A phase 1 and pharmacodynamic study of decitabine in combination with carboplatin in patients with recurrent,platinum‐resistant,epithelial ovarian cancer

BACKGROUND:

Aberrant DNA methylation is a hallmark of cancer, and DNA methyltransferase inhibitors have demonstrated clinical efficacy in hematologic malignancies. On the basis of preclinical studies indicating that hypomethylating agents can reverse platinum resistance in ovarian cancer cells, the authors conducted a phase 1 trial of low‐dose decitabine combined with carboplatin in patients with recurrent, platinum‐resistant ovarian cancer.

METHODS:

Decitabine was administered intravenously daily for 5 days, before carboplatin (area under the curve, 5) on Day 8 of a 28‐day cycle. By using a standard 3 + 3 dose escalation, decitabine was tested at 2 dose levels: 10 mg/m² (7 patients) or 20 mg/m² (3 patients). Peripheral blood mononuclear cells (PBMCs) and plasma collected on Days 1 (pretreatment), 5, 8, and 15 were used to assess global (LINE‐1 repetitive element) and gene‐specific DNA methylation.

RESULTS:

Dose‐limiting toxicity (DLT) at the 20‐mg/m² dose was grade 4 neutropenia (2 patients), and no DLTs were observed at 10 mg/m². The most common toxicities were nausea, allergic reactions, neutropenia, fatigue, anorexia, vomiting, and abdominal pain, the majority being grades 1‐2. One complete response was observed, and 3 additional patients had stable disease for ≥6 months. LINE‐1 hypomethylation on Days 8 and 15 was detected in DNA from PBMCs. Of 5 ovarian cancer‐associated methylated genes, HOXA11 and BRCA1 were demethylated in plasma on Days 8 and 15.

CONCLUSIONS:

Repetitive low‐dose decitabine is tolerated when combined with carboplatin in ovarian cancer patients, and demonstrates biological (ie, DNA‐hypomethylating) activity, justifying further testing for clinical efficacy. Cancer 2010. © 2010 American Cancer Society.     

Phase II study of belotecan, a camptothecin analogue, in combination with carboplatin for the treatment of recurrent ovarian cancer

BACKGROUND:

Belotecan (CKD602; Camtobell, Chong Keun Dang Corp., Seoul, Korea) is a recently developed camptothecin derivative with antitumor properties. This phase II study was designed to evaluate the toxicity and efficacy of belotecan combined with carboplatin in patients with recurrent epithelial ovarian cancer (EOC).

METHODS:

Thirty‐eight patients with recurrent EOC were treated with belotecan 0.3 mg/m²/day (days 1‐5) and carboplatin AUC 5 (day 5) every 3 weeks for 6 cycles. The primary objective was to determine the response rate as defined by Response Evaluation Criteria in Solid Tumors and CA‐125 response. Other end points included toxicities and progression‐free survival (PFS).

RESULTS:

All 38 patients were assessed for toxicity, and 35 patients were assessed for response. The overall response rate was 57.1%; there were 7 complete responses (20.0%), 13 partial responses (37.1%), 6 patients with stable disease (17.1%), and 9 patients with progressive disease (25.7%). Grades 3 and 4 hematologic toxicities included neutropenia (28.8%), thrombocytopenia (19.8%), and anemia (14.4%), and there were 2 episodes of febrile neutropenia. Median PFS was 7 months, with a median follow‐up of 12 months.

CONCLUSIONS:

The newly developed topoisomerase I inhibitor belotecan (CKD‐602) combined with carboplatin is a well‐tolerated regimen with activity in recurrent EOC. Further testing of this regimen is warranted to further characterize efficacy and indications for use. Cancer 2011. © 2010 American Cancer Society.     

Pegylated liposomal doxorubicin as a single agent or as combination therapy with carboplatin in patients with recurrent or refractory epithelial ovarian cancer

