Efficacy, safety, and biomarker analysis of nivolumab in combination with abemaciclib plus endocrine therapy in patients with HR-positive HER2-negative metastatic breast cancer: a phase II study (WJOG11418B NEWFLAME trial)

BACKGROUND

Hormone receptor (HR)-positive breast cancer is a disease for which no immune checkpoint inhibitors have shown promise as effective therapies. Cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors synergistically increased the effectiveness of antiprogrammed cell death protein-1 (anti-PD-1)/programmed death-ligand 1 (PD-L1) antibodies in preclinical studies.

METHODS

This non-randomized, multicohort, phase II study evaluated the efficacy and safety of the anti-PD-1 antibody nivolumab 240 mg administered every 2 weeks in combination with the CDK4/6 inhibitor abemaciclib 150 mg twice daily and either fulvestrant (FUL) or letrozole (LET) as a first-line or second-line treatment for HR-positive HER2-negative metastatic breast cancer. The primary end point was the objective response rate (ORR), and secondary end points were toxicity, progression-free survival, and overall survival. Blood, tissue, and fecal samples were collected at multiple points for correlative studies to evaluate immunity biomarkers.

RESULTS

From June 2019 to early study termination due to safety concerns on July 2020, 17 patients were enrolled (FUL: n=12, LET: n=5). One patient with a prior treatment history in the FUL cohort was excluded. ORRs were 54.5% (6/11) and 40.0% (2/5) in the FUL and LET cohorts, respectively. Treatment-emergent (TE) adverse events (AEs) of grade ≥3 occurred in 11 (92%) and 5 (100%) patients in the FUL and LET cohorts, respectively. The most common grade ≥3 TEAEs were neutropenia (7 (58.3%) and 3 (60.0%) in the FUL and LET cohorts, respectively), followed by alanine aminotransferase elevation (5 (41.6%) and 4 (80.0%)). One treatment-related death from interstitial lung disease occurred in the LET cohort. Ten patients developed liver-related grade ≥3 AEs. Liver biopsy specimens from 3 patients showed hepatitis characterized by focal necrosis with predominant CD8+ lymphocyte infiltration. Marked elevation of tumor necrosis factor-related cytokines and interleukin-11, and a decrease in peripheral regulatory T cells (Tregs), were observed in patients with hepatotoxicity. These findings suggest that treatment-related toxicities were immune-related AEs likely caused by proinflammatory cytokine production and suppression of Treg proliferation due to the addition of abemaciclib to nivolumab therapy.

CONCLUSIONS

Although the combination of nivolumab and abemaciclib was active, it caused severe and prolonged immune-related AEs.

TRIAL REGISTRATION NUMBER

JapicCTI-194782, jRCT2080224706, UMIN000036970.

Significance of the comprehensive geriatric assessment in the administration of chemotherapy to older adults with cancer: Recommendations by the Japanese Geriatric Oncology Guideline Committee

INTRODUCTION

The number of older patients with cancer is expected to continue to increase owing to the aging population. Recently, the usefulness of geriatric assessment (GA) conducted by multiple staff members from different medical backgrounds has been reported; however, a consensus on the effectiveness of GA has not yet been achieved.

MATERIALS AND METHODS

We, as the Japanese Geriatric Oncology Guideline Committee for elderly patients with cancer, conducted a literature search of randomized controlled trials published before August 2021 that used GA or comprehensive GA (CGA) as an intervention for patients with cancer undergoing chemotherapy. As the key outcomes for answering the clinical question, we focused on survival benefit, adverse events, and quality of life (QOL). After a systematic review of these studies, the expert panel member developed recommendations according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system.

RESULTS

For older patients with cancer, GA or CGA is suggested during or before chemotherapy (weakly recommended). Chemotherapy-induced adverse events were significantly reduced by GA/CGA interventions without any adverse effects on survival. Health-related QOL tended to improve with the GA/CGA interventions.

DISCUSSION

Although, in our opinion, GA/CGA does require time and resources, it poses no harm patients. Therefore, we suggest expanding the human resources and educating skills of medical providers for clinical implementation of GA/CGA.

Multicentre, randomised, double-blind, placebo-controlled phase II study of prophylactic olanzapine for patients with metastatic breast cancer receiving T-DXd treatment: protocol for the ERICA study (WJOG14320B)

INTRODUCTION

The antibody-drug conjugate trastuzumab deruxtecan (T-DXd) has led to a change in the clinical management of breast cancer. Nausea and vomiting are the most common adverse events of T-DXd, which cannot be completely alleviated by standard prophylactic regimens. Olanzapine is particularly effective in preventing delayed nausea caused by chemotherapy. In this study, we will evaluate the efficacy of olanzapine in managing persistent nausea and vomiting during T-DXd treatment.

METHODS AND ANALYSIS

The ERICA study is a multicentre, placebo-controlled, double-blind, randomised phase II study with the aim to evaluate the antiemetic effects of the prophylactic olanzapine (5 mg orally, on days 1-6) or placebo combined with a 1,5-hydroxytryptamine-3 (5-HT₃)-receptor antagonist and dexamethasone in patients with human epidermal growth factor receptor 2-positive metastatic breast cancer undergoing T-DXd treatment. For a period of 22 days from the day of T-DXd treatment, patients will document their experience in an electronic symptom diary daily during observational periods. The primary endpoint is the complete response rate, defined as no vomiting and no rescue medications during the 'delayed phase' of 24-120 hours post-T-DXd administration. In addition, we define 120-504 hour as the 'persistent phase' and 0-504 hours as the 'overall phase' for secondary endpoint analysis. We have estimated that a total sample size of at least 156 patients is needed to allow a power of 80% at a one-sided significance level of 20% in this study. The target sample size is set to 166 to account for possible case exclusions.

ETHICS AND DISSEMINATION

The study protocol is approved by the West Japan Oncology Group protocol review committee and the SHOWA University Clinical Research Review Board. The study results will be presented at international conferences and published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

jRCTs031210410.

Abstract P1-12-08: Biomarker analysis of hepatotoxicity in a Phase II study of nivolumab, abemaciclib and endocrine therapy in patients with HR-positive, HER2-negative breast cancer: WJOG11418BTR NEWFLAME_TR

Background Previously, we reported the clinical outcomes of the combination of anti-PD-1 Ab, cyclin-dependent kinase 4/6 inhibitors, and endocrine therapy (ET) in patients with ER positive/HER2 negative advanced breast cancer in SABCS2020; biomarker analysis has been performed to provide insight into the hepatotoxicy frequently observed in the study. Methods Subjects received 240 mg nivolumab IV on days 1 and 15, 150 mg abemaciclib PO twice daily, and either 500 mg fulvestrant (FUL) on days 1, 15, 29, and every 4 weeks thereafter (FUL cohort) or 2.5 mg letrozole (LET) once daily (LET cohort). The primary endpoint was objective response rate and secondary endpoints included toxicity evaluated in the CTCAE along with an exploratory endpoint as related to the biomarker analysis. Archival tumor tissues were collected before study entry and blood and stool samples were collected at baseline and on cycle3 day1. Tumor tissues were subjected to IHC analysis and RNA sequencing followed by subtyping using NGS. High throughput cytokine analysis using ELISA-based assay were performed with serum samples and cell sorting analysis of PBMC was performed with FACS. Results From June 2019 to December 2019, 17 subjects were enrolled (FUL cohort [n = 12], LET cohort [n = 5]). The study was prematurely closed due to safety concerns such as hepatotoxicity and interstitial lung disease. AEs ≥ Grade 3 were observed in 91.7% and 100% of patients in the FUL and LET cohorts, respectively. The most frequent AEs ≥ Grade 3 were elevated liver function tests (LFT; FUL cohort: 50.0%, LET cohort: 60.0%). Serum cytokine analysis from the subjects with severe hepatotoxicity indicated cytokine storm with elevations of sCD30/TNFRSF8, IL-11, -34, Pentraxin-3, sTNF-R1, -R2, TSLP, which was supported by the findings of reduction of effector regulatory T cells in PBMC. IHC study in liver biopsy from three subjects with the toxicity revealed infiltration of CD8+ T cells and FOXP3+ T reg into the liver, suggesting the immune related liver injury upon the treatment with nivolumab and abemaciclib. HLA typing was performed in the 17 patients but no association between HLA type and ILD or hepatotoxicity were observed. Conclusions The frequent and severe immune related hepatotoxicity induced by the combination of anti-DD-1 and CDK 4/6 inhibitors might have been an immune-boosting therapy as suggested in the preclinical studies. This study was supported by the Ono Pharmaceutical Co., LTD. The registration number of the study is UMIN000036970.

Citation Format: Junji Tsurutani, Jun Masuda, Norikazu Masuda, Yuko Tanabe, Tsutomu Iwasa, Masato Takahashi, Manabu Futamura, Koji Matsumoto, Kenjiro Aogi, Hiroji Iwata, Mari Hosonaga, Toru Mukohara, Kiyoshi Yoshimura, Chiyo K. Imamura, Sakiko Miura, Toshiko Yamochi, Kenichi Yoshimura, Toshimi Takano, Hidetaka Kawabata. Biomarker analysis of hepatotoxicity in a Phase II study of nivolumab, abemaciclib and endocrine therapy in patients with HR-positive, HER2-negative breast cancer: WJOG11418BTR NEWFLAME_TR [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-12-08.

