Cutaneous toxicities occurring during palbociclib (CDK4/6 inhibitor) and endocrine therapy in patients with advanced breast cancer: a single-centre experience

From Molecular Insights to Clinical Perspectives in Drug-Associated Bullous Pemphigoid

Bullous pemphigoid (BP), the most common autoimmune blistering disease, is characterized by the presence of autoantibodies targeting BP180 and BP230 in the basement membrane zone. This leads to the activation of complement-dependent and independent pathways, resulting in proteolytic cleavage at the dermoepidermal junction and an eosinophilic inflammatory response. While numerous drugs have been associated with BP in the literature, causality and pathogenic mechanisms remain elusive in most cases. Dipeptidyl peptidase 4 inhibitors (DPP4i), in particular, are the most frequently reported drugs related to BP and, therefore, have been extensively investigated. They can potentially trigger BP through the impaired proteolytic degradation of BP180, combined with immune dysregulation. DPP4i-associated BP can be categorized into true drug-induced BP and drug-triggered BP, with the latter resembling classic BP. Antineoplastic immunotherapy is increasingly associated with BP, with both B and T cells involved. Other drugs, including biologics, diuretics and cardiovascular and neuropsychiatric agents, present weaker evidence and poorly understood pathogenic mechanisms. Further research is needed due to the growing incidence of BP and the increasing identification of new potential triggers.

Retrospective cohort study of CDK4/6-inhibitor-induced alopecia in breast cancer patients

PURPOSE

Dermatologic adverse events commonly result in the interruption of oncologic treatment, and targeted therapies are the most frequently interrupted class of anticancer agents. Alopecia is a common cutaneous adverse event reported with CK4/6i therapy. Though the clinical characteristics and therapeutic response of EIA have been well documented, few studies have characterized alopecia in patients treated with CDK4/6i.

METHODS

This study analyzed a retrospective cohort of 28 breast cancer patients diagnosed with endocrine-induced alopecia (EIA) or CDKiA. Comparative analysis of the clinical characteristics of alopecia and therapeutic response to minoxidil was conducted. Therapeutic response to minoxidil (LDOM or topical [5%] solution or foam) was assessed by both Dean Scale and qualitative clinical improvement by comparison of pretreatment and posttreatment clinical images by single-blinded, board-certified academic dermatologists (ST and BD).

RESULTS

CDKiA was clinically similar to androgenetic alopecia and specific vertex involvement was more common in patients treated with CDK4/6i + ET than endocrine monotherapy (n = 7 [70.0%] vs n = 4 [36.4%]; p = 0.04), respectively. After 4-6 months of minoxidil, there was a moderate to significant qualitative alopecia improvement in 80% of CDKiA patients versus 94.4% of EIA patients. Additionally, superior improvement of mean Dean Score grade was observed in EIA (with change from pre- to posttreatment - 0.44; p = 0.0002).

CONCLUSION

Compared to endocrine monotherapy, patients on combination CDK4/6i + ET had greater extent of vertex involvement and were more recalcitrant to minoxidil. The preferential vertex involvement observed in CDKiA suggests that combination therapy with minoxidil and topical antiandrogens with poor systemic absorption should be studied in this setting.

Dermatologic toxicities to inhibitors of cyclin-dependent kinases CDK 4 and 6: An updated review for clinical practice

Cyclin-dependent kinase (CDK) 4/6 inhibitors (palbociclib, ribociclib and abemaciclib) have revolutionized the treatment of metastatic breast carcinoma. They currently form the first-line treatment, in combination with endocrine agents, for the management of locally advanced or metastatic hormone receptor-positive (HR + ), human epidermal growth factor receptor 2-negative (HER2-) breast cancer, the largest subtype of breast carcinoma. CDK 4/6 inhibitors have shown comparable efficacy outcomes with predictable and manageable adverse events. In this setting, dermatologic toxicity appears to be relatively frequent, accounting for up to 15% of all reported adverse events. It is usually mild to moderate in intensity and does not normally constitute a dose-limiting toxicity. The range of dermatologic adverse events includes both non-specific entities (maculopapular rash, pruritus, alopecia) and more characteristic toxicities related to CDK4/6 inhibitors, such as vitiligo-like lesions or cutaneous lupus erythematosus. Finally, more severe or life-threatening skin reactions can occasionally occur. The main dermatologic manifestations associated with CDK4/6 inhibitors, as well as management thereof, are described in this comprehensive review.

Cyclin-Dependent Kinase 4/6 Inhibitors and Dermatologic Adverse Events: Results from the EADV Task Force "Dermatology for Cancer Patients" International Study

BACKGROUND

The introduction of cyclin-dependent kinase inhibitors (CDK4/6i) was a great advance in therapeutics for patients with estrogen receptor+/human epidermal growth factor receptor (HER2) locally advanced and metastatic breast cancer. Despite the increasing use of these agents, their adverse drug-related events have not yet been fully characterized. We describe the spectrum of cutaneous adverse reactions occurring in advanced breast cancer patients treated with cyclin-dependent kinase inhibitors, analyzing types, severity, time to onset, and possible treatment outcomes.

