Skin rash following Administration of Apalutamide in Japanese patients with Advanced Prostate Cancer: an integrated analysis of the phase 3 SPARTAN and TITAN studies and a phase 1 open-label study

Clinical Outcomes and Risk Stratification in Patients With Metastatic Hormone-Sensitive Prostate Cancer Treated With New-Generation Androgen Receptor Signaling Inhibitors

BACKGROUND

Optimal drug selection for metastatic hormone-sensitive prostate cancer (mHSPC) remains unclear. We therefore assessed the clinical outcomes of mHSPC treated with new-generation androgen receptor pathway inhibitors (ARSIs) and identified risk factors associated with the prognosis of mHSPC.

METHODS

We retrospectively reviewed 324 patients with mHSPC who were treated with ARSIs, including abiraterone acetate, enzalutamide, and apalutamide, between January 2018 and December 2022. In addition to assessing the prostate-specific antigen (PSA) response and overall survival (OS) during ARSI treatment, we investigated several potential risk factors for a poor OS in patients with mHSPC.

RESULTS

Patients with a ≥ 90% PSA reduction (hazard ratio [HR]: 0.24, 95% confidence interval [CI], 0.10-0.58; P = .002) and those whose PSA declined to ≤ 0.2 ng/mL (HR: 0.22, 95% CI, 0.08-0.63; P = .005) showed significantly better OS than other patients. Gleason grade group 5 (GG5), presence of liver metastasis, and an LDH ≥ 250 U/L were identified as prognostic factors significantly associated with a poor OS, with HRs of 2.31 (95% CI, 1.02-5.20; P = .044), 7.87 (95% CI, 2.61-23.8; P < .001) and 3.21 (95% CI, 1.43-7.23; P = .005).

CONCLUSION

We identified GG5, the presence of liver metastasis, and elevated LDH at the diagnosis as significant factors predicting the OS of mHSPC, but the choice of ARSIs did not affect the prognosis. The potential prognostic impact of these markers requires further investigation.

Cutaneous Adverse Reactions to Apalutamide: Case Series with Clinical and Pathological Correlations

Abstract is missing (Short communication)

Comparative analysis of novel hormonal agents in non-metastatic castration-resistant prostate cancer: A Taiwanese perspective

BACKGROUND

Non-metastatic castration-resistant prostate cancer (nmCRPC) is an asymptomatic condition with the potential to progress to metastasis. Novel hormonal agents (NHAs) are currently considered the gold standard treatment for nmCRPC, offering significant survival benefits. However, further evidence is needed to determine whether there are differences in the performance of these drugs among Asian populations.

METHODS

This retrospective analysis of nmCRPC patients aims to compare the efficacy and safety of three NHAs-apalutamide, darolutamide, and enzalutamide. Data were collected from two prominent prostate care centers in Taichung, Taiwan. Patient characteristics, treatment details, PSA responses, and adverse events were analyzed. Statistical comparisons were performed, and the study received Institutional Review Board approval.

RESULTS

Total of 64 patients were recruited in this study, including 29 darolutamide, 26 apalutamide, and 9 enzalutamide patients. Baseline characteristics varied between the three patient groups, but the treatment response still revealed similar results. The apalutamide group experienced more adverse events, notably skin rash. Discontinuation rates due to adverse events differed among the groups, and patients receiving darolutamide were less likely to discontinue treatment.

CONCLUSION

This real-world study provides insights into NHA utilization in nmCRPC within the Taiwanese population. Adverse event profiles varied, emphasizing the need for individualized treatment decisions. The study underscores the importance of regional considerations and contributes valuable data for optimizing treatment outcomes in nmCRPC.

A practical guide for the use of apalutamide for non-metastatic castration-resistant prostate cancer in Australia

Studies of patients with castrate-resistant prostate cancer at high risk of developing overt metastases but with no current evidence of evaluable disease on computed tomography or bone scan non-metastatic castrate-resistant prostrate cancer have demonstrated increased metastasis-free survival and overall survival following treatment with the next-generation oral anti-androgen apalutamide (in addition to therapies that aim to lower testosterone to castrate levels) or luteinizing hormone-releasing hormone antagonist or surgical castration. Patients receiving apalutamide can be managed by medical oncologists, radiation oncologists, or urologists, preferably as part of a multidisciplinary team. However, the importance of additional safety monitoring for significant adverse effects and drug interactions should not be underestimated. The toxicities of apalutamide are manageable with experience and should be managed proactively to minimize their impact on patients. Monitoring of patients for apalutamide-specific toxicities, including skin rash, hypothyroidism, and QT prolongation should be carried out regularly, particularly in the first few months following initiation. Monitoring should continue alongside monitoring for toxicities of androgen deprivation, including cardiovascular risk, hot flashes, weight gain, bone health, muscle wasting, and diabetic risk. This review is a practical guide to the use of apalutamide describing the management of patients including dosing and administration, toxicities, potential drug interactions, and safety monitoring requirements.

