Randomized phase III study of gemcitabine, cisplatin plus S-1 versus gemcitabine, cisplatin for advanced biliary tract cancer (KHBO1401- MITSUBA).

BACKGROUND: Gemcitabine/cisplatin (GC) combination therapy has been the standard palliative chemotherapy for patients with advanced biliary tract cancer (BTC). No randomized clinical trials have been able to demonstrate the survival benefit over GC during the past decade. In our previous phase II trial, adding S-1 to GC (GCS) showed promising efficacy and we aimed to determine whether GCS could improve overall survival compared with GC for patients with advanced BTC. METHODS: We performed a mulitcenter, randomized phase III trial across 39 centers. Enrolled patients were randomly allocated (1:1) to either the GCS or GC arm. The GCS regimen comprised gemcitabine (1000 mg/m2 ) and cisplatin (25 mg/m2 ) infusion on day 1 and 80 mg/m2 of S-1 on days 1-7 every 2 weeks. The primary endpoint was overall survival (OS) and the secondary endpoints were progression-free survival (PFS), response rate (RR), and adverse events (AEs). This study is registered with Clinical trial identification: NCT02182778. RESULTS: Between July 2014 and February 2016, 246 patients were enrolled. The median OS and 1-year OS rate were 13.5 months and 59.4% in the GCS arm and 12.6 months and 53.7% in the GC arm, respectively (hazard ratio [HR] 0.79, 90% confidence interval [CI]: 0.628-0.996; P = .046 [stratified log-rank test]). Median PFS was 7.4 months in the GCS arm and 5.5 months in the GC arm (HR 0.75, 95% CI: 0.577-0.970; P = .015). RR was 41.5% in the GCS arm and 15.0% in the GC arm. Grade 3 or worse AEs did not show significant differences between the two arms. CONCLUSIONS: GCS is the first regimen which demonstrated survival benefits as well as higher RR over GC in a randomized phase III trial and could be the new first-line standard chemotherapy for advanced BTC. To exploit the advantage of its high RR, GCS is now tested in the neoadjuvant setting in a randomized phase III trial for potentially resectable BTC.

Transition of the PD-1 occupancy of nivolumab on T cells after discontinuation and response of nivolumab re-challenge.

Although nivolumab is administered every two or four weeks, high programmed cell death-1 (PD-1) binding of nivolumab on T cells lasting for several months has been reported. A relationship between the PD-1 occupancy rate on T-cells and the efficacy of nivolumab is not yet fully understood. The present study used flow cytometric analyses to determine the time-dependence of PD-1 occupancy in five patients who discontinued nivolumab. The relationship between PD-1 occupancy at relapse and the efficacy of re-challenge was also studied. Occupancies after discontinuation were measured at a total of 32 points. The data indicated that it took 32.4 and 48.9 weeks to decrease occupancy by 50 and 70%, respectively. Subsequently, two patients had recurrence and were re-challenged with nivolumab. At that time, one patient had 70.8% occupancy while the other had 6.6%. Treatment was effective only for the patient with lower occupancy. Overall, the present study suggests that re-challenge with nivolumab may be efficacious in patients with low occupancy at recurrence.

A phase I study of LCL161, a novel oral pan-inhibitor of apoptosis protein (IAP) antagonist, in Japanese patients with advanced solid tumors.

INTRODUCTION: LCL161 is a novel oral pan-inhibitor of apoptosis protein (IAP) antagonist. LCL161 enhances paclitaxel activity in cell lines and xenograft models. A phase I study of LCL161 combined with paclitaxel for the treatment of Japanese patients with advanced solid tumors was conducted. METHODS: Each patient received oral LCL161 in a single weekly dose on days 1, 8, and 15 of a 21-day treatment cycle. In the second cycle, patients received a combination treatment with weekly paclitaxel (80 mg/m2 ) whenever possible. A Bayesian logistic regression model by escalation with the overdose control principle was used. RESULTS: Nine patients were treated with LCL161 at a dose of 600 mg (five patients) or 1200 mg (four patients). Seven patients were treated with LCL161 plus paclitaxel, and two patients received only LCL161 monotherapy. Because this study was terminated early due to a change in the LCL161 development strategy, the maximum tolerated dose (MTD) was not determined. One patient treated with LCL161 monotherapy at a dose of 1200 mg experienced dose limitind toxicity (grade 3 maculopapular rash). Another patient died on day 86 of bacterial pneumonia, which was suspected to be related to the study treatment. The most common serious adverse events were infections and infestations (n = 3). CONCLUSION: The present study suggests that the risk of infection may increase when LCL161 is combined with paclitaxel, but other conclusions about the MTD, pharmacokinetic profile, and preliminary activity of the combination of LCL161 plus paclitaxel were not drawn.

