Phase I dose-escalation and pharmacokinetic study (TED 11576) of cabazitaxel in Japanese patients with castration-resistant prostate cancer

Real-world effectiveness of third-line cabazitaxel in patients with metastatic castration-resistant prostate cancer: CARD-like analysis of data from a post-marketing surveillance in Japan

BACKGROUND

The CARD trial was conducted in patients with metastatic castration-resistant prostate cancer (mCRPC) who had received docetaxel and experienced disease progression within 1 year on an androgen receptor-axis-targeted therapy (ARAT). Subsequent treatment with cabazitaxel had improved clinical outcomes compared with an alternative ARAT. This study aims to confirm the effectiveness of cabazitaxel in real-world patients in Japan and compare their characteristics with those of patients from the CARD trial.

METHODS

This was a post-hoc analysis of a nationwide post-marketing surveillance registering all patients who were prescribed cabazitaxel in Japan between September 2014 and June 2015. Included patients had received docetaxel and ≤ 1 year of an ARAT (abiraterone or enzalutamide) prior to receiving cabazitaxel or an alternative ARAT, as their third-line therapy. The primary effectiveness endpoint was the time to treatment failure (TTF) of the third-line therapy. Patients were matched (1:1) from the cabazitaxel and second ARAT arms based on propensity score (PS).

RESULTS

Of the 535 patients analysed, 247 received cabazitaxel and 288 the alternative ARAT as their third-line therapy, of which, 91.3% (n = 263/288) received abiraterone and 8.7% (n = 25/288) received enzalutamide as their second third-line ARAT. Patients in the cabazitaxel and second ARAT arms had TNM classification of M1 or MX in 73.3% and 68.1%, Gleason score of 8-10 in 78.5% and 79.2% and mean (standard deviation) serum PSA levels of 483 (1370) and 594 (1241) ng/mL, respectively. Initial cabazitaxel dose was ≤ 20 mg/m² in 61.9% (n = 153/247) of the patients in the cabazitaxel arm. The median TTF (95% confidence interval [CI]) of the third-line therapy was 109 (94-128) days for cabazitaxel and 58 (57-66) days for the second ARAT, with a hazard ratio (95% CI) of 0.339 (0.279-0.413) favouring cabazitaxel. Similar results were obtained after PS-matching, with a hazard ratio (95% CI) of 0.323 (95% CI 0.258-0.402) favouring cabazitaxel.

CONCLUSIONS

Consistent with the CARD trial, cabazitaxel demonstrated superior effectiveness over a second alternative ARAT in a real-world patient population in Japan, despite the population having more advanced disease status and a lower dose of cabazitaxel being more frequently administered, than in the CARD trial.

Phase II study of cabazitaxel as second-third line treatment in patients with metastatic adrenocortical carcinoma

Background

Adrenocortical carcinoma (ACC) is a rare and aggressive malignancy with a poor prognosis. No efficacious treatment options are currently available for patients with advanced metastatic disease with disease progression to standard etoposide, doxorubicin, cisplatin and mitotane (EDP-M) therapy. We assessed the activity and tolerability of cabazitaxel as a second/third-line approach in metastatic ACC.

Patients and methods

Patients included in this single-center, phase II study (ClinicalTrials.gov identifier NCT03257891) had disease progression to a cisplatin-containing regimen (such as EDP) plus mitotane, plus/minus a further chemotherapy line. Cabazitaxel was administered intravenously at 25 mg/m² on day 1 of a 21-day cycle, for a maximum of six cycles. The primary endpoint was a disease control rate after 4 months.

Results

From March 2018 to September 2019, 25 eligible patients were enrolled. A disease control rate after 4 months was obtained in six patients (24%). No patients attained a disease response according to RECIST 1.1, 9 patients (36%) had stable disease and 16 patients (64%) progressive disease. Median progression-free survival and overall survival were 1.5 months (range 0.3-7 months) and 6 months (range 1-22.2 months), respectively. Cabazitaxel therapy was well tolerated and only three (12%) patients developed grade 3 toxicity which were nausea in one patient (4%) and anemia in two patients (8%).

