SUMMARY Hand1 regulates development of numerous tissues within the embryo, extraembryonic mesoderm and trophectoderm. Systemic loss of Hand1 results in early embryonic lethality but the cause has remained unknown. To determine if Hand1 expression in extraembryonic mesoderm is essential for embryonic survival, Hand1 was conditionally deleted using the HoxB6-Cre mouse line that expresses Cre in extraembryonic and lateral mesoderm. Deletion of Hand1 using HoxB6-Cre resulted in embryonic lethality identical to systemic knockout. To determine if lethality is due to Hand1 function in extraembryonic mesoderm or lateral mesoderm, we generated a Tlx2-Cre mouse line expressing Cre in lateral mesoderm but not extraembryonic tissues. Deletion of Hand1 using the Tlx2-Cre line results in embryonic survival with embryos exhibiting herniated gut and thin enteric smooth muscle. Our results show that Hand1 regulates development of lateral mesoderm derivatives and its loss in extraembryonic mesoderm is the primary cause of lethality in Hand1-null embryos.

The most cost-effective administration frequency of pembrolizumab in advanced nonesmall-cell lung cancer is unknown. We found that a significant proportion of these patients receive pembrolizumab-based regimens with extended intervals or delays in routine practice, with similar outcomes to those on label-specified 3-week interval treatments. Prospective evaluation of alternative dosing strategies is warranted to develop a more fiscally viable and patient-centered model. Background: Besides modeling/simulation-based analysis, no post-approval studies have evaluated the optimal administration frequency of pembrolizumab in nonesmall-cell lung cancer (NSCLC). Patients and Methods: We performed a multicenter retrospective cohort study to evaluate the association between survival outcomes and treatment extensions/delays of pembrolizumab-based regimens in patients with advanced NSCLC. Those who had received at least 4 cycles in routine practice were divided into 2 groups: nonstandard (Non-Std, 2 cycles at intervals > 3 weeks þ 3 days) and standard (Std, all cycles every 3 weeks or 1 cycle > 3 weeks þ 3 days). Results: Among 150 patients, 92 (61%) were eligible for the study 27; Std, 65). The reasons for patients with extensions/delays in the Non-Std group included: immunerelated adverse events (irAEs) (33%), noneirAE-related medical issues (26%), and patient-physician preference (41%). The Non-Std group was more likely to have a higher programmed death-ligand 1 tumor proportion score, a higher number of treatment cycles, and pembrolizumab monotherapy. Univariate and 6-month landmark analyses showed longer median overall survival and progression-free survival in the Non-Std group compared with the Std group. After multivariable adjustment for confounding factors, there was no significant difference in overall survival (hazard ratio, 1.2; 95% confidence interval, 0.3-4.8; P ¼ .824) or progression-free survival (hazard ratio, 2.6; 95% confidence interval, 0.7-9.6; P ¼ .157) between the 2 groups. Conclusion: Our study shows that a significant proportion of patients with advanced NSCLC receive pembrolizumab-based regimens with extended intervals or delays in routine clinical practice and with similar outcomes to those receiving treatment at label-specified 3-week intervals. Given the durability of benefit seen and the potential for cost reduction and decreased infusion frequency in these patients, this requires validation in prospective trials.

Sonic hedgehog (Shh) plays critical roles during nervous system development, yet little is known about its function in the sympathetic nervous system. Using a mouse Shh null line, we examined the roles of Shh during SNS development. Loss of Shh did not prevent formation of the sympathetic trunk, but the ganglia are hypoplastic and misspatterned. Neuronal differentiation was delayed in Shh mutant embryos showing that Shh is required for correct developmental timing in addition to its role in sympathetic nervous system patterning. Immunohistochemical analyses of the ganglia for expression of the pan-neuronal marker beta3-tubulin, the noradrenergic biosynthetic enzyme tyrosine hydroxylase and the glial marker B-FABP showed that Shh is not required for differentiation of sympathetic neurons or glia.

