Safety and effectiveness of combination versus monotherapy with immune checkpoint inhibitors in patients with preexisting autoimmune diseases

Patients with preexisting autoimmune disease (pAID) are generally excluded from clinical trials for immune checkpoint inhibitors (ICIs) for cancer due to concern of flaring pAID. In this multi-center, retrospective observational study, we compared safety of ICI combination (two ICI agents) versus monotherapy in cancer patients with pAIDs. The primary outcome was time to AEs (immune-related adverse events (irAEs) and/or pAID flares), with progression-free survival (PFS) and overall survival as secondary outcomes. Sixty-four of 133 patients (48%) received ICI combination and 69 (52%) monotherapy. Most had melanoma (32%) and lung cancer (31%). Most common pAIDs were rheumatic (28%) and dermatologic (23%). Over a median follow-up of 15 months (95%CI, 11-18 mo), the cumulative incidence of any-grade irAEs was higher for combination compared to monotherapy (subdistribution hazard ratio (sHR) 2.27, 95%CI 1.35-3.82). No statistically significant difference was observed in high-grade irAEs (sHR 2.31 (0.95-5.66), P = .054) or the cumulative incidence of pAID flares. There was no statistically significant difference for melanoma PFS between combination versus monotherapy (23.2 vs. 17.1mo, P = .53). The combination group was more likely to discontinue or hold ICI, but > 50% of the combination group was still able to continue ICI therapy. No treatment-related deaths occurred. In our cohort with pAIDs, patients had a tolerable toxicity profile with ICI combination therapy. Our results support the use of ICI combination if deemed necessary for cancer therapy in patients with pAIDs, since the ICI toxicities were comparable to monotherapy, able to be effectively managed and mostly did not require ICI interruption.

Selective immune suppression using interleukin-6 receptor inhibitors for management of immune-related adverse events

BACKGROUND

Management of immune-related adverse events (irAEs) is important as they cause treatment interruption or discontinuation, more often seen with combination immune checkpoint inhibitor (ICI) therapy. Here, we retrospectively evaluated the safety and effectiveness of anti-interleukin-6 receptor (anti-IL-6R) as therapy for irAEs.

METHODS

We performed a retrospective multicenter study evaluating patients diagnosed with de novo irAEs or flare of pre-existing autoimmune disease following ICI and were treated with anti-IL-6R. Our objectives were to assess the improvement of irAEs as well as the overall tumor response rate (ORR) before and after anti-IL-6R treatment.

RESULTS

We identified a total of 92 patients who received therapeutic anti-IL-6R antibodies (tocilizumab or sarilumab). Median age was 61 years, 63% were men, 69% received anti-programmed cell death protein-1 (PD-1) antibodies alone, and 26% patients were treated with the combination of anti-cytotoxic T lymphocyte antigen-4 and anti-PD-1 antibodies. Cancer types were primarily melanoma (46%), genitourinary cancer (35%), and lung cancer (8%). Indications for using anti-IL-6R antibodies included inflammatory arthritis (73%), hepatitis/cholangitis (7%), myositis/myocarditis/myasthenia gravis (5%), polymyalgia rheumatica (4%), and one patient each with autoimmune scleroderma, nephritis, colitis, pneumonitis and central nervous system vasculitis. Notably, 88% of patients had received corticosteroids, and 36% received other disease-modifying antirheumatic drugs (DMARDs) as first-line therapies, but without adequate improvement. After initiation of anti-IL-6R (as first-line or post-corticosteroids and DMARDs), 73% of patients showed resolution or change to ≤grade 1 of irAEs after a median of 2.0 months from initiation of anti-IL-6R therapy. Six patients (7%) stopped anti-IL-6R due to adverse events. Of 70 evaluable patients by RECIST (Response Evaluation Criteria in Solid Tumors) V.1.1 criteria; the ORR was 66% prior versus 66% after anti-IL-6R (95% CI, 54% to 77%), with 8% higher complete response rate. Of 34 evaluable patients with melanoma, the ORR was 56% prior and increased to 68% after anti-IL-6R (p=0.04).