Japanese clinical practice guidelines for prostate cancer 2023

This fourth edition of the Japanese Clinical Practice Guidelines for Prostate Cancer 2023 is compiled. It was revised under the leadership of the Japanese Urological Association, with members selected from multiple academic societies and related organizations (Japan Radiological Society, Japanese Society for Radiation Oncology, the Department of EBM and guidelines, Japan Council for Quality Health Care (Minds), Japanese Society of Pathology, and the patient group (NPO Prostate Cancer Patients Association)), in accordance with the Minds Manual for Guideline Development (2020 ver. 3.0). The most important feature of this revision is the adoption of systematic reviews (SRs) in determining recommendations for 14 clinical questions (CQs). Qualitative SRs for these questions were conducted, and the final recommendations were made based on the results through the votes of 24 members of the guideline development group. Five algorithms based on these results were also created. Contents not covered by the SRs, which are considered textbook material, have been described in the general statement. In the general statement, a literature search for 14 areas was conducted; then, based on the general statement and CQs of the Japanese Clinical Practice Guidelines for Prostate Cancer 2016, the findings revealed after the 2016 guidelines were mainly described. This article provides an overview of these guidelines.

Impact of a rash management guide in patients receiving apalutamide for high-risk localized prostate cancer in the Apa-RP study

BACKGROUND/OBJECTIVES

Based on the SPARTAN and TITAN studies, apalutamide is approved for patients with nonmetastatic castration-resistant and metastatic castration-sensitive prostate cancer. Skin rash was a common adverse reaction across indications. We hypothesized that earlier identification and intervention could improve rash outcomes.

SUBJECTS/METHODS

A prespecified rash management guide outlining recommended skin care practices was provided to all patients enrolled in Apa-RP (NCT04523207). Rash-related safety data from Apa-RP were compared descriptively with data from SPARTAN and TITAN.

RESULTS

Patients in Apa-RP experienced improved rash-related outcomes vs those in SPARTAN and TITAN.

CONCLUSIONS

Increased vigilance and proactive management may reduce the incidence, severity, and duration of rash during apalutamide treatment.

Apalutamide-induced ichthyosiform eruption

Not available

Real-world analysis of apalutamide-associated skin rash in Chinese patients with prostate cancer

PURPOSE

This study aimed to explore the clinical characteristics of apalutamide-associated skin rash and management of skin rash in real-world Chinese patients with prostate cancer.

METHODS

We investigated 138 patients with prostate cancer who received apalutamide in the Second Hospital of Tianjin Medical University from January 2022 to March 2023. The primary end points were the incidence of skin rash and the time to skin rash. The second end points were the grade of skin rash, the time to remission, the rate of recurrence of skin rash, clinical risk factors and management of skin rash.

RESULTS

One hundred patients were analyzed. Patients were a median of 73 years old (IQR 68-77.75). Thirty-two patients (32%) developed apalutamide‑associated skin rash. The median time to incidence and remission of skin rash were 57.5 and 11.5 days, respectively. Of 32 skin rash, 27 patients had apalutamide therapy maintained after rash remission. There were seven patients having recurrence of skin rash. By multivariable logistic regression analysis, we revealed that hypertension history (OR 3.22, 95% CI 1.09-9.53, p = 0.035), bad life-styles (OR 3.29, 95% CI 1.11-9.8, p = 0.032), ECOG ≥ 1 (OR 3.92, 95% CI 1.33-11.55, p = 0.013), and high tumor burden (OR 3.13, 95% CI 1.07-9.14, p = 0.037) were independently associated with higher incidence of skin rash.

CONCLUSION

Nearly one-third of Chinese patients experienced skin rash after taking apalutamide in our study. The poor health patients might have a higher incidence of apalutamide-associated skin rash.

