Immune Checkpoint Inhibitor-Induced Myositis/Myasthenia Gravis Overlap.

Immune checkpoint inhibitors (ICIs) have considerably changed the management of several malignancies. Although these agents transformed the scope of management in oncology and proved long-term efficacy, they have been associated with numerous autoimmune-related adverse events. We presented a case of a 61-year-old male with a history of non-small cell lung cancer (NSCLC) who presented with respiratory failure requiring mechanical ventilation. He was discharged with a working diagnosis of myasthenia gravis crisis secondary to the use of pembrolizumab. On further evaluation, he was found to possibly have pembrolizumab-induced myositis. He was treated with plasmapheresis, methylprednisolone, and rituximab and achieved significant improvement. Pembrolizumab, a monoclonal antibody, is an ICI that targets programmed death protein 1 (PD-1), thereby blocking the interaction between PD-1 and PDL-1, leading to an enhancement of T-cell mediated immune response against tumor cells. Pembrolizumab has been used to treat a variety of malignancies including melanoma, NSCLC, and other solid tumors. Though ICIs have revolutionized the field of oncology, they should be used with caution. ICIs can cause immune-related adverse events (irAEs), including myasthenia gravis and myositis. Diagnosing irAEs is challenging due to their nonspecific presentations and lack of antibody markers. Therefore, patients and clinicians should be aware of irAEs in order to initiate timely intervention.

Safety of immune checkpoint inhibitors in patients with preexisting autoimmune disorders.

In recent years, immune checkpoint inhibitors (ICIs) have been approved for a growing number of cancer types. Approximately a quarter of cancer patients have a concomitant diagnosis of autoimmune disorders (AID). Activation of the immune system with ICIs poses a potential risk of AID worsening, thus, the majority of the ICI clinical trials excluded these patients from the study. There is a paucity of data regarding the benefits and risks of ICIs in cancer patients with AIDs. The primary objectives of this study were to determine the incidence of immunotherapy-related AID worsening and all immunotherapy-related adverse events (irAEs). Secondary outcomes were time to AID worsening and survival difference. All adult patients (age >=18 years) with solid malignancy who received ICIs between Jan 2016 and June 2019 were identified using the University of Louisville pharmacy database. Medical records were reviewed to include all the patients with preexisting AIDs. Descriptive statistics were used to determine the incidence of AID worsening and all irAEs. Baseline characteristics were compared between cancer patients with vs without AID worsening using Pearson chi2 and Student's t-test, where appropriate. Multivariate Cox regression analysis was used to compare survival between the 2 groups. A total of 40 patients with AIDs were identified during the study period. The cancer types were melanoma (57.5%), lung (15%), breast (5%), and others (22.5%). AIDs were rheumatological (52.5%), dermatologic (20%), gastroenterological (12.5%), neurologic (12.5%), and hematological (2.5%). The incidence of all irAEs was 60% (grade >=3 in 20%) and AID worsening was 40% (grade >=3 in 15%). The median time from ICI initiation to AID worsening was 94.5 (range 21-431) days. In multivariate Cox regression analysis, adjusted for demographics, cancer type, and stage, survival was similar for patients who had AID worsening vs those who did not (HR 0.30 (95%CI 0.06-1.40, P = 0.128). In our single-institution study, cancer patients with preexisting AID do have an increased risk of irAEs with high-grade toxicities in 20% compared to historically reported 5% in the general cancer population. About 15% of patients reported grade >=3 worsening of their AIDs. Although the risk of irAEs is numerically higher in patients with AIDs, it may be acceptable to the patients if the potential benefits of ICIs outweigh the risks.

Potential clinical and immunotherapeutic utility of talimogene laherparepvec for patients with melanoma after disease progression on immune checkpoint inhibitors and BRAF inhibitors.

