Relationship between pharmacokinetic profile of subcutaneously administered alemtuzumab and clinical response in patients with chronic lymphocytic leukemia

Drug exposure and measurable residual disease in chronic lymphocytic leukemia: a systematic review

For fixed-duration therapies against chronic lymphocytic leukemia (CLL), undetectable measurable residual disease (MRD) predicts overall and progression-free survival more accurately than complete remission. For indefinite therapies, MRD status can direct discontinuation of treatment. We systematically reviewed the relationship between antineoplastic drug exposures and undetectable MRD in CLL. Seventeen trials from MEDLINE and EMBASE met the inclusion criteria; four of which evaluated drug exposures in relation to MRD status. Undetectable MRD was associated with higher trough concentrations of ofatumumab and alemtuzumab, as well as increased maximum concentration and area under the plasma concentration curve (AUC) of ibrutinib. One study found an association between high rituximab AUC and undetectable MRD until adjusting for tumor burden. The limited studies, lack of exposure measurements of concomitant drugs, and high heterogeneity in designs limit the results' generalizability. Further research is needed to explore the exposure-MRD relationship and the possibility for therapeutic drug monitoring in CLL.

The use of proteins and peptides-based therapy in managing and preventing pathogenic viruses

Therapeutic proteins have been employed for centuries and reached approximately 50 % of all drugs investigated. By 2023, they represented one of the top 10 largest-selling pharma products ($387.03 billion) and are anticipated to reach around $653.35 billion by 2030. Growth hormones, insulin, and interferon (IFN α, γ, and β) are among the leading applied therapeutic proteins with a higher market share. Protein-based therapies have opened new opportunities to control various diseases, including metabolic disorders, tumors, and viral outbreaks. Advanced recombinant DNA biotechnology has offered the production of therapeutic proteins and peptides for vaccination, drugs, and diagnostic tools. Prokaryotic and eukaryotic expression host systems, including bacterial, fungal, animal, mammalian, and plant cells usually applied for recombinant therapeutic proteins large-scale production. However, several limitations face therapeutic protein production and applications at the commercial level, including immunogenicity, integrity concerns, protein stability, and protein degradation under different circumstances. In this regard, protein-engineering strategies such as PEGylation, glycol-engineering, Fc-fusion, albumin conjugation, and fusion, assist in increasing targeting, product purity, production yield, functionality, and the half-life of therapeutic protein circulation. Therefore, a comprehensive insight into therapeutic protein research and findings pave the way for their successful implementation, which will be discussed in the current review.

Prolymphocytic Leukemia: New Insights in Diagnosis and in Treatment

PURPOSE OF REVIEW

We aimed to produce a comprehensive update on clinical and biological data regarding two rare lymphoid neoplasms, B and T prolymphocytic leukemias, and assess therapeutic management in the light of new molecular insights and the advent of targeted therapies.

RECENT FINDINGS

B cell prolymphocytic leukemia (B-PLL) diagnosis remains challenging in the absence of clear immunophenotypic or cytogenetic signature and overlap with mantle cell lymphoma. New molecular defects have been identified in T cell prolymphocytic leukemia (T-PLL), especially in the JAK STAT pathway. Like in chronic lymphocytic leukemia (CLL), B-PLL treatment depends on the presence of TP53 dysfunction. In T-PLL, alemtuzumab still remains the standard of care. Allogeneic transplantation is the only curable option. Thanks to reduced intensity conditioning regimens, it has become accessible to a larger number of patients. PLL prognosis remains poor with conventional therapies. However, great advances in the understanding of both T- and B-PLL pathogenesis lead to promising new therapeutic agents.