Prospective evaluation of the relationship between response and exposure of total and unbound erlotinib in non-small cell lung cancer patients

PURPOSE

To evaluate the relationship between treatment efficacy and exposure of total and unbound erlotinib in patients with non-small cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR)-activating mutations.

PATIENTS AND METHODS

EGFR-tyrosine kinase inhibitor naïve NSCLC patients were enrolled, and erlotinib was started at 150 mg/day. Total and unbound exposure of erlotinib were prospectively evaluated.

RESULTS

Of the 70 enrolled patients, 61 had EGFR-activating mutations (30 patients with exon 19 deletions, 31 patients with L858R). The median area under the concentration-time curve from 0 to 24 h (AUC_0-24) of total and unbound erlotinib on day 1 was 37,004 ng·h/mL (range, 9683-63,257 ng·h/mL) and 2338 ng·h/mL (581-5904 ng·h/mL), respectively. The median progression-free survival (PFS) was 10.9 months, and PFS did not differ between each tertile of total and unbound AUC_0-24 on day 1 in 59 patients with EGFR-activating mutations. The worst grade of skin toxicities was significantly correlated with total trough concentration at steady state (C_trough,ss) at each visit for 3 months after the initiation of erlotinib treatment (P < 0.0001). Total and unbound C_trough,ss on day 7-15 in 20 patients whose dose was reduced due to intolerable toxicities was significantly higher than those in 48 patients whose dose was unchanged for 3 months (P = 0.0046, 0.0008).

CONCLUSION

The lack of relationship between efficacy and exposure of total and unbound erlotinib demonstrates that the standard dose of 150 mg/day is sufficient for the treatment of NSCLC harboring EGFR-activating mutations, despite wide inter-individual variability in exposure and dose reduction.

CLINICAL TRIALS REGISTRATION NUMBER

UMIN000012862.

Evaluation of clinical validity of an S-1 dosage formula based on renal function using data of the SPIRITS and the G-SOX trials

BACKGROUND

The aim of this study was to evaluate clinical validity of the S-1 dosage formula based on body surface area (BSA) and creatinine clearance (CLcr) to achieve the target area under the concentration-time curve of 5-FU, which we had developed and refined in each prospective pharmacokinetic study.

METHODS

The recommended dose determined by the refined formula was assessed using data of the SPIRITS (S-1 vs. S-1 plus cisplatin [SP]) and the G-SOX (SP vs. S-1 plus oxaliplatin [SOX]) trials. Nine hundred and thirty-eight patients in these trials were classified into three groups according to their actual S-1 starting doses compared with the recommended doses (under-dosed, <recommended dose; equal-dosed, =recommended dose; over-dosed, >recommended dose).

RESULTS

The patients in the under-dosed group in both trials showed similar tendencies: male, younger, higher BSA, and higher CLcr. The incidence of any grade neutropenia was significantly greater in the over-dosed group compared with the equal-dosed group in the S-1 and the SOX arms. The hazard ratios (HR) of overall survival (OS) (under-dosed vs. equal-dosed) were 1.361 (S-1 arm), 1.259 (SP arm) in the SPIRITS trial, and 1.381 (SOX arm), 0.999 (SP arm) in the G-SOX trial. Multivariate analysis in all the patients demonstrated that OS of the over-dosed group was equivalent (HR 1.002, 95% confidence interval [CI] 0.850-1.182, p = 0.980) and that of the under-dosed group was inferior (HR 1.267, 95% CI 1.005-1.597, p = 0.045) to the equal-dosed group.

CONCLUSIONS

It is suggested that the refined S-1 dosage formula can recommend optimal dose in terms of safety and efficacy.

A case report on severe nivolumab-induced adverse events similar to primary sclerosing cholangitis refractory to immunosuppressive therapy

INTRODUCTION

Immune checkpoint inhibitors (ICIs), particularly anti-PD-1 antibody, have dramatically changed cancer treatment; however, fatal immune-related adverse events (irAEs) can develop. Here, we describe a severe case of sclerosing cholangitis-like irAE. We report the use of 3 immunosuppressive agents that resulted in the death of the patient due to treatment inefficacy. According to a postmarketing study of nivolumab, the frequency of ICI-related sclerosing cholangitis is 0.27% and that of ICI-related cholangitis is 0.20%. There have been 4 case reports of sclerosing cholangitis-like irAE, with imaging findings, including typical intrahepatic bile duct beaded constriction in primary sclerosing cholangitis. Treatment starts with prednisolone and is combined with an immunosuppressant in refractory cases. There are no reports of severe cases that ultimately led to death.

PATIENTS CONCERNS

The patient is a 64-year-old male with Stage IV squamous cell lung carcinoma; he was hospitalized with abdominal pain and elevation of aspartate transaminase and alanine transaminase, approximately 4 months after ICI administration was suspended. This occurred because the patient treated with nivolumab as the second-line chemotherapy and developed type 1 diabetes mellitus after 11 courses.

DIAGNOSIS

A grade 3 increase in bilirubin was observed and he was diagnosed with sclerosing cholangitis, based on magnetic resonance cholangiopancreatography imaging and pathological findings of the liver and bile duct.

INTERVENTIONS

Prednisolone, mycophenolate mofetil, and tacrolimus combination therapy was administered.

OUTCOMES

The treatment was difficult and failed. He died from liver failure 8 months after diagnosis. In this case, hepatitis and cholangitis, mainly alanine transaminase-dominant liver disorder, developed in the early stages of irAEs. Although he showed some improvement after prednisolone administration, bilirubin levels began rising again, and sclerosing cholangitis did not improve even with the use of 3 immunosuppressive agents recommended by the ESMO Clinical Practice Guidelines for immune-related hepatotoxicity management. Although the antitumor effect showed a complete response, liver failure led to death.

CONCLUSION

This is the first case report on the ineffectiveness of triple immunosuppressant combination therapy recommended by the guidelines for immune-related hepatotoxicity. It is necessary to develop more appropriate treatment for severe sclerosing cholangitis-like irAE based on the robust evidence.

Prospective evaluation and refinement of an S-1 dosage formula based on renal function for clinical application

In patients with impaired renal function, S-1-related toxicities increase due to higher exposure of 5-fluorouracil (5-FU). Our previous pharmacokinetic study in 16 cancer patients with various renal functions developed an S-1 dosage formula based on individual creatinine clearance (CLcr) and body surface area (BSA). To evaluate and refine the formula, this prospective study was conducted. Thirty-three patients with various renal functions received S-1 for 4 weeks at doses determined by the nomogram derived from the previously developed formula. A series of blood samples were collected after the first dose to calculate the area under the concentration-time curve (AUC) of 5-FU. Thirty patients with BSA of 1.14-1.84 m² and CLcr of 23.8-96.4 mL/min were assessable for pharmacokinetics. The observed daily AUC ranged from 712.6 to 2868.7 ng·h/mL, and 18 patients achieved the target AUC (1447.8 ± 545.4 ng·h/mL). Three patients experienced S-1-related grade 3 adverse events during the first course. In the population pharmacokinetic analysis from the combined data of 46 patients in this study and the previous study, sex was identified as a statistically significant covariate for 5-FU clearance. Hence, the refined formula includes sex as an additional factor: Recommended daily dose = target AUC × (14.5 + 8.23 × SEX [0 for female and 1 for male] + 0.301 × CLcr) × BSA. Revised nomograms for recommended daily doses derived from the refined formula can be used in clinical practice to achieve the target AUC ensuring efficacy and safety of S-1.

Japanese Lung Cancer Society Guidelines for Stage IV NSCLC With EGFR Mutations

Patients with NSCLC in East Asia, including Japan, frequently contain EGFR mutations. In 2018, we published the latest full clinical practice guidelines on the basis of those provided by the Japanese Lung Cancer Society Guidelines Committee. The purpose of this study was to update those recommendations, especially for the treatment of metastatic or recurrent EGFR-mutated NSCLC. We conducted a literature search of systematic reviews of randomized controlled and nonrandomized trials published between 2018 and 2019 that multiple physicians had reviewed independently. On the basis of those studies and the advice from the Japanese Society of Lung Cancer Expert Panel, we developed updated guidelines according to the Grading of Recommendations, Assessment, Development, and Evaluation system. We also evaluated the benefits of overall and progression-free survival, end points, toxicities, and patients' reported outcomes. For patients with NSCLC harboring EGFR-activating mutations, the use of EGFR tyrosine kinase inhibitors (EGFR TKIs), especially osimertinib, had the best recommendation as to first-line treatment. We also recommended the combination of EGFR TKI with other agents (platinum-based chemotherapy or antiangiogenic agents); however, it can lead to toxicity. In the presence of EGFR uncommon mutations, except for an exon 20 insertion, we also recommended the EGFR TKI treatment. However, we could not provide recommendations for the treatment of EGFR mutations with immune checkpoint inhibitors, including monotherapy, and its combination with cytotoxic chemotherapy, because of the limited evidence present in the literature. The 2020 Japanese Lung Cancer Society Guidelines can help community-based physicians to determine the most appropriate treatments and adequately provide medical care to their patients.

Phase I study of afatinib plus bevacizumab in patients with advanced non-squamous non-small cell lung cancer harboring EGFR mutations

Background

Afatinib is a second-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI). Combination therapies with first-generation EGFR-TKIs and bevacizumab have been reported to prolong progression-free survival (PFS). However, there are few data on the combination of afatinib and bevacizumab.