Real-world prostate-specific antigen response and progression to castration-resistant prostate cancer among men with metastatic castration-sensitive prostate cancer treated with apalutamide: a multi-institutional study in the Chu-shikoku Japan Urological Consortium

BACKGROUND

Japanese men receiving apalutamide often experience skin-adverse events (AEs), possibly requiring treatment interruption or dose reduction. However, concerns have arisen regarding the impact of these adjustments on the efficacy of apalutamide. Our study evaluated the efficacy, safety, and persistence of apalutamide in men with metastatic castration-sensitive prostate cancer (mCSPC).

METHODS

We retrospectively reviewed the medical records of 108 men with mCSPC from 14 Japanese institutions. The primary outcomes were the efficacy of apalutamide: prostate-specific antigen (PSA) response (50%, 90% and < 0.2 decline) and progression to castration-resistant prostate cancer (CRPC). The secondary outcomes were the skin-AE and compliance of apalutamide.

RESULTS

PSA50%, PSA90% and PSA < 0.2 declines were observed in 89.8, 84.3 and 65.7%, and the median time to CRPC progression was not reached. PSA < 0.2 decline and an initial full dose of apalutamide were significantly associated with a longer time to CRPC. The most common AE was skin-AE (50.9%), and there was no association between the occurrence of skin-AE and the time to CRPC (P = 0.72). The median apalutamide persistence was 29 months, which was longer in the initial full dose recipients than in the reduced dose recipients. The dosage is reduced in about 60% of patients within the first year of treatment in the initial full dose recipients.

CONCLUSIONS

Our findings indicate the effectiveness of apalutamide in Japanese men with mCSPC, despite a substantial portion requiring dose reduction within a year among the initial full dose recipients.

Case report: Apalutamide-induced severe lethal cutaneous adverse effects in China

Introduction

Apalutamide is a novel agent for castration-resistant prostate cancer while skin rashes are the most common untoward reactions. Up to now, most of the reported dermatologic adverse events (dAEs) allocated to mild and moderate with a fair prognosis. Herein, we report a case series of severe dAEs in China caused by apalutamide.

Case presentation

The four patients all developed severe and lethal drug eruptions including Stevens-Johnson syndrome and toxic epidermal necrolysis with a mean incubation period of 40 days. On the basis of the medical condition, all the patients were suggested to withdraw apalutamide and three of them recovered. Of note, attempts of rechallenges of apalutamide may be fatal.

Discussion

The incidence of dAEs in previously conducted clinical trials exceeded 20%, with maculopapular rashes being the most common feature. However, the incidence and severity varied in different geographic regions and ethnicities. Inadequate attention was paid to severe cutaneous adverse reactions. Long latency may easily lead to the misdiagnosis of dAEs, and immediate withdrawal of apalutamide is the cornerstone of therapies.

Conclusion

Special and adequate attention should be paid to apalutamide-attributed severe cutaneous adverse effects. Besides, the prognosis of severe drug eruptions may be disappointing, and in-time withdrawal is vital.

Apalutamide for metastatic castration-sensitive prostate cancer: final analysis of the Asian subpopulation in the TITAN trial

The final analysis of the phase 3 Targeted Investigational Treatment Analysis of Novel Anti-androgen (TITAN) trial showed improvement in overall survival (OS) and other efficacy endpoints with apalutamide plus androgen deprivation therapy (ADT) versus ADT alone in patients with metastatic castration-sensitive prostate cancer (mCSPC). As ethnicity and regional differences may affect treatment outcomes in advanced prostate cancer, a post hoc final analysis was conducted to assess the efficacy and safety of apalutamide in the Asian subpopulation. Event-driven endpoints were OS, and time from randomization to initiation of castration resistance, prostate-specific antigen (PSA) progression, and second progression-free survival (PFS2) on first subsequent therapy or death. Efficacy endpoints were assessed using the Kaplan-Meier method and Cox proportional-hazards models without formal statistical testing and adjustment for multiplicity. Participating Asian patients received once-daily apalutamide 240 mg ( n = 111) or placebo ( n = 110) plus ADT. After a median follow-up of 42.5 months and despite crossover of 47 placebo recipients to open-label apalutamide, apalutamide reduced the risk of death by 32% (hazard ratio [HR]: 0.68; 95% confidence interval [CI]: 0.42-1.13), risk of castration resistance by 69% (HR: 0.31; 95% CI: 0.21-0.46), PSA progression by 79% (HR: 0.21; 95% CI: 0.13-0.35) and PFS2 by 24% (HR: 0.76; 95% CI: 0.44-1.29) relative to placebo. The outcomes were comparable between subgroups with low- and high-volume disease at baseline. No new safety issues were identified. Apalutamide provides valuable clinical benefits to Asian patients with mCSPC, with an efficacy and safety profile consistent with that in the overall patient population.