Talimogene laherparepvec is a genetically modified herpes simplex virus type 1-based oncolytic immunotherapy for the local treatment of unresectable subcutaneous and nodal tumors in patients with melanoma recurrent after initial surgery. We report on two patients with melanoma who, after progression on numerous systemic therapies, derived clinical benefit from talimogene laherparepvec in an expanded-access protocol (ClinicalTrials.gov, NCT02147951). Intralesional talimogene laherparepvec (day 1, ≤4 ml 10 PFU/ml; after 3 weeks, ≤4 ml 10 PFU/ml every 2 weeks) was administered until complete response, no injectable tumors, progressive disease, or intolerance occurred. Patient 1 was 71 years old, had stage IIIB disease, and had previously received granulocyte-macrophage colony-stimulating factor, vemurafenib, metformin, ipilimumab, dabrafenib, trametinib, and pembrolizumab. Patient 2 was 45 years old, had stage IIIC disease, and had previously received nivolumab/ipilimumab combination therapy. There were marked reductions in the number and size of melanoma lesions during treatment with talimogene laherparepvec. Both patients experienced mild-to-moderate nausea and vomiting, which were managed using ondansetron, metoclopramide, and pantoprazole. Both patients completed treatment with talimogene laherparepvec in the expanded-access protocol on 24 November 2015, but received talimogene laherparepvec in clinical practice. Patient 1 continues to receive therapy (>60 weeks); patient 2 experienced a complete response at 23 weeks. Immunohistochemistry of a biopsied dermal metastasis from patient 1 showed a marked infiltration of CD4 and CD8 T cells after 1 year of treatment. Talimogene laherparepvec was active in patients with advanced melanoma with disease progression following multiple previous systemic therapies; no new safety signals were identified.

Understanding and Managing Immune-Related Adverse Events Associated With Immune Checkpoint Inhibitors in Patients With Advanced Melanoma.

The immune checkpoint inhibitors ipilimumab, nivolumab, and pembrolizumab represent a substantial improvement in treating advanced melanoma but are associated with adverse events (AEs) likely related to general immunologic enhancement. To ensure that patients receive optimal benefit from these agents, prompt assessment and treatment of AEs are essential. We review the efficacy and safety profiles of these immune checkpoint inhibitors and describe guidelines for managing immune-related AEs. We also present case studies describing the management of toxicities in patients receiving immune checkpoint inhibitor therapy. These cases illustrate the importance of collecting a detailed medical history when administering immunotherapy, as this information is necessary to establish baseline, inform monitoring, and determine the etiology of symptoms. Advanced practice nurses and physician assistants are uniquely positioned to educate patients on the early recognition of AEs and have an important role in establishing appropriate monitoring and open dialogue among services.

TGF-beta1 enhances cardiomyogenic differentiation of skeletal muscle-derived adult primitive cells.

The optimal medium for cardiac differentiation of adult primitive cells remains to be established. We quantitatively compared the efficacy of IGF-1, dynorphin B, insulin, oxytocin, bFGF, and TGF-beta1 in inducing cardiomyogenic differentiation. Adult mouse skeletal muscle-derived Sca1+/CD45-/c-kit-/Thy-1+ (SM+) and Sca1-/CD45-/c-kit-/Thy-1+ (SM-) cells were cultured in basic medium (BM; DMEM, FBS, IGF-1, dynorphin B) alone and BM supplemented with insulin, oxytocin, bFGF, or TGF-beta1. Cardiac differentiation was evaluated by the expression of cardiac-specific markers at the mRNA (qRT-PCR) and protein (immunocytochemistry) levels. BM+TGF-beta1 upregulated mRNA expression of Nkx2.5 and GATA-4 after 4 days and Myl2 after 9 days. After 30 days, BM+TGF-beta1 induced the greatest extent of cardiac differentiation (by morphology and expression of cardiac markers) in SM- cells. We conclude that TGF-beta1 enhances cardiomyogenic differentiation in skeletal muscle-derived adult primitive cells. This strategy may be utilized to induce cardiac differentiation as well as to examine the cardiomyogenic potential of adult tissue-derived stem/progenitor cells.

Noncanonical Wnt11 signaling is sufficient to induce cardiomyogenic differentiation in unfractionated bone marrow mononuclear cells.