Conclusions

Cabazitaxel has a manageable toxicity profile but is poorly active as second/third-line treatment in advanced ACC patients. These results do not support further evaluation of cabazitaxel in this setting.

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Cabazitaxel is well tolerated but poorly active as second/third-line treatment in patients with advanced ACC.

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Combining RECIST and Choi criteria could be of value in the assessment of disease response to chemotherapy in ACC patients.

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Older age, elevated cortisol and LDH blood level correlate with a greater risk of death in multivariate analysis.

Bioadhesive poly(methyl vinyl ether-co-maleic anhydride)-TPGS copolymer modified PLGA/lipid hybrid nanoparticles for improving intestinal absorption of cabazitaxel

A bioadhesive nanocarrier, PTNP, was constructed by utilizing a novel poly(methyl vinyl ether-co-maleic anhydride)- D-α-Tocopheryl polyethylene glycol succinate (PVMMA-TPGS) copolymer in the PLGA/lipid hybrid nanoparticles (PLGA NPs) for improving oral delivery of cabazitaxel (CTX). The PVMMA-TPGS was synthesized by the ring-opening polymerization of the anhydride groups with the hydroxyl groups, combining the bioadhesive property of PVMMA with P-glycoprotein (P-gp) inhibitory effect of TPGS. The CTX-loaded PTNPs (CTX-PTNPs) were prepared by an emulsification-solvent evaporation method and performed a spherical appearance with a uniform particle size of 192.2 nm. The CTX-PTNPs were surface negatively charged, and exhibited good drug loading (10.2%) and encapsulation efficiency (92.1%). A sustained drug release and high stability in simulated gastrointestinal environment were confirmed in in vitro studies. The in vitro mucin adhesion and in vivo intestinal retention experiments indicated that the PTNPs had a stronger bioadhesive effect and a notably longer intestinal retention than the control PLGA NPs, due to the interaction of PVMMA on the PTNP surface with the intestinal mucosa. Moreover, an enhanced intestinal permeability of the PTNPs was also verified in in vivo and ex vivo intestinal permeation studies, which was probably attributed to the extended retention of PTNPs in intestinal mucosa and the P-gp inhibitory effect of TPGS. As respected, in in vivo pharmacokinetic study, the T_max and oral bioavailability of CTX were dramatically improved to 1.08 h and 28.84% by the PTNPs, respectively, obviously superior to the CTX solution and the PLGA NPs, further demonstrating the high-efficiency in oral delivery of CTX. Hence, this bioadhesive carrier is proposed to be a potential and promising strategy for increasing oral absorption of small molecule insoluble drugs.

Long-Term Prostate-Specific Antigen Response on a Low-Dose Cabazitaxel Regimen for Metastatic Castration-Resistant Prostate Cancer: A Case Report

BACKGROUND Cabazitaxel is a second-generation taxane approved for patients with metastatic castration-resistant prostate cancer (CRPC). Although cabazitaxel improves overall survival when used following docetaxel chemotherapy, duration of the clinical response is relatively short, and few patients achieve a long-term response. CASE REPORT A 71-year-old man with prostate adenocarcinoma with an initial prostate-specific antigen (PSA) level of 4956 ng/ml, Gleason score 4+5 and cTxN0M1b was referred to our department for treatment. Several therapeutic approaches, including androgen deprivation therapy, with a combination of bicalutamide and a luteinizing hormone-releasing hormone analogue, and 4 sequential hormonal therapies including flutamide, estramustine, enzalutamide, and abiraterone, all failed to prevent disease progression. Subsequently, after 5 cycles of docetaxel chemotherapy were also ineffective, cabazitaxel chemotherapy at a dose of 20 mg/m² together with prednisone and pegfilgrastim was initiated. The patient developed grade 4 thrombocytopenia during the first 4 cycles, and the dosage of cabazitaxel had to be tapered to 12.5 mg/m² by the fifth cycle. In subsequent cycles, the treatment was continued without grade 4 thrombocytopenia or any other toxicities ³grade 3. The patient achieved a long-term clinical response over 4 years and his PSA level continued to decrease, from 29.8 ng/ml at treatment initiation to a nadir of 2.0 ng/ml after the 60th cycle. CONCLUSIONS The present case is a rare example of a sustained response to low-dose cabazitaxel, and suggests its potential as a treatment option for metastatic CRPC patients. In our patient, this approach achieved a good clinical response with manageable toxicity over the long term.