Apalutamide-induced lichenoid reaction in a patient with non-metastatic castrate-resistant prostate cancer

INTRODUCTION

Apalutamide is an oral selective androgen receptor inhibitor, approved by the FDA for the treatment of patients with non-metastatic, castration-resistant prostate cancer (M0 CRPC) at high risk of developing metastases and for patients with metastatic castration-sensitive prostate (mHSPC) in association with androgen deprivation therapy (ADT). In the registration studies, skin reactions were reported among the most common side effects and as an adverse event of special interest.

CASE REPORT

Apalutamide-induced rash includes a wide spectrum of different types of skin reactions, but few cases reports and case series have described this adverse event. Here, we report an M0 CRPC patient who experienced a rare skin adverse event, a lichenoid reaction.

MANAGEMENT & OUTCOME

After 4 months of therapy with apalutamide, the patient reported dorsal pricking and dry skin. Lichenoid reaction was confirmed histologically and its correlation to the drug was demonstrated after pursuing a multidisciplinary approach.

DISCUSSION

To our knowledge, this is one of the first cases of Apalutamide-related lichenoid reaction and this clinical case showed the relevance of a multidisciplinary management when assessing drug-related adverse events. A broader knowledge of the spectrum of drug-related reactions would allow for a better diagnosis and therapy management by both physicians and patients.

A real-world disproportionality analysis of apalutamide: data mining of the FDA adverse event reporting system

Background: Apalutamide is a new drug class, which is approved to treat prostate cancer (PCa). The aim of our study was to assess the safety profiles of apalutamide in real-world through data mining of the United States Food and Drug Administration Adverse Event Reporting System (FAERS). Method: We included adverse event (AE) reports regarding apalutamide submitted to the FAERS from 2018 quarter 1 (2018Q1) to 2022 quarter 1 (2022Q1). Disproportionality analyses, including reporting odds ratio (ROR), were performed to identify the signals of AEs in patients receiving apalutamide. A signal was detected if the lower limit of the 95% confidence interval (CI) of ROR >1 and at least 3 AEs were reported. Results: The FAERS database documented 4,156 reports regarding apalutamide from 1 January 2018, to 31 March 2022. A total of 100 significant disproportionality preferred terms (PTs) were retained. Frequently observed AEs in patients receiving apalutamide included rash, fatigue, diarrhea, hot flush, fall, weight decreased, hypertension. The most significant system organ class (SOC) was "skin and subcutaneous tissue disorders", which mainly consisted of dermatological adverse events (dAEs). The additional AEs observed with the significantly signal contain lichenoid keratosis, increased eosinophil count, bacterial pneumonia, pulmonary tuberculosis, hydronephrosis. Conclusion: Our findings provide valuable evidence for apalutamide safety profile in the real-world, which could help clinicians and pharmacists to enhance their vigilance and improve the safety of apalutamide in clinical practice.

A retrospective study on the incidence, management and risk factors of skin rash in patients with advanced prostate cancer in Japan

BACKGROUND

Worldwide, prostate cancer (PC) is the second most diagnosed cancer and the fifth leading cause of cancer death in men. Hormonal therapies, commonly used for PC, are associated with a range of treatment-emergent adverse events (TEAEs). The population from Japan seems to be at higher risk of developing TEAEs of skin rash compared to the overall global population. This study was conducted to get a better insight into the incidence, management, and risk factors for skin rash during active treatment for advanced PC in Japan.

METHODS

A retrospective cohort of PC patients was identified and subsequently categorized, into non-metastatic and metastatic castration-resistant prostate cancer patients (nmCRPC and mCRPC), and metastatic castration-naïve prostate cancer patients (mCNPC). The analysis was based on a dataset from the Medical Data Vision (MDV) database. Descriptive statistics were determined, and a multivariate Cox proportional hazards model was used to the associated risk factors for the onset of rash.

RESULTS

Overall, 1,738 nmCRPC patients, 630 mCRPC patients, and 454 mCNPC patients were included in this analysis. The median age was 78 years old and similar across the three cohorts. The skin rash incidence was 19.97% for nmCRPC cohort, 28.89% for mCRPC cohort, and 28.85% for mCNPC cohort. The median duration of skin rash ranged from 29 to 42 days. Statistically significant risk factors for developing skin rash included a history of allergy or hypersensitivity (all cohorts), increased age (nmCRPC and mCRPC), a body mass index (BMI) of < 18.5 (nmCRPC and mCRPC), and a PSA level higher than the median (nmCRPC). Skin rash was commonly managed with systemic and topical corticosteroids which ranged from 41.76% to 67.03% for all cohorts. Antihistamines were infrequently used.