METHODS

We performed a multicentric retrospective study including patients with advanced breast cancer who developed cutaneous lesions during treatment with CDK4/6i in the period from June 2020 to June 2021. Patients > 18 years were recruited at eleven onco-dermatology units located in Albania (1), Argentina (1), France (1), Greece (3), Italy (3), and Spain (2). We evaluated patients' epidemiological and clinical characteristics, types of cutaneous adverse events, their time to onset, and treatment outcomes. The severity of the skin reactions was assessed using the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 score.

RESULTS

Seventy-nine patients (median age: 62.3 years; range 39-83 years) were included in the study, and, collectively, we recorded a total of 165 cutaneous adverse events during follow-up visits. The most frequent cutaneous reactions were pruritus (49/79 patients), alopecia (25/79), and eczematous lesions (24/79). Cutaneous toxicities were usually mild in severity (>65%) and occurred after a median of 6.5 months. Only four patients (5%) required treatment discontinuation due to the severity of the skin lesions. The majority of the skin reactions were managed with topical treatments.

CONCLUSIONS

To the best of our knowledge, we present the largest case series of cutaneous adverse events developing in advanced breast cancer patients treated with CDK4/6i. We showed that cutaneous toxicities are usually mild in severity, and manageable with standard supportive care; however, in selected cases, they can lead to treatment discontinuation with possible implications for patients' clinical outcomes.

Skin Toxicities with Cyclin-Dependent Kinase 4/6 Inhibitors in Breast Cancer: Signals from Disproportionality Analysis of the FDA Adverse Event Reporting System

BACKGROUND

Cyclin-dependent kinase (CDK)-4/6 inhibitors have been associated with dermatologic reactions, especially alopecia, in pivotal trials.

OBJECTIVE

We aimed to comprehensively describe skin toxicities with CDK4/6 inhibitors reported in the real world through the US FDA Adverse Event Reporting System (FAERS).

METHODS

Cutaneous adverse events (AEs) were characterized in terms of spectrum and clinical features, including seriousness (with fatality proportion), latency, and discontinuation. Disproportionality analyses were performed through the reporting odds ratio (ROR) and 95% confidence interval (CI) by comparing CDK4/6 inhibitors with other anticancer drugs used in breast cancer.

RESULTS

As of December 2020, a total of 7986 cutaneous events were reported with CDK4/6 inhibitors (15% of total AEs with CDK4/6 inhibitors), mainly by consumers (39.6%), with 43.5% classified as serious and 25% requiring discontinuation. In 49% of the cases, five or more noncutaneous events were co-reported. The most frequently reported cutaneous events were alopecia (N = 3528), rash (N = 1493), and pruritus (N = 1211): rashes were recorded in the first month (median onset 28 days), whereas alopecia and nail alterations were recorded after a median of 67 and 112 days, respectively. Several cutaneous AEs were associated with increased reporting, including vitiligo (N = 6; ROR 8.88; 95% CI 2.95-22.46) and bullous dermatitis with ribociclib (N = 7; ROR 2.90; 95% CI 1.13-6.27); erythema multiforme with abemaciclib (N = 9; ROR 5.80; 95% CI 2.57-11.48); onychoclasis (N = 142, ROR 2.27; 95% CI 1.83-2.79) and trichorrhexis (N = 22; ROR 3.27; 95% CI 1.78-5.93) with palbociclib.

CONCLUSIONS

Although causality cannot be demonstrated, a diverse reporting pattern of cutaneous AEs emerged from FAERS, including dermal/epidermal conditions, hair/nail disorders, and serious bullous conditions, with variable onsets and a remarkable proportion of discontinuations. The potential differential reporting among CDK4/6 inhibitors deserves further investigation.

Diverse landscape of dermatologic toxicities from small-molecule inhibitor cancer therapy

BACKGROUND

Advances in molecular biology and genetics have contributed to breakthrough treatments directed at specific pathways associated with the development of cancer. Small-molecule inhibitors (Nibs) aimed at a variety of cellular pathways have been efficacious; however, they are associated with significant dermatologic toxicities.

METHODS

We conducted a comprehensive review of dermatologic toxicities associated with Nibs categorized into the following five groups: (a) mitogen-activated protein kinase; (b) growth factor/multi-tyrosine kinase; (c) cell division/DNA repair; (d) signaling associated with myeloproliferative neoplasms; and (e) other signaling pathways. Prospective phase I, II, or III clinical trials, retrospective literature reviews, systematic reviews/meta-analyses, and case reviews/reports were included for analysis.

RESULTS

Dermatologic toxicities reviewed were associated with every class of Nibs and ranged from mild to severe or life-threatening adverse skin reactions. Inflammatory reactions manifesting as maculopapular, papulopustular/acneiform, and eczematous lesions were frequent types of dermatologic toxicities seen with Nibs. Squamous cell carcinoma with keratoacanthoma-like features was associated with a subset of Nibs. Substantial overlap in dermatologic toxicities was found between Nibs.

CONCLUSIONS

Dermatologic toxicities from Nibs are diverse and may overlap between classes of Nibs. Recognition of the various types of toxicities from Nibs is critical for patient care in the era of "oncodermatology/dermatopathology."