CONCLUSION

Targeting IL-6R could be an effective approach to treat several irAE types without hindering antitumor immunity. This study supports ongoing clinical trials evaluating the safety and efficacy of tocilizumab (anti-IL-6R antibody) in combination with ICIs (NCT04940299, NCT03999749).

A phase 1/2 study of REGN4336, a PSMAxCD3 bispecific antibody, alone and in combination with cemiplimab in patients with metastatic castration-resistant prostate cancer

TPS284

Background: Prostate cancer is the leading cause of new cancer diagnoses and the second most common cause of cancer-related death in American men. Prognosis is especially poor for men with metastatic castration resistant prostate cancer (mCRPC). Prostate-specific membrane antigen (PSMA) is highly expressed on malignant prostate tissue but shows limited expression on normal tissue. As such, PSMA is an excellent research target for treatment of mCRPC. REGN4336 is a PSMAxCD3 bispecific antibody designed to facilitate T-cell–mediated killing of PSMA-expressing tumor cells. In preclinical models, REGN4336 demonstrated strong PSMA-dependent antitumor activity that was dose-dependent. Preclinical data also support clinical research into the combination of REGN4336 with cemiplimab (anti–programmed cell death-1) for treating mCRPC. Methods: This is an open-label, Phase 1/2, first-in-human, multicenter dose-escalation study with dose expansion evaluating safety, tolerability, pharmacokinetics (PK), and antitumor activity of REGN4336 administered subcutaneously alone and in combination with intravenous cemiplimab in patients with mCRPC (NCT05125016). Patients must have received at least two prior lines of systemic therapy approved for metastatic and/or castration-resistant disease including a second-generation anti-androgen therapy. In Module 1, REGN4336 as monotherapy is administered weekly but may be extended to once every 3 weeks following identification of the minimal pharmacologically active dose. In Module 2, REGN4336 will be administered in combination with cemiplimab (350 mg) once every 3 weeks after a 4-week REGN4336 monotherapy lead-in cycle. Study therapies are administered until disease progression, intolerable adverse events, withdrawal of consent, or a study withdrawal criterion is met. The primary objectives in dose escalation are to evaluate the safety, tolerability, PK, and recommended phase 2 dosing regimen (RP2DR) of REGN4336 alone and in-combination with cemiplimab. Expansion cohort(s) will be enrolled once RP2DRs have been determined. During the expansion phase, the primary objective is to assess clinical activity, as measured by objective response rate with REGN4336 alone or in combination with cemiplimab per modified Prostate Cancer Working Group 3 criteria. At selected sites, PSMA positron emission tomography/computed tomography scans will be performed at predefined timepoints on study. This study is currently open to enrollment. Clinical trial information: NCT03088540 .

Preliminary results from a phase 1/2 study of co-stimulatory bispecific PSMAxCD28 antibody REGN5678 in patients (pts) with metastatic castration-resistant prostate cancer (mCRPC)