Apixaban in Japanese patients with cancer-associated venous thromboembolism: a multi-center phase II trial.

BACKGROUND: Recent pivotal phase III trials involving direct oral anticoagulant (DOAC) versus low molecular weight heparin have demonstrated the utility of DOACs in Western patients with cancer-associated venous thromboembolism (VTE). However, these trials did not include Japanese patients. This phase II trial evaluated the safety and efficacy of apixaban in Japanese patients with cancer-associated VTE (UMIN000028447). METHOD AND RESULTS: Apixaban was initiated at 10 mg twice daily for 7 days, followed by 5 mg twice daily for 23 weeks. The primary endpoint was the incidence of major or clinically relevant non-major (CRNM) bleeding events during the treatment period. The study was terminated due to safety concerns after enrolling 27 patients. Median age was 71 years; median body weight was 51.3 kg; and major primary tumor sites were the gastrointestinal tract (26%) and lung (19%). During the median follow-up period of 5.4 months, major or CRNM bleeding occurred in in 26% of patients (major, n = 5; CRNM, n = 2; 95% confidence interval, 11-46%). No recurrent VTE or VTE-related death occurred. Estimated overall survival at 6 months was 68%. CONCLUSION: This study demonstrated the excessive bleeding risk of apixaban at the standard dose in Japanese patients with cancer-associated VTE.

Microsatellite instability-high colorectal cancer patient-derived xenograft models for cancer immunity research.

CONTEXT: There is an increasing demand for appropriate preclinical mice models for evaluating the efficacy of cancer immunotherapies. AIMS: Therefore, we established a humanized patient-derived xenograft (PDX) model using microsatellite instability-high (MSI-H) colorectal cancer (CRC) tissues and patient-derived peripheral blood mononuclear cells (PBMCs). SUBJECTS AND METHODS: The CRC tissues of patients scheduled for surgery were tested for MSI status, and CRC tumors were transplanted into NOD/LtSz-scid/IL-2Rg-/-(NSG) mice to establish MSI-H PDX models. PDX tumors were compared to the original patient tumors in terms of histological and genetic characteristics. To humanize the immune system of MSI-H PDX models, patient PBMCs were injected through the tail vein. RESULTS: PDX models were established from two patients with MSI-H CRC; one patient had a germline mutation in MLH1 (c.1990-2A > G), and the other patient had MLH1 promoter hypermethylation. PDX with the germline mutation was histologically similar to the patient tumor, and retained the genetic characteristics, including MSI-H, deficient mismatch repair (dMMR), and MLH1 mutation. In contrast, the histological features of the other PDX from a tumor with MLH1 promoter hypermethylation were clearly different from those of the original tumor, and MLH1 promoter hypermethylation and MSI-H/dMMR were lost in the PDX. When T cells from the same patient with MLH1 mutation were injected into the PDX through the tail vein, they were detected in the PDX tumor. CONCLUSIONS: The MSI-H tumor with an MMR mutation is suitable for MSI-H PDX model generation. The PBMC humanized MSI-H PDX has the potential to be used as an efficient model for cancer immunotherapy research.

Immunosuppressive effects and mechanisms of three myeloid-derived suppressor cells subsets including monocytic-myeloid-derived suppressor cells, granulocytic-myeloid-derived suppressor cells, and immature-myeloid-derived suppressor cells.

CONTEXT: Myeloid-derived suppressor cells (MDSC) are a heterogeneous population of immune cells of myeloid lineage. Recent reports have suggested that human MDSC are divided into three subsets: monocytic MDSC (M-MDSC), granulocytic MDSC (G-MDSC), and immature MDSC (I-MDSC). However, the characteristics of each human MDSC subset still remain unclear. MATERIALS AND METHODS: To evaluate the immunosuppressive effects and mechanisms, we first performed a T-cell suppression assay using cells obtained from healthy donor peripheral blood samples. The levels of immune inhibitory molecules in the culture supernatant of each MDSC subset were measured to reveal the T-cell suppressive mechanisms. Then, we compared these results with the results from cells obtained from cancer patient blood samples. Finally, we investigated the difference in the frequency of each MDSC subset between the healthy donors and the cancer patients. RESULTS: Although M-MDSC and G-MDSC suppressed T-cell activation, I-MDSC had no T-cell suppressive effect. We found that the culture supernatant of M-MDSC and G-MDSC contained high levels of interleukin-1 receptor antagonist (IL-1RA) and arginase, respectively, in both healthy donors and cancer patients. No inhibitory molecules were detected in the culture supernatant of I-MDSC. The population of functional MDSC (M-MDSC and G-MDSC) in the total MDSC was significantly increased in cancer patients compared with that in healthy donors. CONCLUSIONS: Although M-MDSC and G-MDSC, which released IL-1RA and arginase, respectively, suppressed T-cell activation, I-MDSC did not have an immunosuppressive effect. The population of functional MDSC was increased in cancer patients compared with that in healthy donors.

