Historically, metastatic melanoma was considered a highly lethal disease. However, recent advances in drug development have allowed a significative improvement in prognosis. In particular, BRAF/MEK inhibitors and anti-PD1 antibodies have completely revolutionized the management of this disease. Nonetheless, not all patients derive a benefit or a durable benefit from these therapies. To overtake this challenges, new clinically active compounds are being tested in the context of clinical trials. CDK4/6 inhibitors are drugs already available in clinical practice and preliminary evidence showed a promising activity also in melanoma. Herein we review the available literature to depict a comprehensive landscape about CDK4/6 inhibitors in melanoma. We present the molecular and genetic background that might justify the usage of these drugs, the preclinical evidence, the clinical available data, and the most promising ongoing clinical trials.

Background: Elevated plasmatic lactate dehydrogenase (LDH) levels are associated with worse prognosis in various malignancies, including metastatic breast cancer (MBC). Nevertheless, no data are available on the prognostic role of LDH as a dynamic biomarker during first-line treatment in unselected MBC. Methods: We reviewed data of 392 women with MBC to evaluate the association between LDH variation after 12 weeks of first-line treatment and survival. The prognostic impact was tested by multivariate Cox regression analysis. Results: Plasmatic LDH was confirmed as an independent prognostic factor in MBC. Patients who maintained elevated LDH levels after 12 weeks of first-line treatment experienced worse progression-free survival (PFS, HR 2.88, 95% CI: 1.40–5.89, p = 0.0038) and overall survival (OS, HR 2.61, 95% CI 1.16–5.86, p = 0.02) compared to patients with stable normal LDH levels, even after adjustment for other prognostic factors. Notably, LDH low-to-high variation emerged as an unfavorable prognostic factor for PFS (HR 3.96, 95% CI 2.00–7.82, p = 0.0001). Conclusions: Plasmatic LDH and its variation during first-line treatment predict PFS and OS in MBC, providing independent prognostic information. It would be worthwhile to prospectively evaluate the association between LDH variation and therapeutic benefit in MBC, and explore how it may affect treatment strategies.

Purpose: To assess the efficacy and exploratory biomarkers of continuing palbociclib plus endocrine therapy (ET) beyond progression on prior palbociclib-based regimen in patients with hormone receptor–positive/HER2-negative (HR+/HER2−) advanced breast cancer (ABC). Patients and Methods: The multicenter, open-label, phase II BioPER trial included women who had experienced a progressive disease (PD) after having achieved clinical benefit on the immediately prior palbociclib plus ET regimen. Palbociclib (125 mg, 100 mg, or 75 mg daily orally for 3 weeks and 1 week off as per prior palbociclib-based regimen) plus ET of physician's choice were administered in 4-week cycles until PD or unacceptable toxicity. Coprimary endpoints were clinical benefit rate (CBR) and percentage of tumors with baseline loss of retinoblastoma (Rb) protein expression. Additional endpoints included safety and biomarker analysis. Results: Among 33 patients enrolled, CBR was 34.4% [95% confidence interval (CI), 18.6–53.2; P < 0.001] and 13.0% of tumors (95% CI, 5.2–27.5) showed loss of Rb protein expression, meeting both coprimary endpoints. Median progression-free survival was 2.6 months (95% CI, 1.8–6.7). No new safety signals were reported. A signature that included baseline mediators of therapeutic resistance to palbociclib and ET (low Rb score, high cyclin E1 score, ESR1 mutation) was independently associated with shorter median progression-free survival (HR, 22.0; 95% CI, 1.71–282.9; P = 0.018). Conclusions: Maintaining palbociclib after progression on prior palbociclib-based regimen seems to be a reasonable, investigational approach for selected patients. A composite biomarker signature predicts a subset of patients who may not derive a greater benefit from palbociclib rechallenge, warranting further validation in larger randomized controlled trials.

