Ibrutinib-related skin cancer: A pharmacovigilance study from the Food and Drug Administration Adverse Event Reporting System

Toxicity and Dermatokinetic Analysis of Ibrutinib in Human Skin Models

Background/Objectives: Ibrutinib (IBR) is a tyrosine kinase inhibitor under investigation in preclinical and clinical settings as an alternative treatment for melanoma. Nevertheless, the limited oral bioavailability of IBR and the need for high doses of the drug to kill melanoma cells are major drawbacks for this purpose. Considering that melanoma is restricted to the skin at early stages, the topical application of IBR might constitute an effective and safer administration route. In this study, we determined IBR's toxicity and dermatokinetics using human primary cells and human organotypic skin explant cultures (hOSECs). Methods: After demonstrating that human primary fibroblasts and keratinocytes present IBR target genes, the cytotoxicity of the drug was determined using the MTT and annexin V/PI staining assays. IBR toxicity in the skin was assessed using the TTC assay, and the irritation potential was established using histological assessment. Finally, IBR cutaneous permeation was assessed ex vivo to determine the drug dermatokinetics. Results: Our findings reveal that IBR exerts dose-dependent toxicity towards skin cells, presenting an IC50 in the same range as melanoma cells. The topical application of the drug successfully reduced irritation and toxicity in the skin, and the drug was shown to successfully permeate the stratum corneum and reach the viable skin layers in therapeutic concentrations. Conclusions: Overall, our data encourage the topical application of IBR to treat melanoma, paving the way for future studies in this theme.

Skin Malignancies Due to Anti-Cancer Therapies

Skin cancers involve a significant concern in cancer therapy due to their association with various treatment modalities. This comprehensive review explores the increased risk of skin cancers linked to different anti-cancer treatments, including classic immunosuppressants such as methotrexate (MTX), chemotherapeutic agents such as fludarabine and hydroxyurea (HU), targeted therapies like ibrutinib and Janus Kinase inhibitors (JAKi), mitogen-activated protein kinase pathway (MAPKP) inhibitors, sonic hedgehog pathway (SHHP) inhibitors, and radiotherapy. MTX, a widely used immunosuppressant in different fields, is associated with basal cell carcinoma (BCC), cutaneous squamous cell carcinoma (cSCC), and cutaneous melanoma (CM), particularly at higher dosages. Fludarabine, HU, and other chemotherapeutic agents increase the risk of non-melanoma skin cancers (NMSCs), including cSCC and BCC. Targeted therapies like ibrutinib and JAKi have been linked to an elevated incidence of NMSCs and CM. MAPKP inhibitors, particularly BRAF inhibitors like vemurafenib, are associated with the development of cSCCs and second primary melanomas (SPMs). SHHP inhibitors like vismodegib have been linked to the emergence of cSCCs following treatment for BCC. Additionally, radiotherapy carries carcinogenic risks, especially for BCCs, with increased risks, especially with younger age at the moment of exposure. Understanding these risks and implementing appropriate screening is crucial for effectively managing patients undergoing anti-cancer therapies.

Drug-induced tumoral disease: A global pharmacovigilance database analysis

INTRODUCTION

Cancer remains a worldwide threat, having caused almost 10 million deaths in 2020. The American Cancer Society has identified both known and probable carcinogens, including commonly used drugs. The aim of this study is to describe the drugs most frequently reported in the occurrence of cancer.

METHODS

Among all individual case safety reports (ICSRs) in the global pharmacovigilance database VigiBase, we searched for the 50 most reported drugs with an adverse drug reaction term belonging to the query "Malignant or unspecified tumors" until June 30, 2023. Then, we extracted the disproportionality measurement data, information component (IC), and reporting odds ratio (ROR) in order to assess a disproportionality signal.

RESULTS

Among all ICSRs in VigiBase, 871,925 contained an ADR belonging to the SMQ "Malignant or unspecified tumors". Ranitidine was the drug with the most reported ADRs related to cancer (n=106,484), followed by lenalidomide (n=13,466), and etanercept (n=8014). The drugs with the highest IC were ranitidine (IC=5.2, 95% confidence interval [95% CI]=5.2-5.2), pioglitazone (1353 ICSRs, IC=4.2, 95% CI=4.2-4.2), and regorafenib (1272 ICSRs, IC=2.8, 95% CI=2.8-2.8).

DISCUSSION

Our results show that the main pharmacological mechanisms are associated with ranitidine (link with levels of N-nitrosodimethylamine in ranitidine-based drugs), gene-activating drugs (pioglitazone: link with agonist effects on PPAR-γ gene activation), various pharmacological families with immunosuppressive effects (protein kinase inhibitors, immunomodulators, azathioprine, etc.), certain types of protein kinase inhibitors whose oncogenic mechanisms remain unclear (regorafenib, sorafenib, imatinib, ibrutinib, etc.), and hormone antagonists (tamoxifen, letrozole). Special monitoring of patients exposed to these drugs may be required. Further studies are needed to assess the risk with certain drugs in this ranking.

Cutaneous malignancies in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is a common lymphoid malignancy that is associated with an increased risk of developing cutaneous malignancies. Clinical outcomes for these malignancies, including melanoma and keratinocyte cancers (KC), are worse for patients with CLL. Individuals with CLL develop an immunodeficiency of both the adaptive and innate immune system, which plays a role in the increased prevalence of skin cancers. This review focuses on the complex interplay between genetics, immunity, and pathogens that influence the cellular composition and biology of skin tumors and their microenvironment in CLL patients, and in comparison with other chronic hematological malignancies. It is paramount for dermatologists to be aware of the association between CLL (and chronic hematological malignancies more broadly) and cutaneous malignancies. This is a high-risk population who require regular and vigorous dermatologic follow-up.

Risk of melanoma and nonmelanoma skin cancer with immunosuppressants, part II: Methotrexate, alkylating agents, biologics, and small molecule inhibitors

In solid organ transplant recipients, skin cancer risk associated with posttransplant immunosuppression has been well-described, and screening practices generally reflect these risks. In addition to agents used posttransplant, other classes of immunosuppressants also have the potential to raise the risk of nonmelanoma skin cancer (NMSC) or melanoma. In the present manuscript, the evidence for melanoma and NMSC risk associated with methotrexate, cyclophosphamide, biologic cytokine inhibitors including TNF (tumor necrosis factor)-alpha and interleukin inhibitors, costimulation blockers such as abatacept, integrin inhibitors such as natalizumab, targeted B-cell, and T-cell inhibitors including CD20 (cluster of differentiate 20), CD52, and BTK (Bruton's tyrosine kinase) inhibitors, and JAK (Janus kinase) inhibitors is reviewed. Based on the available data, we recommend regular skin cancer screening for select nontransplant patients receiving immunosuppressive regimens that are shown to raise the risk of NMSC or melanoma. We also offer suggestions for conscientious use of these therapies in high-risk patients. Finally, a comprehensive summary of the relative risk associated with each immunosuppressant class and associated recommendations is presented.