Utility of prophylactic antibiotics for preventing febrile neutropenia during cabazitaxel therapy for castration-resistant prostate cancer

The aim was to investigate the efficacy of prophylactic antibiotics for the prevention of febrile neutropenia (FN) during cabazitaxel therapy for castration-resistant prostate cancer (CRPC) with G-CSF. We retrospectively studied 443 cycles of cabazitaxel therapy given to 56 patients with CRPC at Keio University Hospital between May 2012 and August 2018. Statistical analysis was conducted to determine whether the combination of prophylactic G-CSF and antibiotics was more effective in preventing FN, compared with prophylactic G-CSF alone. Prophylactic PEG-G-CSF or G-CSF was administered in all 443 cycles. Only fluoroquinolones were used as prophylactic antibiotics and were administered in 328 cycles (74.0%). FN occurred in 5 cycles (1.1%). Prophylactic antibiotics were administered in 327 cycles (74.6%) in the FN-negative group and in only 1 cycle (20.0%) in the FN-positive group. Chi-square test indicated the incidence of FN was significantly lower in the group that received prophylactic antibiotics compared with the group that did not receive prophylactic antibiotics (P = 0.017). Compared with prophylactic G-CSF alone, prophylactic G-CSF and antibiotics significantly suppressed the occurrence of FN.

Influence of prostate cancer status on the prevalence of medication-related osteonecrosis of the jaw

OBJECTIVE

The aim of this study was to evaluate the risk of osteonecrosis of the jaw (ONJ) in patients with prostate cancer, particularly the relationship between prostate cancer progression and ONJ development.

STUDY DESIGN

This single-center, retrospective, observational study included 113 patients who received zoledronic acid or denosumab for prostate cancer with bone metastasis between January 2012 and March 2020. The risk of ONJ was evaluated regarding age; antiresorptive drugs; duration of antiresorptive treatment; prostate cancer status, including castration-resistant prostate cancer (CRPC) and prostate-specific antigen level; chemotherapy; radium-223 treatment; corticosteroid treatment; diabetes mellitus; and dental extractions.

RESULTS

Overall, 28 patients had ONJ; 10 patients received zoledronic acid and 18 patients received denosumab. Multiple logistic regression analysis demonstrated that CRPC (odds ratio = 6.01; 95% confidence interval, 1.76-20.05; P = .004) and dental extractions (odds ratio = 12.40; 95% confidence interval, 3.42-44.70; P < .001) were significantly associated with ONJ. In addition, antiresorptive treatment lasting more than 1 year partially mediated between CRPC and development of ONJ.

CONCLUSION

CRPC and dental extraction are risk factors for developing ONJ, and antiresorptive treatment lasting more than 1 year is a partial mediator between CRPC and ONJ.

Real-world efficacy and safety of two doses of cabazitaxel (20 or 25 mg/m2) in patients with castration-resistant prostate cancer: results of a Japanese post-marketing surveillance study

Background

The recommended starting dose of cabazitaxel for castration-resistant prostate cancer (CRPC) is 25 mg/m² in Japan and Europe. Although lower doses are established alternatives based on randomized controlled trials, the safety and efficacy of 25 and 20 mg/m² in real-world settings are not well established. Therefore, we investigated the safety and efficacy of cabazitaxel at the recommended starting dose or a lower dose (20 mg/m²) in real-world clinical practice.