Methods

In this phase I trial, we evaluated the safety of afatinib plus bevacizumab in patients with advanced non-squamous non-small cell lung cancer (NSCLC) harboring EGFR mutations. This study consisted of two cohorts. In the dose-finding cohort, enrolled patients were treated with afatinib at a dose of 20, 30, or 40 mg/day (days 1-21) plus bevacizumab at a dose of 15 mg/kg (day 1) in 21-day cycles. This cohort was performed according to a 3 + 3 manner. In the expansion cohort, enrolled patients received the recommended dose (RD) based on the results of the dose-finding cohort. The serum trough concentration of afatinib was determined at the steady state.

Results

Seventeen patients were enrolled in this study (6 patients in the dose-finding cohort and 11 patients in the expansion cohort). There were no dose-limiting toxicities (DLTs) with afatinib at a dose of 30 mg/day. With afatinib at a dose of 40 mg/day, two of two patients experienced DLTs (grade 3 diarrhea) in cycle 1. With these results, afatinib at a dose of 30 mg/day plus bevacizumab at a dose of 15 mg/kg was determined as the RD. Eleven patients in the expansion cohort were treated with the RD. Common treatment-related adverse events (AEs) with the RD were diarrhea (79%), rash (71%), perionychia (64%), and stomatitis (50%). Grade 3 AEs with the RD were diarrhea (7%), perionychia (7%), and hypertension (7%). There were no grade 4/5 AEs or cases of interstitial lung disease. Dose-proportional increases in serum afatinib trough concentrations at steady state were not observed. The response rates (RRs) and disease control rates were 55% and 100% in EGFR-TKI-naïve patients. Re-biopsy was performed in eight patients after progressive disease following the study treatment, and three patients acquired a T790M mutation.

Conclusions

Afatinib at a dose of 30 mg/day plus bevacizumab at a dose of 15 mg/kg q3w is well tolerated.

Optimizing antiemetic treatment for chemotherapy-induced nausea and vomiting in Japan: Update summary of the 2015 Japan Society of Clinical Oncology Clinical Practice Guidelines for Antiemesis

Patients with cancer should appropriately receive antiemetic therapies against chemotherapy-induced nausea and vomiting (CINV). Antiemetic guidelines play an important role in managing CINV. Accordingly, the first Japanese antiemetic guideline published in 2010 by the Japan Society of Clinical Oncology (JSCO) has considerably aided Japanese medical staff in providing antiemetic therapies across chemotherapy clinics. With the yearly advancements in antiemetic therapies, the Japanese antiemetic guidelines require revisions according to published evidence regarding antiemetic management worldwide. A revised version of the first antiemetic guideline that considered several upcoming evidences had been published online in 2014 (version 1.2), in which several updated descriptions were included. The 2015 JSCO clinical practice guideline for antiemesis (version 2.0) (in Japanese) has addressed clinical antiemetic concerns and includes four major revisions regarding (1) changes in emetogenic risk categorization for anti-cancer agents, (2) olanzapine usage as an antiemetic drug, (3) the steroid-sparing method, and (4) adverse drug reactions of antiemetic agents. We herein present an English update summary for the 2015 JSCO clinical practice guideline for antiemesis (version 2.0).

Pharmacokinetics, Efficacy and Safety of Bosutinib in a Pediatric Patient With Chronic Myeloid Leukemia

Bosutinib is a second-generation tyrosine kinase inhibitor indicated for treatment of chronic myeloid leukemia (CML) in adult patients. The safety and efficacy of bosutinib in patients younger than 18 years of age have not been established. We here report the case of a 4-year-old male with CML who was treated with bosutinib during coordination of human leukocyte antigen-matched unrelated bone-marrow transplantation because of insufficient responses to imatinib and dasatinib. The patient achieved a complete cytogenetic response immediately after starting bosutinib at 180 mg/day (290 mg/m²/day). Because toxicity was tolerable, the dose was increased to 200 mg/day (330 mg/m²/day). A complete cytogenetic response was maintained, but a major molecular response was not achieved 6 months after initiation of treatment with bosutinib. At steady state, maximum plasma concentration, minimum plasma concentration, and area under the plasma concentration-time curve were 89.2 ng/mL, 16.7 ng/mL, and 1017.4 ng·hr/mL, respectively, at 290 mg/m²/day; and 141.1 ng/mL, 18.9 ng/mL, and 1278.5 ng·hr/mL, respectively, at 330 mg/m²/day. To the best of our knowledge, this is the first case report to show the pharmacokinetics of bosutinib with efficacy and safety in a pediatric patient with CML. This rare case in a very young child with CML can also be valuable reference for clinical practice.

Weekly paclitaxel plus ramucirumab versus weekly nab-paclitaxel plus ramucirumab for unresectable advanced or recurrent gastric cancer with peritoneal dissemination refractory to first-line therapy-the P-SELECT trial (WJOG10617G)-a randomised phase II trial by the West Japan Oncology Group

BACKGROUND

Ramucirumab (RAM) with weekly paclitaxel (wPTX) is a standard second-line therapy for advanced or recurrent gastric cancer. Nanoparticle albumin-bound paclitaxel (nab-PTX), an albumin-bound form of PTX, was developed to improve the therapeutic index of taxane treatment. However, the ABSOLUTE trial showed the non-inferiority of weekly nab-PTX (w-nab-PTX) to wPTX with respect to overall survival (OS) as second-line therapy for advanced or recurrent gastric cancer, and subgroup analysis of patients with peritoneal dissemination showed favourable OS and progression-free survival (PFS) in the w-nab-PTX arm compared to those in the wPTX arm. This study evaluated whether w-nab-PTX plus RAM is more effective than wPTX plus RAM for patients with peritoneal dissemination.

METHODS

The P-SELECT trial (WJOG10617G) is a prospective, open-label, multicentre, randomised phase II study evaluating wPTX plus RAM (arm A) versus w-nab-PTX plus RAM (arm B). Key eligibility criteria include the following: 1) histologically proven adenocarcinoma, 2) unresectable or recurrent gastric cancer, 3) peritoneal dissemination, 4) intolerance or refractory to first-line therapy including fluoropyrimidines, and 5) ECOG Performance Status (PS) 0-2. Patients are randomised to either arm at a 1:1 ratio stratified by institution, PS, and severity of ascites. PTX (80 mg/m2; days 1, 8, and 15) and RAM (8 mg/kg; days 1 and 15) are administered every 4 weeks in arm A, while nab-PTX (100 mg/m2; days 1, 8, and 15) instead of PTX is administered in arm B. The primary endpoint is OS, and the main secondary endpoints are PFS, objective response rate, safety, neuropathy-specific quality of life, and biomarkers. To maintain a probability of ≥70% to ensure the hazard ratio for OS in arm B is lower than 0.90, 105 subjects are required. The study was initiated in October 2018 and is being conducted in 58 centres of the West Japan Oncology Group.

DISCUSSION

The results of this study will determine whether w-nab-PTX plus RAM has the potential to be a preferred therapeutic option for advanced and recurrent gastric cancer with peritoneal dissemination, compared to wPTX plus RAM.

TRIAL REGISTRATION

This study was prospectively registered in the Japan Registry of Clinical Trials (jRCTs031180022, October 1, 2018).

Clinical impact of baseline renal function on safety and early discontinuation of adjuvant capecitabine plus oxaliplatin in elderly patients with resected colon cancer: a multicenter post-marketing surveillance study

BACKGROUND

Adjuvant capecitabine and oxaliplatin (CAPOX) is a standard treatment for resected colon cancer; however, in patients with moderate renal impairment, the incidence of CAPOX-related adverse events (AEs) and the rate of early discontinuation are higher than in patients with no or mild renal impairment. The aim of this retrospective study was to assess the impact of baseline renal function on the safety and discontinuation of adjuvant CAPOX therapy started with the standard dose of capecitabine in elderly patients with colon cancer.

METHODS

Data from patients aged ≥65 years old who received CAPOX at the standard starting dose as adjuvant therapy for stage II/III colon cancer were collected and analyzed retrospectively. Patients were divided into two groups based on their renal function: CLcr-H (patients with a creatinine clearance [CLcr] ≥50 ml/min) and CLcr-L (CLcr <50 ml/min), and AEs and discontinuations were assessed.

RESULTS

Overall, 189 patients were assessed (CLcr-H group = 137 and CLcr-L group = 52). No patients experienced grade 4 AEs. The incidence of grade 3 CAPOX-related AEs was higher in the CLcr-L group (42.3%) than in the CLcr-H group (31.3%). The proportion of patients who discontinued treatment within four cycles due to AEs was also higher in the CLcr-L group (21.1%) than in the CLcr-H group (2.9%). Multivariate analysis identified that CLcr <50 ml/min was the only significant risk factor for CAPOX therapy discontinuation due to AEs (P = 0.0008).

CONCLUSIONS

This study demonstrates that the tolerability of adjuvant CAPOX therapy was decreased in elderly patients with impaired renal function.

CLINICAL TRIAL REGISTRATION

University Hospital Medical Information Network Clinical Trials Registry number UMIN000016446.

A double-blind, randomized, multicenter phase 3 study of palonosetron vs granisetron combined with dexamethasone and fosaprepitant to prevent chemotherapy-induced nausea and vomiting in patients with breast cancer receiving anthracycline and cyclophosphamide

Purpose

To investigate whether palonosetron is better than granisetron in preventing chemotherapy‐induced nausea and vomiting (CINV) in a three‐drug combination with dexamethasone and fosaprepitant (Fos) in patients with breast cancer who are placed on anthracycline and cyclophosphamide (AC‐based regimen).