Docetaxel plus cisplatin in recurrent and/or metastatic non-squamous-cell head and neck cancer: a multicenter phase II trial.

The clinical utility of systemic therapy and genomic profiling in non-squamous-cell head and neck cancer (NSCHNC) has not been fully elucidated. This phase II trial evaluated the efficacy and safety of docetaxel and cisplatin combination in the first-line setting. Eligibility criteria were recurrent and/or metastatic NSCHNC; progressive disease within the last 6 months; no prior systemic therapy; and ECOG performance status of 0-1. Patients received docetaxel (75 mg/m2 on day 1) and cisplatin (75 mg/m2 on day 1), repeated every 21 days for 6 cycles. The primary endpoint was confirmed objective response rate (ORR). The secondary endpoints included progression-free survival (PFS), overall survival (OS), and adverse events. Next-generation sequencing (NGS) was performed using the Ion AmpliSeq Cancer Hotspot Panel v2. Twenty-three patients were enrolled from November 2012 to October 2016, of whom 8 were male. Median age was 57 years. Ninety-six percent of cases were metastatic. Among 22 evaluable patients, confirmed ORR was 45% (95% confidential interval 24-68%). With a median follow-up period of 18.8 months, median PFS and OS were 6.7 and 20.1 months, respectively. Grade 3/4 adverse events included febrile neutropenia (39%) and anemia (22%). No treatment-related deaths were observed. NGS analysis revealed potential treatment targets, including ERBB2, KIT, and ALK. The docetaxel and cisplatin combination regimen can be considered a new treatment option in recurrent and/or metastatic NSCHNC, although primary prophylaxis for febrile neutropenia should be considered. Diverse genomic alterations may lead novel treatment options.This trial was registered with the UMIN Clinical Trials Registry as UMIN000008333 on [September 1st, 2012].

Exploratory Analysis to Predict Optimal Tumor Burden for Starting Lenvatinib in Patients With Radioiodine-Refractory Differentiated Thyroid Cancer.

BACKGROUND: We previously reported that a high tumor burden is a prognostic factor based on an analysis of 26 patients with radioactive iodine-refractory differentiated thyroid cancer (RR-DTC) who were treated with lenvatinib. However, the optimal tumor burden for starting lenvatinib still remains to be defined. The aim of this retrospective study was to further explore in the same patient cohort the optimal timing for the start of lenvatinib by focusing on the pre- and post-treatment tumor burden. METHODS: The 26 patients were treated with lenvatinib from 2012 to 2017. We explored the optimal timing for the start of lenvatinib by comparing the characteristics of long-term responders who were defined as patients with progression-free survival ≥ 30 months and non-long-term responders. RESULTS: Long-term responders had a smaller post-treatment tumor burden at maximum shrinkage than non-long-term responders. Further, post-treatment tumor burden had a strong linear correlation with baseline tumor burden. We created an estimation formula for baseline tumor burden related to prognosis, using these regression lines. Patients with a sum of diameters of target lesions < 60 mm or maximum tumor diameter < 34 mm at baseline were estimated to have significantly better survival outcomes. CONCLUSIONS: We found a strong linear correlation between pre- and post-treatment tumor burden. Our results suggested a cut-off value for baseline tumor burden for long-term prognosis among patients treated with lenvatinib.

Incidence of venous thromboembolism in patients with solid cancers in Japan: retrospective study of 2735 patients.