154

Background: Pts with mCRPC have a poor prognosis with limited treatment options, including minimal response to immunotherapies. REGN5678 is a first-in-class, full-length anti-PSMAxCD28 bispecific costimulatory antibody designed to target prostate cancer cells and enhance T-cell activation. We report preliminary results from the dose escalation part of a first-in-human, open-label, Phase 1/2 study (NCT03972657) examining REGN5678 in combination with cemiplimab, a PD-1 blocking antibody. Methods: Pts with mCRPC had received ≥2 lines of systemic therapy in the metastatic and/or castration-resistant setting, including ≥1 second-generation anti-androgen. Pts received REGN5678 weekly at dose levels [DL] 0.1–300 mg, initially as monotherapy for 3 weeks, followed by combination with cemiplimab (350 mg Q3W) until progression or toxicity. Primary objectives are safety, tolerability, and pharmacokinetics. Preliminary efficacy measurements include decline in prostate-specific antigen (PSA) from the start of combination treatment and radiographic response from baseline. Results: At the data cutoff (DCO; July 27 2022), 35 pts had been treated. Treatment-emergent adverse events (TEAEs) ≥Grade (G)3 occurred in 54% (19/35) of pts. Cytokine release syndrome occurred in 6 pts (all G1) and there were 2 dose-limiting toxicities (both G3): pain (at 1 mg) and Guillain-Barré syndrome (at 300 mg). 4 pts (11%) experienced a ≥G3 immune-mediated adverse event (imAE; at DLs 30–300 mg). REGN5678 exposure was non-linear over the tested DLs (more than dose proportional). There were minimal signs of efficacy at lower DLs (REGN5678 0.1–10 mg), with only 1/16 pts showing a PSA decline (of 21%). More PSA declines occurred at higher DLs: 1/4 pts at 30 mg (a PSA decline of 100%), 3/8 at 100 mg (>99%, 44%, 22%), and 3/4 at 300 mg (>99%, 99%, 82%). Notably, all ≥G3 imAEs occurred in pts with PSA declines. Among pts with measurable disease and ≥1 on-treatment scan, radiographic response per RECIST 1.1 occurred in 1/3 pts at 30 mg (complete response), 1/4 at 100 mg (unconfirmed partial response [PR]), and 1/1 at 300 mg (PR confirmed after DCO). Conclusions: Preliminary data on REGN5678 plus cemiplimab in pts with mCRPC provide first evidence of clinical activity of a CD28 co-stimulatory bispecific antibody in solid tumors. Clinical activity was observed at DLs 30–300 mg. ≥G3 imAEs occurred in pts with PSA declines, suggesting a possible association. The study is ongoing to determine the maximum tolerated and recommended Phase 2 doses. Clinical trial information: NCT03972657 . [Table: see text]

A phase 1/2 study of REGN4336, a PSMAxCD3 bispecific antibody, alone and in combination with cemiplimab in patients with metastatic castration-resistant prostate cancer

TPS5105

Background: Prostate cancer is the leading cause of new cancer diagnoses and the second most common cause of cancer-related death in American men. Prognosis is especially poor for men with metastatic castration resistant prostate cancer (mCRPC). Prostate-specific membrane antigen (PSMA) is highly expressed on malignant prostate tissue but shows limited expression on normal tissue. As such, PSMA is an excellent research target for treatment of mCRPC. REGN4336 is a PSMAxCD3 bispecific antibody designed to facilitate T-cell–mediated killing of PSMA-expressing tumor cells. In preclinical models, REGN4336 demonstrated strong PSMA-dependent antitumor activity that was dose-dependent. Preclinical data also support clinical research into the combination of REGN4336 with cemiplimab (anti–programmed cell death-1) for treating mCRPC. Methods: This is an open-label, Phase 1/2, first-in-human, multicenter dose-escalation study with dose expansion evaluating safety, tolerability, pharmacokinetics (PK), and antitumor activity of REGN4336 administered subcutaneously alone and in combination with intravenous cemiplimab in patients with mCRPC (NCT05125016). Patients must have received at least two prior lines of systemic therapy approved for metastatic and/or castration-resistant disease including a second-generation anti-androgen therapy. In this study, REGN4336 as monotherapy is administered weekly but may be extended to once every 3 weeks following identification of the minimal pharmacologically active dose. REGN4336 in combination with cemiplimab (350 mg) will be administered once every 3 weeks after a 4-week REGN4336 monotherapy lead-in cycle. Study therapies are administered until disease progression, intolerable adverse events, withdrawal of consent, or study withdrawal criterion is met. The primary objectives in dose escalation are to evaluate the safety, tolerability, PK, and recommended phase 2 dosing regimen (RP2DR) of REGN4336 alone and in-combination with cemiplimab. Expansion cohort(s) will be enrolled once RP2DRs have been determined. During the expansion phase, the primary objective is to assess clinical activity, as measured by objective response rate with REGN4336 alone or in combination with cemiplimab per modified Prostate Cancer Working Group 3 criteria. At selected sites, PSMA positron emission tomography/computed tomography scans will be performed at predefined timepoints on study. This study is currently open to enrollment. Clinical trial information: NCT03088540.