Patients and Methods

Chemo‐naive women with primary breast cancer were randomly administered either palonosetron 0.75 mg (day 1) or granisetron 1 mg (day 1) combined with dexamethasone (12 mg at day 1, 8 mg at day 2 and day 3) and Fos 150 mg (day 1) before receiving AC‐based regimen in a double‐blind study. The primary endpoint was the complete response (CR) rate of emesis in cycle 1 in the delayed phase. This was defined as neither vomiting nor rescue drug usage for emesis at >24‐120 hours after chemotherapy. Secondary endpoints were the CR in the acute/overall phase (0‐24/0‐120 hours, respectively, after chemotherapy), no nausea and vomiting, Patient‐Reported Outcomes version of the Common Terminology Criteria for Adverse Events (PRO‐CTCAE), and safety.

Results

From December 2012 to October 2014, 326 patients were treated and evaluated (164/162 evaluable patients in granisetron/palonosetron arm, respectively). The CR during the delayed phase was 60.4% in the granisetron regimen and 62.3% in the palonosetron regimen. The CR during acute phase (73.2% vs 75.9%, respectively) and the CR during overall phase (54.9% in both regimens) were very identical. A significantly higher number of patients in the palonosetron arm were free from nausea during the delayed phase (28% vs 40.1%; P = .029). Adverse events were also identical, although infusion site reactions (ISR) were higher (20.3%‐23.3%) than preceding studies in both regimens.

Conclusion

In combination with dexamethasone and Fos, this study suggests that palonosetron is not better than granisetron in chemo‐naive patients with primary breast cancer receiving AC‐based regimen. Administration of Fos in peripheral veins after AC‐based regimen increased ISR.

Evaluation of gefitinib systemic exposure in EGFR-mutated non-small cell lung cancer patients with gefitinib-induced severe hepatotoxicity

PURPOSE

Severe hepatotoxicity induced by the standard dose of gefitinib (250 mg daily) often becomes manageable by dose reduction to 250 mg every other day. Thus, we hypothesized that systemic exposure of standard-dose gefitinib in patients with experience of severe hepatotoxicity might be higher than that in patients without severe hepatotoxicity.

METHODS

Patients with advanced epidermal growth factor receptor-mutated non-small cell lung cancer who were receiving gefitinib either at a reduced dose (250 mg every other day) because of intolerable severe toxicity or at a standard dose (250 mg daily) were enrolled. A series of blood samples were collected to estimate pharmacokinetic parameters and calculate systemic exposure of standard-dose gefitinib (area under the concentration-time curve from 0 to 24 h at steady state, AUC_0-24,ss). Systemic exposure of unbound gefitinib (fu·AUC_0-24,ss) was also assessed, because gefitinib is extensively bound to serum proteins.

RESULTS

Of the 38 enrolled patients, 34 (23 patients without experience of severe hepatotoxicity, 11 patients with experience of severe hepatotoxicity) were evaluable. There was no significant differences in total AUC_0-24,ss or unbound fu·AUC_0-24,ss between patients with and without experience of severe hepatotoxicity. Analysis of the time to severe hepatotoxicity indicated no difference between patients with a high AUC_0-24,ss and those with a low AUC_0-24,ss of either total or unbound gefitinib.

CONCLUSION

This study suggests that reversible severe hepatotoxicity is not caused by high systemic exposure of gefitinib.

CYP2D6 Genotype-Guided Tamoxifen Dosing in Hormone Receptor-Positive Metastatic Breast Cancer (TARGET-1): A Randomized, Open-Label, Phase II Study

PURPOSE

In patients taking tamoxifen, the CYP2D6 genotype causes different exposure of active metabolite endoxifen. The objective of this randomized, open-label, multicenter, phase II study was to prospectively evaluate whether CYP2D6 genotype-guided tamoxifen dosing in patients with hormone receptor-positive metastatic breast cancer could have an impact on the clinical outcome.

METHODS

Patients who needed first-line tamoxifen therapy were enrolled. Based on individual CYP2D6 genotype, patients heterozygous (wild type [wt]/variant [V]) or homozygous (V/V) for variant alleles of decreased or no function were randomly assigned to receive tamoxifen at an increased dose (ID arm; 40 mg daily) or regular dose (RD arm; 20 mg daily), and patients homozygous for wild-type alleles (wt/wt) received tamoxifen at 20 mg daily. The primary endpoint was the progression-free survival (PFS) rate at 6 months. The secondary endpoints included PFS and correlation of Z-endoxifen concentration with clinical outcomes.

RESULTS

Between December 2012 and July 2016, 186 patients were enrolled in Japan. Of 184 evaluable patients, 136 carried wt/V or V/V (ID arm, 70; RD arm, 66), and 48 carried wt/wt. PFS rates at 6 months were not significantly different between the ID and RD arms (67.6% v 66.7%). The serum trough concentrations of Z-endoxifen in the ID arm were significantly higher than those in the RD arm (median, 89.2 nM v 51.1 nM; P < .0001) and were also higher compared with wt/wt patients (72.0 nM; P = .045). No significant difference in Z-endoxifen concentrations was observed between patients with disease progression and those who were progression free at 6 months (P = .43).

CONCLUSION

In patients with CYP2D6-variant alleles, increasing tamoxifen dosing did not achieve a higher PFS rate at 6 months. The CYP2D6 genotype solely cannot explain individual variability in the efficacy of tamoxifen.

A Phase II Study of Regorafenib With a Lower Starting Dose in Patients With Metastatic Colorectal Cancer: Exposure-Toxicity Analysis of Unbound Regorafenib and Its Active Metabolites (RESET Trial)

BACKGROUND

Regorafenib demonstrated survival benefits as salvage therapy for patients with metastatic colorectal cancer. However, severe toxicities frequently occurred early in the treatment with the standard dose (160 mg/day), resulting in a dose reduction or interruption. To improve the tolerability and maintain sufficient efficacy, we conducted a phase II study of regorafenib with a lower starting dose (120 mg/day).

PATIENTS AND METHODS

Regorafenib was initiated at 120 mg/day, and the dosage was increased to 160 mg/day on day 15 of the first cycle for patients who had met the dose escalation criteria. The primary endpoint was the disease control rate (DCR). The pharmacokinetics of the total and unbound regorafenib and its active metabolites (M2, M5) were assessed.

RESULTS

A total of 70 patients were enrolled from September 2016 to December 2017. Only 6 patients achieved dose escalation to 160 mg on day 15 as planned. For the 68 evaluable patients, the DCR was 32.4% (95% confidence interval, 21.5%-44.8%), which was less than the threshold (30%) of our statistical hypothesis. The serum concentrations of total regorafenib for patients whose dose was escalated to 160 mg/day were significantly lower than those of the patients whose dose was not escalated (median, 3978 vs. 7244 nM; P = .027). The serum unbound concentrations of the sum of regorafenib and the active metabolites correlated significantly with the maximum grade of regorafenib-related symptomatic adverse events in the first cycle (11,138 vs. 19,096 pM; P = .035).

CONCLUSION

Regorafenib with a low starting dose of 120 mg/day did not achieve the expected DCR. A relationship of unbound exposure with toxicity was found.

Abstract 3882: Exposure-toxicity analysis of unbound regorafenib and its active metabolites by dose escalation strategy with low starting dose in patients with colorectal cancer

Background: As regorafenib (REG) and its active metabolites are extensively bound to serum proteins, their unbound exposure are considered to be more relevant to pharmacological and toxicological responses than total (unbound plus bound) exposure. We thus investigated the relationships between toxicity and serum unbound concentrations of REG and active metabolites M-2 and M-5 in patients with colorectal cancer.

Patients and Methods: REG was administered orally once daily for the first 21 days of each 28-day cycle. The dose was started at 120 mg/day, and escalated to standard dose of 160 mg/day on day 15 of the first cycle in patients who experienced neither hand-foot skin reaction nor grade ≥2 REG-related adverse events (AEs) without dose reduction or interruption until day 14. Serum concentrations of REG, M-2 and M-5 were evaluated on days 8, 15, and 22 of the first cycle in patients without interruption of REG treatment until each sampling point. Unbound fraction was obtained by equilibrium dialysis, and concentrations were determined by the UPLC-MS/MS method. AEs were graded according to CTCAE ver. 4.0.

Results: Among all 68 enrolled patients, 57 patients on day 8, 42 patients on day 15, and 23 patients on day 22 were assessable. On day 8, the median total concentrations of REG, M-2 and M-5 in serum were 6801 nM (range, 2487-17621), 2596 nM (321-12107), and 834 nM (49-12315), respectively. Unbound fraction of REG, M-2 and M-5 varied from 0.019-0.441 %, 0.000-0.477 % and 0.041-2.381 %, respectively, showing no association with levels of serum albumin (28-50 mg/mL) which is a major binding protein. Serum concentrations of total REG or sum of total REG, M-2 and M-5 (total SUM) on day 8 were not related with maximum grade (grade ≤2 vs. grade ≥3) of AEs (excluding laboratory abnormalities) in the first cycle. On the other hand, higher serum concentrations of unbound REG on day 8 tended to associate with severity of maximum grade of AEs in the first cycle (P=0.0711), and concentrations of sum of unbound REG, M-2 and M-5 (unbound SUM) on day 8 were significantly correlated with maximum grade of AEs in the first cycle (P=0.0345). In addition, concentrations of total REG and unbound REG on day 8 in six patients whose dose were escalated to 160 mg/day on day 15 were significantly lower than those in 50 patients whose dose were not escalated (total, 3978 vs. 7005 nM in median, P=0.0270; unbound, 2834 vs. 7244 pM in median, P=0.0455). There were also significant association between concentrations of unbound REG or unbound SUM on day 15 and severity of REG-related AEs (grade 1 vs. grade ≥2) on day 15 (P=0.0495, P=0.0126, respectively).

