[Vemurafenib-induced toxic epidermal necrolysis]

Evaluation of Delayed-Type Hypersensitivity to Antineoplastic Drugs-An Overview

Nowadays, clinical practice encounters the problem of delayed-type hypersensitivity (DTH) induced by several drugs. Antineoplastic treatments are among the drugs which show an elevated proportion of DHT reactions, leading to the worsening of patients' quality of life. The range of symptoms in DHT reactions can vary from mild, such as self-limiting maculopapular eruptions, to severe, such as Stevens-Johnson Syndrome. The development of these reactions supposes a negative impact, not only by limiting patients' quality of life, but also leading to economic loss due to market withdrawal of the affected drugs and high hospitalization costs. However, despite this problem, there are no available standard in vitro or in vivo methods that allow for the evaluation of the sensitizing potential of drugs in the preclinical phase. Therefore, the aim of this review is to summarize the skin reactions caused by the different antineoplastic families, followed by a comprehensive evaluation of the in vitro and in vivo methods used to detect DTHs and that could be suitable to test antineoplastic hypersensitivity reactions.

Potentially life‑threatening severe cutaneous adverse reactions associated with tyrosine kinase inhibitors (Review)

Tyrosine kinase inhibitors (TKIs) have emerged as a new frontier of cancer therapy. These agents include inhibitors of epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (HER2), BRAF, mitogen‑activated protein kinase kinase (also referred to as MEK), bcr‑abl, c‑KIT, platelet‑derived growth factor (PDGFR), fibroblast growth factor receptor (FGFR), anaplastic lymphoma kinase (ALK) and vascular endothelial growth factor (VEGF). Along with the evolving applications of TKIs, there has been an increased recognition of the breadth of potential cutaneous toxicities to these agents. In this review, we provide an overview of potentially life‑threatening severe cutaneous adverse reactions (SCARs) that may occur during therapy with TKIs. These toxicities include Stevens‑Johnson Syndrome (SJS), toxic epidermal necrolysis (TEN), drug reaction with eosinophilia and systemic symptoms (DRESS), and acute generalized exanthematous pustulosis (AGEP).

Cobimetinib- and vemurafenib-induced granulomatous dermatitis and erythema induratum: A case report

Metastatic melanoma is an aggressive malignancy. Survival can be increased with the combination of BRAF and MEK inhibition. BRAF inhibitor-induced cutaneous toxicities can be attenuated with MEK inhibition. Here, we describe the first reported case of a patient with metastatic melanoma who developed granulomatous dermatitis and erythema induratum when treated with combination BRAF (vemurafenib) and MEK inhibitor (cobimetinib) therapy and discuss the clinical features and management of dermatologic side-effects secondary to BRAF +/– MEK inhibition.

Severe skin toxicity with organ damage under the combination of targeted therapy following immunotherapy in metastatic melanoma

Targeted therapy combination (TTC: antiRAF+antiMEK) is known to improve metastatic melanoma survival. Few severe skin toxicities (grade ≥3) are described with first-line TTC (17% for vemurafenib+cobimetinib and none for dabrafenib+trametinib) in a phase III trial. Among our 42 patients treated by TTC between January 2014 and March 2017, 4.8% (2/42) of those treated in the first line presented severe skin rash versus 19% (8/42) of patients treated in the second line after previous immunotherapy. In particular, we observed one case of Stevens-Johnson syndrome and four cases of severe drug reaction with eosinophilia and systemic symptoms syndrome under TTC in patients who had received immunotherapy previously. Thus, previous immunotherapy appears to play an important role in the skin rash onset and severity induced by TTC.