Methods

We compared the safety and efficacy of cabazitaxel between patients who received cabazitaxel at starting doses of 25 and 20 mg/m² (C25 and C20, respectively) in a Japanese post-marketing surveillance study of 662 patients with docetaxel-refractory CRPC. Safety was assessed in terms of adverse drug reactions (ADRs). Prostate-specific antigen (PSA) response rate, overall survival (OS), and time-to-treatment failure (TTF) were compared between the C25 and C20 groups in unmatched patients and after applying propensity score matching.

Results

The C20 and C25 groups comprised 190 and 159 patients without matching and 112 patients per group after matching. In unmatched patients, any-grade (C25 vs C20: 89.3% vs 78.4%, Fisher’s p < 0.01) and grade ≥ 3 (81.1% vs 61.1%) ADRs were more frequent in the C25 group. Neutropenia (any grade: 61.6% vs 54.2%; grade ≥ 3: 55.3% vs 42.6%) and febrile neutropenia (grade ≥ 3: 30.2% vs 14.7%) were more frequent in the C25 group. In matched patients, the PSA response rate (reduction in PSA ≥30% from a baseline ≥5 ng/mL) was 26.4 and 32.0% in the C20 and C25 groups, respectively, median OS was 291 days (95% CI 230–not reached) versus not reached (hazard ratio 0.73, 95% CI 0.50–1.08), and TTF favored C25 (hazard ratio 0.75, 95% CI 0.57–0.99).

Conclusions

Clinicians should consider the patient’s risk of clinically significant ADRs and prophylactic granulocyte colony stimulating factor when selecting the starting dose of cabazitaxel for CRPC. Some patients at high risk of ADRs or unfit patients may benefit from a lower starting dose of 20 mg/m², whereas fit patients may be candidates for a starting dose of 25 mg/m².

Trial registration

Not applicable.

Safety and efficacy of cabazitaxel in 660 patients with metastatic castration-resistant prostate cancer in real-world settings: results of a Japanese post-marketing surveillance study

Objective

To evaluate the real-world safety and efficacy of cabazitaxel in Japanese patients with metastatic castration-resistant prostate cancer (mCRPC) previously treated with a docetaxel-containing regimen.

Methods

This prospective multicenter observational study registered all patients with mCRPC treated with cabazitaxel following its launch in Japan in September 2014. Patient enrollment continued until at least 500 patients were enrolled. Adverse drug reactions (ADRs) were evaluated according to CTCAE ver. 4.0. Efficacy endpoints were assessed for up to 1 year, and included prostate specific antigen (PSA) response rates (defined as a decrease of ≥30% or ≥50% from baseline), overall survival (OS), and time to treatment failure (TTF).

Results

A total of 660 mCRPC patients were enrolled across 316 centers by June 2016. Frequent ADRs (any grade) were neutropenia (49.1%), febrile neutropenia (18.0%) and anemia (15.0%). Most ADRs occurred in cycle 1. Neutropenia and febrile neutropenia were significantly less frequent in patients who received prophylactic granulocyte colony-stimulating factor. The PSA response rates for decrease of ≥30% or ≥50% from baseline were 28.1% and 17.5%, respectively, in patients with baseline PSA of ≥5 ng/ml. Median OS and TTF were 319 days (95% confidence interval: 293.0–361.0) and 116 days (95% confidence interval: 108.0–135.0), respectively.

Conclusions

This study of cabazitaxel in 660 Japanese patients treated in real-world settings, the largest study of cabazitaxel to date, demonstrated a safety profile that was generally consistent with those of pivotal clinical studies. Cabazitaxel was also effective in terms of the PSA response, OS, and TTF.