Comparison of Subcutaneous versus Intravenous Alemtuzumab for Graft-versus-Host Disease Prophylaxis with Fludarabine/Melphalan-Based Conditioning in Matched Unrelated Donor Allogeneic Stem Cell Transplantation

The objective of this study was to compare infusion-related reactions and outcomes of using subcutaneous (subQ) alemtuzumab versus intravenous (i.v.) alemtuzumab as graft-versus-host disease (GVHD) prophylaxis for matched unrelated donor stem cell transplantations. Outcomes include incidence of cytomegalovirus (CMV)/Epstein-Barr (EBV) viremia, development of CMV disease or post-transplantation lymphoproliferative disorder, fatal infections, acute and chronic GVHD, time to engraftment, relapse rate, and survival. We conducted a retrospective study of all adult matched unrelated donor stem cell transplantations patients who received fludarabine/melphalan with subQ or i.v. alemtuzumab in combination with tacrolimus as part of their conditioning for unrelated donor transplantation at New York-Presbyterian/Weill Cornell Medical Center from January 1, 2012 to March 21, 2014. Alemtuzumab was administered at a total cumulative dose of 100 mg (divided over days −7 to −3). Forty-six patients received an unrelated donor stem cell transplantation with fludarabine/melphalan and either subQ (n = 26) or i.v. (n = 20) alemtuzumab in combination with tacrolimus. Within the evaluable population, 130 subQ and 100 i.v. alemtuzumab doses were administered. For the primary outcome, ≥grade 2 infusion-related reactions occurred in 11 (8%) versus 25 (25%) infusions in the subQ and i.v. cohorts, respectively (P = .001). Overall, 12 injections (9%) in the subQ arm versus 26 infusions (26%) in the i.v. arm experienced an infusion-related reaction of any grade (P = .001). There were no significant differences between the subQ and i.v. arms in rates of reactivation of CMV/EBV, development of CMV disease or post-transplantation lymphoproliferative disorder, fatal infections, acute and chronic GVHD, relapse, or survival. Subcutaneous administration of alemtuzumab for GVHD prophylaxis was associated with fewer infusion-related reactions compared with i.v. administration in the SCT setting. Incidences of acute and chronic GVHD were similar between both arms. There was also no difference in reactivation of CMV/EBV viremia, development of CMV disease or post-transplantation lymphoproliferative disorder, fatal infections, relapse, or survival.

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We conducted a retrospective comparison of intravenous versus subcutaneous administration of alemtuzumab for graft-versus-host disease prophylaxis in unrelated donor transplant recipients.

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We observed a significant reduction in grade ≥ 2 infusion-related reactions after subcutaneous injections. The incidences of acute and chronic graft-versus-host disease were similar. There was no difference in incidence of viral reactivation or fatal bacterial infections.

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There was no difference in 30-day mortality or 1-year overall survival between the 2 arms.

Impact of Alemtuzumab Therapy and Route of Administration in T-Prolymphocytic Leukemia: A Single-Center Experience

OBJECTIVE

We conducted a single-center retrospective analysis to determine the impact of the anti-CD52 monoclonal antibody alemtuzumab including route of administration compared to non-alemtuzumab-containing regimens in T-prolymphocytic leukemia (T-PLL).

PATIENTS AND METHODS

The study was a retrospective analysis of a consecutive cohort of adult patients diagnosed with T-PLL at Mayo Clinic Rochester from January 1, 1997, through September 30, 2014.

RESULTS

A total of 41 patients were diagnosed with T-PLL per the World Health Organization 2008 classification. The median age was 66 years, and 23 (56%) were male. After a median follow-up of 18 months (range, 0.4-66.1 months), 32 patients (78%) had died, with a median overall survival of 16.9 months. Approximately half the cohort was treated with alemtuzumab, almost exclusively after 2004. Median survival for patients receiving intravenous alemtuzumab-based therapy was 40.5 versus 10.3 months for all other therapies (P = .0004). A significant survival difference between intravenous versus subcutaneous alemtuzumab administration of 40.5 versus 13.7 months was noted (P = .0014). Only 4 (14%) of 28 patients aged < 70 years underwent hematopoietic stem cell transplantation, with a median survival after transplantation of 4 months.

CONCLUSION

In this large series of T-PLL patients treated at a single tertiary-care center, we confirmed the prior observation of the superiority of intravenous alemtuzumab over other therapies. Hematopoietic stem cell transplantation was feasible in a minority of potentially eligible patients. Early transplant referral should be considered for all eligible patients.