CONCLUSION

This study provides a better understanding of the real-world incidence, onset, duration, management and risk factors of skin rash in patients on active PC treatment in Japan. It was observed that approximately 20-30% of PC patients experience skin rash. Development of skin rash was associated with previous allergy or hypersensitivity, BMI of < 18.5, increased age and higher PSA levels, and was usually treated with corticosteroids.

Darolutamide for non-metastatic castration-resistant prostate cancer: Efficacy, safety, and clinical perspectives of use

Darolutamide, a second-generation androgen receptor inhibitor (SGARI), has been shown to increase metastasis-free survival and overall survival among men with non-metastatic castration-resistant prostate cancer (nmCRPC). Its unique chemical structure potentially provides efficacy and safety advantages over the SGARIs apalutamide and enzalutamide, which are also indicated for nmCRPC. Despite a lack of direct comparisons, the SGARIs appear to have similar efficacy, safety, and quality of life (QoL) results. Indirect evidence suggests that darolutamide is preferred for its good adverse event profile, an attribute valued by physicians, patients, and their caregivers for maintaining QoL. Darolutamide and others in its class are costly; access may be a challenge for many patients and may lead to modifications to guideline-recommended regimens.

Effects of apalutamide dose reduction on skin-related adverse events in patients with advanced prostate cancer: A multicenter retrospective study

BACKGROUND

We aimed to evaluate the effects of apalutamide dose reduction on skin-related adverse events (AEs) and castration-resistant prostate cancer (CRPC)-free survival in patients with advanced prostate cancer (PC).

METHODS

We retrospectively evaluated 35 patients with nonmetastatic CRPC and 72 patients with treatment-naïve metastatic castration-sensitive PC (mCSPC) who were treated with apalutamide. The primary outcome was the effect of apalutamide dose reduction on skin-related AEs. The secondary outcomes were the effect of apalutamide dose reduction on skin-related AEs in patients with small body size, postskin AE apalutamide discontinuation rate, and CRPC-free survival in patients with mCSPC treated with upfront apalutamide plus androgen deprivation therapy.

RESULTS

Of the 107 patients, 65 (60.7%) and 42 (39.3%) were treated with full and reduced doses of apalutamide, respectively. The skin-related AE rate was not significantly different between the groups (55% vs. 43%, p = 0.761). In the group receiving reduced apalutamide dose, the incidence of skin-related AEs was significantly lower in patients with small body sizes (body weight <67 kg and body mass index <24 kg/m² ) than in those with other body sizes. The postskin AE apalutamide discontinuation rate was significantly differed between patients receiving the full (50%) and reduced (16.7%) doses. In the 72 patients with mCSPC, CRPC-free survival was not significantly different between the full and reduced dose groups.

CONCLUSION

Apalutamide dose reduction was not significantly associated with the incidence of skin-related AEs. However, dose reduction in patients with small body sizes may alleviate skin-related AEs without sacrificing oncological outcomes.

Apalutamide-Induced Toxic Epidermal Necrolysis in a Caucasian Patient with Metastatic Castration-Sensitive Prostate Cancer: A Case Report and Review of the Literature

Apalutamide is a novel nonsteroidal androgen receptor inhibitor that has been shown to improve outcomes for patients with nonmetastatic castration-resistant prostate cancer and metastatic castration-sensitive prostate cancer when combined with androgen deprivation therapy. Apalutamide-induced skin rash occurred commonly in clinical trials, with 23.8-27.1% of patients experiencing a rash of any grade, and 5.2-6.3% experiencing a rash of grade three or higher. There were no cases of severe cutaneous adverse reactions (SCARs) such as Stevens-Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN) reported in clinical trials; however, there are rare cases reported in the literature with the majority occurring in Asian patients. An 83-year-old Caucasian male was commenced on apalutamide, combined with degarelix, for the management of metastatic castration-sensitive prostate cancer. During week five of apalutamide treatment, the patient developed a widespread erythematous maculopapular rash. On presentation, the rash affected 80% of his body surface area (BSA) and a diagnosis of a severe cutaneous drug eruption was made. He was commenced on methylprednisolone (MP) therapy. Despite 5 days of MP, the rash continued to deteriorate involving 95% of his BSA. Nikolsky's sign was positive. A diagnosis of overlap SJS/TEN was made, supported by skin biopsy. His SCORTEN score was three. He was then commenced on intravenous immunoglobulin and transferred to the intensive care unit. Over the coming days, the rash began to stabilise, and his steroid dose was weaned. He was discharged from hospital 38 days after rash onset. We report the first suggested case of apalutamide-induced SJS/TEN in a Caucasian patient. We discuss other cases of apalutamide-induced SCARs reported in the literature. Risk factors seem to include low body weight and Japanese race, as well as short time to onset of rash.