Conclusion: Unbound exposure was well correlated with toxicity in patients treated with REG. Exposure of sum of REG, M-2 and M-5 was associated with toxicity more than exposure of REG alone. Serum albumin levels didn’t affect unbound fraction of REG, M-2 and M-5.

Citation Format: Hironaga Satake, Takeshi Suzuki, Chiyo K. Imamura, Yasutaka Sukawa, Toshiki Masuishi, Yosuke Kumekawa, Shinsuke Funakoshi, Masahito Kotaka, Yoshiki Horie, Sadayuki Kawai, Hiroyuki Okuda, Tetsuji Terazawa, Chihiro Kondoh, Ken Kato, Kenichi Yoshimura, Hideki Ishikawa, Yasuo Hamamoto, Narikazu Boku, Hiromasa Takaishi, Takanori Kanai. Exposure-toxicity analysis of unbound regorafenib and its active metabolites by dose escalation strategy with low starting dose in patients with colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3882.

The Japanese Lung Cancer Society Guideline for non-small cell lung cancer, stage IV

According to rapid development of chemotherapy in advanced non-small cell lung cancer (NSCLC), the Japan Lung Cancer Society has been updated its own guideline annually since 2010. In this latest version, all of the procedure was carried out in accordance with grading of recommendations assessment, development and evaluation (GRADE) system. It includes comprehensive literature search, systematic review, and determination of the recommendation by multidisciplinary expert panel which consisted of medical doctors, pharmacists, nurses, statisticians, and patients from patient advocacy group. Recently, we have had various types of chemotherapeutic drugs like kinase inhibitors or immune-checkpoint inhibitors. Thus, the guideline proposes to categorize patients into three entities: (1) driver oncogene-positive, (2) PD-L1 ≥ 50%, and (3) others. Based on this subgroup, 31 clinical questions were described. We believe that this attempt enables clinicians to choose appropriate treatment easier. Here, we report an English version of the Japan Lung Cancer Society Guidelines 2018 for NSCLC, stages IV.

Prospective evaluation of a developed S-1 dosage formula based on renal function

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Background: S-1 is an oral anticancer drug, containing tegafur (a prodrug of 5-FU), 5-chloro-2,4-dihydroxypyridine (CDHP, inhibitor of dihydoropyrimidine dehydrogenase) and potassium oxonate. Because CDHP is excreted in urine, renal dysfunction increases incidence of severe adverse drug reactions due to higher exposure of 5-FU. As approved dose of S-1 is determined by body surface area (BSA) for patients with normal renal function, dose of S-1 is practically reduced according to renal function of creatinine clearance (CLcr) estimated by the Cockcroft-Gault equation. In a previous pharmacokinetic study (n = 16), we had developed an S-1 dosage formula based on renal function achieving the target area under the concentration-time curve (AUC) of 5-FU: Dose = target AUC x (21.9 + 0.375 x CLcr) x BSA. We conducted a prospective study to evaluate and refine this formula if necessary. Methods: Thirty patients with various renal function received S-1 at dose determined by our developed formula. A series of blood samples were obtained at predefined times after the first dose to calculate the AUC of 5-FU. Predictability of the formula was evaluated by comparison between the observed and the target AUCs. Results: The observed daily AUC was ranged from 712.6 to 2868.7 ng‧h/mL in 30 patients with BSA in the range of 1.14-1.84 m2 and CLcr in the range of 23.8-96.4 mL/min. Eighteen patients of them achieved the target AUC (1447.8 ± 545.4 ng‧h/mL). Since population pharmacokinetic analysis using combined pharmacokinetic data of 30 patients in this study and 16 patients in the previous study demonstrated that clearance of 5-FU is significantly lower in female than in male, the S-1 dosage formula was refined including gender as an additional factor: Dose = target AUC × (14.5 + 8.23 x GENDER [0 for female and 1 for male] + 0.301 × CLcr) × BSA. Revised nomograms showing recommended daily dose of S-1 were proposed for males and females taking into account tablet strengths. Conclusions: The refined formula for determining S-1 dosage on the basis of renal function, BSA and gender can be applied to clinical practice to ensure efficacy and safety for cancer patients treated with S-1. Clinical trial information: UMIN 000023880.

Application of PBPK Modeling and Virtual Clinical Study Approaches to Predict the Outcomes of CYP2D6 Genotype-Guided Dosing of Tamoxifen

The Tamoxifen Response by CYP2D6 Genotype‐based Treatment‐1 (TARGET‐1) study (n = 180) was conducted from 2012–2017 in Japan to determine the efficacy of tamoxifen dosing guided by cytochrome P450 2D6 (CYP2D6) genotypes. To predict its outcomes prior to completion, we constructed the comprehensive physiologically based pharmacokinetic (PBPK) models of tamoxifen and its metabolites and performed virtual TARGET‐1 studies. Our analyses indicated that the expected probability to achieve the end point (demonstrating the superior efficacy of the escalated tamoxifen dose over the standard dose in patients carrying CYP2D6 variants) was 0.469 on average. As the population size of this virtual clinical study (VCS) increased, the expected probability was substantially increased (0.674 for n = 260). Our analyses also informed that the probability to achieve the end point in the TARGET‐1 study was negatively impacted by a large variability in endoxifen levels. Our current efforts demonstrate the promising utility of the PBPK modeling and VCS approaches in prospectively designing effective clinical trials.

Dynamic changes in CD44v-positive cells after preoperative anti-HER2 therapy and its correlation with pathologic complete response in HER2-positive breast cancer

Chemotherapy has been reported to increase the proportion of cancer stem cells (CSCs) and to promote epithelial-mesenchymal transition (EMT) phenotype changes. Anti-HER2 therapy may provide a strategy for eliminating CSC and EMT, which contribute to therapeutic resistance. No study has determined the changes in the quantity or characteristics of CSCs or circulating tumor cells (CTCs) with EMT phenotype during preoperative anti-HER2 therapy, and whether these changes correlate to response to dual anti-HER2 therapy. In a prospective clinical trial to evaluate pharmacodynamic biomarkers, 18 patients with operable primary HER2-positive breast cancer received dual anti-Her2 preoperative therapy with trastuzumab and lapatinib with paclitaxel. Proportions of tumor cells with CSC characteristics and EMT markers in CTC's were estimated at baseline, after 6 and 18 weeks of preoperative therapy to determine the quantitative cutoff value to predict pathologic complete response (pCR). Out of 18 patients, 8 (44%) had a pCR; 5 of these 8 patients (62%) were positive for CD44v at baseline and none were positive on the 6-week biopsy. In contrast, 6 of the 10 patients without pCR exhibited persistent levels, or enrichment of CD44v proportion and expression at 6 and 18 weeks (p=0.0128). Other biomarkers were not statistically significant predictors of pCR. Enrichment of CD44v-positive tumor cells after dual anti-HER2 therapy alone may predict poor response to dual anti-HER2 therapy plus chemotherapy.

The effects of advanced age and serum α1 -acid glycoprotein on docetaxel unbound exposure and dose-limiting toxicity in cancer patients

AIM

α₁ -Acid glycoprotein (AAG), which is a major binding protein of docetaxel, is considered to be a determinant for docetaxel pharmacokinetics. However, there are no reports about the impact of serum AAG on pharmacokinetics and pharmacodynamics in elderly patients treated with docetaxel. The aim of this prospective study was to elucidate the effects of advanced age and serum AAG on docetaxel unbound exposure and neutropenia, dose-limiting toxicity, in cancer patients.

METHODS

Docetaxel was administered at 60 mg m^-2 to 51 patients with non-small cell lung cancer, 17 of whom were ≥75 years of age. Pharmacokinetics, unbound fraction (fu), neutropenia, serum protein levels of AAG and albumin, as well as baseline absolute neutrophil count (ANC) were assessed during the first course. Population pharmacokinetic and pharmacodynamic analyses were performed to evaluate the influence of clinically relevant factors on docetaxel pharmacokinetics and neutropenia.

RESULTS

Clearance of docetaxel and degree of fu were significantly associated with serum AAG level, but not with age. Area under the concentration-time curve of unbound docetaxel (fu·AUC) was significantly higher in patients aged ≥75 years (0.389 μg·h ml^-1 , 95% CI; 0.329-0.448 μg·h ml^-1 ) compared with patients aged <75 years (0.310 μg·h ml^-1 , 95% CI; 0.268-0.352 μg·h ml^-1 ). Percent decrease in ANC at nadir related to fu·AUC, and was dependent on baseline ANC.

CONCLUSION

Regardless of ageing, serum level of AAG determines docetaxel unbound exposure and related dose-limiting toxicity. Serum AAG level and ANC at baseline appear to be predictive of neutropenia for patients of all ages following the administration of docetaxel.