816 Selective immune suppression using interleukin-6 blockade in immune related adverse events

Background

Managing immune-related adverse events (irAEs) has become a critical challenge with the increasing implementation of immune-checkpoint inhibitors (ICIs) in cancer treatment. IrAEs may cause treatment interruption or discontinuation, the rate of which is higher with multi-agent ICI regimen needed to overcome resistant tumor microenvironment. Herein, we describe our clinical experience using interleukin-6 receptor antagonists (IL-6RA) to manage irAEs in cancer patients receiving ICIs.

Methods

We conducted a retrospective, multi-center study to evaluate the safety and efficacy of IL-6RA for irAE management. Eligible patients were identified from the institutional databases (pharmacy records, tumor registries, oncology and specialty clinic records for diagnosis and management of irAEs). The primary objective was assessing changes in irAE symptoms. The secondary objective was assessing overall response rate (ORR) before and after IL-6RA treatment.

Results

A total of 81 patients received an IL-6RA (tocilizumab or sarilumab); median age was 66 years, 41% were females, 70% received single-agent anti-PD-1 and 23% received nivolumab plus ipilimumab. Cancer types were primarily melanoma (44%), genitourinary cancer (37%), and lung cancer (8.6%). Indications for using IL-6RA were inflammatory arthritis (74%), polymyalgia rheumatica (6%), myositis/myocarditis/myasthenia gravis (5%) encephalitis (5%), and 1% each with pneumonitis, colitis, hepatitis, central nervous system vasculitis, oral mucositis, and flare of pre-existing myasthenia gravis, psoriasis, and Crohn's disease. Notably, 83 % of patients received corticosteroids as first-line therapy, and 29% received disease-modifying antirheumatic drugs, without improvement. After initiation of IL-6RA, improvement of irAEs was observed in 78% after a median of 2.1 months. Of evaluable patients with inflammatory arthritis, the median clinical disease activity index (CDAI) at IL-6RA initiation was 28, indicating high disease activity, and dropped to 6 after treatment, indicating low disease activity. The median CRP level at IL-6RA initiation was 59.5 mg/L and dropped to 1.5 mg/L within 10 weeks of treatment. Seventy-two patients tolerated IL-6RA, and nine stopped treatment due to side effects. Thirty-eight patients were evaluated for tumor response by RECIST 1.1 criteria; the ORR was 58% prior to IL-6RA and 66% after treatment. Of 21 evaluable melanoma patients, the ORR was 62% prior to IL-6RA compared to 71% after treatment (figure 1).

Conclusions

Our study demonstrated that targeting IL-6R could be an effective approach to mitigate autoimmunity while maintaining and possibly boosting tumor immunity. Clinical trials are currently evaluating the safety and efficacy of tocilizumab in combination with ICIs in patients with melanoma, non-small cell lung cancer, and urothelial carcinoma (NCT04940299, NCT03999749).

Ethics Approval

The study was approved by The University of Texas MD Anderson Cancer Center intuition's Ethics Board, approval number PA19-0089

Abstract 816 Figure 1

A patient with sinonasal malignant melanoma involving the ethmoid air cells. (A) Baseline maximum intensity projection (MIP) PET image at 1 month before initiation of ICI (ipilimumab and nivolumab) shows avid FDG uptake of the tumor at the ethmoid air cells (arrow). (B) MIP PET image at 7 months after ICI initiation shows resolution of the FDG uptake at the site of the tumor, consistent with complete response. (C) Concurrent MIP PET and corresponding fused PET-CT images 7 months after initiation of ICI show avid radiotracer uptake at the knee joints, suggestive of arthritis. (D) MIP PET image at 10 months after concomitant therapy with IL6R antagonist and nivolumab shows persistent absence of hypermetabolic radiotracer activity at the paranasal sinuses, consistent with complete response. (E) Concurrent MIP PET and corresponding fused PET-CT images show physiologic radiotracer uptake at the knee joints, consistent with resolving arthritis.