A phase I study of PRO131921, a novel anti-CD20 monoclonal antibody in patients with relapsed/refractory CD20+ indolent NHL: correlation between clinical responses and AUC pharmacokinetics

PRO131921 is a third-generation, humanized anti-CD20 monoclonal antibody with increased antibody-dependent cytotoxicity and complement-dependent cytotoxicity compared to rituximab. In this phase I study, PRO131921 was administered as a single agent to patients with CD20+, relapsed or refractory, indolent non-Hodgkin lymphoma (NHL) who had been treated with a prior rituximab-containing regimen. The primary aim of this study was safety and tolerability of PRO131921. The secondary aim of the study, and focus of this report, was to determine the pharmacokinetics (PK) profile of PRO131921 and establish a correlation between drug exposure and clinical efficacy. Patients were treated with PRO131921 by intravenous infusion weekly for 4 weeks and the dose was escalated based on safety in a 3+3 design. Twenty-four patients were treated with PRO131921 at doses from 25mg/m(2) to 800 mg/m(2). Analysis of PK data demonstrated a correlation between higher normalized drug exposure (normalized AUC) and tumor shrinkage (p = .0035). Also, normalized AUC levels were higher among responders and subjects displaying tumor shrinkage versus subjects progressing or showing no regression (p = 0.030). In conclusion, PRO131921 demonstrated clinical activity in rituximab-relapsed and refractory indolent NHL patients. The observation that higher normalized AUC may be associated with improved clinical responses has potential implications in future trials of monoclonal antibody-based therapies, and emphasizes the importance of early PK studies to optimize antibody efficacy.

Frontline low-dose alemtuzumab with fludarabine and cyclophosphamide prolongs progression-free survival in high-risk CLL

Frontline FCA increases progression-free survival in CLL and, in a post hoc analysis, also survival in younger patients. With the low-dose approach, no increase in treatment related mortality is seen.

Impact of physiochemical properties on pharmacokinetics of protein therapeutics

Physicochemical properties, such as molecular weight, size, partition coefficient, acid dissociation constant and solubility have a great impact on pharmacokinetics of traditional small molecule drugs and substantially used in development of small drugs. However, predicting pharmacokinetic fate (absorption, distribution, metabolism and elimination) of protein therapeutics from their physicochemical parameters is extremely difficult due to the macromolecular nature of therapeutic proteins and peptides. Their structural complexity and immunogenicity are other contributing factors that determine their biological fate. Therefore, to develop generalized strategies concerning development of therapeutic proteins and peptides are highly challenging. However, reviewing the literature, authors found that physiochemical properties, such as molecular weight, charge and structural modification are having great impact on pharmacokinetics of protein therapeutics and an attempt is made to provide the major findings in this manuscript. This manuscript will serve to provide some bases for developing protein therapeutics with desired pharmacokinetic profile.

B- and T-cell prolymphocytic leukemia: antibody approaches

B- and T-cell subtypes of prolymphocytic leukemia (PLL) are rare, aggressive lymphoid malignancies with characteristic morphologic, immunophenotypic, cytogenetic, and molecular features. Prognosis for these patients remains poor, with short survival times and no curative therapy. The advent of mAbs has improved treatment options. In B-PLL, rituximab-based combination chemoimmunotherapy is effective in fitter patients. TP53 abnormalities are common and, as for chronic lymphocytic leukemia, these patients should generally be managed using an alemtuzumab-based therapy. Currently, the best treatment for T-PLL is IV alemtuzumab, which has resulted in very high response rates of more than 90% when given as frontline treatment and a significant improvement in survival. Consolidation of remissions with autologous or allogeneic stem cell transplantation further prolongs survival times, and the latter may offer potential cure. The role of allogeneic transplantation with nonmyeloablative conditioning needs to be explored further in both T- and B-PLL to broaden the patient eligibility for what may be a curative treatment.

High-dose monoclonal antibodies via the subcutaneous route: challenges and technical solutions, an industry perspective

This review summarizes the various challenges in product development involved in subcutaneous administration of high-dose monoclonal antibodies and attempts to provide an industry perspective of some of the available technologies and potential avenues to overcome these challenges.

