Irinotecan in patients with relapsed or cisplatin-refractory germ cell cancer: a phase II study of the German Testicular Cancer Study Group

Overcoming Chemotherapy Resistance in Germ Cell Tumors

Testicular germ cell tumors (GCTs) are highly curable malignancies. Excellent survival rates in patients with metastatic disease can be attributed to the exceptional sensitivity of GCTs to cisplatin-based chemotherapy. This hypersensitivity is probably related to alterations in the DNA repair of cisplatin-induced DNA damage, and an excessive apoptotic response. However, chemotherapy fails due to the development of cisplatin resistance in a proportion of patients. The molecular basis of this resistance appears to be multifactorial. Tracking the mechanisms of cisplatin resistance in GCTs, multiple molecules have been identified as potential therapeutic targets. A variety of therapeutic agents have been evaluated in preclinical and clinical studies. These include different chemotherapeutics, targeted therapies, such as tyrosine kinase inhibitors, mTOR inhibitors, PARP inhibitors, CDK inhibitors, and anti-CD30 therapy, as well as immune-checkpoint inhibitors, epigenetic therapy, and others. These therapeutics have been used as single agents or in combination with cisplatin. Some of them have shown promising in vitro activity in overcoming cisplatin resistance, but have not been effective in clinical trials in refractory GCT patients. This review provides a summary of current knowledge about the molecular mechanisms of cisplatin sensitivity and resistance in GCTs and outlines possible therapeutic approaches that seek to overcome this chemoresistance.

Irinotecan and nedaplatin as salvage therapy for patients with advanced germ cell tumors following intensive treatment with cisplatin-based combination chemotherapies

BACKGROUND

To analyze the clinical outcomes of the irinotecan plus nedaplatin (IN) regimen in patients with advanced germ cell tumors (GCTs) refractory to cisplatin-based combination chemotherapies.

METHODS

This study included a total of 20 consecutive advanced GCT patients who were categorized into intermediate- or poor-risk GCT groups according to the International Germ Cell Consensus Classification, and were judged to show refractory or relapsed disease after bleomycin, etoposide and cisplatin and cisplatin, ifosfamide and paclitaxel therapies. All 20 patients subsequently received IN therapy (irinotecan 100 mg/m(2) on days 1 and 15; nedaplatin 100 mg/m(2) on day 1) every 4 weeks.

RESULTS

Following a median of 3 cycles of IN, 9 patients (45 %) achieved normalization of serum tumor markers. In addition, surgical resection of the residual tumors following IN was performed in 5 patients, of whom 4 were pathologically diagnosed with no viable cancer cells. At a median follow-up of 9 months, 11 patients (55 %) were alive, including 7 (35 %) with no evidence of disease, whereas the remaining 9 (45 %) died of disease progression. The median duration of overall survival after the introduction of IN to these 20 patients was 13.4 months. Severe hematological toxicities were observed in all patients, but were manageable. Although fatal treatment-related interstitial pneumonia occurred in 1 patient, other non-hematological toxicities were generally tolerable.

CONCLUSIONS

Considering the markedly unfavorable characteristics of the included patients with advanced GCT who were intensively treated with cisplatin-based combination chemotherapies, IN could be regarded as having promising therapeutic activity with an acceptable toxicity profile.

Salvage combined chemotherapy with paclitaxel, ifosfamide and nedaplatin for patients with advanced germ cell tumors

OBJECTIVES

To investigate the efficacy of combined regimen with paclitaxel, ifosfamide and nedaplatin as salvage chemotherapy in patients with cisplatin-refractory or multiple relapsed germ cell tumors.

METHODS

A total of 65 patients refractory to cisplatin-based chemotherapy or with relapse after induction or salvage chemotherapy received paclitaxel 210 mg/m(2) on day 1, ifosfamide 1.2 g/m(2) on days 2-6 and nedaplatin 100 mg/m(2) on day 2 of a 3-week cycle. The primary and secondary end-points were the response rate and overall survival, respectively.

RESULTS

Paclitaxel, ifosfamide and nedaplatin therapy was carried out as second-line therapy in 17 patients, third-line in 31 and fourth-line or later in 17. Patients were pretreated with a median of six cycles of platinum-based chemotherapy (range 3-15 cycles). The overall response rate was 62.9%, including one patient with complete response and 38 with partial response. Serum tumor marker levels normalized in 35 (56.5%) patients. Overall survival at a median follow up of 34 months was 59.3%, and median time to progression was 12 months. Multivariate analysis showed that serum tumor marker normalization was the only independent predictor of better progression-free survival and overall survival. Grade 3/4 of neutropenia, anemia and thrombocytopenia was observed in 96.9%, in 81.5%, and in 90.8% of patients, respectively.

CONCLUSION

Paclitaxel, ifosfamide and nedaplatin chemotherapy appears to be effective when used as first or second salvage treatment in advanced relapsed germ cell tumors. Even after fourth-line therapy, patients with serum tumor marker normalization might have a chance for a cure.

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.

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.

A phase II study using a topoisomerase I-based approach in patients with multiply relapsed germ-cell tumours

BACKGROUND

The outcome of patients with germ-cell tumours (GCTs), who relapse more than once or relapse with a mediastinal primary is poor. We have shown that topoisomerase 1 may be an attractive target in relapsed GCT. We investigated the role of irinotecan, paclitaxel and oxaliplatin (IPO) followed by topotecan-based high-dose therapy in responding patients, in this patient population.

PATIENTS AND METHODS

Twenty-eight patients with multiply relapsed gonadal and mediastinal GCT were recruited to this phase 2 study. All patients received IPO chemotherapy and 12 (43%) went on to receive high-dose therapy. The outcome of these patients was assessed using the Kaplan-Meier method with a median progression-free follow-up of 1 year.

