Potential interactions between antineoplastic agents and medicines used to treat Covid-19.

INTRODUCTION: Cancer patients with Covid-19 are exposed to treatment combinations that can potentially result in interactions that adversely affect patient outcomes. This study aimed to identify potential drug-drug interactions between antineoplastic agents and medicines used to treat Covid-19. METHODS: We conducted a search for potential interactions between 201 antineoplastic agents and 26 medicines used to treat Covid-19 on the Lexicomp® and Micromedex® databases. The following data were extracted: interaction severity ("major" and "contraindicated") and interaction effects (pharmacokinetic and pharmacodynamic). We also sought to identify the therapeutic indication of the antineoplastic drugs involved in the potential drug-drug interactions. RESULTS: A total of 388 "major" or "contraindicated" drug-drug interactions were detected. Eight drugs or combinations (baricitinib, lopinavir/ritonavir, atazanavir, darunavir, azithromycin, chloroquine, hydroxychloroquine, and sirolimus) accounted for 91.5% of these interactions. The class of antineoplastic agents with the greatest potential for interaction was tyrosine kinase inhibitors (accounting for 46.4% of all interactions). The findings show that atazanavir, baricitinib, and lopinavir/ritonavir can affect the treatment of all common types of cancer. The most common pharmacokinetic effect of the potential drug-drug interactions was increased plasma concentration of the antineoplastic medicine (39.4%). CONCLUSIONS: Covid-19 is a recent disease and pharmacological interventions are undergoing constant modification. This study identified a considerable number of potential drug-drug interactions. In view of the vulnerability of patients with cancer, it is vital that health professionals carefully assess the risks and benefits of drug combinations.

Determinants of COVID-19 Mortality in Patients With Cancer From a Community Oncology Practice in Brazil.

PURPOSE: The COVID-19 pandemic remains a public health emergency of global concern. Determinants of mortality in the general population are now clear, but specific data on patients with cancer remain limited, particularly in Latin America. MATERIALS AND METHODS: A longitudinal multicenter cohort study of patients with cancer and confirmed COVID-19 from Oncoclínicas community oncology practice in Brazil was conducted. The primary end point was all-cause mortality after isolation of the SARS-CoV-2 by Real-Time Polymerase Chain Reaction (RT-PCR) in patients initially diagnosed in an outpatient environment. We performed univariate and multivariable logistic regression analysis and recursive partitioning modeling to define the baseline clinical determinants of death in the overall population. RESULTS: From March 29 to July 4, 2020, 198 patients with COVID-19 were prospectively registered in the database, of which 167 (84%) had solid tumors and 31 (16%) had hematologic malignancies. Most patients were on active systemic therapy or radiotherapy (77%), largely for advanced or metastatic disease (64%). The overall mortality rate was 16.7% (95% CI, 11.9 to 22.7). In univariate models, factors associated with death after COVID-19 diagnosis were age ≥ 60 years, current or former smoking, coexisting comorbidities, respiratory tract cancer, and management in a noncurative setting (P < .05). In multivariable logistic regression and recursive partitioning modeling, only age, smoking history, and noncurative disease setting remained significant determinants of mortality, ranging from 1% in cancer survivors under surveillance or (neo)adjuvant therapy to 60% in elderly smokers with advanced or metastatic disease. CONCLUSION: Mortality after COVID-19 in patients with cancer is influenced by prognostic factors that also affect outcomes of the general population. Fragile patients and smokers are entitled to active preventive measures to reduce the risk of SARS-CoV-2 infection and close monitoring in the case of exposure or COVID-19-related symptoms.

Fibroblasts protect melanoma cells from the cytotoxic effects of doxorubicin.

Melanoma is the most aggressive form of skin cancer and until recently, it was extremely resistant to radio-, immuno-, and chemotherapy. Despite the latest success of BRAF V600E-targeted therapies, responses are typically short lived and relapse is all but certain. Furthermore, a percentage (40%) of melanoma cells is BRAF wild type. Emerging evidence suggests a role for normal host cells in the occurrence of drug resistance. In the current study, we compared a variety of cell culture models with an organotypic incomplete skin culture model (the "dermal equivalent") to investigate the role of the tissue microenvironment in the response of melanoma cells to the chemotherapeutic agent doxorubicin (Dox). In the dermal equivalent model, consisting of fibroblasts embedded in type I collagen matrix, melanoma cells showed a decreased cytotoxic response when compared with less complex culture conditions, such as seeding on plastic cell culture plate (as monolayers cultures) or on collagen gel. We further investigated the role of the microenvironment in p53 induction and caspase 3 and 9 cleavage. Melanoma cell lines cultured on dermal equivalent showed decreased expression of p53 after Dox treatment, and this outcome was accompanied by induction of interleukin IL-6, IL-8, and matrix metalloproteinases 2 and 9. Here, we show that the growth of melanoma cells in the dermal equivalent model inflects drug responses by recapitulating important pro-survival features of the tumor microenvironment. These studies indicate that the presence of stroma enhances the drug resistance of melanoma in vitro, more closely mirroring the in vivo phenotype. Our data, thus, demonstrate the utility of organotypic cell culture models in providing essential context-dependent information critical for the development of new therapeutic strategies for melanoma. We believe that the organotypic model represents an improved screening platform to investigate novel anti-cancer agents, as it provides important insights into tumor-stromal interactions, thus assisting in the elucidation of chemoresistance mechanisms.