Background: To evaluate the capability of basal and one-month differed white blood cells (WBC), neutrophil, lymphocyte and platelet values and their ratios (neutrophils-to-lymphocytes ratio, NLR, and platelets-to-lymphocytes ratio, PLR) in predicting the response toimmune checkpoint inhibitors (ICI) in metastatic melanoma (MM).Methods: We performed a retrospective study of 272 BRAF wild-type MM patients treated with first line ICI. Bivariable analysis was used to correlate patient/tumor characteristics with clinical outcomes. Variations between time 1 and time 0 (Δ) of blood parameters were also calculated and dichotomized using cut-off values assessed by ROC curve.Results: At baseline, higher neutrophils and NLR negatively correlated with PFS, OS and disease control rate (DCR). Higher PLR was also associated with worse OS. In multivariable analysis, neutrophils (p = 0.003), WBC (p = 0.069) and LDH (p = 0.07) maintained their impact on PFS, while OS was affected by LDH (p < 0.001), neutrophils (p < 0.001) and PLR (p = 0.022), while DCR by LDH (p = 0.03) and neutrophils (p = 0.004). In the longitudinal analysis, PFS negatively correlated with higher Δplatelets (p = 0.039), ΔWBC (p < 0.001), and Δneutrophils (p = 0.020), and with lower Δlymphocytes (p < 0.001). Moreover, higher ΔNLR and ΔPLR identified patients with worse PFS, OS and DCR. In the multivariable model, only ΔNLR influenced PFS (p = 0.004), while OS resulted affected by higher ΔWBC (p < 0.001) and lower Δlymphocytes (p = 0.038). Higher ΔWBC also affected the DCR (p = 0.003). When clustering patients in 4 categories using basal LDH and ΔNLR, normal LDH/lower ΔNLR showed a higher PFS than high LDH/higher ΔNLR (20 vs 5 months). Moreover, normal LDH/higher Δlymphocytes had a higher OS than high LDH/lower Δlymphocytes (50 vs. 10 months).Conclusions: Baseline and early variations of blood cells, together with basal LDH, strongly predict the efficacy of ICI in MM. Our findings propose simple, inexpensive biomarkers for a better selection of patient treatments. Prospective multicenter studies are warranted to confirm these data.

Aims: It is debated whether the NRAS-mutant melanoma is more aggressive than NRAS wildtype. It is equally controversial whether NRAS-mutant metastatic melanoma (MM) is more responsive to checkpoint inhibitor immunotherapy (CII). 331 patients treated with CII as first-line were retrospectively recruited: 162 NRAS-mutant/BRAF wild-type (mut/wt) and 169 wt/wt. We compared the two cohorts regarding the characteristics of primary and metastatic disease, disease-free interval (DFI) and outcome to CII. No substantial differences were observed between the two groups at melanoma onset, except for a more frequent ulceration in the wt/wt group (p = 0.03). Also, the DFI was very similar in the two cohorts. In advanced disease, we only found lung and brain progression more frequent in the wt/wt group. Regarding the outcomes to CII, no significant differences were reported in overall response rate (ORR), disease control rate (DCR), progression free survival (PFS) or overall survival (OS) (42% versus 37%, 60% versus 59%, 12 (95% CI, 7–18) versus 9 months (95% CI, 6–16) and 32 (95% CI, 23–49) versus 27 months (95% CI, 16–35), respectively). Irrespectively of mutational status, a longer OS was significantly associated with normal LDH, <3 metastatic sites, lower white blood cell and platelet count, lower neutrophil-to-lymphocyte (N/L) ratio. Our data do not show increased aggressiveness and higher responsiveness to CII in NRAS-mutant MM.

Patients with newly resected stage II melanoma (n = 104) were randomized to receive adjuvant vitamin D3 (100,000 IU every 50 days) or placebo for 3 years to investigate vitamin D3 protective effects on developing a recurrent disease. Median age at diagnosis was 50 years, and 43% of the patients were female. Median serum 25-hydroxy vitamin D (25OHD) level at baseline was 18 ng/mL, interquartile range (IQ) was 13–24 ng/mL, and 80% of the patients had insufficient vitamin D levels. We observed pronounced increases in 25OHD levels after 4 months in the active arm (median 32.9 ng/mL; IQ range 25.9–38.4) against placebo (median 19.05 ng/mL; IQ range 13.0–25.9), constantly rising during treatment. Remarkably, patients with low Breslow score (<3 mm) had a double increase in 25OHD levels from baseline, whereas patients with Breslow score ≥3 mm had a significantly lower increase over time. After 12 months, subjects with low 25OHD levels and Breslow score ≥3 mm had shorter disease-free survival (p = 0.02) compared to those with Breslow score <3 mm and/or high levels of 25OHD. Adjusting for age and treatment arm, the hazard ratio for relapse was 4.81 (95% CI: 1.44–16.09, p = 0.011). Despite the evidence of a role of 25OHD in melanoma prognosis, larger trials with vitamin D supplementation involving subjects with melanoma are needed.