Severe cutaneous adverse reactions induced by targeted anticancer therapies and immunotherapies

With the increasing use of targeted anticancer drugs and immunotherapies, there have been a substantial number of reports concerning life-threatening severe cutaneous adverse reactions (SCARs), including Stevens–Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), drug rash with eosinophilia and systemic symptoms, drug-induced hypersensitivity syndrome, and acute generalized exanthematous pustulosis. Although the potential risks and characteristics for targeted anticancer agent- and immunotherapy-induced SCAR were not well understood, these serious adverse reactions usually result in morbidity and sequela. As a treatment guideline for this devastating condition is still unavailable, prompt withdrawal of causative drugs is believed to be a priority of patient management. In this review, we outline distinct types of SCARs caused by targeted anticancer therapies and immunotherapies. Also, we discuss the clinical course, latency, concomitant medication, tolerability of rechallenge or alternatives, tumor response, and mortality associated with these devastating conditions. Imatinib, vemurafenib, and rituximab were the top three offending medications that most commonly caused SJS/TEN, while EGFR inhibitors were the group of drugs that most frequently induced SJS/TEN. For drug rash with eosinophilia and systemic symptoms/drug-induced hypersensitivity syndrome and acute generalized exanthematous pustulosis, imatinib was also the most common offending drug. Additionally, we delineated 10 SCAR cases related to innovative immunotherapies, including PD1 and CTLA4 inhibitors. There was a wide range of latency periods: 5.5–91 days (median). Only eight of 16 reported patients with SCAR showed clinical responses. Targeted anticancer drugs and immunotherapies can lead to lethal SCAR (14 deceased patients were identified as suffering from SJS/TEN). The mortality rate of TEN was high: up to 52.4%. The information compiled herein will serve as a solid foundation to formulate ideas for early recognition of SCAR and to discontinue offending drugs for better management.

Skin toxicity in BRAF(V600) mutated metastatic cutaneous melanoma patients treated with vemurafenib

Introduction

The use of orally available BRAF kinase inhibitor – vemurafenib is associated with numerous adverse skin reactions.

Aim

To assess the safety and early side effects of vemurafenib treatment in the unselected group of patients treated at the outpatient clinic, in particular the assessment of the incidence of skin cancer.

Material and methods

We carried out a systematic study of patients (pts) treated with vemurafenib. Skin toxicity during vemurafenib therapy was analyzed. Toxicity was determined on the basis of the toxicity scale CTCAE, version 4.0.

Results

The most common cutaneous side effects were hyperkeratotic perifollicular rash (69%) and photosensitivity (15%). Skin rash developed more frequently in the first month of treatment. Squamous cell carcinoma occurred in 38% of patients. Patients with skin cancer development during vemurafenib therapy had non-significantly longer overall survival (OS) than patients without skin cancer, p = 0.4. Skin cancer developed more often in women than in men (60% vs. 25%), p = 0.249. It was detected only in patients with normal weight compared to overweight patients (55% vs. 0), p = 0.09. The median OS was 26 months and median OS from the time of distant metastases diagnosis was 9.8 months. In patients with a low body mass index, shorter OS was observed, p = 0.09.

Conclusions

The incidence of squamous cell carcinoma was high (38%). This study has many limitations mostly due to a small group of patients. That is why the results should be taken into consideration with caution. The proper symptomatic treatment in cooperation with dermatologists allows to continue the vemurafenib therapy.

Vemurafenib-induced toxic epidermal necrolysis: possible cross-reactivity with other sulfonamide compounds

Vemurafenib is a newly licensed target-directed medication. It has been proven to improve the survival of patients with metastatic melanoma and the BRAF(V600E) mutation; however, adverse cutaneous reactions are frequent. Few cases of life-threatening severe cutaneous adverse reactions (SCARs) induced by vemurafenib have been reported. Dabrafenib, another selective BRAF inhibitor, has been licensed recently as an alternative drug with the same indications. From a molecular point of view, both vemurafenib and dabrafenib contain a sulfonamide group; cross-reactivity to sulfonamide compounds has been reported in allergic patients. We report on a patient with vemurafenib-induced toxic epidermal necrolysis (TEN). In vitro analysis of lymphocyte reactivity to vemurafenib showed positive results, confirming drug causality. In addition, lymphocytes from the patient reacted to dabrafenib and to the antibiotic sulfonamide drug sulfamethoxazole. Moreover, lymphocytes from two patients with cutaneous adverse reactions to sulfamethoxazole also reacted to vemurafenib and dabrafenib in vitro. These data strongly suggest that there might be clinical cross-reactivity between BRAF inhibitors and sulfonamides in some patients. Thus, precautions should be taken to avoid sulfonamide drugs as much as possible in patients showing serious hypersensitivity reactions to vemurafenib and vice versa.