Initial treatment outcome and feasibility of low-dose cabazitaxel against docetaxel- and castration-resistant prostate cancer in a Japanese hospital

Introduction: Cabazitaxel (CBZ) is used worldwide for castration-resistant prostate cancer after docetaxel treatment. In July 2014 the drug was approved in Japan with the same induction dose used for Caucasian patients. In this study, we examined and compared the results of an initial low-dose CBZ treatment in patients admitted to our hospital.

Patients and Methods: Between July 2014 and August 2018, sixteen mCRPC patients were enrolled and underwent a low-dose CBZ treatment at our hospital. We compared the results with those of a Japanese metastatic docetaxel- and castration-resistant prostate cancer Phase I study.

Results: The median patient age was 77 years (range, 53–84 years). Of the 16 patients, eight (50%) had a lymph node metastasis and 11 (68.8%) had a distant metastasis, 10 of whom had only a bone metastasis. The median dose of CBZ was 30 mg (range, 20–32 mg) and the median number of CBZ cycles was 2.5 (range, 1–18). The PSA level of 9 (56.3%) patients decreased after CBZ treatment, including 4 (25%) who showed a decrease to <50%. The median time interval in which the PSA level decreased was 2 months (range, 1–18 months). The observed adverse events (AE) were neutropenia (31.3%), febrile neutropenia (6.3%), fatigue (43.8%), nausea (18.8%), diarrhea (12.5%), decreased appetite (25%), dysgeusia (6.3%), white blood cell count decrease (43.8%), platelet count decrease (12.3%), and anemia (75%). However, no patient listed an AE as the reason for discontinuing the treatment.

Conclusions: Even at a low dose, CBZ could improve the PSA value in patients with CRPC previously treated with docetaxel. Dose reduction and prophylactic administration of sustained G-CSF were also safe treatment options. Further studies involving an introduction period including a modulation of duration and dose are necessary, especially in Japanese patients.

Prognosis of patients with prostate cancer and middle range prostate - specific antigen levels of 20 - 100 ng / mL

Introduction:

Prostate - specific antigen (PSA) is a useful biomarker for detection of prostate cancer (PCa) and for risk classification in addition to TNM classification and Gleason score (GS). We reported the role of PSA in patients with low (< 20 ng / mL) and extremely high (≥ 100 ng / mL) PSA levels. However, it is unclear whether a correlation exists between middle range PSA levels (20 – 100 ng / mL) at diagnosis and prognosis.

Materials and Methods:

Between January 2000 and December 2014, 1873 patients underwent prostate biopsy at Kanazawa University Hospital. Of 802 patients who were diagnosed with PCa, 148 patients with middle range PSA levels (20 – 100 ng / mL) were retrospectively analyzed.

Results:

The percentage of patients with T3 – 4 consistently increased as PSA levels increased from 20 to 100 ng / mL. Although the percentage of patients with GS ≥ 8 or metastases increased as PSA levels increased up to approximately 70 ng / mL, there was no significant increase between 70 and 100 ng / mL. PCa - specific and castration - resistant PCa - free survivals were adversely associated with PSA levels up to 70 ng / mL, but not between 70 and 100 ng / mL.

Conclusion:

PSA is a useful biomarker for predicting prognosis at levels between 20 and 70 ng / mL. However, PSA cannot be used as a prognostic factor in patients with PCa and PSA levels ≥ 70 ng / mL. When the PSA level reaches approximately 70 ng / mL, prognosis might bottom and reach a plateau.

No significant impact of patient age and prior treatment profile with docetaxel on the efficacy of cabazitaxel in patient with castration-resistant prostate cancer

BACKGROUND

The correlation of the oncological outcomes of docetaxel and cabazitaxel in Japanese metastatic castration-resistant prostate cancer (mCRPC) patients has not been unclear.

MATERIALS AND METHODS

This study included a total of 47 consecutive Japanese mCRPC patients treated with cabazitaxel and assessed the prognostic significance of cabazitaxel, focusing on patient age and the correlation of efficacy between docetaxel and cabazitaxel.