OBJECTIVE Pegylated liposomal doxorubicin （PLD; CAELYX ）, a novel formulation of doxorubicin with enhanced therapeutic efficacy and reduced toxicity, has demonstrated improved progression-free survival in recurrent or refractory ovarian cancer. The objective of this open-label, noncomparative, observational study was to determine the efficacy and safety of PLD monotherapy or combination therapy with carboplatin for patients with cancer. recurrent or refractory ovarian METHODS Sixty-two patients with recurrent or refractory ovarian cancer who completed a platinum-based chemotherapy regimen and demonstrated platinum sensitivity for first-line treatment at least 6 months prior to study entry were enrolled in 20 centers in China. PLD was given as monotherapy （50 mg/m2 infused over 60 minutes） or as combination therapy （30 mg/m2 1-hour infusion） with carboplatin （area under the curve 5 mg.min/mL 1-hour infusion） on day 1 every 28 days for 4 cycles. The primary endpoint was objective response （OR） rate or CA-125 level. Secondary endpoints included time to response, time-to-progression, health-related quality of life, and safety. RESULTS Overall, 48% of the 62 evaluable patients achieved a confirmed OR. More patients receiving PLD and carboplatin achieved an OR vs the PLD monotherapy group （63% vs. 37%）. The median time to response and disease progression was 58.5 days and 56.0 days, respectively. Overall and drug-related adverse events were reported for 39% and 34%, respectively. The most commonly reported adverse events were stomatitis （22.6%） and palmar-plantar erythroderma （9.7%）. Two deaths were reported. CONCLUSION PLD is an effective and well tolerated agent in women with recurrent or refractory epithelial ovarian cancer.     

A dose-finding study of carboplatin-epirubicin-docetaxel in advanced epithelial ovarian cancer

The docetaxel-carboplatin combination is active and well tolerated in patients with epithelial ovarian cancer. We added epirubicin to this combination to investigate additional benefits of anthracyclines in epithelial ovarian cancer. Twenty-one patients, FIGO Ic-IV, performance status 0-1, were treated in four dose cohorts. Docetaxel was fixed at 75 mg m(-2), carboplatin doses were AUC 4-5 and epirubicin doses were 50-60 mg m(-2). Drugs were given on day 1, every 3 weeks, except in cohort 3, where epirubicin was given on day 8. Dexamethasone was given prophylactically. One dose-limiting toxicity occurred in cohorts 1, 2 and 4, two occurred in cohort 3. Complicated neutropenia occurred in two patients in cohorts 1 and 2 and one patient in cohorts 3 and 4. Two patients experienced grade III diarrhoea or stomatitis in cohort 1 and two in cohort 3. There were no treatment-related deaths. Grade II sensory neuropathy occurred in one patient. No cardiac toxicity or significant oedema was observed. The overall response rate was 36%, and 62% were CA125 responders. The predefined maximum tolerated dose was exceeded in cohort 3. The cohort 4 dose level (epirubicin 50 mg m(-2), carboplatin AUC 4, docetaxel 75 mg m(-2)), warrants further study.     

Phase II study of the combination carboplatin and paclitaxel in patients with ovarian cancer

Background: Recently the feasibility of combining carboplatin withpaclitaxel has been demonstrated in dose-finding studies. Maximum tolerateddoses were 550 mg/m² and 200 mg/m² (threehours), respectively. We report now a phase II study in ovarian cancerpatients.Patients and methods: Twenty-one chemo-naïve patients with optimally(n = 6) or suboptimally (n = 15) debulked stage III or IV ovarian cancer weretreated every three weeks for six courses with paclitaxel (200mg/m²) as a three-hour infusion, immediately followed bycarboplatin (550 mg/m²) as a 30-minute infusion.Results: Uncomplicated neutropenia was the principal toxicity, with mildanemia occurring regularly. As observed in the preceding phase I study, arelative lack of thrombocytopenia, generally grade III was found. Othertoxicities consisted of mild neurotoxicity, nausea and vomiting, alopecia,myalgia, and bone pain. All suboptimally debulked patients responded totherapy. Overall, 12 patients underwent second-look laparoscopy, whichrevealed a pathologically confirmed complete remission in six. The medianfollow-up interval at the time of analysis was 14 months. Twelve patients arecurrently free of progression, at 8+ to 19± months after the start oftherapy.Conclusion: The carboplatin/paclitaxel combination appears to be awell-tolerated regimen, yielding high response rates. This combination has nowgone forward to be evaluated in prospective randomized trials versus thecisplatin/paclitaxel combination.     