Profile of vemurafenib-induced severe skin toxicities

BACKGROUND

Vemurafenib, a BRAF inhibitor, is commonly associated with skin toxicity. The impact of severe forms is unknown.

OBJECTIVE

To determine the rate of permanent vemurafenib discontinuation due to grade 3-4 skin toxicity, features of these toxicities, their recurrence rate after a switch to dabrafenib and their impact on overall survival.

METHODS

Retrospective cohort study of 131 patients treated with vemurafenib for melanoma between November 2010 and December 2014. Data on skin toxicities, the need for vemurafenib adjustment and the impact of switching to dabrafenib were collected. Regarding survival analysis, a conditional landmark analysis was performed to correct lead-time bias.

RESULTS

Among the 131 vemurafenib-treated patients, 26% developed grade 3-4 skin toxicity. Forty-four percent of them permanently discontinued their treatment, mainly due to rash and classic skin adverse reactions (Steven-Johnson syndrome, Drug Reaction with Eosinophilia and Systemic Symptoms). Conversely, photosensitivity and carcinomas rarely required treatment adjustment. Grade 3-4 rashes were associated with clinical or biological abnormalities in 94% of patients. Among the 10 patients who subsequently switched to dabrafenib, skin toxicity recurred only in one patient. Overall survival was significantly prolonged in case of severe skin toxicity emerging within the first 4 (P = 0.014) and 8 weeks (P = 0.038) on vemurafenib, with only a trend at 12 weeks (P = 0.052). Median overall survival was also prolonged in case of severe rash.

CONCLUSION

In this study, vemurafenib was continued in 56% of patients with grade 3-4 skin toxicity, which was associated with prolonged overall survival when emerging within the first 4 and 8 weeks of treatment. While developing severe skin adverse reactions permanently contraindicates vemurafenib use, other rashes should lead to retreatment attempts with dose reduction. In case of recurrence, dabrafenib seems to be an interesting option. For other skin toxicities, including photosensitivity and cutaneous carcinoma, treatment adjustment is usually not needed.

Early-Onset Vemurafenib-Induced DRESS Syndrome

Vemurafenib is a BRAF inhibitor indicated in metastatic or unresectable melanoma in patients with BRAF mutations. Vemurafenib is frequently toxic, but the toxicity is often not serious. The third case of vemurafenib-induced drug rash with eosinophilia and systemic symptoms (DRESS) syndrome is reported herein. The case is unusual in that the onset was early, with symptoms emerging as of day 8 of treatment. Treatment of DRESS syndrome is not currently based on precise recommendations, but systemic corticosteroid therapy is effective in serious cases. Severe toxidermias under vemurafenib are exceptional; immediate discontinuation of treatment upon diagnosis is imperative. Switching from vemurafenib to dabrafenib then seems to constitute an interesting therapeutic alternative, since its efficacy is the same but with fewer cutaneous adverse reactions. This case highlights the importance of awareness of the risk of DRESS syndrome associated with vemurafenib and monitoring for warning signs from treatment initiation.

BRAF inhibitors: experience in thyroid cancer and general review of toxicity

The US Food and Drug Administration-approved BRAF inhibitors, vemurafenib and dabrafenib, have demonstrated superior efficacy in patients with BRAF-mutant melanomas but have limited efficacy in BRAF-mutant colorectal cancer. Little is known at this time regarding BRAF inhibitors in thyroid cancer. Initial reports in patients with progressive, radioactive iodine-refractory BRAF-mutant papillary thyroid cancer suggest response rates of approximately 30-40%. In this review, we discuss BRAF inhibitors in the context of thyroid cancer, the toxicities associated with BRAF inhibitors, and the suggested management of those toxicities. The management of vemurafenib and dabrafenib toxicities is applicable across all tumor types and may serve as a practical guide to their use.