Long-term safety of rituximab in patients with rheumatoid arthritis

Infectious Complications of Biological and Small Molecule Targeted Immunomodulatory Therapies

The past 2 decades have seen a revolution in our approach to therapeutic immunosuppression. We have moved from relying on broadly active traditional medications, such as prednisolone or methotrexate, toward more specific agents that often target a single receptor, cytokine, or cell type, using monoclonal antibodies, fusion proteins, or targeted small molecules. This change has transformed the treatment of many conditions, including rheumatoid arthritis, cancers, asthma, and inflammatory bowel disease, but along with the benefits have come risks. Contrary to the hope that these more specific agents would have minimal and predictable infectious sequelae, infectious complications have emerged as a major stumbling block for many of these agents. Furthermore, the growing number and complexity of available biologic agents makes it difficult for clinicians to maintain current knowledge, and most review articles focus on a particular target disease or class of agent. In this article, we review the current state of knowledge about infectious complications of biologic and small molecule immunomodulatory agents, aiming to create a single resource relevant to a broad range of clinicians and researchers. For each of 19 classes of agent, we discuss the mechanism of action, the risk and types of infectious complications, and recommendations for prevention of infection.

Cancer chemotherapeutics in rheumatoid arthritis: A convoluted connection

Chemotherapy is one of the most popular therapeutic strategies to treat cancer. However, cancer chemotherapeutics have often been associated with impairment of the immune system, which might consequently lead to an augmented risk of autoimmune disorders, such as rheumatoid arthritis. Though the accurate mechanistic facets of rheumatoid arthritis induction have not been interpreted yet, a conglomeration of genetic and environmental factors might promote its etiology. What makes the scenario more challenging is that patients with rheumatoid arthritis are at a significantly elevated risk of developing various types of cancer. It is intriguing to note that diverse cancer chemotherapy drugs are also commonly used to treat symptoms of rheumatoid arthritis. However, a colossal multitude of such cancer therapeutics has demonstrated highly varied results in rheumatoid arthritis patients, including both beneficial and adverse effects. Herein, we attempt to present a holistic account of the variegated modalities of this complex tripartite cross-talk between cancer, rheumatoid arthritis and chemotherapy drugs in order to decode the sinuous correlation between these two appalling pathological conditions.

Beyond peptides and mAbs--current status and future perspectives for biotherapeutics with novel constructs

Biotherapeutics are attractive anti-cancer agents due to their high specificity and limited toxicity compared to conventional small molecules. Antibodies are widely used in cancer therapy, either directly or conjugated to a cytotoxic payload. Peptide therapies, though not as prevalent, have been utilized in hormonal therapy and imaging. The limitations associated with unmodified forms of both types of biotherapeutics have led to the design and development of novel structures, which incorporate key features and structures that have improved the molecules' abilities to bind to tumor targets, avoid degradation, and exhibit favorable pharmacokinetics. In this review, we highlight the current status of monoclonal antibodies and peptides, and provide a perspective on the future of biotherapeutics using novel constructs.

Primary vs. secondary antibody deficiency: clinical features and infection outcomes of immunoglobulin replacement

Secondary antibody deficiency can occur as a result of haematological malignancies or certain medications, but not much is known about the clinical and immunological features of this group of patients as a whole. Here we describe a cohort of 167 patients with primary or secondary antibody deficiencies on immunoglobulin (Ig)-replacement treatment. The demographics, causes of immunodeficiency, diagnostic delay, clinical and laboratory features, and infection frequency were analysed retrospectively. Chemotherapy for B cell lymphoma and the use of Rituximab, corticosteroids or immunosuppressive medications were the most common causes of secondary antibody deficiency in this cohort. There was no difference in diagnostic delay or bronchiectasis between primary and secondary antibody deficiency patients, and both groups experienced disorders associated with immune dysregulation. Secondary antibody deficiency patients had similar baseline levels of serum IgG, but higher IgM and IgA, and a higher frequency of switched memory B cells than primary antibody deficiency patients. Serious and non-serious infections before and after Ig-replacement were also compared in both groups. Although secondary antibody deficiency patients had more serious infections before initiation of Ig-replacement, treatment resulted in a significant reduction of serious and non-serious infections in both primary and secondary antibody deficiency patients. Patients with secondary antibody deficiency experience similar delays in diagnosis as primary antibody deficiency patients and can also benefit from immunoglobulin-replacement treatment.

Serum immunoglobulin levels and risk factors for hypogammaglobulinaemia during long-term maintenance therapy with rituximab in patients with granulomatosis with polyangiitis

OBJECTIVE

Rituximab (RTX) is a B cell depleting agent used to induce and maintain remission in patients with granulomatosis with polyangiitis (GPA). As the development of hypogammaglobulinaemia in GPA patients on long-term RTX has not been addressed, the aim of this study was to investigate changes in immunoglobulin levels and risk factors for hypogammaglobulinaemia during long-term RTX maintenance therapy in GPA.

METHODS

We used a single-centre cohort study of 29 GPA patients who received a median total cumulative dose of CYC of 17 g and were treated with 2 g RTX followed by re-treatment with either 2 g once annually, 1 g biannually or a combination of both. Ig levels were measured before each RTX re-treatment and hypogammaglobulinaemia was defined as levels of total immunoglobulin <6 g/l.

RESULTS

During a median follow-up of 4 years, patients received a cumulative dose of 9 g RTX. While serum Ig levels decreased during RTX maintenance, the largest decrease occurred after the first infusion. Baseline Ig levels and the CYC cumulative dose predicted Ig levels, whereas the RTX cumulative dose did not. Eight patients (28%) discontinued RTX due to hypogammaglobulinaemia. Male gender [hazard ratio (HR) = 8.7, P = 0.044], kidney involvement (HR = 6.5, P = 0.083) and the 1 g biannual regimen (HR = 8.0, P = 0.024) increased the risk to discontinue RTX due to hypogammaglobulinaemia, whereas orbital-subglottic involvement (HR = 0.23, P = 0.080) decreased it.

CONCLUSION

Hypogammaglobulinaemia occurred in one-quarter of GPA patients during RTX maintenance, independent of the RTX cumulative dose. Male gender, kidney involvement and the 1 g biannual RTX regimen constitute risk factors for severe hypogammaglobulinaemia necessitating withdrawal of RTX.

Secondary antibody deficiency

Secondary antibody deficiencies are defined by a quantitative or qualitative decrease in antibodies that occur most commonly as a consequence of renal or gastrointestinal immunoglobulin loss, hematological malignancies and corticosteroid, immunosuppressive or anticonvulsant medications. Patients with hematological malignancies or requiring immunosuppressive medications are known to be at increased risk of infection, but few studies directly address this relationship in the context of antibody deficiency. Immunoglobulin replacement therapy has been shown to be effective in reducing infections in primary and some secondary antibody deficiencies. The commonly encountered causes of secondary antibody deficiencies and their association with infection-related morbidity and mortality are discussed. Recommendations are made for screening and clinical management of those at risk.