipeline, including interesting new approaches to treatment. Owing to patients' convenience of at home administration and reduced number of hospital visits as well as the reduction in treatment costs, subcutaneous (SC) administration of biologics is of increasing interest. Although several avenues for treatment using biotherapeutics are being explored, there is still a sufficient gap in knowledge regarding the interplay of formulation conditions, immunogenicity, and pharmacokinetics (PK) of the absorption of these compounds when they are given SC. This review seeks to highlight the major concerns and important factors governing this route of administration and suggest a holistic approach for effective SC delivery.

Subcutaneous rituximab with recombinant human hyaluronidase in the treatment of non-Hodgkin lymphoma and chronic lymphocytic leukemia

The anti-CD20 monoclonal antibody rituximab (MabThera^®/Rituxan^®) has been proven to improve outcomes in a range of B-cell malignancies. Initially developed as a formulation for intravenous infusion, administration times for rituximab can be prolonged and associated with infusion-related reactions, prompting a combined clinical development program investigating subcutaneous delivery in combination with recombinant human hyaluronidase. As this program comes to fruition, this article reviews the evidence demonstrating subcutaneous rituximab to have noninferior pharmacokinetics when delivered at a fixed-dose as well as equivalent clinical outcomes in the treatment of follicular lymphoma, chronic lymphocytic leukemia and diffuse large B-cell lymphoma. This mode of delivery is more preferable to patients and healthcare professionals and is associated with time and cost savings.

Pharmacokinetics of monoclonal antibodies and Fc-fusion proteins

There are many factors that can influence the pharmacokinetics (PK) of a mAb or Fc-fusion molecule with the primary determinant being FcRn-mediated recycling. Through Fab or Fc engineering, IgG-FcRn interaction can be used to generate a variety of therapeutic antibodies with significantly enhanced half-life or ability to remove unwanted antigen from circulation. Glycosylation of a mAb or Fc-fusion protein can have a significant impact on the PK of these molecules. mAb charge can be important and variants with pI values of 1-2 unit difference are likely to impact PK with lower pI values being favorable for a longer half-life. Most mAbs display target mediated drug disposition (TMDD), which can have significant consequences on the study designs of preclinical and clinical studies. The PK of mAb can also be influenced by anti-drug antibody (ADA) response and off-target binding, which require careful consideration during the discovery stage. mAbs are primarily absorbed through the lymphatics via convection and can be conveniently administered by the subcutaneous (sc) route in large doses/volumes with co-formulation of hyaluronidase. The human PK of a mAb can be reasonably estimated using cynomolgus monkey data and allometric scaling methods.

Efficacy and safety of subcutaneous and intravenous rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone in first-line diffuse large B-cell lymphoma: the randomized MabEase study

Intravenous rituximab plus chemotherapy is standard treatment for diffuse large B-cell lymphoma. A subcutaneous formulation of rituximab is expected to simplify and shorten drug preparation and administration, and to reduce treatment burden. MabEase (clinicaltrials.gov Identifier: 01649856) examined efficacy, safety and patient satisfaction with subcutaneous rituximab plus chemotherapy in treatment-naïve patients with diffuse large B-cell lymphoma. Patients were randomized 2:1 to subcutaneous rituximab (intravenous 375 mg/m2 cycle 1; subcutaneous 1,400 mg cycles 2-8) or intravenous rituximab (375 mg/m2 cycles 1-8) plus cyclophosphamide, doxorubicin, vincristine, and prednisone every 14 or 21 days. The primary endpoint was investigator-assessed complete response/unconfirmed complete response. Secondary endpoints included safety, treatment satisfaction (Cancer Treatment Satisfaction Questionnaire and Rituximab Administration Satisfaction Questionnaire), time savings, and survival. Of 576 randomized patients, 572 (378 subcutaneous; 194 intravenous) received treatment. End of induction complete response/unconfirmed complete response rates were 50.6% (subcutaneous) and 42.4% (intravenous). After a median 35 months, median overall, event-free and progression-free survivals were not reached. Grade ≥3 adverse events (subcutaneous 58.3%; intravenous 54.3%) and administration-related adverse events (both groups 21%) were similar between arms. Injection-site reactions were more common with subcutaneous injections (5.7% versus 0%, respectively). Rituximab Administration Satisfaction Questionnaire scores for 'impact on activities of daily living', 'convenience', and 'satisfaction' were improved with subcutaneous versus intravenous injections; Cancer Therapy Satisfaction Questionnaire scores were similar between arms. Median administration time (6 minutes vs 2.6 to 3.0 hours), chair/bed and overall hospital times were shorter with subcutaneous versus intravenous rituximab. Overall, subcutaneous and intravenous rituximab had similar efficacy and safety, with improved patient satisfaction and time savings.

Subcutaneous Rituximab for the Treatment of B-Cell Hematologic Malignancies: A Review of the Scientific Rationale and Clinical Development

Rituximab (MabThera®/Rituxan®), a chimeric murine/human monoclonal antibody that binds specifically to the transmembrane antigen CD20, was the first therapeutic antibody to enter clinical practice for the treatment of cancer. As monotherapy and in combination with chemotherapy, rituximab has been shown to prolong progression-free survival and, in some indications overall survival, in patients with various B-cell malignancies, while having a well-established and manageable safety profile and a wide therapeutic window. As a result, rituximab is considered to have revolutionized treatment practices for patients with B-cell malignancies. A subcutaneous (SC) formulation of rituximab has been developed, comprising the same monoclonal antibody as the originally marketed formulation [rituximab concentrate for solution for intravenous (IV) infusion], and has undergone a detailed, sequential clinical development program. This program demonstrated that, at fixed doses, rituximab SC achieves non-inferior serum trough concentrations in patients with non-Hodgkin lymphoma and chronic lymphocytic leukemia, with comparable efficacy and safety relative to the IV formulation. The added benefit of rituximab SC was demonstrated in dedicated studies showing that rituximab SC allows for simplified and shortened drug preparation and administration times resulting in a reduced treatment burden for patients as well as improved resource utilization (efficiency) at the treatment facility. The improved efficiency of delivering rituximab's benefit to patients may broaden patient access to rituximab therapy in areas with low levels of healthcare resources, including IV-chair capacity constraints. This article is a companion paper to G. Salles, et al., which is also published in this issue.