紫杉醇脂质体联合卡铂治疗晚期卵巢上皮癌的临床分析

目的研究紫杉醇脂质体联合卡铂方案化疗治疗晚期卵巢上皮癌的临床疗效和毒副作用。方法对经减瘤术后病理组织学确诊的Ⅲ一Ⅳ卵巢上皮癌患者26例,采用紫杉醇脂质体联合卡铂方案化疗,其中紫杉醇脂质体130～175mg／m^2第1天静脉滴注;卡铂300mg／m^2第2天静脉滴注,每21天为1个周期,每2个周期评价1次疗效。结果26例患者完全可以评价疗效,其中完全缓解7例,部分缓解11例,稳定6例,进展3例,总有效率为69．23％,其中Ⅲ期有效率为72．22％,Ⅳ期有效率为62．50％。中位疾病进展时间（MTYP）10个月（5～13个月）,无复发生存期5个月。毒副作用主要为骨髓抑制和胃肠道反应。结论紫杉醇脂质体联合卡铂方案治疗晚期卵巢上皮癌近期疗效好,毒副作用可以耐受,值得临床推广使用。     

Phase I/II study of the combination of carboplatin and paclitaxel as first-line chemotherapy in patients with advanced epithelial ovarian cancer

Purpose: We performed a phase I/II study evaluating the combination ofpaclitaxel and carboplatin as first-line chemotherapy in patients withadvanced ovarian cancer. The aim of this study was to define a feasible andsafe combination regimen that could be recommended for future phase IIIstudies.Design: This study was a parallel two-arm, non-randomized, open trial. Ina first step, carboplatin was administered at a fixed dose of AUC 5 andpaclitaxel was escalated in 25 mg/m² steps starting at 135mg/m². Paclitaxel was given as a three-hour infusion.Carboplatin was administered on day 1 following paclitaxel in one study armand 24 hours after paclitaxel infusion on day 2 in the other study arm.Carboplatin was escalated to AUC 6 and AUC 7.5 after the MTD for paclitaxelhad been defined. Treatment was repeated every three weeks.Patients: Sixty-one patients with untreated histologically confirmedepithelial ovarian cancer were recruited of whom 59 were found eligible andevaluable for toxicity. Thirty-three patients with bidimensionally measurabledisease were evaluable for tumor response.Results: We could not detect any advantage of the two-day schedule comparedwith the more convenient one-day schedule. Dose limiting toxicities wereneutropenia, thrombocytopenia, and neurotoxicity. Except for two patients,toxicity was acceptable and clinically managable. One patient died ofneutropenic sepsis and one further patient developed grade III peripheralneurotoxicity that did not resolve within two months after chemotherapy hadbeen terminated. Overall objective response rate was 70%. The MTD forpaclitaxel was 185 mg/m² and AUC 6 for carboplatin,respectively. Secondary prophylaxis with G-CSF did not allow further doseescalation and therefore is not generally recommended.Conclusions: Paclitaxel 185 mg/m² given as three-hourinfusion followed by carboplatin AUC 6 is a feasible and safe regimen and canbe recommended for phase III trials. Observed response rates justify furtherevaluation of this combination. A randomized phase III trial comparing athree-hour infusion of paclitaxel 185 mg/m² combined witheither carboplatin AUC 6 or cisplatin 75 mg/m² as first-linechemotherapy of advanced ovarian cancer has recently been initiated by ourgroup.     

Phase II study of docetaxel-vinorelbine in platinum-resistant, paclitaxel-pretreated ovarian cancer.

BACKGROUND: This multicenter, prospective phase II study evaluated the safety and efficacy of the combination of docetaxel and vinorelbine in patients with platinum-resistant, paclitaxel-pretreated recurrent ovarian cancer. PATIENTS AND METHODS: Treatment consisted of vinorelbine 25 mg/m(2) as a 20-min i.v. infusion (days 1 and 8), and docetaxel 70 mg/m(2), as a 1-h i.v. infusion (day 8). Granulocyte colony-stimulating factor support was administered prophylactically on days 12-16. Treatment was repeated every 21 days. RESULTS: Forty-six patients were enrolled. The median number of previous chemotherapeutic regimens was one (range 1-3) with a median treatment-free interval of 4.3 months. Four chemotherapy cycles per patient were administered. Almost 75% of the planned doses for both drugs were given. Forty-one patients are evaluable for response. Three patients (6.5% of all patients; 7.3% of evaluable patients) achieved complete response and eight (17.4% and 19.5%, respectively) a partial response to chemotherapy, leading to overall response rates of 23.9% and 26.8%, respectively. Another 34.8% (39.0%) had stable disease. At a median follow-up of 30 months, the median disease-free survival was 13 months, relapse-free survival was 5 months, time to progression was 4.5 months, and overall survival was 9.3 months. Severe toxicities included leukopenia (31%), neutropenia (35%) and febrile neutropenia (20%). CONCLUSIONS: The combination of docetaxel/vinorelbine is an effective regimen with manageable toxicity for the treatment of platinum-resistant, paclitaxel-pretreated ovarian cancer.     

