Phase II Trial of Temozolomide in Patients with Cisplatin-Refractory Germ Cell Tumors

MGMT and CALCA promoter methylation are associated with poor prognosis in testicular germ cell tumor patients

Testicular germ cell tumors (TGCT) represent the second main cause of cancer-related death in young men. Despite high cure rates, refractory disease results in poor prognosis. Epigenetic reprogramming occurs during the development of seminomas and non-seminomas. Understanding the molecular and genetic basis of these tumors would represent an important advance in the search for new TGCT molecular markers. Hence the frequency of methylation of a gene panel (VGF, MGMT, ADAMTS1, CALCA, HOXA9, CDKN2B, CDO1 and NANOG) was evaluated in 72 primary TGCT by quantitative methylation specific PCR. A high frequency of MGMT (90.9%, 20/22; p=0.019) and CALCA (90.5%, 19/21; p<0.026) methylation was associated with non-seminomatous tumors while CALCA methylation was also associated with refractory disease (47.4%, 09/19; p=0.005). Moreover, promoter methylation of both genes predicts poor clinical outcome for TGCT patients (5-year EFS: 50.5% vs 77.1%; p=0.032 for MGMT and 51.3% vs 77.0%; p=0.029 for CALCA). The findings of this study indicate that methylation of MGMT and CALCA are frequent and could be used as new molecular markers of prognosis in TGCT.

Current chemotherapeutic approaches for recurrent or refractory germ cell tumors

INTRODUCTION

Up to 25% of patients with metastatic testicular germ cell tumour (GCT) are not cured by first line therapy and require treatment for refractory or relapsed disease.

METHODS

A literature search was conducted through PubMed, Medline, Cochrane and EMBASE from January 1950 to April 2014 for articles relating to trials of chemotherapy for patients with relapsed or refractory germ cell tumours. Relevant review papers and conference proceedings were hand searched for additional references.

RESULTS

A range of conventional dose chemotherapy (CDCT) regimens can provide durable remissions in 20-30% of patients at first or subsequent salvage.

CONCLUSIONS

This article reviews the evidence underlying commonly used salvage CDCT based on ifosfamide and cisplatin such as TIP, VIP and VeIP; other active combinations; and single agent salvage regimens. The treatment of growing teratoma syndrome and malignant transformation of teratoma will also be discussed. Companion articles will explore the role of high dose chemotherapy (HDCT) and novel targeted agents.

Progression-free and overall survival in patients with relapsed/refractory germ cell tumors treated with single-agent chemotherapy: endpoints for clinical trial design

BACKGROUND

Refractory germ cell tumor (GCT) patients have a poor prognosis and limited treatment options. The identification of novel active agents may be impaired by use of response as the primary endpoint in phase 2 trials. Improved endpoints could enhance the development of new effective agents.

METHODS

The characteristics and outcome of refractory GCT patients enrolled in 7 single-agent phase 2 trials conducted at Memorial Sloan-Kettering Cancer Center from 1990 to 2008 were reviewed. The study agents were suramin, all-transretinoic acid, topotecan, pyrazoloacridine, temozolomide, ixabepilone, and sunitinib. The major endpoints evaluated were response, progression-free survival (PFS), and overall survival (OS).

RESULTS

Ninety patients (87 male, 3 female) were treated. The primary tumor site was testis in 65 patients, mediastinum in 17 patients, retroperitoneum in 4 patients, and other in 4 patients. Eighty-six patients had nonseminoma, and 4 patients had pure seminoma. Best responses were 1 (1%) partial response (ixabepilone), 15 (17%) stable disease, and 74 (82%) progressive disease. Median PFS and OS were 1.0 month (95% confidence interval [CI], 0.8-1.3) and 4.7 months (95% CI, 3.5-6.4), respectively. Eighty-six of the 90 patients have died. The 12- and 16-week PFS rates were 9% (95% CI, 3-15%) and 6% (95% CI, 1%-11%), respectively.