Risk of Toxicity After Initiating Immune Checkpoint Inhibitor Treatment in Patients With Rheumatoid Arthritis

INTRODUCTION

Immune checkpoint inhibitors (ICIs) are increasingly used to treat advanced cancer. Rheumatoid arthritis (RA) is associated with an increased risk of malignancies; however, patients with RA have been excluded from ICI trials. In this study, we evaluated risk of toxicity after initiation of ICI treatment in RA patients.

METHODS

We conducted a single-institution, medical records review analysis to assess the incidence of immune-related adverse events (irAEs) and autoimmune disease (AID) flares among patients with AIDs treated with ICIs from 2011 to 2018. A subgroup analysis for RA patients was performed with frequencies of irAEs and AID flares reported.

RESULTS

Twenty-two patients with RA who were treated with ICI for malignancy were identified. At the time of ICI initiation, 86% had inactive RA disease activity. Immune-related adverse events occurred in 7 (32%) of patients, with 2 (9%) developing grade 3 (i.e., severe) irAEs. Immune checkpoint inhibitors were temporarily discontinued because of irAEs in 5 patients (23%), and permanently in 1 patient. Rheumatoid arthritis flares occurred in 12 patients (55%). Of those, 10 (83%) received oral corticosteroids with an adequate treatment response.

CONCLUSIONS

Our analysis suggests that irAEs following ICI treatment are not increased among RA patients compared with other cancer patients. Heightened RA disease activity during ICI treatment is common, but most adverse events are manageable with oral corticosteroids, and few require permanent ICI discontinuation. A close collaboration between the oncologist and rheumatologist is advisable when considering ICIs in patients with RA.

Role of IVIG in the Treatment of Autoimmune Conditions With Concurrent Immune Checkpoint Inhibitors for Metastatic Cancer

Immune checkpoint inhibitors (ICIs) are a class of medications targeting mostly the PD-1/PD-L1 and CTLA-4 immune pathways in the treatment of many cancers. Despite the encouraging success of ICIs, they are associated with immune-related adverse events as well as exacerbation of underlying autoimmune conditions. The treatment of these conditions often involves discontinuation of ICI in addition to the utilization of immunomodulatory agents. In this report, we discuss a case in which a patient with metastatic renal cell carcinoma experienced exacerbation of underlying paraneoplastic dermatomyositis after treatment with ICI. He was successfully continued on ICI with the use of intravenous immunoglobulin. The patient experienced adequate control of his myositis but also experienced deepening of his antitumor response.

SHP2 Targets ITK Downstream of PD-1 to Inhibit T Cell Function

PD-1 is a critical therapeutic target in cancer immunotherapy and antibodies blocking PD-1 are approved for multiple types of malignancies. The phosphatase SHP2 is the main effector mediating PD-1 downstream signaling and accordingly attempts have been made to target this enzyme as an alternative approach to treat immunogenic tumors. Unfortunately, small molecule inhibitors of SHP2 do not work as expected, suggesting that the role of SHP2 in T cells is more complex than initially hypothesized. To better understand the perplexing role of SHP2 in T cells, we performed interactome mapping of SAP, an adapter protein that is associated with SHP2 downstream signaling. Using genetic and pharmacological approaches, we discovered that SHP2 dephosphorylates ITK specifically downstream of PD-1 and that this event was associated with PD-1 inhibitory cellular functions. This study suggests that ITK is a unique target in this pathway, and since ITK is a SHP2-dependent specific mediator of PD-1 signaling, the combination of ITK inhibitors with PD-1 blockade may improve upon PD-1 monotherapy in the treatment of cancer.

