Vemurafenib-associated gingival hyperplasia in patient with metastatic melanoma

Oral Adverse Events Associated with BRAF and MEK Inhibitors in Melanoma Treatment: A Narrative Literature Review

BACKGROUND

Melanoma cancer represents the most lethal type of skin cancer originating from the malignant transformation of melanocyte cells. Almost 50% of melanomas show the activation of BRAF mutations. The identification and characterization of BRAF mutations led to the development of specific drugs that radically changed the therapeutic approach to melanoma.

METHODS

We conducted a narrative review of the literature according to a written protocol before conducting the study. This article is based on previously conducted studies. We identified articles by searching electronic databases (Medline, Google Scholar and PubMed). We used a combination of "melanoma", "Braf-Mek inhibitors", " targeted therapy" and "oral side effects".

RESULTS

Eighteen studies were reported in this article showing the relationship between the use of targeted therapy in melanoma cancer and the development of oral side effects, such as mucositis, hyperkeratosis and cellular proliferation.

CONCLUSION

Targeted therapy plays an important role in the treatment of melanoma cancer, showing a notable increase in response rate, prolonged progression-free survival and overall survival in BRAF-mutated melanoma patients. Oral side effects represent a common finding over the course of treatment. However, these adverse effects can be easily managed in a multidisciplinary approach involving collaboration between medical oncologists and dental doctors.

Oral Manifestations in Melanoma Patients Treated with Target or Immunomodulatory Therapies

BACKGROUND

BRAF (v-raf murine sarcoma viral oncogene homolog B1) and MEK (mitogen activated protein kinase) inhibitors, as well as immunotherapy against cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) and the programmed cell death 1 (PD-1) receptor and its ligand (PD-L1), have shown good results in improving the disease-free survival of patients with metastatic melanoma (MM). The aim of this review is to summarize the main oral adverse events (oAEs) occurring in patients undergoing target or immunotherapy. We proposed two separate sections: oAEs during the treatment with (1) target therapies with BRAF and MEK inhibitors and tyrosine kinase inhibitors (gingival hyperplasia, pigmentation disorders, squamo-proliferative lesions) and (2) immunotherapies with CTLA-4 or PD1 inhibitors (lichenoid reactions, immuno-bullous reactions, xerostomia and other reactions). Adverse events frequently include oAEs, although these are often misdiagnosed and under-reported. Indeed, the oral cavity is not routinely evaluated during clinical practice. The symptomatology related to oAEs is significant since it may represent the first manifestation of a severe systemic reaction, possibly leading to difficulties in nutrition with a consequent impact on patients' quality of life. A careful examination of the oral cavity is recommended during the evaluation of oncologic patients in order to promptly detect the onset of new manifestations.

Oral Mucosal Injury Caused by Targeted Cancer Therapies

Targeted cancer therapies have fundamentally transformed the treatment of many types of cancers over the past decade, including breast, colorectal, lung, and pancreatic cancers, as well as lymphoma, leukemia, and multiple myeloma. The unique mechanisms of action of these agents have resulted in many patients experiencing enhanced tumor response together with a reduced adverse event profile as well. Toxicities do continue to occur, however, and in selected cases can be clinically challenging to manage. Of particular importance in the context of this monograph is that the pathobiology for oral mucosal lesions caused by targeted cancer therapies has only been preliminarily investigated. There is distinct need for novel basic, translational, and clinical research strategies to enhance design of preventive and therapeutic approaches for patients at risk for development of these lesions. The research modeling can be conceptually enhanced by extrapolating "lessons learned" from selected oral mucosal conditions in patients without cancer as well. This approach may permit determination of the extent to which pathobiology and clinical management are either similar to or uniquely distinct from oral mucosal lesions caused by targeted cancer therapies. Modeling associated with oral mucosal disease in non-oncology patients is thus presented in this context as well. This article addresses this emerging paradigm, with emphasis on current mechanistic modeling and clinical treatment. This approach is in turn designed to foster delineation of new research strategies, with the goal of enhancing cancer patient treatment in the future.

[Actinomycosis revealed by ulceration of the palate and gingiva]

BACKGROUND

Actinomycosis is a chronic and extensive granulomatous, bacterial infection. Revelation by oral ulceration is rare.

PATIENTS AND METHODS

A 76-year-old patient with diabetes was treated with dabrafenib for stage IV melanoma. A follow-up visit revealed two ulcerated, infiltrated and hyperalgesic lesions of the palate and gingiva. There were no associated signs. The laboratory findings were normal. The possibility of squamous cell carcinoma occurring with BRAF inhibitors was discussed, despite the rarity of such cases in the literature. Histological examination showed an actinomycotic grain. A scan of the facial mass showed no osteitis. Antimicrobial therapy was initiated with amoxicillin for four months, with a favorable outcome.