BACKGROUND: The incidence of cancer-associated venous thromboembolism (CA-VTE) in Japan has not been fully investigated. METHODS AND RESULTS: Clinicopathological information from patients with solid malignancies who first visited our department between November 2011 and March 2018 were retrospectively reviewed from medical records. The primary outcome was incidence of CA-VTE, defined as deep-vein thrombosis (DVT) and/or pulmonary embolism (PE). On median follow-up of 187 days, 91 of 2735 patients (3.3%) developed CA-VTE during their clinical course, giving an incidence rate of 40.7 per 1000 person-years. Of the 91 patients, 75 (82%) were diagnosed with DVT alone, 6 (7%) with PE alone, and 10 (11%) with both DVT and PE. CA-VTE was most frequent in non-small cell lung cancer (10.8%), followed by cancer of unknown origin (5.8%). Forty-four patients (48%) had one or more symptoms at the initial diagnosis of VTE. Five patients (6%) had a normal D-dimer level (≤ 1.0 µg/mL); of these, 2 were asymptomatic. CONCLUSIONS: In this retrospective study, the incidence of CA-VTE in Japanese patients with cancer was equivalent to that in Western populations. Approximately half of CA-VTE patients were asymptomatic and 6% had normal D-dimer levels, indicating the need for closer attention to occult CA-VTE.

Device-related Mycobacterium mageritense Infection in a Patient Treated with Nivolumab for Metastatic Breast Cancer.

Treatment with anti-programmed cell death-1 (PD-1) antibodies improves the anti-cancer immune response and can provide a meaningful clinical benefit to cancer patients. However, this treatment can result in specific autoimmune toxicities, termed immune-related adverse events (irAEs). Although irAEs are well recognized, the development of infectious diseases due to this treatment is not often observed. Some recent reports have indicated that patients who receive anti-PD-1 antibodies are at a higher risk for tuberculosis than others. However, reports on nontuberculous mycobacterial infection during anti-PD-1 antibody treatment are still rare. We herein report the first case of Mycobacterium mageritense infection during anti-PD-1 antibody treatment.

Secondary CIC-rearranged sarcoma responsive to chemotherapy regimens for Ewing sarcoma: A case report.

Capicua transcriptional repressor (CIC)-rearranged sarcoma is an Ewing-like sarcoma with an aggressive clinical course and poor prognosis. No standard treatment has been established. The present study describes a case of CIC-rearranged sarcoma with lung metastases developing in a 24-year-old woman as a therapy-associated malignancy following chemotherapy for anaplastic large cell lymphoma at nine years old. This was treated with palliative regimens used for Ewing sarcoma. The patient achieved disease control for one year. Of note, ifosfamide and etoposide (IE), which were used as a second line treatment lead to a partial response. The case described in the present study indicated that treatment with Ewing regimens is a reasonable option for patients with metastatic CIC-rearranged sarcoma, including those with a second malignant case.

Serum Soluble Interleukin-2 Receptor as a Potential Biomarker for Immune-related Adverse Events.

BACKGROUND/AIM: Biomarkers for immune-related adverse events (irAEs) induced by immune checkpoint inhibitors (ICIs) are required. We encountered a patient whose skin irAE fluctuated in parallel with serum soluble interleukin-2 receptor (sIL-2R). PATIENTS AND METHODS: We examined 15 patients with cancer who received ICIs. Serum sIL-2R levels before and during ICI treatment were measured. The sIL-2R levels of preserved serum samples from another five patients who developed grade 3 irAEs were measured. RESULTS: Twelve patients showed no significant changes in sIL-2R levels during ICI treatment. Baseline serum sIL-2R levels in three patients increased beyond the normal range before the second cycle. These three patients had grade ≥2 irAEs at the second cycle treatment visit, supporting our hypothesis. Furthermore, at diagnosis of irAEs, the sIL-2R levels of all preserved samples from patients with grade 3 irAEs were significantly elevated. CONCLUSION: Serum sIL-2R is a promising biomarker for the diagnosis of irAEs.

Regorafenib-induced exacerbation of chronic immune thrombocytopenic purpura in remission: A case report.

Regorafenib is an oral multi-kinase inhibitor which targets tumor angiogenesis, the tumor microenvironment and oncogenesis. Based on this mode of action, regorafenib has a broad spectrum of toxicities. However, at present, few reports have focused on autoimmune adverse events. We report a first case of regorafenib-induced exacerbation of chronic immune thrombocytopenic purpura in remission during treatment for the patients with heavily treated advanced colorectal cancer. This case report highlights the need for caution with regard to regorafenib treatment in patients with cancer with concomitant immune thrombocytopenic purpura.

Phase I study of the antiprogrammed cell death-1 Ab spartalizumab (PDR001) in Japanese patients with advanced malignancies.