RESULTS

Twenty patients (71%) responded to the therapy including five complete remissions (18%), 13 (46%) marker-negative partial responses and two (7%) marker-positive partial responses. Nine (32%) patients continue to be progression free, and the median survival for the whole group currently measures 17 months. Out of 12 individuals who received subsequent high-dose therapy consolidation, seven (58%) remain progression free. The commonest grade III/IV toxicity was infection (68%) and there were no IPO-related toxic deaths; there was one death from high-dose therapy.

CONCLUSION

Topoisomerase I-based IPO chemotherapy that lacks etoposide is very active in multiply relapsed GCT. This data merit further investigation.

Management of Recurrent Testicular Germ Cell Tumors

Although front-line chemotherapy cures most men with testicular germ cell tumors, salvage therapy is still important in a small but significant minority. Second-line conventional-dose or high-dose chemotherapy with stem cell rescue may cure 25%-50% of patients. New chemotherapeutic agents, including the taxanes gemcitabine and oxaliplatin, have added to the therapeutic armamentarium. Salvage surgical resection has an important role in selected patients. Cisplatin-refractory patients have a poor prognosis with current therapy, and novel chemotherapeutic and biologic agents need to be discovered for such patients.

Phase II Study of Oxaliplatin and Gemcitabine Salvage Chemotherapy in Patients with Cisplatin-Refractory Nonseminomatous Germ Cell Tumor

OBJECTIVE

Cisplatin-refractory germ cell tumors (GCTs) represent a subset of germinal neoplasms with a poor prognosis. Conventional-dose chemotherapy induces objective response in 10-20% of these patients with rare durable complete remissions. We investigated the activity and tolerance of a chemotherapeutic regimen with oxaliplatin and gemcitabine.

PATIENTS AND METHODS

Treatment consisted of oxaliplatin 130 mg/m(2) day 1, and gemcitabine 1,250 mg/m(2), days 1 and 8, every three weeks.

RESULTS

Eighteen patients were enrolled and were assessable for response and toxicity. Primary site was testis in twelve cases, retroperitoneum in four, and mediastinum in two. Seven patients (39%) were cisplatin-refractory, while eleven (61%) absolutely cisplatin-refractory. A median of three cycles (range, 1-6) per patient were given. One patient achieved a clinical complete remission, one a partial remission with negative marker in whom complete surgical resection of residual masses yielded mature teratoma only, and one a partial remission with positive marker in whom complete surgical resection of residual masses yielded viable tumor cells. These three cases were characterized by testicular primary embryonal carcinoma. They remained disease-free at 44+, 20+, and 18+ months of follow-up.

CONCLUSION

The oxaliplatin-gemcitabine combination is a safe and active standard-dose regimen for patients with cisplatin-refractory testicular primary GCT.

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.

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.

A phase II trial of TIP (paclitaxel, ifosfamide and cisplatin) given as second-line (post-BEP) salvage chemotherapy for patients with metastatic germ cell cancer: a medical research council trial

This phase II trial describes the use of TIP chemotherapy (paclitaxel, ifosfamide and cisplatin) as salvage for patients with metastatic germ cell cancer (GCC) who have failed initial BEP (bleomycin, etoposide and cisplatin) chemotherapy. Patients with first relapse following BEP for metastatic GCC, confirmed by biopsy or sequentially rising markers, received four courses of TIP (paclitaxel 175 mg m⁻² day 1, followed on days 1–5 by ifosfamide 1 g m⁻² intravenously (i.v.) and cisplatin 20 mg² i.v.) at 3-weekly intervals. The primary outcome measure was response to TIP. In all, 51 patients were registered, of whom 43 were eligible for response assessment. Eight achieved complete remission (CR) and 18 a partial remission with negative markers (PR^−ve); favourable response rate (FRR=CR+PR^−ve) 60%, 95% CI (44–75%); survival at 1 year was 70% (56–84%) and failure-free survival 36% (22–50%). In the group of 26 patients meeting the ‘good-risk’ criteria described by the Memorial Hospital, the FRR was 73% (52–88%) compared with 41% (18–67%) for the 17 ‘poor-risk’ patients. These results are inferior to those previously reported for TIP in a single-centre study when it was given more intensively, at higher dose and with growth factor support. Nonetheless, TIP as described here can cure a substantial proportion of patients.

Part II: testicular cancer--management of advanced disease

Up to 80% of metastatic germ-cell tumours are curable with conventional chemotherapy. The combination of cisplatin, bleomycin, and etoposide has become the gold standard in this disease. Patients can be divided into good, intermediate, and poor prognosis groups. For those patients with good prognostic features, cure rates reach 90% and attempts have been made to reduce toxic effects of treatment while maintaining efficacy. Patients that relapse require salvage treatment. This can involve the incorporation of drugs such as ifosfamide and taxol into conventional protocols or the use of high-dose chemotherapy with stem-cell transplants. Patients with poor prognosis disease are much more likely to fail conventional chemotherapy and are candidates for dose-intensive protocols or transplants as first-line treatment. Although the results obtained in treating metastatic germ-cell tumours are superior to those with other solid tumour types, there are still many areas that require further improvement.

Germ cell tumors: review of selected studies from 2002

Testicular cancer remains a major success story in the realm of solid tumors. There are still many remaining challenges in diagnosis, treatment, and prevention of long-term toxicity. Surgery and platinum-based chemotherapy, however, still encompass the main treatment modalities. Attempts to limit toxicity from both surgery and chemotherapy remain at the forefront of research. New chemotherapeutic options are available for patients with platinum-resistant disease, and stem cell transplant remains an area of active study.