上皮性卵巢癌组织中环氧化酶-2的表达与化疗耐药的相关性研究

目的:探讨上皮性卵巢癌组织中环氧化酶-2(cyclooxygenase-2,COX-2)表达与化疗耐药的关系,以及与p53表达的相关性。方法:用免疫组化SP法检测108例上皮性卵巢癌组织和20例正常卵巢组织中COX-2和p53表达。结果:COX-2和p53在上皮性卵巢癌组织中阳性表达率分别为48.1%和59.3%,正常卵巢组织均未见表达,差异有极显著性(P<0.01);COX-2和p53表达呈显著正相关(P<0.01)。COX-2表达与患者病理类型、临床分期、病理分级及年龄无关,与术后残留灶直径有显著相关性(P<0.01)。COX-2和p53阳性表达率,耐药组和非耐药组相比均有显著差别(P<0.01)。多因素分析显示,卵巢癌患者COX-2、p53表达和术后残留灶直径是与化疗耐药密切相关的独立因素。结论:COX-2表达是与化疗耐药相关的独立危险因素。COX-2过表达与抑癌基因p53的突变可能具有相互促进作用,在卵巢癌化疗耐药中起重要作用。     

Sphingosine kinase 1 as a potential therapeutic target in epithelial ovarian cancer

Sphingosine kinase 1 (SK1) is over‐expressed in multiple types of human cancer. SK1 has growth‐promoting effects and has been proposed as a potential therapeutic target. We investigated the therapeutic effects of SK1 inhibition in epithelial ovarian carcinoma (EOC). SK1 siRNA or inhibitors were tested in EOC cell lines, including A2780, SKOV3ip1, A2780‐CP20, SKOV3‐TR, ES2 and RMG2. Cells were treated with SK inhibitor or FTY720, and cell proliferation, apoptosis, angiogenesis and invasion were examined by MTT, FACS, ELISA and wound‐healing assays, respectively. In vivo experiments were performed to test the effects of FTY720 on tumor growth in orthotopic mouse xenografts of EOC cell lines A2780 or SKOV3ip1 and a patient‐derived xenograft (PDX) model of clear cell ovarian carcinoma (CCC). Blocking SK1 with siRNA or inhibitors significantly reduced proliferation, angiogenesis and invasion, and increased apoptosis in chemosensitive (A2780 and SKOV3ip1) and chemoresistant (A2780‐CP20, SKOV3‐TR, ES2 and RMG2) EOC cells. SK1 inhibitors also decreased the intracellular enzymatic activity of SK1. Furthermore, FTY720 treatment significantly decreased the in vivo tumor weight in xenograft models of established cell lines (A2780 and SKOV3ip1) and a PDX model for CCC compared to control (p < 0.05). These results support therapeutic targeting of SK1 as a potential new strategy for EOC.     

上皮性卵巢癌多药耐药相关信号传导通路及其靶向药物研究进展*

卵巢癌是严重威胁女性生殖健康的肿瘤之一,死亡率居各类妇科肿瘤的首位。上皮性癌是卵巢癌中最常见的病理类型,近年来虽然手术及放化疗技术不断提高,但75% ～80% 晚期患者在治疗后仍出现复发或进展。多药耐药是导致上皮性卵巢癌治疗后复发、转移和死亡的重要原因,严重制约上皮性卵巢癌患者生存率的提高。信号传导通路是多药耐药的重要调控机制之一,目前对其作用机制的研究取得了一定进展,其靶向药物亦在临床各期试验获得了良好效果。本文拟对信号传导通路在上皮性卵巢癌多药耐药机制及目前相关靶向药物在临床研究进展进行综述,为其进一步在临床应用提供指导价值。     