RESULTS

Prostate-specific antigen (PSA) decline was observed in 27 patients (57.4%), including 19 (40.0%) achieving the response defined by PSA decline ≥ 30%. The median overall survival (OS) periods after the introduction of cabazitaxel was 16.1 months. Twenty (42.6%) were judged to have responded to cabazitaxel with a PSA decrease ≥ 30% from the baseline. A 30% PSA response to cabazitaxel was achieved in 4 (50.0%) patients with ≧ 75 years (n = 8) and 16 (41.0%) patients with less than 75 years (n = 39). There was no significant correlation between the PSA response and patients' age (p = 0.707). A 30% PSA response to cabazitaxel was achieved in 13 (46.4%) and 7 (36.8%) patients with and without that to docetaxel, respectively. A 30% PSA response to cabazitaxel was achieved in 5 (16.6%) and 7 (41.2%) patients who had treated with less than 10 cycles docetaxel or 10 ≦ cycles, respectively. Univariate and multivariate analyses revealed that there were no significant correlation of patient age (p = 0.537), the response to prior docetaxel therapy (p = 0.339) or cycles of docetaxel therapy (p = 0.379) with shorter OS.

CONCLUSION

These results indicate that the introduction of cabazitaxel for Japanese mCRPC patients could result in oncological outcomes without any association with patient's age and the profiles of previous docetaxel therapy.

Risk stratification of castration-resistant prostate cancer patients treated with cabazitaxel

Patient characteristics before administering the first cycle of cabazitaxel for metastatic castration-resistant prostate cancer (mCRPC) were collected to assess prognostic factors for overall survival (OS). Multivariate analysis revealed that prostate-specific antigen (PSA) ≥100 ng/ml prior to cabazitaxel treatment, visceral metastasis, and low absolute monocyte count were independent prognostic indicators for OS. The aim of the present study was to investigate prognostic biomarkers in patients treated with cabazitaxel among Japanese metastatic castration-resistant prostate cancer (mCRPC) patients. In this retrospective study, 45 patients with mCRPC treated with cabazitaxel were reviewed retrospectively. Clinicopathological factors and laboratory data before administering the first cycle of cabazitaxel were collected to assess the prognostic factors for overall survival (OS). Treatment was generally well tolerated, with a median of 5 cycles (range, 1-26). Median OS from the start of cabazitaxel treatment was 16.1 months (95% confidence interval 6.8-25.5). Univariate analysis revealed that poor performance status, visceral metastasis, hemoglobin <11 mg/dl, absolute monocyte count <400/µl, and prostate-specific antigen ≥100 ng/ml prior to cabazitaxel treatment (P=0.002) were significantly associated with shorter OS. Multivariate analysis revealed that PSA ≥100 ng/ml prior to cabazitaxel treatment, visceral metastasis, and absolute monocyte count <400/µl were independent prognostic indicators for OS. Based on the relative risk of death, patients with mCRPC before cabazitaxel therapy were divided into three risk groups: Low, intermediate, and high (P<0.001). In conclusion, the practical implications of our results may assist in tailoring the introduction of cabazitaxel.

Prognostic significance of grade 3/4 neutropenia in Japanese prostate cancer patients treated with cabazitaxel