How I treat prolymphocytic leukemia

T- and B-cell subtypes of prolymphocytic leukemia (PLL) are rare, aggressive lymphoid malignancies with characteristic morphologic, immunophenotypic, cytogenetic, and molecular features. Recent studies have highlighted the role of specific oncogenes, such as TCL-1, MTCP-1, and ATM in the case of T-cell and TP53 mutations in the case of B-cell prolymphocytic leukemia. Despite the advances in the understanding of the biology of these conditions, the prognosis for these patients remains poor with short survival and no curative therapy. The advent of monoclonal antibodies has improved treatment options. Currently, the best treatment for T-PLL is intravenous alemtuzumab, which has resulted in very high response rates of more than 90% when given as first-line treatment and a significant improvement in survival. Consolidation of remissions with autologous or allogeneic stem cell transplantation further prolongs survival, and the latter may offer potential cure. In B-PLL, rituximab-based combination chemo-immunotherapy is effective in fitter patients. TP53 abnormalities are common and, as for chronic lymphocytic leukemia, these patients should be managed using an alemtuzumab-based therapy. The role of allogeneic transplant with nonmyeloablative conditioning needs to be explored further in both T- and B-cell PLL to broaden the patient eligibility for what may be a curative treatment.

Pharmacokinetics and toxicology of therapeutic proteins: Advances and challenges

Significant progress has been made in understanding pharmacokinetics (PK), pharmacodynamics (PD), as well as toxicity profiles of therapeutic proteins in animals and humans, which have been in commercial development for more than three decades. However, in the PK arena, many fundamental questions remain to be resolved. Investigative and bioanalytical tools need to be established to improve the translation of PK data from animals to humans, and from in vitro assays to in vivo readouts, which would ultimately lead to a higher success rate in drug development. In toxicology, it is known, in general, what studies are needed to safely develop therapeutic proteins, and what studies do not provide relevant information. One of the major complicating factors in nonclinical and clinical programs for therapeutic proteins is the impact of immunogenicity. In this review, we will highlight the emerging science and technology, as well as the challenges around the pharmacokinetic- and safety-related issues in drug development of mAbs and other therapeutic proteins.

Subcutaneous administration of alemtuzumab in patients with highly active multiple sclerosis

Alemtuzumab is an anti-CD52 monoclonal antibody with remarkable efficacy in relapsing multiple sclerosis (MS). In clinical trials and off-label use in MS, alemtuzumab has been administered intravenously (IV). Alemtuzumab is approved for chronic lymphoid leukemia as IV. Oncology guidelines recommend alemtuzumab subcutaneous (SC) over IV. There is no report of alemtuzumab SC in MS. We report two patients with highly active relapsing MS who were treated with SC alemtuzumab, had significant improvement and tolerated SC alemtuzumab well without the typical infusion-associated adverse events. SC alemtuzumab in MS warrants further studies as this may enhance patient convenience and minimize infusion-associated adverse events.

Alemtuzumab therapy in T-cell prolymphocytic leukemia: comparing efficacy in a series treated intravenously and a study piloting the subcutaneous route

Intravenous alemtuzumab is an effective and well-tolerated treatment for T-cell prolymphocytic leukemia (T-PLL). Alemtuzumab given intravenously as first-line treatment in 32 patients resulted in an overall response rate of 91% with 81% complete responses. Studies in B-cell chronic lymphocytic leukemia have shown subcutaneous alemtuzumab to be equally as effective as intravenous alemtuzumab. The UKCLL05 pilot study examined the efficacy and toxicity of this more convenient method of administration in 9 previously untreated patients with T-PLL. Only 3 of 9 patients (33%) responded to treatment. Furthermore, 2 of 9 patients (22%) died while on treatment. Recruitment was terminated because of these poor results. After rescue therapy with intravenous alemtuzumab and/or pentostatin, median progression-free survival and overall survival were similar to the intravenous group. Alemtuzumab delivered intravenously, but not subcutaneously, remains the treatment of choice for previously untreated T-PLL.