紫杉醇治疗复发卵巢上皮癌31例临床疗效观察

目的比较紫杉醇为主的联合化疗在治疗复发卵巢上皮癌时,紫杉醇周疗与月疗不同给药方法的近期疗效、复发后生存时间及毒副作用。方法回顾性分析1997年1月至2004年12月期间我科用紫杉醇联合化疗的31例复发性卵巢上皮癌患者。紫杉醇周疗组14例紫杉醇60mg/m2静脉滴注每周1次,连续3周为1周期。月疗17例,紫杉醇135mg/m2静脉滴注3周1次为1周期。铂类等药用法两组相同顺铂70mg/m2,或卡铂300mg/m2或AUC=4~5,或奥沙利铂100mg/m2静脉滴注d2,均3周重复1次。结果全组31例病人均可进行近期疗效评价,总有效率为38.71%。周疗组和月疗组的有效率分别为42.86%(6/14)和35.29%(6/17)。随访的26例病例中,中位生存时间22个月。周疗组和月疗组中位生存时间分别是26.5个月、20个月。紫杉醇的毒副作用以白细胞下降、恶心呕吐、肌肉关节痛、手足麻木、脱发等常见。两组间毒副作用的发生率无明显差异,但周疗组毒副作用发生程度较低。结论紫杉醇无论对铂类敏感或对铂类耐药的复发卵巢上皮癌病例,均有较高的疗效,是复发卵巢癌的首选药物。紫杉醇周疗与月疗治疗复发卵巢上皮癌的近期疗效相近,而紫杉醇周疗在降低药物毒副作用、改善患者生存质量、延长生存时间方面比紫杉醇月疗更好。     

Hypodontia phenotype in patients with epithelial ovarian cancer

Background

Ovarian cancer is usually diagnosed in an advanced stage and the present clinical and diagnostic molecular markers for early OC screening are insufficient. The aim of this study was to identify potential relationship between the hypodontia and epithelial ovarian cancer (EOC).

Patients and methods

A retrospective study was conducted on 120 patients with EOC treated at the Department of Gynaecologic and Breast Oncology at the University Clinical Centre and 120 gynaecological healthy women (control group) of the same mean age. Women in both groups were reviewed for the presence of hypodontia and the patients with EOC also for clinicopathological characteristics of EOC according to hypodontia phenotype.

Results

Hypodontia was diagnosed in 23 (19.2%) of patients with EOC and 8 (6.7%) controls (p = 0.004; odds ratio [OR] = 3.32; confidence interval [CI], 1.42–7.76). There was no statistically significant difference in patients with EOC with or without hypodontia regarding histological subtype (p = 0.220); they differed in regard to FIGO stage (p = 0.014; OR =3.26; CI, 1.23–8.64) and tumour differentiation grade (p = 0.042; OR = 3.1; CI, 1.01–9.53). Also, bilateral occurrence of EOC was more common than unilateral occurrence in women with hypodontia (p = 0.021; OR = 2.9; CI, 1.15–7.36). We also found statistically significant difference between the ovarian cancer group and control group in presence of other malignant tumours in subjects (p < 0.001).

Conclusions

The results of the study suggest a statistical association between EOC and hypodontia phenotype. Hypodontia might serve as a risk factor for EOC detection.     

A phase II study of gemcitabine in platinum pre-treated patients with advanced epithelial ovarian cancer

Background: Most patients with advanced ovarian cancer will relapse following platinum-based combination chemotherapy and be considered for second-line treatment. Gemcitabine, a nucleoside analogue, is active against a range of solid tumors. This phase II study investigated the activity of single-agent gemcitabine in patients with recurrent ovarian cancer.Patients and methods: Thirty-eight patients with FIGO stage III (34%) or IV (64%) ovarian cancer who were previously treated with platinum-containing regimens were enrolled. Patients received 1200 mg/m2 gemcitabine on days 1, 8 and 15 of a 28-day cycle.Results: Patients completed an average of 3.6 cycles. Two complete and three partial responses were seen in 36 evaluable patients, for an overall response rate of 13.9% (95% CI: 4.7%–29.5%). The median survival time was 6.7 months. Toxicities were generally mild. The most common were grade 3–4 neutropenia and grade 3 leukopenia reported in 23.7% and 10.5% of patients, respectively. One patient had grade 4 pulmonary toxicity.Conclusion: Single-agent gemcitabine is active and well tolerated in patients with recurrent ovarian cancer.     