BackgroundThyroid dysfunction is a well known side effect of immune checkpoint blockade (ICB) and is one of the most common causes of immune-related adverse events (IRAE). The incidence varies with each individual therapy but generally estimated to be in the range between 6–18% per one study. Hypothyroidism and thyroiditis are the most common manifestations. Initial hyperthyroidism followed by hypothyroidism is another manifestation. Hypothyroidism is more common with an incidence of 10% whereas hyperthyroidism has an incidence of 5%. Less is known about the incidence of worsening thyroid dysfunction in patients with pre-existing thyroid dysfunction treated with ICB.MethodsA retrospective analysis was collected on 370 patients who received immunotherapy from April 2015 to April 2019. Of those, 212 had abnormal thyroid function tests. We analyzed a subgroup of these patients who had baseline thyroid dysfunction for worsening thyroid dysfunction after they were given ICB. Fifty-three patients were included in the analysis and had an abnormal baseline TSH at the start of immunotherapy. Type of immunotherapy, worst TSH, duration between initiation of immunotherapy to worst TSH, treatment type, and grade of abnormality as per Immune Checkpoint Inhibitor Related Adverse Events Common Terminology Criteria for Adverse Events (IRAE-CTCAE) were also recorded. Analysis was done for patients to compare likelihood of worsening TSH resulting in change in treatment for thyroid disorder.ResultsOf the identified patients (N=53) with abnormal TSH screening values outside of the institution’s normal reference range 0.35 - 4.95 uIU/ml, 45.7% (N=16) were hypothyroid and 54.3% (N=19) were hyperthyroid at baseline. Of those who were hypothyroid, 50% (N=8) had worsening TSH and 50% (N=8) had unchanged TSH during treatment. Of those who were hyperthyroid, 31.6% (N=6) had unchanged TSH, 52.6% (N=10) had worsened TSH, and 15.8% (N=3) had normalization of TSH compared to baseline. Overall 26.4% had worsening and of those 11.3% required treatment change.ConclusionsThyroid dysfunction is one of the most common IRAE’s associated with immune checkpoint inhibitors. Little is known about the impact of immunotherapy on patients with existing thyroid dysfunction. Patients who have underlying thyroid dysfunction are at an increased risk for worsening thyroid dysfunction with the use of ICB but though not unduly above the risk general population. Of those with change, only a modest percentage required an alteration of their endocrine therapy. Of interest, our data suggests a potential increased risk in patients with baseline hyperthyroidism compared to hypothyroidism which may be clinically relevant.Ethics ApprovalThe study was approved by ECU Brody School of Medicine Institution’s Ethics Board, approval number 19-000710.ReferencesBarroso-Sousa R, Barry WT, Garrido-Castro AC, et al. Incidence of Endocrine Dysfunction Following the Use of Different Immune Checkpoint Inhibitor Regimens: A Systematic Review and Meta-analysis. JAMA oncology. 2018;4:173–182.Fessas P, Possamai LA, Clark J, et al. Immunotoxicity from checkpoint inhibitor therapy: clinical features and underlying mechanisms. Immunology. 2019; 2020;159:167–177.Brody HM, Macherla S, Bulumulle A, Namireddy P, Cherry CR. The real-world incidence of immunotherapy-related thyroid dysfunction: A retrospective analysis of a single center’s experience over five years. Journal of clinical oncology. 2020;38:98–98.Iyer PC, Cabanillas ME, Waguespack SG, et al. Immune-Related Thyroiditis with Immune Checkpoint Inhibitors. Thyroid (New York, N.Y.). 2018;28:1243–1251.Presotto EM, Rastrelli G, Desideri I, et al. Endocrine toxicity in cancer patients treated with nivolumab or pembrolizumab: results of a large multicentre study. Journal of endocrinological investigation. 2019; 2020;43:337–345.Chalan P, Di Dalmazi G, Pani F, De Remigis A, Corsello A, Caturegli P. Thyroid dysfunctions secondary to cancer immunotherapy. Journal of endocrinological investigation. 2017; 2018;41:625–638.Mangla A, Paydary K, Yadav U, Liu J, Lad TE. Predictors and outcomes of thyroid dysfunction with immunotherapy: A single institution observational experience. Journal of clinical oncology. 2019;37:e14134-e14134.Basak EA, van der Meer, Jan W M, Hurkmans DP, et al. Overt Thyroid Dysfunction and Anti-Thyroid Antibodies Predict Response to Anti-PD-1 Immunotherapy in Cancer Patients. Thyroid (New York, N.Y.). 2020;30:966–973.Kassi E, Angelousi A, Asonitis N, et al. Endocrine-related adverse events associated with immune-checkpoint inhibitors in patients with melanoma. Cancer medicine (Malden, MA). 2019;8:6585–6594.