Spartalizumab is a humanized IgG4/κ mAb directed against human programmed cell death-1 (PD-1). In this phase I study, we investigated safety, pharmacokinetics, preliminary antitumor activity, and toxicity of spartalizumab in patients with advanced malignancies. Patients (n = 18) with a range of tumor types received spartalizumab i.v. at doses of 1, 3, and 10 mg/kg every 2 weeks until disease progression, unacceptable toxicity, or discontinuation at the discretion of the investigator or patient. Most patients (61%) had received five or more prior lines of therapy. No dose-limiting toxicities were reported and, hence, the maximum tolerated dose was 10 mg/kg or more. Pharmacokinetics in Japanese patients aligned with those reported in a global dose-escalation study. The safety profile was consistent with other approved anti-PD-1 mAbs; the most common drug-related adverse events were maculopapular rash (22%), followed by malaise and increased blood alkaline phosphatase (11% each). Partial responses were reported in two patients (11%), one with transitional cell carcinoma and the other with hepatocellular carcinoma. In conclusion, this study confirmed the safety of spartalizumab given at a dose of up to 10 mg/kg every 2 weeks in Japanese patients with cancers.

Phase 1 study of Gemcitabine/Nab-paclitaxel/S-1 in patients with unresectable pancreatic cancer (GeNeS1S trial).

PURPOSE: We conducted a phase 1 study to determine the maximum tolerated dose and the recommended dose of gemcitabine/nab-paclitaxel/S-1 combination chemotherapy in patients with unresectable pancreatic cancer. METHODS: We enrolled patients aged 20 years or older with unresectable pancreatic cancer and who had not been treated with chemotherapy or radiation therapy. Gemcitabine and nab-paclitaxel were administered on days 1 and 8, and S-1 was administered orally twice daily for 2 weeks, repeated every 3 weeks. The starting dose was level 0 [gemcitabine 700 mg/m2, nab-paclitaxel 90 mg/m2, S-1 60/80/100 mg/day (< 1.25 m2/1.25-1.50 m2/ > 1.5 m2)]. Dose-limiting toxicities were determined during the first course, and a classical 3 + 3 dose finding design was planned. RESULTS: From March 2018 to October 2019, 20 patients were enrolled. At dose level 0, three of six patients experienced dose-limiting toxicities; one grade 3 skin rash on day 8, and two grade 3 or 4 neutropenia on day 8. At dose level-1 (gemcitabine 600 mg/m2, nab-paclitaxel 90 mg/m2, and S-1 50/70/80 mg/day), two of twelve patients experienced dose-limiting toxicities, all of which were grade 3 neutropenia on day 8. The most frequently observed toxicity during eight courses was neutropenia. Other treatment-related adverse events were mild. Eleven out of 19 (58%) patients achieved partial response. CONCLUSION: We defined the maximum tolerated dose and the recommended dose for combination therapy with gemcitabine/nab-paclitaxel/S-1 as dose level-1. Considering the observed response rate, further studies are warranted in order to determine the efficacy of this regimen (UMIN-CTR 000030007).

Relationship between PDGFR expression and the response to pazopanib in intimal sarcoma of the pulmonary artery: A case report.

Intimal sarcoma of the pulmonary artery (PAIS) is a rare disease with a poor prognosis. Pazopanib, which has been indicated in metastatic non-adipocytic soft-tissue sarcomas and is expected to be active in PAIS, is a multi-kinase inhibitor that targets the tyrosine kinase activity of vascular endothelial growth factor receptor (VEGFR), platelet-derived growth factor receptor (PDGFR) and stem cell factor receptor. The present study reports findings related to two cases of PAIS with PDGF and VEGF expression following treatment with pazopanib. A case with a moderate to strong expression of PDGFR-α and -ß presented a long-term stable disease when treated with pazopanib (progression-free survival, 5.8 months). In a second case with a weak expression of PDGFR-α and -ß, the disease progressed rapidly on pazopanib (progression-free survival, 1.1 months). VEGFR-2 was not expressed in the tumors of both cases. The level of PDGFR expression in the tumor tissue may therefore be predictive of pazopanib efficacy.

A Case of Multi-System Langerhans Cell Histiocytosis with Local Invasion of the Orbital Apex.