Phase I study of salazosulfapyridine in combination with cisplatin and pemetrexed for advanced non-small-cell lung cancer

Spliced variant isoforms of CD44 (CD44v) are a marker of cancer stem cells in solid tumors. They stabilize the xCT subunit of the transporter system xc(–) and thereby promote synthesis of the antioxidant glutathione. Salazosulfapyridine (SASP) is an inhibitor of xCT and suppresses the proliferation of CD44v‐positive cancer cells. Chemotherapy‐naïve patients with advanced non‐squamous non‐small‐cell lung cancer were enrolled in a dose‐escalation study (standard 3 + 3 design) of SASP in combination with cisplatin and pemetrexed. The primary end‐point was the percentage of patients who experience dose‐limiting toxicity. Fifteen patients were enrolled in the study. Dose‐limiting toxicity was observed in one of six patients at a SASP dose of 1.5 g/day (elevation of aspartate and alanine aminotransferase levels, each of grade 3), two of five patients at 3 g/day (hypotension or pneumonitis, each of grade 3), and two of three patients at 4.5 g/day (anorexia of grade 3). The maximum tolerated dose was thus 3 g/day, and the recommended dose was 1.5 g/day. The overall response rate was 26.7% and median progression‐free survival was 11.7 months, much longer than that for cisplatin–pemetrexed alone in previous studies. Exposure to SASP varied markedly among individuals according to ABCG2 and NAT2 genotypes. The serum concentration of free CD44v protein was increased after the first cycle of treatment, possibly reflecting death of cancer stem cells. Salazosulfapyridine was thus given safely in combination with cisplatin–pemetrexed, with the addition of SASP tending to prolong progression‐free survival. This trial is registered in the UMIN Clinical Trials Registry as UMIN000017854.

Comprehensive assessment of cancer stem cell like cells in prediction of pathologic complete response to preoperative dual anti–HER2 therapy for HER2–positive primary breast cancer

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Background: Chemotherapy for breast cancer destroys non–stem cells while sparing cancer stem cells (CSCs). In contrast, anti–HER2 therapy may eliminate resistant cells because HER2 may be a key driver of CSCs. CSC biomarkers have been found to be prognostic of poor outcome and predictive of resistance to therapy. However, there are no comprehensive studies of the impact of anti-HER2 therapies on CSC–related biomarkers. We conducted a prospective biomarker determination study of breast CSCs characterized by CD44v expression and increased aldehyde dehydrogenase 1 (ALDH1) enzymatic activity or expression. Methods: In a prospective trial (ClinicalTrials.gov: NCT01688609), 18 patients with operable primary HER2+ breast cancer (≥T2 excluding inflammatory, any N; median age of 54 yrs) were treated with preoperative anti–HER2 therapy following the NeoALTTO trial dual therapy arm regimen, with a goal of identifying novel predictive biomarkers for pCR. Proportions of tumor cells with CSC characteristics, defined as CD44v+ and ALDH1+, were estimated at baseline, at 6 weeks (after therapy with lapatinib/trastuzumab) and at 18 weeks (after therapy with lapatinib/trastuzumab and paclitaxel) to assess adaptive response. We determined changes in the quantity and characteristics of CSC–related biomarkers during preoperative therapy and correlated them to tumor response. Results: Out of 18 patients, 8 (44%) had a pCR; 5 of these 8 patients (62%) were positive for CD44v staining on tumor cells at baseline and none were positive on the 6–week biopsy. In contrast, 6 of the 10 patients without pCR exhibited persistent levels, or enrichment of CD44v proportion and expression at 6 and 18 weeks (p = 0.0128). ALDH1 expression and other biomarkers were not statistically significant predictors of pCR. Conclusions: Enrichment of CD44v+ tumor cells after double anti–HER2 therapy may predict poor response to dual anti–HER2 therapy with cytotoxic chemotherapy. A second biopsy after the start of preoperative therapy may reflect biological changes useful for the guidance and application of therapeutic strategies for patients with HER2+ breast cancer. Clinical trial information: NCT01688609.

Dose adjustment of axitinib based on AUC in sunitinib-pretreated metastatic renal cell carcinoma

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Background: Axitinib is one of the standard second-line therapies after sunitinib in patients (pts) with metastatic renal cell carcinoma (mRCC). The previous study showed that higher exposure and diastolic blood pressure (dBP) were independently associated with better clinical outcomes. However, many factors, such as antihypertensive agents use, usually affect dBP. Therefore, axitinib dose adjustment based on its exposure could be more adequate than that based on dBP. Methods: We conducted a prospective phase II trial of axitinib dose adjustment for Japanese pts with mRCC previously treated with sunitinib. Starting dose of axitinib was 5 mg BID. We assayed blood axitinib levels on day 1 and calculated the area under concentration-time curve from 0 to 12 hours (AUC0-12). We determined the individual sufficient dose (SD) to reach AUC0-12 value at the steady state of 150 ng*hr/mL. After day 15, axitinib dose was adjusted to keep over SD according to adverse drug reaction for each patient. The primary endpoint is 6-month progression-free survival (6m-PFS) rate. Secondary endpoints include toxicity and objective response rate. With power of 80% and one-sided alpha of 10%, thirty-two pts were required to reject 48% of 6m-PFS rate under expected 69% 6m-PFS rate. Results: Between May 2013 to March 2015, 26 pts were enrolled when the trial closed for poor accrual. Pts’ characteristics were: median age 71 years, male 20 (77%), PS 0 19 (73%), and International Metastatic RCC Database Consortium intermediate risk 24 (92%). Median SD of axitinib was 3 mg BID (range 1-16). SD was given at a median of 78% (range 0-100) of total administration day until 6 months. Two pts did not receive the planned SD because their SD was over 10 mg BID. Therefore, the two pts were excluded from safety analysis; meanwhile all pts were included in efficacy analysis. The 6m-PFS rate was 85% (95% CI 66-94, p < 0.01). The median PFS was 10.6 months (95% CI 7.2-16.7). The most common grade 3 to 4 adverse events during the first 6 months were hypertension (79%), decrease appetite (29%), fatigue (13%), and hand-foot syndrome (13%). Conclusions: The individual dose adjustment of axitinib to keep over 150 ng*hr/mL of AUC0-12 on day 1 for sunitinib-pretreated mRCC is feasible. Clinical trial information: UMIN000009579.

Effect of everolimus on the glucose metabolic pathway in mouse skeletal muscle cells (C2C12)

INTRODUCTION

Everolimus selectively inhibits mammalian target of rapamycin complex 1 (mTORC1) and exerts an antineoplastic effect. Metabolic disturbance has emerged as a common and unique side effect of everolimus.

OBJECTIVES

We used targeted metabolomic analysis to investigate the effects of everolimus on the intracellular glycometabolic pathway.

METHODS

Mouse skeletal muscle cells (C2C12) were exposed to everolimus for 48 h, and changes in intracellular metabolites were determined by capillary electrophoresis time-of-flight mass spectrometry. mRNA abundance, protein expression and activity were measured for enzymes involved in glycometabolism and related pathways.

RESULTS

Both extracellular and intracellular glucose levels increased with exposure to everolimus. Most intracellular glycometabolites were decreased by everolimus, including those involved in glycolysis and the pentose phosphate pathway, whereas no changes were observed in the tricarboxylic acid cycle. Everolimus suppressed mRNA expression of enzymes related to glycolysis, downstream of mTOR signaling enzymes and adenosine 5'-monophosphate protein kinases. The activity of key enzymes involved in glycolysis and the pentose phosphate pathway were decreased by everolimus. These results show that everolimus impairs glucose utilization in intracellular metabolism.

CONCLUSIONS

The present metabolomic analysis indicates that everolimus impairs glucose metabolism in muscle cells by lowering the activities of glycolysis and the pentose phosphate pathway.

Abstract 1425: Prospective evaluation of serum unbound fraction of docetaxel as a key determinant of its pharmacokinetics and neutropenia in the elderly

Background: Although elderly patients are at increased risk for treatment-related toxicities of docetaxel (DOC), total body clearance (CL) is unaltered by advanced age. Because the elderly patients show large interindividual variability in pharmacokinetics and toxicities, the profiles of DOC in older patients remain unclear. The present prospective study was conducted to elucidate a key determinant of pharmacokinetics and hematological toxicities of DOC in the elderly focusing on the unbound fraction in serum.

Patients and Methods: DOC was administered at a dose of 60 mg/m2 once every 3 weeks to patients with non-small cell lung cancer. Pharmacokinetics and toxicity were assessed during the first cycle of therapy. Blood samples were taken immediately before and at the end of the DOC infusion, and at 3 points until 24 h. Unbound DOC was obtained by equilibrium dialysis, and DOC concentrations were determined by the UPLC-MS/MS method. Population pharmacokinetic (PPK) analysis was performed using NONMEM version 7.3.

Results: Of 51 patients treated, median age was 66 years (range 34-84 years), alpha1-acid glycoprotein (AAG) level was 1.21 g/L in median (range 0.5-2.64 g/L), and albumin (ALB) level was 37 g/L in median (range 22-48 g/L). The estimated CL, area under the concentration-time curve (AUC), volume of distribution of the central component (V1), volume of distribution at steady state (Vss) and serum unbound fraction were 23.91 ± 5.78 L/hr, 4.22 ± 1.24 mg/hr/L, 9.10 ± 0.94 L, 128.44 ± 9.09 L, and 0.08 ± 0.03, respectively (mean ± SD). In the PPK analysis, levels of serum proteins were significant covariates affecting pharmacokinetics of DOC but age was not statistically significant. AAG and ALB were associated with CL and V1 (both p&lt;0.01), respectively. In addition, significant correlation was observed between unbound fraction and AAG (p&lt;0.01) which is the major binding protein of DOC, whereas ALB showed marginal correlation (p = 0.055). In 49 patients evaluable of adverse events, decrease in neutrophil counts was well correlated with AUC of unbound DOC (p&lt;0.05), but not with total drug AUC.

