A model-based approach leveraging in vitro data to support dose selection from the outset: A framework for bispecific antibodies in immuno-oncology.

FAP-4-1BBL is a bispecific antibody exerting 4-1BB-associated T-cell activation only while simultaneously bound to the fibroblast activation protein (FAP) receptor, expressed on the surface of cancer-associated fibroblasts. The trimeric complex formed when FAP-4-1BBL is simultaneously bound to FAP and 4-1BB represents a promising mechanism to achieve tumor-specific 4-1BB stimulation. We integrated in vitro data with mathematical modeling to characterize the pharmacology of FAP-4-1BBL as a function of trimeric complex formation when combined with the T-cell engager cibisatamab. This relationship was used to prospectively predict a range of clinical doses where trimeric complex formation is expected to be at its maximum. Depending on the dosing schedule and FAP-4-1BBL plasma: tumor distribution, doses between 2 and 145 mg could lead to maximum trimeric complex formation in the clinic. Due to the expected variability in both pharmacokinetic and FAP expression in the patient population, we predict that detecting a clear dose-response relationship would remain difficult without a large number of patients per dose level, highlighting that mathematical modeling techniques based on in vitro data could aid dose selection.

Symptoms and impacts of ambulatory nonsense mutation Duchenne muscular dystrophy: a qualitative study and the development of a patient-centred conceptual model.

BACKGROUND: Duchenne muscular dystrophy is a rare genetic neuromuscular disorder, which can result in early death due to disease progression. Ataluren is indicated for the treatment of nonsense mutation Duchenne muscular dystrophy, in ambulatory individuals aged two years and older. This study explored the symptoms and impacts of nonsense mutation Duchenne muscular dystrophy and experience with ataluren. METHODS: Qualitative interviews were conducted with caregivers in the UK. Interviews were conducted by telephone, were recorded and transcribed. Data were analysed using thematic analysis and saturation was recorded. RESULTS: Ten interviews were conducted with parents of individuals aged 4-19 years. Key symptoms included muscle weakness and muscle breakdown, which were associated with limitations in physical function and pain. These impacted individuals' daily activities, social activities and emotional wellbeing. These concepts and relationships were illustrated in a conceptual model, along with positive and negative moderating factors. Experience with ataluren and changes since initiation with treatment were discussed. CONCLUSION: Individuals with nonsense mutation Duchenne muscular dystrophy experience a range of interrelated symptoms and functional issues which impact their broader health-related quality of life. Treatments which address this high unmet need have the potential to improve the health-related quality of life of these individuals.

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 (Ctrough ) 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. Ctrough 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.

Rituximab dosing in hematological malignancies: an old question, revisited.

Rituximab is the standard of care for most B-cell malignancies. Its rapid clinical development enabled patients to receive this life-prolonging medicine sooner; however, it precluded a thorough assessment of dose selection. Extensive clinical pharmacology data collected from the recent subcutaneous development program enabled re-examination of this old question and support that the approved rituximab dosing regimens in non-Hodgkin's lymphoma and chronic lymphocytic leukemia appear to maximize the clinical benefit in the majority of patients.

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.

Efficacy and safety of subcutaneous rituximab versus intravenous rituximab for first-line treatment of follicular lymphoma (SABRINA): a randomised, open-label, phase 3 trial.

BACKGROUND: Intravenous rituximab is the standard of care in B-cell non-Hodgkin lymphoma, and is administered over 1·5-6 h. A subcutaneous formulation could reduce patients' treatment burden and improve resource utilisation in health care. We aimed to show the pharmacokinetic non-inferiority of subcutaneous rituximab to intravenous rituximab in follicular lymphoma and to provide efficacy and safety data. METHODS: SABRINA is a two-stage, randomised, open-label phase 3 study at 113 centres in 30 countries. Eligible patients were aged 18 years or older and had histologically confirmed, previously untreated, CD20-positive grade 1, 2, or 3a follicular lymphoma; Eastern Co-operative Oncology Group performance statuses of 0-2; bidimensionally measurable disease (by CT or MRI); life expectancy of 6 months or more; adequate haematological function for 28 days or more; and one or more symptoms requiring treatment according to the Groupe d'Etudes des Lymphomes Folliculaires criteria. Patients were randomly assigned (1:1) by investigators or members of the research team via a dynamic randomisation algorithm to 375 mg/m2 intravenous rituximab or 1400 mg subcutaneous rituximab, plus chemotherapy (six-to-eight cycles of cyclophosphamide, doxorubicin, vincristine, and prednisone [CHOP] or eight cycles of cyclophosphamide, vincristine, and prednisone [CVP]), every 3 weeks during induction, then rituximab maintenance every 8 weeks. Randomisation was stratified by selected chemotherapy, Follicular Lymphoma International Prognostic Index, and region. The primary endpoint for stage 2 was overall response (ie, confirmed complete response, unconfirmed complete response, and partial response) at the end of induction. Efficacy analyses were done in the intention-to-treat population. Pooled data from stages 1 and 2 are reported on the basis of the clinical cutoff date of the last patient completing the maintenance phase of the study. This trial is registered with ClinicalTrials.gov, number NCT01200758; new patients are no longer being recruited, but some patients are still being followed up. FINDINGS: Between Feb 15, 2011, and May 15, 2013, 410 patients were randomly assigned, 205 to intravenous rituximab and 205 to subcutaneous rituximab. Investigator-assessed overall response at the end of induction was 84·9% (95% CI 79·2-89·5) in the intravenous group and 84·4% (78·7-89·1) in the subcutaneous group. The frequency of adverse events was similar in both groups (199 [95%] of 210 in the intravenous group vs 189 [96%] of 197 in the subcutaneous group); the frequency of adverse events of grade 3 or higher was also similar (116 [55%] vs 111 [56%]). The most common grade 3 or higher adverse event was neutropenia, which occurred in 44 patients (21%) in the intravenous group and 52 (26%) in the subcutaneous group. Serious adverse events occurred in 72 patients (34%) in the intravenous group and 73 (37%) in the subcutaneous group. Administration-related reactions occurred in 73 patients (35%) in the intravenous group and 95 (48%) patients in the subcutaneous group (mainly grade 1 or 2 local injection-site reactions). INTERPRETATION: Intravenous and subcutaneous rituximab had similar efficacy and safety profiles, and no new safety concerns were noted. Subcutaneous administration does not compromise the anti-lymphoma activity of rituximab when given with chemotherapy. FUNDING: F Hoffmann-La Roche.