Breast Conservation in Women with Autoimmune Disease: The Role of Active Autoimmune Disease and Hypofractionation on Acute and Late Toxicity in a Case-Controlled Series

PURPOSE

Autoimmune connective tissue disease (CTD) has historically represented a relative contraindication to breast conservation (BC) among patients with early-stage breast cancer. Controversy exists regarding the use of hypofractionated radiation therapy (RT) among patients with CTDs. We evaluated acute and late toxicity in patients with breast cancer and CTD treated with BC.

METHODS AND MATERIALS

Of 1983 patients treated with BC from 2012 to 2016, we identified 91 patients with an autoimmune disease (AD). Each patient was matched to a control without AD based on age, RT field, and fractionation. RT toxicity and clinician-rated cosmesis were compared between cases and controls. Overall survival, disease-free survival, and local recurrence-free survival were estimated using the Kaplan-Meier method.

RESULTS

The median follow-up was 49.9 months for cases and 53.0 months for controls, and 67% of cases and controls were treated with hypofractionated RT. There was no difference in grade 2/3 acute toxicity between cases and controls (26.4% vs. 16.5%, respectively; P = .148). There was a significantly higher rate of grade 2/3 late toxicity among cases (25.8% vs 12.1% among controls; P = .049). Active AD at the time of RT increased the rate of grade 2/3 late toxicity compared with controls (41.7% in cases vs. 11.4% in controls; P = .018). Among patients treated with hypofractionated RT, there was no difference in acute or late grade 2/3 toxicity between cases and controls (acute: 13.1% in cases vs. 11.5% in controls [P > 0.9]; late: 11.9% in cases vs. 13.1% in controls [P > 0.9]). The rates of good/excellent clinician-rated cosmesis were similar between groups (92.9% in cases vs. 98.9% in controls; P = .142).

CONCLUSIONS

In the largest matched case-control study of patients with CTD treated with conventional and hypofractionated RT, we demonstrate low rates of radiation toxicity, with good to excellent clinician-rated cosmesis. There was increased late toxicity in cases, especially in patients with active AD at time of RT. There was no increase in acute or late toxicity in the patients treated with hypofractionation.

Immunotherapy to treat malignancy in patients with pre-existing autoimmunity

In the past 10 years, immune checkpoint inhibitors (ICIs) have become an additional pillar of cancer therapy by activating the immune system to treat a number of different malignancies. Many patients receiving ICIs develop immune-related adverse events (irAEs) that mimic some features of classical autoimmune diseases. Unfortunately, patients with underlying autoimmune conditions, many of whom have an increased risk for malignancy, have been excluded from clinical trials of ICIs due to a concern that they will have an increased risk of irAEs. Retrospective data from patients with autoimmune diseases and concomitant malignancy treated with ICIs are encouraging and suggest that ICIs may be tolerated safely in patients with specific autoimmune diseases, but there are no prospective data to guide management. In this manuscript, we review the relationship between pre-existing autoimmune disease and irAEs from checkpoint inhibitors. In addition, we assess the likelihood of autoimmune disease exacerbations in patients with pre-existing autoimmunity receiving ICI.