FUNDING

F. Hoffmann-La Roche Ltd.

Optimizing the Bioavailability of Subcutaneously Administered Biotherapeutics Through Mechanochemical Drivers

The subcutaneous route offers myriad benefits for the administration of biotherapeutics in both acute and chronic diseases, including convenience, cost effectiveness and the potential for automation through closed-loop systems. Recent advances in parenteral administration devices and the use of additives which enhance drug dispersion have generated substantial additional interest in IV to SQ switching studies. Designing pre-clinical and clinical studies using SQ mediated delivery however requires deep understanding of complex inter-related physiologies and transport pathways governing the interstitial matrix, vascular system and lymphatic channels. This expert review will highlight key structural features which contribute to transport and biodistribution in the subcutaneous space and also assess the impact of drug formulations. Based on the rapidly growing interest in the SQ delivery route, a number of potential areas for future development are highlighted, which are likely to allow continued evolution and innovation in this important area.

Pharmacokinetics, safety, and efficacy of subcutaneous versus intravenous rituximab plus chemotherapy as treatment for chronic lymphocytic leukaemia (SAWYER): a phase 1b, open-label, randomised controlled non-inferiority trial

BACKGROUND

Part one of the two-part SAWYER study predicted that subcutaneous rituximab 1600 mg would achieve trough serum concentrations that were non-inferior to those achieved with intravenous rituximab 500 mg/m(2) in patients with chronic lymphocytic leukaemia. In part two of the study, we aimed to confirm the pharmacokinetic non-inferiority of subcutaneous rituximab, and investigate its safety and efficacy.

METHODS

We did this phase 1b, open-label, randomised controlled non-inferiority study at 68 centres in 19 countries in Europe, North America, South America, and Australasia. Patients aged 18 years or older with untreated chronic lymphocytic leukaemia were randomly assigned, via an interactive voice-response system with a permuted block randomisation scheme (block size of ten), to receive subcutaneous rituximab 1600 mg or intravenous rituximab 500 mg/m(2) plus fludarabine and cyclophosphamide every 4 weeks for up to six cycles. In cycle one, all patients received intravenous rituximab 375 mg/m(2). Randomisation was stratified by Binet stage and fludarabine and cyclophosphamide administration route (oral vs intravenous). Study investigators and patients were not masked to group allocation, but allocation was concealed from the statistician, clinical scientist, and clinical pharmacologist. The primary endpoint was trough serum concentration at cycle five, with a non-inferiority margin of 0·8 for the adjusted geometric mean ratio of the subcutaneous to the intravenous dose. We did the primary analysis in patients in the intention-to-treat population with complete pharmacokinetic data (pharmacokinetic population). This trial is registered with ClinicalTrials.gov, number NCT01292603, and is ongoing, although the treatment stage is now complete.

FINDINGS

Between Aug 20, 2012, and June 17, 2013, we randomly assigned 176 patients to receive subcutaneous rituximab (n=88) or intravenous rituximab (n=88); 134 (76%) patients comprised the pharmacokinetic population. As of May 7, 2014, median follow-up was 13·9 months (IQR 11·9-16·0) for patients in the subcutaneous group and 14·1 months (11·6-16·5) for patients in the intravenous group. At cycle five, the geometric mean trough serum concentration in patients given subcutaneous rituximab was non-inferior to that in patients given intravenous rituximab (97·5 μg/mL vs 61·5 μg/mL), with an adjusted geometric mean ratio of 1·53 (90% CI 1·27-1·85). In the safety analysis, the proportion of patients reporting adverse events was similar between the subcutaneous and intravenous groups (all grades: 82 [96%] of 85 patients and 81 [91%] of 89 patients; serious adverse events: 25 [29%] and 29 [33%] patients; grade ≥3: 59 [69%] and 63 [71%] patients, respectively). The most common adverse event of grade 3 or higher was neutropenia (48 [56%] patients in the subcutaneous group and 46 [52%] patients in the intravenous group); the most common serious adverse event was febrile neutropenia (n=9 [11%] and n=4 [4%], respectively). We recorded administration-related reactions in 37 (44%) patients given subcutaneous rituximab and 40 (45%) patients given the intravenous dose, with differences between administration routes for injection-site erythema (n=10 [12%] and n=0, respectively) and nausea (n=2 [2%] and n=11 [12%], respectively). More patients reported local cutaneous reactions after subcutaneous rituximab (n=36 [42%]) than after intravenous rituximab (n=2 [2%]); most of these reactions were grade 1 or 2.

INTERPRETATION

When combined with fludarabine and cyclophosphamide, subcutaneous rituximab 1600 mg achieved trough serum concentrations that were pharmacokinetically non-inferior to those achieved with intravenous rituximab 500 mg/m(2), with a similar safety and efficacy profile between the two groups. Treatment with subcutaneous rituximab should allow patients with chronic lymphocytic leukaemia to receive clinical benefit from the drug via a more convenient delivery method than the intravenous route, and might also be used in combination regimens with approved and emerging oral regimens.

FUNDING

F Hoffmann-La Roche.