Reproductive factors and epithelial ovarian cancer survival in the EPIC cohort study

Background:

Reproductive factors influence the risk of developing epithelial ovarian cancer (EOC), but little is known about their association with survival. We tested whether prediagnostic reproductive factors influenced EOC-specific survival among 1025 invasive EOC cases identified in the European Prospective Investigation into Cancer and Nutrition (EPIC) study, which included 521 330 total participants (approximately 370 000 women) aged 25–70 years at recruitment from 1992 to 2000.

Methods:

Information on reproductive characteristics was collected at recruitment. Cox proportional hazards regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs), and multivariable models were adjusted for age and year of diagnosis, body mass index, tumour stage, smoking status and stratified by study centre.

Results:

After a mean follow-up of 3.6 years (±3.2 s.d.) following EOC diagnosis, 511 (49.9%) of the 1025 women died from EOC. We observed a suggestive survival advantage in menopausal hormone therapy (MHT) users (ever vs never use, HR=0.80, 95% CI=0.62–1.03) and a significant survival benefit in long-term MHT users (⩾5 years use vs never use, HR=0.70, 95% CI=0.50–0.99, P_trend=0.04). We observed similar results for MHT use when restricting to serous cases. Other reproductive factors, including parity, breastfeeding, oral contraceptive use and age at menarche or menopause, were not associated with EOC-specific mortality risk.

Conclusions:

Further studies are warranted to investigate the possible improvement in EOC survival in MHT users.     

Phase I/II study of sagopilone (ZK-EPO) plus carboplatin in women with recurrent platinum-sensitive ovarian cancer

Background:

Sagopilone is the first fully synthetic epothilone in clinical development and has demonstrated promising preclinical activity. This phase I/II, prospective, open-label trial investigated the efficacy and safety of sagopilone plus carboplatin in patients with recurrent platinum-sensitive ovarian cancer (OC).

Methods:

In phase I (dose-escalation stage), patients with OC recurring at least 6 months after platinum-containing chemotherapy received 3-h infusions of sagopilone (initial dose of 12 mg m⁻²) followed by carboplatin every 3 weeks, for 2–6 treatment courses. Patients enrolled in phase II received 3-h infusions of 16 mg m⁻² sagopilone. Efficacy was assessed using modified Response Evaluation Criteria in Solid Tumors (modRECIST) and Gynecologic Cancer InterGroup CA125 criteria. The safety and tolerability of sagopilone were also evaluated.

Results:

In all, 45 patients received sagopilone at 12 mg m⁻² or 16 mg m⁻². There were 29 confirmed tumour responses (21 modRECIST and 8 CA125) across both treatment groups, indicating that the primary objective of the study was reached. The main adverse events (AEs) reported were peripheral neuropathy (75.6%), fatigue (71.1%) and nausea (64.4%). Grade ⩾3 AEs occurred in 35 patients (77.8%). No deaths related to the study drug were reported.

Conclusion:

Sagopilone in combination with carboplatin was effective and toxicities were manageable in patients with recurrent platinum-sensitive OC.     

HSP90 identified by a proteomic approach as druggable target to reverse platinum resistance in ovarian cancer

Acquired resistance to platinum (Pt)‐based therapies is an urgent unmet need in the management of epithelial ovarian cancer (EOC) patients. Here, we characterized by an unbiased proteomics method three isogenic EOC models of acquired Pt resistance (TOV‐112D, OVSAHO, and MDAH‐2774). Using this approach, we identified several differentially expressed proteins in Pt‐resistant (Pt‐res) compared to parental cells and the chaperone HSP90 as a central hub of these protein networks. Accordingly, up‐regulation of HSP90 was observed in all Pt‐res cells and heat‐shock protein 90 alpha isoform knockout resensitizes Pt‐res cells to cisplatin (CDDP) treatment. Moreover, pharmacological HSP90 inhibition using two different inhibitors [17‐(allylamino)‐17‐demethoxygeldanamycin (17AAG) and ganetespib] synergizes with CDDP in killing Pt‐res cells in all tested models. Mechanistically, genetic or pharmacological HSP90 inhibition plus CDDP ‐induced apoptosis and increased DNA damage, particularly in Pt‐res cells. Importantly, the antitumor activities of HSP90 inhibitors (HSP90i) were confirmed both ex vivo in primary cultures derived from Pt‐res EOC patients ascites and in vivo in a xenograft model. Collectively, our data suggest an innovative antitumor strategy, based on Pt compounds plus HSP90i, to rechallenge Pt‐res EOC patients that might warrant further clinical evaluation.