Toxicities of single agent and combination immune checkpoint inhibitors in patients with autoimmune diseases

e14176

Background: Autoimmunity is associated with increased risk of malignancy. However, patients with pre-existing autoimmune diseases (AIDs) have been excluded from trials of immune checkpoint inhibitors (ICIs) known to cause immune activation and lead to immune related adverse events (irAEs). Data is limited on the safety and efficacy of these agents when used in AID patients and physicians are therefore wary to use them in this at-risk population. Methods: We conducted a single institution retrospective study to evaluate the safety and efficacy of ICI therapy in patients with pre-existing AIDs from 2011 to 2018. Primary endpoints were irAEs and AID flares. The secondary endpoint was overall survival (OS). Results: Of 84 total patients, 70 (83%) received ICI monotherapy and 14 (17%) received combination therapy. AIDs included: rheumatic 40 (48%), dermatologic 25 (30%), endocrine 16 (19%) and gastrointestinal 14 (17%) diseases of which 18 (21%) were on immune suppression. Combination therapy was associated with higher rates of severe grade 3-4 irAEs in 5/14 (36%) patients versus 8/70 (11%) with monotherapy (p = 0.022). ICIs were discontinued due to irAEs in 10/84 (12%) of all patients; 4/14 (29%) in the combination group and 6/70 (9%) in the monotherapy group (p = 0.057). While 32 patients (38%) had at least one AID flare, ICI was only permanently discontinued in 2 patients. Flare rates were higher for combination use: 8/14 (57%) compared to 23/70 (33%) for monotherapy (p = 0.086). Combination therapy was associated with higher median OS 27.8 months [95% CI 11.4-44.3] compared to monotherapy 12.3 months [95% CI 9.7-14.8] (p = 0.0007). OS had a positive correlation with flare (p = 0.007) and severe irAEs (p = 0.037). Conclusions: Our data suggest that rates of irAEs in patients with pre-existing AIDs are similar to those reported in the literature with single agent ICIs. While risk of severe irAEs and flares is increased with combination therapy, they are associated with overall survival. In our cohort, irAEs and flares were manageable and in most patients did not require permanent discontinuation for monotherapy or combination therapy suggesting that ICIs should be offered to this population, albeit with caution.

Immune-Related Adverse Events in Cancer Patients Treated With Immune Checkpoint Inhibitors

PURPOSE OF REVIEW

With the advent of cancer immunotherapy and immune checkpoint inhibitors, patients with malignancies can now achieve durable remissions for conditions previously described as terminal. However, immune-related adverse events (irAEs) associated with cancer immunotherapy have become an anticipated consequence of enhanced T cell activation. Through an extensive literature review, we assess the most recent clinical and basic research data concerning immune checkpoint blockade and describe the spectrum of associated irAEs as well as their management.

RECENT FINDINGS

Anti-PD-1, anti-PD-L1, and anti-CTLA-4 antibodies are widely used in the management of an array of tumors with incredible clinical remissions. However, irAEs cause significant morbidity and mortality and in some cases, result in withdrawal of cancer therapy and initiation of immunosuppression. While this is an exciting time in oncology, irAEs are a barrier to adequate care and therefore deserve close attention and improved capacity to predict and prevent toxicity. Rheumatologists should be familiar with these topics in the eventuality of patient evaluation and management.

Targeting the programmed cell death-1 pathway in rheumatoid arthritis

Since the introduction of TNF-α inhibitors and other biologic agents, the clinical outcome for many treated rheumatoid arthritis patients has significantly improved. However, there are still a substantial proportion of patients that are intolerant, or have inadequate responses, with current agents that have become the standards of care. While the majority of these agents are designed to affect the inflammatory features of the disease, there are also agents in the clinic that instead target lymphocyte subsets (e.g., rituximab) or interfere with lymphocyte co-receptor signaling pathways (e.g., abatacept). Due in part to their ability to orchestrate downstream inflammatory responses that lead to joint damage and disease progression, pathogenic expansions of T and B lymphocytes are appreciated to play key roles in the pathogenesis of rheumatoid arthritis. New insights into immune regulation have suggested novel approaches for the pharmacotherapeutic targeting of lymphocytes. In this review, we discuss deepening insights into human genetics and our understanding of the interface with rheumatoid arthritis pathogenesis providing a strong rationale for exploiting the co-inhibitory receptor programmed cell death-1 signaling pathway as a better approach for the treatment of this chronic, often progressive destructive joint disease.