Acute generalized exanthematous pustulosis during apalutamide treatment in a patient with prostate cancer

Introduction

Acute generalized exanthematous pustulosis is a type of severe cutaneous drug adverse reaction. While apalutamide is known for its high incidence of cutaneous adverse events, it remains unknown whether acute generalized exanthematous pustulosis can develop during apalutamide treatment.

Case presentation

A 72-year-old man with metastatic castration-sensitive prostate cancer developed small erythema on the face and trunk after 41 days of apalutamide treatment. Three days later, apalutamide was discontinued. However, 9 days after the discontinuation of apalutamide, the patient had a high fever with hemodynamic instability and showed diffuse erythema throughout the body with numerous small pustules. Skin biopsy revealed subcorneal and intraepidermal pustules admixed with many eosinophils, which led to the diagnosis of acute generalized exanthematous pustulosis. The skin rash improved in 14 days with systemic corticosteroid administration.

Conclusion

We present the first case of a skin rash with clinical features of acute generalized exanthematous pustulosis during apalutamide treatment.

Toxic Epidermal Necrolysis Caused by Apalutamide: A Case Report of Treatment Using Etanercept with Conventional Steroid Therapy

Abstract is missing (Short communication)

Real-world analysis of apalutamide-associated skin adverse events in Japanese patients with advanced prostate cancer: a multi-institutional study in the Chu-shikoku Japan Urological Consortium

BACKGROUND

Apalutamide-associated skin adverse events are more common in the Japanese than in the global population. However, limited clinical data have hampered further understanding. This real-world study investigated the clinical characteristics of skin adverse events in patients with advanced prostate cancer.

METHODS

We retrospectively reviewed 119 patient records from 16 institutions in Japan. Skin adverse events were graded according to the Common Terminology Criteria for Adverse Events (v5.0). The incidence and characteristics of skin adverse events (along with the clinical risk factors for their incidence, worsening, and recurrence) were evaluated.

RESULTS

Fifty-five patients (46.2%) experienced skin adverse events. The median times to the incidence and remission of skin adverse events were 62 and 30 days, respectively. Grade 3 skin adverse events were observed in 15 patients (12.6%). The median time from the first incidence to apalutamide interruption was significantly longer in patients with progression to grade 3 skin adverse events than in those without such a progression (8 vs. 0 days, p = 0.005). Skin adverse events were observed in 45.2% of patients who resumed apalutamide treatment (median treatment interruption time: 31.5 days). Sixteen patients (13.4%) permanently discontinued apalutamide due to skin adverse events. No significant clinical risk factors for the incidence, worsening and recurrence of apalutamide-associated skin adverse events were observed.

CONCLUSIONS

Nearly half of the Japanese patients in this study experienced skin adverse events following apalutamide administration. The time to apalutamide discontinuation after the incidence of skin adverse events was positively correlated with the worsening of these events.

Apalutamide-associated skin rash in patients with prostate cancer: Histological evaluation by skin biopsy

INTRODUCTION

Apalutamide-associated skin rash is a more common adverse event in the Japanese population than in the global population. However, its mechanism remains elusive, and limited histopathological information hampers further understanding.

CASE PRESENTATION

Case 1: a 71-year-old man with metastatic castration-sensitive prostate cancer developed a skin rash after 70 days of apalutamide treatment. Case 2: a 71-year-old man with non-metastatic castration-resistant prostate cancer developed a skin rash after 71 days of apalutamide treatment. In both cases, the skin rash presented as a slightly exudative erythema. The histology showed spongiosis of the epidermis and perivascular and interstitial infiltration of lymphocytes and eosinophils in the upper dermis without necrotic keratinocytes.

CONCLUSION

Apalutamide-induced skin rashes can involve an eczematous reaction clinically and histologically.