The present study aimed to evaluate the efficacy of cabazitaxel in Japanese patients affected by metastatic castration-resistant prostate cancer (mCRPC) previously treated with a docetaxel-containing regimen. In this retrospective study, 41 patients with mCRPC treated with cabazitaxel at Keio University Hospital were retrospectively reviewed. Cabazitaxel at a dose of 20-25 mg/m² was administered every 3 or 4 weeks. Clinicopathological factors and laboratory data were collected to assess the prognostic factors for overall survival (OS) and progression-free survival (PFS). An upfront dose-reduction was required in 52.5% of patients due to their reduced general condition or advanced age. Prophylactic G-CSF was prescribed to all the patients. Grade ≥3 neutropenia and febrile neutropenia occurred in 21 patients (53.6%) and 3 patients (6.8%), respectively. Treatment was generally well tolerated, with a median of 5 cycles (range 1-17). Median PFS and OS from the start of cabazitaxel treatment were 4.4 and 15.0 months (95% CI 8.9-21.2), respectively. Waterfall plot analysis revealed that a prostate-specific antigen (PSA) decline >50% was noticed in n = 11 patients receiving cabazitaxel (26.8%). Univariate analysis revealed that poor performance status, PSA ≥100 ng/mL prior to cabazitaxel treatment, visceral metastasis, absence of grade 3/4 neutropenia during cabazitaxel therapy and neutrophil-lymphocyte ratio were significantly associated with shorter overall survival. Multivariate analysis revealed that poor performance status, visceral metastasis, and the absence of grade 3/4 neutropenia during cabazitaxel therapy were the independent prognostic indicators for OS. The practical implication of our results might be to tailor cabazitaxel dosing on the basis of its hematological effects.

Mechanism of paclitaxel resistance in a human prostate cancer cell line, PC3-PR, and its sensitization by cabazitaxel

Paclitaxel (PTX) is a microtubule-targeting drug widely used for the treatment of a variety of cancers. However, drug resistance can emerge after a series of treatments, and this can seriously affect the patient's prognosis. Here, we analyzed the mechanism of PTX resistance using a human prostate cancer cell line, PC3, and its PTX-resistant subline, PC3-PR. Compared with PC3, PC3-PR exhibited some unique phenotypes that might be associated with PTX resistance, including decreased expression of acetylated α-tubulin and the cell cycle regulator p21, and increased expression of βIII tubulin, histone deacetylase 6 (HDAC6), and the anti-apoptotic protein Bcl2. The drug exporters MDR1 and MRP1 were not involved in PTX resistance. Although cabazitaxel (CTX), a novel taxoid, has been reported to overcome PTX resistance, its mechanism of action is unknown. We found that treatment of PC3-PR cells with CTX induced expression of acetylated α-tubulin and p21, but not the related regulators p27, p15, and p16 or the Bcl2 family proteins. The pan-HDAC inhibitors trichostatin A and suberanilohydroxamic acid and the HDAC6-specific inhibitor tubacin inhibited PC3-PR proliferation and increased expression of p21 and acetylated α-tubulin in a manner similar to CTX. Our data shed light on the cellular response to PTX and CTX.

A Phase I study of cabazitaxel in patients with advanced gastric cancer who have failed prior chemotherapy (GASTANA)

PURPOSE

This Phase I dose-escalation study (GASTANA) evaluated the safety, tolerability, pharmacokinetics and preliminary antitumor activity of cabazitaxel in Asian patients with advanced gastric adenocarcinoma failing two prior chemotherapy regimens.

METHODS

Cabazitaxel safety/tolerability was determined using a standard 3 + 3 dose-escalation design based on dose-limiting toxicities (DLTs) in Cycle 1. Three dose levels (DL) were planned: 20, 25 and 15 mg/m(2) (DL 1, DL 2 and DL -1).

RESULTS

Fifteen patients were evaluable for DLTs. At DL 1, no DLTs occurred in three patients. At DL 2, four patients were enrolled (one patient discontinued), with only one DLT observed [Grade 4 febrile neutropenia (FN)]; however, all four patients experienced FN, hence three more patients were enrolled at DL 1 who experienced two DLTs (Grade 4 neutropenia >7 days). In response, DL -1 was opened, with no DLTs observed in six patients. In the total population (n = 16), frequent Grade 3/4 toxicities included neutropenia (63%) and FN (38%), best overall responses included one partial response (6.3%; DL -1) and eight stable disease (50%), and median progression-free survival was 83 days.

CONCLUSIONS

No unexpected safety findings were observed. Significant toxicities included neutropenia and FN, potentially due to patients being heavily pretreated and the accumulated toxicity of prior taxane therapy.