Devayani Machiraju

The success of anti-CTLA4 or anti-PD1 immune checkpoint inhibitors varies widely in melanoma, with the individual modes of action in tumors and treatment-specific biomarkers still being explored. We analyzed pre- and on-treatment tumor samples from melanoma patients treated with anti-CTLA4 or anti-PD1 to characterize immune cell infiltration and molecular pathways in the tumor microenvironment and correlate these findings with treatment response and survival. We observed a prominent role for immune cell infiltration in the tumor microenvironment (TME) for clinical benefit from anti-PD1 therapy, in contrast to anti-CTLA4 therapy. A higher degree of infiltration with CD3+ T cells (p = 0.046), PD1+ (p = 0.002), and INOS+ (p = 0.042) cells was significantly associated with disease control on anti-PD1 treatment. Whereas, a higher degree of infiltration with CD138+ B cells was significantly associated with longer progression-free survival (p = 0.048, HR: 0.301 (95% CI: 0.092–0.989)). The association between immune cell infiltration, TCR richness in tumor samples, and treatment outcomes was even more striking in on-treatment biopsies from patients receiving anti-PD1 treatment. An enrichment of the immunoglobulin signature in on-treatment tumor samples was observed in responding patients. The study highlights the importance of pre-existing immune infiltration in the TME, particularly B cell infiltration, for anti-PD1 success in melanoma patients.

Background: Immune checkpoint inhibitors (ICIs) have shown promising anti-tumor activities and are widely used for the treatment of advanced cancers. However, they may lead to immune-related adverse events (irAEs) and some of them, such as hypophysitis, can be life-threatening. Here, early diagnosis is critical. Methods: We retrospectively analyzed 40 melanoma patients who developed hypophysitis during ICI treatment with either ipilimumab and/or anti-PD1 therapy and compared them to 40 control patients who did not develop hypophysitis during the ICI treatment, matched for age, gender, type of immunotherapy, and stage. Clinical data and blood values such as LDH, CRP, TSH, T3, T4, and absolute immune cell counts were retrieved from the medical records. Patient characteristics, laboratory values, progression-free survival, and overall survival were compared between the two groups. Results: Patients with ir-hypophysitis had a median age of 59 years, and most of them were male. Clinically, frequent symptoms were fatigue, headache, dizziness, and gastrointestinal symptoms such as nausea or abdominal pain. The onset of ir-hypophysitis differed much between ipilimumab- (median 8 weeks) and anti-PD1 (median 40 weeks)-induced hypophysitis (p < 0.001). At baseline, besides a slightly increased CRP level (p = 0.06), no differences were observed in patients who later developed hypophysitis compared to the control. After treatment started, hypophysitis patients showed a constant and significant decline in T4 levels from the start of therapy until diagnosis (p < 0.05), independent of the ICI treatment regime. However, a decline in T3 and TSH was only noted in patients with ipilimumab-induced ir-hypophysitis. Furthermore, serum sodium levels declined rapidly at the diagnosis of hypophysitis (p < 0.001). In addition, there was a constant increase in the absolute counts of eosinophils and lymphocytes from baseline in hypophysitis patients (p < 0.05). Conclusion: Ir-hypophysitis reveals different clinical pictures and onset times depending on the ICI regime used. Whereas a drop in T4 levels was indicative of developing hypophysitis independent of the ICI regime, TSH levels only declined in patients under ipilimumab-based ICI regimes. To best monitor our patients, it is important to recognize these differences.

Metastatic uveal melanoma (mUM) is one of the most rapidly progressing tumors, with a bad prognosis and no standard-of-care treatment. Immune checkpoint inhibitors have revolutionized cancer therapy and improved overall survival in patients with metastatic cutaneous melanoma (mCM). However, this approach has been largely unimpressive, with no significant impact on the survival of mUM patients. Technical advances in immunotherapies have led to the development of novel T cell receptor (TCR)-based approaches to fight cancer. For the first time in over 50 years, compelling evidence demonstrates the power of TCR-based approaches for survival in mUM patients. Hence, this review summarizes novel TCR-based immunotherapeutic strategies currently in clinical studies for mUM treatment. We also discuss the potential combinational treatments to these strategies to maximize the clinical benefits.

The impact of age on the clinical benefit of anti-PD1 immunotherapy in advanced melanoma patients has been evolving recently. Due to a reduced immune function in elderly patients, young patients with a robust immune system are theoretically expected to benefit more from the treatment approach. However, in contrast to this hypothesis, recent studies in patients with metastatic melanoma have demonstrated that immunotherapy, especially with anti-PD1 treatment, is less effective in patients below 65 years, on average, with significantly lower responses and reduced overall survival compared to patients above 65 years of age. Besides, data on young patients are even more sparse. Hence, in this review, we will focus on age-dependent differences in the previously described resistance mechanisms to the treatment and discuss the development of potential combination treatment strategies for enhancing the anti-tumor efficacy of anti-PD1 or PDL1 treatment in young melanoma patients.

Tumor antigen-specific redirection of cytotoxic T cells (CTLs) or natural killer (NK) cells including chimeric antigen receptor (CAR-) and T cell receptor (TCR-) cell therapy is currently being evaluated in different tumor entities including melanoma. Expression of melanoma-specific antigen recognized by the respective CAR or TCR directly or presented by HLA molecules is an indispensable prerequisite for this innovative therapy. In this study, we investigated in 168 FFPE tumor specimens of patients with stage I-IV melanoma the protein expression of HER2, TRP2, ABCB5, gp100, p53, and GD2 by immunohistochemistry (IHC). These results were correlated with clinical parameters. Membrane expression of HER2 and GD2 was also investigated in ten melanoma cell lines by flow cytometry for which corresponding tumors were analyzed by IHC. Our results demonstrated that gp100 was the most frequently overexpressed protein (61%), followed by TRP2 (50%), GD2 (38%), p53 (37%), ABCB5 (17%), and HER2 (3%). TRP2 expression was higher in primary tumors compared to metastases (p = 0.005). Accordingly, TRP2 and ABCB5 expression was significantly associated with lower tumor thickness of the primary (p = 0.013 and p = 0.025). There was no association between protein expression levels and survival in advanced melanoma patients. Flow cytometric analysis revealed abundant surface expression of GD2 and HER2 in all melanoma cell lines. The discordant HER2 expression in situ and in vitro suggests a tissue culture associated induction. In summary, our data support the use of gp100 and GD2 as a potential target for developing engineered TCR- or CAR-cell therapies, respectively, against melanoma.