CONCLUSIONS

Patients with refractory GCT progressed rapidly to these single agents. PFS and OS may be useful endpoints for designing phase 2 trials testing novel agents in this population. Twelve-week PFS (with comparison to the 9% benchmark rate reported herein) is the recommended endpoint for phase 2 trial design and median OS (using 4.7 months as the predicted median for the control arm) is suggested for phase 3 trials.

Brief report: phase II multicenter study of temozolomide in patients with cisplatin-resistant germ cell tumors

PURPOSE

To determine the activity and toxicity of temozolomide in a phase II multicenter trial in patients diagnosed with relapsed or cisplatin-refractory germ cell tumors.

PATIENTS AND METHODS

During a recruitment period of 30 months, 20 patients received temozolomide 150 mg/m(2)/day p.o. for 5 days every 4 weeks, escalating to 200 mg/m(2)/day if grade II toxicity was not observed in the first cycle. Eligibility criteria were tumor progression or relapse after previous cisplatin and ifosfamide-containing chemotherapy, creatinine clearance of >40 ml/min, and a performance status of 0-2.

RESULTS

The median age was 38 years (range 27-56). Seventeen patients had nonseminomatous tumors, and 3 had seminomatous tumors. Six of the patients had extragonadal primary tumors (3 retroperitoneal and 3 mediastinal). The median number of prior cisplatin-containing cycles was 11 (range 7-20). Eight patients received prior high-dose chemotherapy and 14 were refractory or absolutely refractory to cisplatin. A total of 45 cycles were administered. Two partial responses lasting 9 and 3.5 months (overall response rate 10%, 95% CI 1.2-31.7) were observed. One of these responses was seen in a patient with a cisplatin-refractory tumor that had previously been treated with high-dose chemotherapy. The median time to progression and the median overall survival were 1.5 and 3.1 months, respectively. Grade III hematological toxicity consisted of thrombocytopenia in 2 patients and anemia in 1 patient. No grade IV toxicity was observed.

CONCLUSIONS

Temozolomide had some activity in heavily pretreated patients resistant to cisplatin-based chemotherapy.

Recent advances in management of patients with platinum-refractory testicular germ cell tumors

With the use of cisplatin-based combination chemotherapy, metastatic testicular germ cell tumors can be cured in 70-80% of patients, but patients refractory to cisplatin-based chemotherapy continue to have a very poor prognosis. Various chemotherapeutic agents have been evaluated in intensively pretreated or cisplatin-refractory patients, but as single agents, only orally administered etoposide, paclitaxel, gemcitabine, and, most recently, oxaliplatin have been shown to be active with selected patients achieving complete remissions. This has for the first time lead to clinical evaluation of combination chemotherapy regimens such as gemcitabine-paclitaxel or oxaliplatin-gemcitabine, demonstrating the feasibility of combination therapy in these heavily pretreated patients. High response rates of up to 45% were observed in particular with the latter combination. Salvage surgery remains a very important treatment option for patients with resectable disease. The molecular mechanisms of cisplatin resistance have been intensively studied, and several mechanisms have been discussed such as a decreased intracellular concentration of the drug, increased repair of the drug-induced damage, or an altered apoptotic response to this damage. This increasing knowledge may now allow design of new therapeutic options. Ongoing studies in refractory germ cell tumors are evaluating 3-drug regimens such as gemcitabine-paclitaxel-oxaliplatin but also biologic approaches such as inhibitors of the epidermal growth factor receptor or the vascular endothelial growth factor. This research may eventually allow the development of a noncross-resistant multidrug combination regimen that can be evaluated in an earlier line of therapy.