Pharmacokinetics and safety of subcutaneous rituximab in follicular lymphoma (SABRINA): stage 1 analysis of a randomised phase 3 study.

BACKGROUND: Intravenous rituximab is a mainstay of treatment for follicular lymphoma. A subcutaneous formulation that achieves equivalent rituximab serum concentrations might improve convenience and save health-care resources without sacrificing clinical activity. We aimed to assess pharmacokinetic non-inferiority of 3 week cycles of fixed-dose subcutaneous rituximab versus standard intravenous rituximab. METHODS: In our two-stage, randomised, open-label, phase 3 trial, we enrolled patients with previously untreated grade 1-3a, CD20-positive follicular lymphoma at 67 centres in 23 countries. In stage 1, we randomly allocated patients 1:1 with the Pocock and Simon algorithm to intravenous rituximab (375 mg/m(2)) or fixed-dose subcutaneous rituximab (1400 mg), stratified by induction chemotherapy regimen (cyclophosphamide, doxorubicin, vincristine, prednisone or cyclophosphamide, vincristine, prednisone), Follicular Lymphoma International Prognostic Index score, and region. After randomisation, patients received one induction dose of intravenous rituximab in cycle 1 and then allocated treatment for cycles 2-8. Patients with a complete or partial response following induction therapy continued intravenous or subcutaneous rituximab as maintenance every 8 weeks. The primary endpoint was the ratio of observed rituximab serum trough concentrations (Ctrough) between groups at cycle 7 (before cycle 8 dosing) of induction treatment in a per-protocol population. Patients were analysed as treated for safety endpoints. Stage 2 follow-up is ongoing and is fully accrued. This study is registered with ClinicalTrials.gov, number NCT01200758. FINDINGS: Between Feb 4, 2010, and Oct 21, 2011, we enrolled 127 patients. Pharmacokinetic data were available for 48 (75%) of 64 patients randomly allocated intravenous rituximab and 54 (86%) of 63 patients randomly allocated subcutaneous rituximab. Geometric mean Ctrough was 83·13 µg/mL in the intravenous group and 134·58 µg/mL in the subcutaneous group (ratio 1·62, 90% CI 1·36-1·94), showing non-inferiority of subcutaneous rituximab. 57 (88%) of 65 patients in the intravenous rituximab safety population had adverse events (30 [46%] grade ≥3), as did 57 (92%) of 62 patients in the subcutaneous rituximab safety population (29 [47%] grade ≥3). The most common grade 3 or worse adverse event in both groups was neutropenia (14 [22%] patients in the intravenous group and 16 [26%] patients in the subcutaneous group). Adverse events related to administration were mostly grade 1-2 and occurred in 21 (32%) patients in the intravenous group and 31 (50%) patients in the subcutaneous group. INTERPRETATION: Stage 1 data show that the pharmacokinetic profile of subcutaneous rituximab was non-inferior to intravenous rituximab and was not associated with new safety concerns. Stage 2 will provide data for efficacy and safety of the subcutaneous administration. FUNDING: F Hoffmann-La Roche.

Health-economic comparison of paricalcitol, calcitriol and alfacalcidol for the treatment of secondary hyperparathyroidism during haemodialysis.

This study evaluated the health-economic consequences of use of intravenous paricalcitol (Zemplar), oral calcitriol or oral and intravenous alfacalcidol for the treatment of patients with secondary hyperparathyroidism, focusing on a third-party payer perspective through inclusion of medication and hospital costs, survival rates and utilities. Cost values were based on German treatment recommendations and prices. Reference values for survival rates and utilities were based on the results of a MEDLINE search. The analysis showed a clear advantage for intravenous paricalcitol with respect to costs, effectiveness and utilities compared with treatment with oral calcitriol or intravenous alfacalcidol. Since the results were very cost sensitive with respect to selected diagnosis-related groups (DRGs) for kidney disease with dialysis, a sensitivity analysis was performed. This demonstrated first-order dominance of intravenous paricalcitol for a wide range of hospitalisation costs. In conclusion, this analysis suggested a clear benefit from the perspective of a third-party payer for intravenous paricalcitol compared with oral calcitriol and intravenous alfacalcidol in the treatment of patients with secondary hyperparathyroidism.