No abstract

Plitidepsin is a cyclic depsipeptide that was first isolated from a Mediterranean marine tunicate (Aplidium albicans) and, at present, is manufactured by total synthesis and commercialized as Aplidin®. Its antitumor activity, observed in preclinical in vitro and in vivo studies has prompted numerous clinical trials to be conducted over the last 17 years, alone or in combination with other anticancer agents. Single-agent plitidepsin has shown limited antitumor activity and a tolerable safety profile in several malignancies, such as noncutaneous peripheral T-cell lymphoma, melanoma, and multiple myeloma. In patients with relapsed or refractory multiple myeloma, plitidepsin activity seems to be enhanced after addition of dexamethasone while remaining well tolerated, and a Phase III trial comparing plitidepsin plus dexamethasone vs dexamethasone alone is underway. Additional studies are required to better define the role of plitidepsin in combination with other active agents in these indications. Results of plitidepsin activity in other hematological malignancies or solid tumors have been disappointing so far. Further studies analyzing its mechanisms of action and potential biomarkers will help select patients who may benefit most from this drug. In this review, we critically analyze the published studies on plitidepsin in hematological malignancies and solid tumors and discuss its current role and future perspectives in treating these malignancies. We also review its design, pharmaceutical data, and mechanism of action.

The diagnostic criteria for follicular lymphoma (FL) transformation vary among the largest series, which commonly exclude histologically-documented transformation (HT) mandatorily. The aims of this retrospective observational multicentre study by the Spanish Grupo Español de Linfoma y Transplante Autólogo de Médula Ósea, which recruited 1734 patients (800 males/934 females; median age 59 years), diagnosed with FL grades 1-3A, were, (i) the cumulative incidence of HT (CI-HT); (ii) risk factors associated with HT; and (iii) the role of treatment and response on survival following transformation (SFT). With a median follow-up of 6·2 years, 106 patients developed HT. Ten-year CI-HT was 8%. Considering these 106 patients who developed HT, median time to transformation was 2·5 years. High-risk FL International Prognostic Index [Hazard ratio (HR) 2·6, 95% confidence interval (CI): 1·5-4·5] and non-response to first-line therapy (HR 2·9, 95% CI: 1·3-6·8) were associated with HT. Seventy out of the 106 patients died (5-year SFT, 26%). Response to HT first-line therapy (HR 5·3, 95% CI: 2·4-12·0), autologous stem cell transplantation (HR 3·9, 95% CI: 1·5-10·1), and revised International Prognostic Index (HR 2·2, 95% CI: 1·1-4·2) were significantly associated with SFT. Response to treatment and HT were the variables most significantly associated with survival in the rituximab era. Better therapies are needed to improve response. Inclusion of HT in clinical trials with new agents is mandatory.

Prognostic factors in Hodgkin lymphoma (HL) still fail to accurately identify high-risk patients. Tumor microenvironment in HL is a current focus of research for risk definition but few studies have focused on infiltrating lymphocytes. Here, we analyzed the number of tumor infiltrating lymphocytes by flow cytometry in diagnostic biopsies from 96 HL homogeneously treated patients with ABVD with or without radiotherapy. Most lymph node cells were lymphocytes (90 ± 17), with a median T/B/NK distribution of 74%/26%/0.7%, and CD4 T-cell predominance. The amount of CD19 B cells, and NK cells did not show association with disease features. However, high numbers of CD8 and CD4 cells were associated with better and poorer outcomes, respectively. Patients with ≥15% cytotoxic CD8 cells among the total cell population had a longer 10-year freedom from treatment failure (FFTF) (93% vs. 73%, p=.04). In turn, cases with ≥75% of CD4 infiltrating cells showed a significantly decreased FFTF (73% vs. 96%, p=.021). Consequently, CD4/CD8 ratio ≥5 associated with a poorer 10-year FFTF (69.5% vs. 94%, p=.02). This deleterious effect was particularly prominent in advanced disease (n = 58, p=.01). In multivariate analysis, a CD4/CD8 ratio ≥5 was the only independent variable to predict for treatment failure (HR = 4.5, 95% confidence interval, 1.2-16.8). In conclusion, our study shows that high CD4 and low CD8 T-cells infiltrates of tumor specimens associate with poor prognosis in HL patients, and CD4/CD8 ratio might be potentially useful for tailoring therapy.