DISCUSSION

Actinomycetes are Gram-positive filamentous saprophytic bacteria of the oral cavity and the gastrointestinal tract. They can become pathogenic under the influence of several factors. Cervicofacial involvement in the form of a peri-mandibular inflammatory nodule with secondary fistulation on the skin or in the mouth is the classic presentation. To our knowledge, no cases of opportunistic infection under BRAF inhibitors have been described. Only two cases of tuberculosis have been reported with sorafenib. The initial presentation led to suspicion of squamous cell carcinoma. In our patient, poor oral hygiene and diabetes were the two key factors considered. Moreover, this is the first case reported under dabrafenib, which does not appear to be a favoring factor. We would stress the importance of mucosal examination in patients treated with BRAF inhibitors.

Oral mucosal changes induced by anticancer targeted therapies and immune checkpoint inhibitors

Development of biological targeted therapies and immune checkpoint inhibitors has redefined the treatment for many cancers; however, the increasing use of new protocols has led to physicians observing a new spectrum of toxicities. To date, oral adverse events induced by these new anticancer therapies have been mainly reported using nonspecific terminology ("stomatitis," "mucosal inflammation," "mucositis") and remain poorly characterized, with the exception of mammalian target of rapamycin (mTOR) inhibitor-associated stomatitis. Oral toxicities of targeted therapies often display very characteristic features which clearly differ from classic oral injuries observed with cytotoxic chemotherapy and/or radiotherapy. In addition, they frequently affect more than 20% of treated patients and can lead to a significant morbidity or permanent treatment discontinuation. Oral mucosal toxicities described in this review include mTOR inhibitor-associated stomatitis (mIAS); stomatitis, benign migratory glossitis, and osteonecrosis of the jaw associated with multi-targeted kinase inhibitors of the VEGF and PDGF receptors; mucositis induced by EGFR inhibitors (in monotherapy or in combination with head and neck radiotherapy and/or chemotherapy); hyperkeratotic lesions with BRAF inhibitors; pigmentary changes and lichenoid reactions secondary to imatinib; and more recent data on the "Osler-Weber-Rendu-like syndrome" described with the antibody-drug conjugate, TDM-1. Finally, we provide, to our knowledge, the first available structured data on oral toxicities induced by the new recently FDA- and EMA-approved monoclonal antibodies targeting PD-1. Clinical management of these targeted therapy-related oral changes is also discussed.

Dabrafenib: a new opportunity for the treatment of BRAF V600-positive melanoma

Prior to 2011, the 1-year survival rates for patients suffering from advanced or metastatic melanoma was as low as 33%, with a median overall survival of about 9 months. Several chemotherapeutic regimens have been applied, either as monochemotherapy or as polychemotherapy, overall not resulting in an improvement of progression-free or overall survival. Novel insights into the epidemiology and biology of melanoma allowed the development of newer therapies. The discovery of mutations in BRAF, a part of the mitogen-activated protein kinase, allowed the development of two BRAF inhibitors, vemurafenib and dabrafenib, which significantly improved the outcome of metastatic melanoma treatment. This article reviews the mechanism of action, efficacy, and safety profile of dabrafenib. An in-depth knowledge of this medication will encourage clinicians to select the appropriate therapeutic strategy for each patient, as well as to prevent or adequately manage side effects, optimizing, thus, the drug's applicability.

Novel Drugs and Combination Therapies for the Treatment of Metastatic Melanoma

Metastatic melanoma (MM) still remains as one of the most worrisome cancer known to mankind. In last two decades, treatment of melanoma took a dramatic turn with the discovery of targeted therapy which targets the mutations in mitogen-activated protein kinase (MAPK) pathway and immune checkpoint inhibitors. These new findings have led to emergence of many novel drugs that have been approved by FDA. Targeted therapy drugs such as vemurafenib, trametinib and dabrafenib target the MAPK pathway whereas immunotherapies such as ipilimumab, nivolumab and pembrolizumab block immune checkpoint receptors on T lymphocytes. All these drugs have shown to improve the overall survival in MM. Despite these recent discoveries, treatment of MM remains challenging because of rapid development of resistance to targeted therapy. This review will discuss recently approved drugs and their adverse effects and also shed light on combination therapy in treatment of melanoma.