BACKGROUND: Despite the frequent clinical use of adult unfractionated bone marrow mononuclear cells (BMMNCs) for cardiac repair, whether these cells are capable of undergoing cardiomyogenic differentiation in vitro remains uncertain. In addition, the role of Wnt signaling in cardiomyogenic differentiation of adult cells is unclear. METHODS AND RESULTS: Unfractionated BMMNCs were isolated from adult mice via Ficoll-Paque density-gradient centrifugation and cultured in the presence of Wnt3a or Wnt11. In control BMMNCs, Wnt11 was not expressed, whereas the expression of markers of pluripotency (Oct-4 and Nanog), as well as that of Wnt3a and beta-catenin, decreased progressively during culture. Exposure to Wnt3a rescued beta-catenin expression and markedly increased the expression of Oct-4 and Nanog, concomitant with increased cell proliferation and CD45 expression. In contrast, exposure to ectopically expressed noncanonical Wnt11 markedly decreased the expression of Oct-4 and Nanog and induced mRNA expression (quantitative real-time reverse-transcription polymerase chain reaction) of cardiac-specific genes (Nkx2.5, GATA-4, atrial natriuretic peptide, alpha- and beta-myosin heavy chain, and cardiac troponin T) by day 3 with subsequent progression to a pattern characteristic of the cardiac fetal gene program. After 21 days, 27.6+/-0.6% and 29.6+/-1.4% of BMMNCs expressed the cardiac-specific antigens cardiac myosin heavy chain and cardiac troponin T, respectively (immunocytochemistry), indicating cardiomyogenic lineage commitment. Wnt11-induced cardiac-specific expression was completely abolished by the protein kinase C inhibitor bisindolylmaleimide I, partially abolished by the c-Jun-N-terminal kinase inhibitor SP600125, and attenuated by the Wnt inhibitor Dickkopf-1. CONCLUSIONS: In adult density-gradient separated BMMNCs, canonical Wnt3a promotes stemness, proliferation, and hematopoietic commitment, whereas noncanonical signaling via Wnt11 induces robust cardiomyogenic differentiation in a protein kinase C- and c-Jun-N-terminal kinase-dependent manner.

Sca-1 expression is associated with decreased cardiomyogenic differentiation potential of skeletal muscle-derived adult primitive cells.

Adult stem cells from skeletal muscle (SM) have been shown to differentiate into multiple lineages. The impact of stem cell antigen-1 (Sca-1) expression on cardiomyogenic differentiation potential of SM-derived primitive cells remains unknown. Cardiomyogenic differentiation was induced in freshly isolated or culture-expanded Sca-1+/CD45-/c-kit-/Thy-1+ (SM+) and Sca1-/CD45-/c-kit-/Thy-1+ (SM-) cells isolated from SM of C57BL/6 mice. Expression of mRNA of cardiac-specific antigens and those associated with pluripotency was examined by real-time RT-PCR. Phenotypic analysis of expanded cells was performed during each passage by flow cytometry. Cardiomyocytic differentiation in vitro was verified by morphologic analysis, immunocytochemistry, and contractile properties. In freshly isolated cells, compared with unfractionated SM-derived cells as well as SM+ cells, mRNA expression of cardiac-specific antigens and those associated with cellular pluripotency was greater in SM- cells. Compared with SM- cells, SM+ cells exhibited greater expansion capacity. Freshly isolated SM- cells exhibited greater cardiac differentiation potential compared with freshly isolated SM+ cells (21.8+/-0.3% of SM- cells positive for cardiac markers vs. 9.1+/-0.7% of SM+ cells, P=0.00009). Differentiated SM- cells acquired a cardiomyocytic phenotype and exhibited spontaneous rhythmic contractions in vitro. The number of Sca-1+ cells in the SM- population increased markedly with time (0.9+/-0.1% in freshly isolated cells vs. 11.9+/-0.9% after the first passage vs. 99.0+/-0.6% after the second passage). This increase in Sca-1 expression was associated with a marked decline in the expression of cardiac markers following differentiation induction in culture-expanded SM- cells (21.8+/-0.3% in unexpanded cells vs. 16.6+/-1.3% after the first passage vs. 6.0+/-0.5% after the second passage, P=0.00001 vs. unexpanded cells). In contrast, the SM+ cells did not exhibit any consistent pattern in either phenotypic or differentiation capability with expansion. We conclude that SM- cells are inherently predisposed to undergo cardiac differentiation and are enriched in markers of pluripotency. While both Sca-1+ and Sca-1- primitive cells from SM can undergo cardiac differentiation, Sca-1- cells exhibit greater cardiomyogenic potential, and the appearance of Sca-1 during expansion is associated with a decline in cardiac differentiation plasticity.