Langerhans cell histiocytosis (LCH) is characterised by tissue destruction caused by the abnormal proliferation of pathogenic dendritic cells. We report a rare case of multi-system LCH with local invasion of the orbital apex. A 56-year-old woman suffered from a decrease of visual acuity in the left eye caused by central scotoma and the limitation of eye movement in all directions. Magnetic resonance imaging revealed an enhanced lesion in the left orbital apex, suggesting optic nerve compression. She had been diagnosed with eosinophilic granuloma 24 years previously. Two weeks after the current presentation, we admitted the patient for optic canal and orbital apex decompression and subtotal tumour resection. Histopathological analysis confirmed the diagnosis of LCH. Post-surgical treatment with low-dose cytarabine was initiated for the residual tumour. However, it was ceased because of myelosuppression-induced pyelonephritis. After surgery, the central scotoma disappeared on day 5 and eye movement palsy resolved by 6 months. After the cessation of cytarabine, she has received low-dose steroid therapy for 2 years with no recurrence. Early surgical intervention with low-dose steroid therapy can lead to recovery of visual acuity and resolve eye movement palsy in patients with lesions of the orbital apex caused by multi-system LCH.

Exploratory analysis of prognostic factors for lenvatinib in radioiodine-refractory differentiated thyroid cancer.

BACKGROUND: Multitarget kinase inhibitors (m-TKI), including lenvatinib, are now available as treatment options for radioiodine-refractory differentiated thyroid cancer (RR-DTC). However, the optimal timing of treatment initiation with m-TKI in these patients remains to be defined. METHODS: We retrospectively reviewed the clinical records of 30 consecutive patients with RR-DTC. The relationship between clinical characteristics was evaluated, including tumor growth parameters at pretreatment/post-treatment and efficacy of lenvatinib. RESULTS: A total of 26 patients with RR-DTC treated with lenvatinib were evaluable for response and eligible for analysis. From the results of multivariate analysis, baseline tumor size and tumor-related symptoms were independent negative prognostic factors for overall survival (OS) and progression-free survival (PFS). Pretreatment tumor growth parameters were not prognostic for either PFS or OS. CONCLUSIONS: Patients with RR-DTC with a high tumor burden and tumor-related symptoms had significantly worse prognosis. Greater tumor reduction after starting lenvatinib may lead to better prognosis, irrespective of pretreatment high tumor growth rate.

Adapalene Gel 0.1% Versus Placebo as Prophylaxis for Anti-Epidermal Growth Factor Receptor-Induced Acne-Like Rash: A Randomized Left-Right Comparative Evaluation (APPEARANCE).

LESSONS LEARNED: The results of the APPEARANCE trial indicate that adapalene does not prevent acne-like rash over placebo when added to topical moisturizer and oral minocycline but instead may have a detrimental effect. Therefore, adapalene is not recommended as prophylaxis against acne-like rash induced by anti-epidermal growth factor receptor therapies.Given that acne-like rash was completely controlled with placebo in approximately half of patients, predictive measures to identify patients needing intensive prophylaxis are required. BACKGROUND: Anti-epidermal growth factor receptor (EGFR) therapies are frequently associated with acne-like rash. To evaluate the prophylactic efficacy of adapalene, a topical retinoid used as first-line therapy for acne vulgaris, we conducted a randomized, placebo-controlled, evaluator-blinded, left-right comparative trial. METHODS: Patients with non-small cell lung, colorectal, or head and neck cancer scheduled to receive anti-EGFR therapies were randomly assigned to once-daily adapalene application on one side of the face, with placebo on the other side. All patients had topical moisturizer coapplied to both sides of the face, and received oral minocycline. The primary endpoint was the difference in total facial lesion count of acne-like rash at 4 weeks. Secondary endpoints included complete control rate (CCR) of acne-like rash (≤5 facial lesions) and global skin assessment (Investigator's Global Assessment [IGA] scale, grade 0-4) at 4 weeks. Two blinded dermatologists independently evaluated the endpoints from photographs. RESULTS: A total of 36 patients were enrolled, of whom 26 were evaluable. Adapalene treatment was associated with a greater lesion count than placebo at 4 weeks, although the difference was not statistically significant (mean, 12.6 vs. 9.8, p = .12). All four patients with a difference >10 in lesion count between face sides had a greater count on the adapalene-treated side. No significant differences were observed in CCR of acne-like rash (54% vs. 50%) or IGA scale (mean grade, 1.9 vs. 1.7) between the adapalene and placebo sides. CONCLUSION: Adapalene is not recommended as prophylaxis against acne-like rash induced by anti-EGFR therapies.