Conclusion: Pharmacokinetics of DOC, which is bound to serum proteins extensively (&gt;90%), was influenced by not only AAG but also ALB levels in serum. The key determinant of DOC pharmacokinetics was the unbound fraction caused by individual variations in AAG and ALB levels regardless of patients’ age. The present results suggest that the severe hematologic toxicity induced by higher unbound exposure can be predicted by serum protein levels in patients treated with DOC and it is useful especially for the elderly.

Citation Format: Hirotsugu Kenmotsu, Chiyo K. Imamura, Akira Ono, Shota Omori, Kazuhisa Nakashima, Kazushige Wakuda, Tetsuhiko Taira, Tateaki Naito, Haruyasu Murakami, Toshiaki Takahashi, Yusuke Tanigawara. Prospective evaluation of serum unbound fraction of docetaxel as a key determinant of its pharmacokinetics and neutropenia in the elderly. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1425.

Development of an S-1 dosage formula based on renal function by a prospective pharmacokinetic study

BACKGROUND

S-1 is an oral anticancer drug, containing tegafur (a prodrug of 5-fluorouracil, 5-FU), 5-chloro-2,4-dihydroxypyridine, and potassium oxonate. As renal dysfunction is known to increase exposure of 5-FU following S-1 administration, the incidence of severe adverse reactions is increased in patients with impaired renal function. However, no reliable information on its dose modification for patients with renal dysfunction has been provided.

METHODS

We conducted a prospective pharmacokinetic study to develop an S-1 dosage formula based on renal function. Sixteen cancer patients with various degrees of renal function received a single dose of S-1 at 40 mg/m(2). A series of blood samples were collected at predefined times within 24 h to assess the plasma concentration profiles of 5-FU, 5-chloro-2,4-dihydroxypyridine, and tegafur. A mathematical model for the relationship between renal function and exposure of 5-FU was constructed by a population pharmacokinetic analysis.

RESULTS

The clearance of 5-FU following S-1 administration was related to body surface area and creatinine clearance in the range 15.9-108.8 mL/min as estimated by the Cockcroft-Gault equation. The S-1 dosage formula was derived as follows:[Formula: see text]where AUC is the area under the concentration-time curve, CLcr is creatinine clearance, and BSA is body surface area. The recommended daily doses of S-1 in Asia and Europe were also proposed as nomograms according to exposure matching to the previously reported area under the concentration-time curve of 5-FU, which confirmed the efficacy and toxicity in pivotal registration studies.

CONCLUSIONS

We have developed a novel formula for determining the S-1 dosage on the basis of renal function. Further validation is needed to confirm the formula for practical application.

Abstract P3-07-58: CD44v as a potential predictive biomarker for pathologic complete response in primary HER2+ breast cancer: Utility of adaptive response biopsy in preoperative therapy

Background: Preoperative dual anti-HER2 therapy with lapatinib and trastuzumab in combination with conventional chemotherapy demonstrates a higher pathologic complete response rate (pCR) than trastuzumab with chemotherapy in patients with HER2+ breast cancer. Preoperative chemotherapy has been reported to increase the fraction of cancer stem-like cells (CSCs) in breast cancer, but this effect has not been well validated in clinical setting. Cancer cells with the epithelial-mesenchymal transition (EMT) phenotype also exhibit stem cell–like properties with drug resistance. Our goal was to determine the quantitative values of various biomarkers in baseline and adaptive response biopsy specimens and in subsequent surgical specimens to predict pCR in patients treated with dual anti-HER2 therapy as demonstrated by reduction of CSCs, phosphorylated receptors and signaling kinases, and circulating tumor cells (CTC) with the EMT phenotype. Methods: Eighteen patients with operable primary HER2+ invasive breast cancer (≥T2 excluding inflammatory breast cancer, any N) were eligible. Patients received lapatinib (1000 mg PO daily) + trastuzumab (4 mg/kg at loading, then 2 mg/kg IV weekly) for the first 6 weeks, then lapatinib (750 mg daily) + trastuzumab (2 mg/kg IV weekly) + paclitaxel (80 mg/m2 IV weekly) for 12 weeks, followed by surgery (ClinicalTrials.gov Identifier: NCT01688609). Tumor and blood specimens were collected before (baseline), after the 6 weeks of dual anti-HER2 therapy (adaptive response biopsy), and at 18 weeks, after 12 weeks of dual anti-HER2 therapy + paclitaxel (surgical specimens). We measured CSC biomarkers CD44 variant (CD44v) and aldehyde dehydrogenase-1 in tumor tissues, EMT markers in CTCs (TWIST1, SNAIL1, SLUG, ZEB1, and FOXC2) in blood samples by quantitative RT-PCR, and the ratios of phosphorylated EGFR (pEGFR)/EGFR, pHER2/HER2, pERK/ERK, and pAkt/Akt in tumor tissues. All tissue and CTC biomarker levels at all three time points were evaluated for their association with response via Fisher's exact test, McNemar's test, and Wilcoxon rank sum test according to the variables. Results: Eight of 18 patients (44.4%) achieved pCR after dual anti-HER2 therapy + concurrent paclitaxel. All patients who achieved pCR showed reduction or disappearance of CD44v+ cells over the treatment course. Five of the 10 non-pCR patients showed consistent CD44v expression or enrichment after dual anti-HER2 therapy in both the adaptive response biopsy and the surgical specimens. None of the eight pCR patients had detectable CD44v in the 7-week adaptive response biopsy specimen (Fisher exact test, two-tailed, P = 0.0359). None of the other markers significantly predicted pCR. Conclusion: Persistent expression or enrichment of CD44v was suggested to be predictive for non-pCR in breast cancer patients treated with preoperative dual anti-HER2 therapy plus concurrent cytotoxic chemotherapy. A single evaluation of biomarkers before therapy is insufficient for prediction of clinical response. Application of the adaptive response biopsy during the course of preoperative therapy might play a significant role in the success of therapeutic strategies that target CSCs.

Citation Format: Yamauchi T, Imamura CK, Yamauchi H, Jinno H, Takahashi M, Kitagawa Y, Nakamura S, Lim B, Krishnamurthy S, Reuben JM, Liu D, Tripathy D, Zujewski JA, Chen H, Takebe N, Saya H, Ueno NT. CD44v as a potential predictive biomarker for pathologic complete response in primary HER2+ breast cancer: Utility of adaptive response biopsy in preoperative therapy. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-07-58.

Impact of cytochrome P450 2C19 polymorphisms on the pharmacokinetics of tacrolimus when coadministered with voriconazole

This study evaluated the effects of cytochrome P450 (CYP) 2C19 polymorphisms on tacrolimus pharmacokinetics when coadministered with voriconazole. Eighteen healthy volunteers, including 6 individuals in each CYP2C19 genotype (extensive metabolizers [EMs], intermediate metabolizers [IMs], and poor metabolizers [PMs]), received a single oral dose of 3 mg tacrolimus alone or in combination with 200 mg voriconazole twice daily at steady state. When tacrolimus was coadministered with voriconazole, a significant increase in area under its concentration‐time curve (AUC_0‐24) was observed for all genotypes. AUC_0‐12 of voriconazole in IMs and PMs were significantly higher than that in EMs (P < .05 and P < .01, respectively). Consequently, AUC_0‐24 of tacrolimus in combination with voriconazole in IMs and PMs were also significantly higher than that in EMs (P < .05). These results demonstrate that CYP2C19 genotypes influenced the exposure of tacrolimus when coadministered with voriconazole, although tacrolimus is mainly metabolized by CYP3A.

[Dose optimization of anticancer drugs in the elderly]

Age-related physiological changes affect pharmacokinetics and pharmacodynamics in elderly individuals. Cancer treatment in the elderly requires a careful and multidisciplinary assessment of each patient prior to therapy initiation with respect to treatment decisions and dose optimization considerations, given the wide interpatient variability in this population. As renal function declines with age, renal function assessments are necessary when drugs increasing exposure in renal impairment will be administered to elderly patients. Serum creatinine is an insufficient marker for evaluating renal function in elderly patients because muscle mass decreases with age. Renal function should be assessed according to the index used for dosing recommendation at drug administration planning; in most of drugs, does adjustment is recommended according to the creatinine clearance (Ccr) calculated using the Cockcroft-Gault equation. Elderly patients are apparently more sensitive to cytotoxic agent-induced neutropenia and therefore should be monitored closely. Following the first cycle, a proper assessment of tolerability should be conducted before the second cycle; such assessments are required to discuss the appropriateness of the initiation dose and determine doses during the following cycles for each patient.

Sunitinib-induced severe toxicities in a Japanese patient with the ABCG2 421 AA genotype

Background

Sunitinib is a multi-targeted receptor tyrosine kinase inhibitor that acts against receptors for vascular endothelial growth factor and platelet-derived growth factor. Common toxicities of sunitinib treatment include hypertension, hand–foot syndrome, vomiting, and diarrhea, and the proportion of grade 3 or 4 adverse events relating to sunitinib treatment range from 1 to 13% for all categories. It is reported that increased exposure to sunitinib is associated with improved clinical outcomes but also carries an increased risk of adverse effects.