The management of poor-prognosis, non-seminomatous germ-cell tumours

Despite a high cure rate in men with testicular cancer, some men in the poor-prognosis group have a less favourable outcome. Poor-prognosis non-seminomatous germ-cell tumours (NSGCT) are defined as those with high tumour markers, non-pulmonary visceral metastases or a mediastinal primary site at presentation. When treated with standard chemotherapy regimens, such as bleomycin, etoposide and cisplatin (BEP), cure rates of less than 50% have been achieved in an international pooled analysis. Some strategies aimed at improving results include the use of multi-agent regimens (e.g. POMB/ACE), intensive-induction chemotherapy (e.g. CBOP/BEP), new chemotherapy drugs, such as ifosfamide, gemcitabine, oxaliplatin, paclitaxel, high-dose chemotherapy, including autotransplantation. To date, no schedule has been proven to be better than standard BEP in randomised trials. We will review the published data relating to first-line and salvage treatment of poor-prognosis NSGCT. To advance the management of this disease, physicians treating poor-prognosis disease are urged to support multi-centre trials, such as the recently launched MRC TE23 study comparing BEP and CBOP/BEP.

Incidence of late-relapse germ cell tumor and outcome to salvage chemotherapy

PURPOSE

To define the incidence, clinical features, and outcome to salvage chemotherapy in patients with late-relapse germ cell tumor (GCT) after a complete response to first-line chemotherapy.

PATIENTS AND METHODS

Two patient populations were examined. First, retrospective analysis of 246 patients treated on a clinical trial with salvage chemotherapy was performed; 29 patients with late-relapse GCT were identified and evaluated for treatment outcome and survival. Salvage regimens included paclitaxel, ifosfamide, and cisplatin, single agents, or a high-dose chemotherapy program. Second, the incidence of late relapse was assessed by retrospective analysis of 551 patients after a complete response (CR) to first-line chemotherapy.

RESULTS

Twenty-nine patients received salvage chemotherapy on a clinical trial for late relapse GCT. The median survival was 23.9 months. At a median follow-up of 50.6 months, there were nine survivors. The chemotherapy regimens varied, but the only CRs were observed in patients treated with paclitaxel, ifosfamide, and cisplatin. Seven (50%) of 14 patients treated with paclitaxel, ifosfamide, and cisplatin achieved a continuous CR. Among the second population of 551 patients who had previously achieved a CR to a first-line chemotherapy trial, 17 were identified as having a late relapse (3%). The median time to relapse for these 17 patients was 7.8 years.

CONCLUSION

Late-relapse GCT is uncommon and is associated with a poor prognosis resulting from a high degree of resistance to chemotherapy. Chemotherapy with paclitaxel, ifosfamide, and cisplatin followed by surgery may be effective in patients with late-relapse GCT who are not considered candidates for primary surgery.

Recent Advances in Conventional-Dose Salvage Chemotherapy in Patients with Cisplatin-Resistant or Refractory Testicular Germ Cell Tumors

Testicular germ cell tumors represent the most frequent malignancy in young males aged 20-35 years. Despite the considerably high cure rates provided by platinum-based chemotherapy, 20-30% of cases with advanced disease do not achieve a long-term disease-free survival with first-line chemotherapy. These patients are candidates for conventional-dose or high-dose salvage chemotherapy. The current conventional-dose salvage regimens of reference are the vinblastine-ifosfamide-cisplatin or etoposide-ifosfamide-cisplatin combinations, which are expected to cure approximately 25% of non-seminomatous germ-cell tumour patients. Paclitaxel has also been proved effective both as monotherapy in heavily-pretreated cases and as part of first-line salvage regimens; the combination of paclitaxel-ifosfamide-cisplatin, followed or not by high-dose chemotherapy, induced a favorable long-term disease-free survival rate, especially in patients with good prognosis. Newer cytotoxic drugs, such as gemcitabine and oxaliplatin have also been proved effective, while other agents, such as temozolamide, or targeted therapies, such as trastuzumab in cases over-expressing HER2/neu (20% of relapsing germ-cell tumors) are currently under evaluation. Seminomas have generally a better prognosis than non-seminomatous tumors and salvage therapy is expected to cure about 50% of all cases.