The Potential Role of Inhibitory Receptors in the Treatment of Psoriasis

Psoriasis is a common autoimmune disorder that affects the skin. Approximately 30% of individuals with psoriasis will develop inflammatory arthritis, often in the setting of human leukocyte antigen B27. Both forms of disease are thought to be the result of prolonged inflammation mediated by T lymphocytes, dendritic cells, and keratinocytes. While there are treatments aimed at immunomodulation, targeting T cell co-inhibitory receptors signaling pathways may provide therapeutic benefit. This review will discuss in detail four T cell co-inhibitory receptors and their potential application for the treatment of psoriasis and psoriatic arthritis.

Borrelia burgdorferi genotype predicts the capacity for hematogenous dissemination during early Lyme disease

BACKGROUND

Lyme disease, the most common tickborne disease in the United States, is caused exclusively by Borrelia burgdorferi sensu stricto in North America. The present study evaluated the genotypes of >400 clinical isolates of B. burgdorferi recovered from patients from suburban New York City with early Lyme disease associated with erythema migrans; it is the largest number of borrelial strains from North America ever to be investigated.

METHODS

Genotyping was performed by restriction fragment-length polymorphism polymerase chain reaction analysis of the 16S-23S ribosomal RNA spacer and reverse line blot analysis of the outer surface protein C gene (ospC). For some isolates, DNA sequence analysis was also performed.

RESULTS

The findings showed that the 16S-23S ribosomal spacer and ospC are in strong linkage disequilibrium. Most B. burgdorferi genotypes characterized by either typing method were capable of infecting and disseminating in patients. However, a distinct subset of just 4 of the 16 ospC genotypes identified were responsible for >80% of cases of early disseminated Lyme disease.

CONCLUSIONS

This study identified the B. burgdorferi genotypes that pose the greatest risk of causing hematogenous dissemination in humans. This information should be considered in the future development of diagnostic assays and vaccine preparations.

The propensity of different Borrelia burgdorferi sensu stricto genotypes to cause disseminated infections in humans

Lineages of Borrelia burgdorferi, the bacterium that causes Lyme disease, can be characterized by distinct alleles at the outer surface protein C (ospC) locus. The lineages marked by ospC genotypes have been shown to be differentially invasive in different species of mammals, including humans; genotypes A, B, I, and K effectively disseminate to human blood and cerebrospinal fluid. In this report, we extend the sample of genotypes isolated from human blood to include genotypes N, H, C, M, and D, and rank each by their probability of disseminating from ticks to the blood of humans. Our results demonstrate that only some genotypes of B. burgdorferi present in ticks have a high propensity to disseminate in humans.

Multiple uracil-DNA glycosylase activities in Deinococcus radiodurans

The extremely radiation resistant bacterium, Deinococcus radiodurans, contains a spectrum of genes that encode for multiple activities that repair DNA damage. We have cloned and expressed the product of three predicted uracil-DNA glycosylases to determine their biochemical function. DR0689 is a homologue of the Escherichia coli uracil-DNA glycosylase, the product of the ung gene; this activity is able to remove uracil from a U : G and U : A base pair in double-stranded DNA and uracil from single-stranded DNA and is inhibited by the Ugi peptide. DR1751 is a member of the class 4 family of uracil-DNA glycosylases such as those found in the thermophiles Thermotoga maritima and Archaeoglobus fulgidus. DR1751 is also able to remove uracil from a U : G and U : A base pair; however, it is considerably more active on single-stranded DNA. Unlike its thermophilic relatives, the enzyme is not heat stable. Another putative enzyme, DR0022, did not demonstrate any appreciable uracil-DNA glycosylase activity. DR0689 appears to be the major activity in the organism based on inhibition studies with D. radiodurans crude cell extracts utilizing the Ugi peptide. The implications for D. radiodurans having multiple uracil-DNA glycosylase activities and other possible roles for these enzymes are discussed.