Case presentation

A 73-year-old Japanese woman with metastatic renal cell carcinoma who received sunitinib at a dose of 50 mg once daily suffered a high-grade fever on day 11 of treatment. Sunitinib treatment was discontinued on day 12; however, severe thrombocytopenia and transaminase elevation occurred and persisted more than a week. Additionally, severe hypoxia due to pleural effusion and pulmonary edema developed despite immediate discontinuation of sunitinib. On day 14, three days after the discontinuation of sunitinib, the plasma concentrations of sunitinib and its major active metabolite N-desethyl sunitinib (SU12662) were extremely high (131.9 ng/mL and 28.4 ng/mL, respectively). By day 25, all toxicities had resolved, and a CT scan revealed marked tumor shrinkage. Genotyping of seven single-nucleotide polymorphisms that are potentially relevant to the pharmacokinetics of sunitinib was performed. The patient’s genotype of ABCG2 (ATP-binding cassette, sub-family G (WHITE), member 2) 421C > A was homozygous for the variant allele (AA), which was reported to be associated with high exposure to sunitinib. Therefore, we speculated that the extremely high plasma concentrations of sunitinib and SU12662 caused by the ABCG2 421 AA genotype might have resulted in severe toxicities to the patient.

Conclusion

The minor allele frequencies of ABCG2 421C > A are approximately three-fold higher in Asians than in Caucasians. Our report suggests that pharmacogenetic factors should be considered when severe and rapid-onset adverse drug reactions occur in Asian patients, including Japanese treated with sunitinib.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-14-964) contains supplementary material, which is available to authorized users.

International models of investigator-initiated trials: implications for Japan

BACKGROUND

Academic/institutional investigator-initiated clinical trials benefit individuals and society by supplementing gaps in industry-sponsored clinical trials.

MATERIALS

In May 2010, experts from Japan, the Republic of Korea, the UK, and the United States, met at a symposium in Tokyo, Japan, to discuss how policies related to the conduct of clinical trials, which have been shown to be effective, may be applied to other regions of the world.

RESULTS

In order to increase the availability of anticancer drugs world-wide, nations including Japan should examine the benefits of increasing the number of investigator-initiated clinical trials. These trials represent one of the most effective ways to translate basic scientific knowledge into clinical practice. These trials should be conducted under GCP guidelines and include Investigational New Drug application submissions with the ultimate goal of future drug approval.

CONCLUSIONS

To maximize the effectiveness of these trials, a policy to educate health care professionals, cancer patients and their families, and the public in general on the benefits of clinical trials should be strengthened. Finally, policies that expedite the clinical development of novel cancer drugs which have already been shown to be effective in other countries are needed in many nations including Japan to accelerate drug approval.

Phase I trial of the combination of flavopiridol and imatinib mesylate in patients with Bcr-Abl+ hematological malignancies

PURPOSE

Imatinib is an inhibitor of the Bcr-Abl tyrosine kinase; however, resistance is common. Flavopiridol, a cyclin-dependent kinase (CDK) inhibitor, down-regulates short-lived anti-apoptotic proteins via inhibition of transcription. In preclinical studies, flavopiridol synergizes with imatinib to induce apoptosis. We investigated this novel combination regimen in patients with Bcr-Abl(+) malignancies.

METHODS

In a phase I dose-escalation study, imatinib was administered orally daily, and flavopiridol by 1 h intravenous infusion weekly for 3 weeks every 4 weeks. Adults with chronic myelogenous leukemia or Philadelphia chromosome-positive acute leukemia were eligible. Patients were divided into two strata based on peripheral blood and bone marrow blast counts. The primary objective was to identify the recommended phase II doses for the combination. Correlative pharmacokinetic and pharmacodynamic studies were also performed.

RESULTS

A total of 21 patients received study treatment. Four dose levels were evaluated before the study was closed following the approval of the second-generation Bcr-Abl tyrosine kinase inhibitors (TKIs). Five patients responded, including four sustained responses. Four patients had stable disease. All but one responder, and all patients with stable disease had previously been treated with imatinib. One patient had a complete response sustained for 30 months. Changes in expression of phospho-Bcr/Abl, -Stat5, and Mcl-1 were monitored. No major pharmacokinetic interaction was observed.

CONCLUSIONS

This is the first study to evaluate the combination of a CDK inhibitor and a TKI in humans. The combination of flavopiridol and imatinib is tolerable and produces encouraging responses, including in some patients with imatinib-resistant disease.

Expression changes in arrestin β 1 and genetic variation in catechol-O-methyltransferase are biomarkers for the response to morphine treatment in cancer patients

Genetic differences in individuals with regard to opioid-receptor signaling create clinical difficulties for opioid treatment; consequently, useful pharmacodynamic and predictive biomarkers are needed. In this prospective study, we studied gene expression changes in peripheral blood leukocytes using a microarray and real-time RT-PCR analysis to identify pharmacodynamic biomarkers for monitoring the effect of morphine in a cohort of opioid-treatment-naïve cancer patients. We also examined genetic variations in opioid receptor mu 1 (OPRM1, 118A→G) and catechol-O-methyltransferase (COMT, 472G→A) to evaluate predictive biomarkers of the treatment outcome of morphine. The plasma concentration of morphine was measured using a liquid chromatography-tandem mass spectrometry method. Microarray analysis revealed that the mRNA expression levels of arrestin β 1 (ARRB1) were significantly down-regulated by morphine treatment. Real-time RT-PCR analysis against independent samples confirmed the results (P=0.003) and changes during treatment were negatively correlated with the plasma morphine concentration (R=-0.42). No correlation was observed between the genotype of OPRM1 and morphine treatment; however, the plasma concentration of morphine and the required dose of morphine were significantly lower for the A/A genotype of COMT (vs. A/G+G/G, P=0.008 and 0.03). We found that changes in the expression of ARRB1 may be a novel pharmacodynamic biomarker and the COMT 472G→A genotype may be a predictive biomarker of the response to morphine treatment.

Prospective study evaluating the plasma concentrations of twenty-six cytokines and response to morphine treatment in cancer patients

Cytokine signaling is involved in pain and opioid-receptor signaling. In this prospective study, we studied the plasma cytokine levels in order to identify candidate biomarkers for predicting resistance to morphine treatment in a cohort of opioid-treatment-naïve cancer patients. We analyzed pain rating and the plasma concentrations of 26 cytokines at baseline and after morphine treatment using a multiplex immunoassay system for the following cytokines: eotaxin, colony stimulating factor, granulocyte (G-CSF), colony stimulating factor granulocyte-macrophage (GM-CSF), interferon α2 (IFN-α2), IFN-γ, interleukin 1α (IL-1α), IL-1β, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12 (p40), IL-12 (p70), IL-13, IL-15, IL-17, IP-10, monocyte chemotactic protein 1 (MCP-1), macrophage inflammatory protein 1α (MIP-1α), MIP-1β, tumor necrosis factor-α (TNF-α) and TNF-β. No correlation was observed between the clinical characteristics and the numerical rating scale for pain at baseline or among patients who developed resistance to morphine treatment. Interestingly, the plasma concentration of MIP-1α significantly decreased during morphine treatment (day 8 vs. baseline, p=0.03). Regarding the baseline plasma cytokine concentrations, none of the cytokine levels were correlated with the numerical rating scale for pain at baseline; however, the baseline plasma concentrations of eotaxin, IL-8, IL-12 (p40), IL-12 (p70), MIP-1α and MIP-1β were significantly lower in patients who required a high dose of morphine or who developed resistance to morphine treatment. In conclusion, this is the first report revealing that the plasma concentrations of several cytokines were significantly modulated during treatment and were correlated with treatment outcome of morphine. Our results suggest that plasma cytokine levels may be promising biomarkers for morphine treatment and that they warrant further study.

A phase I study of paclitaxel and continuous daily CAI in patients with refractory solid tumors

BACKGROUND

Carboxyamido-triazole (CAI) is a calcium influx inhibitor with anti-angiogenic and anti-invasive properties and stabilizes tumor progression in patients. We hypothesized daily oral micronized CAI with q3 week paclitaxel would be well-tolerated and active.

RESULTS

Twenty-nine heavily pretreated patients [median 3 [0-7]] were enrolled on five dose levels. No additive or cumulative toxicity was observed, and grade III nonhematological toxicity was rare. Neutropenia was the most common hematologic toxicity, seen in 79% of patients, with a trend towards increasing grade with higher paclitaxel doses. The recommended phase II dose defined by the maximum tolerated dose (MTD) was CAI 250 mg daily and paclitaxel 200 mg/m(2) q3weeks. Pharmacokinetic analysis revealed paclitaxel increases CAI trough concentration at all dose levels by over 100% (p < 0.0001). A trend towards higher steady-state CAI trough concentrations was found in patients with a partial response (PR; p = 0.09). Six patients had confirmed PR (24%; 4-67 cycles, median 10); two patients had minor responses.

PATIENTS AND METHODS

Eligible patients with solid tumors received micronized CAI daily (150-250 mg PO) and paclitaxel intravenously q3weeks (175-250 mg/m(2)), sequentially escalating each drug. CAI preceded paclitaxel by one week to permit pharmacokinetic analysis. Patients were assessed for toxicity, pharmacokinetics and disease outcome.

CONCLUSIONS

The MTD of the combination of CAI and paclitaxel is 250 mg daily and 200 mg/m(2) q3weeks, respectively. The combination is tolerable and has potential antitumor activity.