High dose chemotherapy and stem cell support in the treatment of germ cell cancer

Promising novel therapies for relapsed and refractory testicular germ cell tumors

INTRODUCTION

Germ cell tumors (GCTs) are the most common solid malignancies in young men. The overall cure rate of GCT patients in metastatic stage is excellent, however; patients with relapsed or refractory disease have poor prognosis. Attempts to treat refractory disease with novel effective treatment to improve prognosis have been historically dismal and the ability to predict prognosis and treatment response in GCTs did not sufficiently improve in the last three decades.

AREAS COVERED

We performed a comprehensive literature search of PubMed/MEDLINE to identify original and review articles (years 1964-2020) reporting on current improvement salvage treatment in GCTs and novel treatment options including molecularly targeted therapy and epigenetic approach. Review articles were further searched for additional original articles.

EXPERT OPINION

Despite multimodal treatment approaches the treatment of relapsed or platinum-refractory GCTs remains a challenge. High-dose chemotherapy (HDCT) regimens with autologous stem-cell transplant (ASCT) from peripheral blood showed promising results in larger retrospective studies. Promising results from in vitro studies raised high expectations in molecular targets. So far, the lacking efficacy in small and unselected trials do not shed a light on targeted therapy. Currently, wide inclusion of patients into clinical trials is highly advised.

Lovastatin induces neuronal differentiation and apoptosis of embryonal carcinoma and neuroblastoma cells: enhanced differentiation and apoptosis in combination with dbcAMP

Differentiation-based therapeutics are an underutilized but a potentially significant treatment option for cancer patients. We show that lovastatin, a competitive inhibitor of the rate-limiting enzyme of mevalonate synthesis HMG-CoA reductase, is able to induce tumour cell differentiation and apoptosis in vitro. We used embryonal carcinoma (EC) and neuroblastoma (NB) cell lines and found that lovastatin promoted apoptosis and induced expression of the neuronal differentiation markers, tyrosine hydroxylase (TH), and growth-associated protein 43. The apoptotic and differentiation responses were time and dose-dependant and rescued by the co-administration of mevalonate. The expression of TH is regulated primarily by a cyclic AMP (cAMP) response element (CRE) in its promoter. Lovastatin enhanced the expression of a CRE-driven luciferase construct in P19 cells. Furthermore, combining lovastatin with 1 mM dibutyryladenosine 3',5'-cyclic monophosphate treatments induced higher expression from the CRE construct, enhanced differentiation and cytotoxicity. This study suggests the potential of combining these therapeutic approaches in EC and NB patients.

Phase II Study of Paclitaxel Plus Gemcitabine Salvage Chemotherapy for Germ Cell Tumors After Progression Following High-Dose Chemotherapy With Tandem Transplant

Purpose

To determine long-term survival and potential cure with salvage chemotherapy with paclitaxel plus gemcitabine after progression after both cisplatin combination chemotherapy and subsequent high-dose chemotherapy with tandem transplantation.

Patients and Methods

One hundred eighty-four patients received salvage high-dose chemotherapy at Indiana University (Indianapolis, IN) from February 1996 to December 2004. After further evidence of progressive disease, 32 patients were subsequently treated with paclitaxel 100 mg/n2 over 1 hour plus gemcitabine 1,000 mg/m2 over 30 minutes, days 1, 8, and 15 every 4 weeks for a maximum of six courses. This is a retrospective review of this patient population. Patients were evaluated for response, duration of response, and survival. Patients were ineligible if they received prior paclitaxel or gemcitabine.

Results

Ten (31%) of 32 patients achieved objective response, including four partial remissions (2- to 6-month duration) and six complete responses (CRs). Four of these six CRs (12.5% of total patient population) are continuously disease free (NED) with paclitaxel plus gemcitabine alone (no postchemotherapy surgery) at more than 20, 40, 44, and 57 months from start of paclitaxel plus gemcitabine, respectively. One additional CR is currently NED more than 63 months after paclitaxel plus gemcitabine with two subsequent resections of carcinoma.

Conclusion

Long-term disease-free survival is possible with paclitaxel plus gemcitabine in this patient population that progressed after high-dose chemotherapy, and had not received prior paclitaxel or gemcitabine.

High-dose chemotherapy for male germ cell tumor

Today, 20-30% of male patients with advanced germ cell tumor (GCT) do not have durable, complete remission in spite of cis-platinum (CDDP)-based chemotherapy. High-dose chemotherapy (HDCT) has been tried in CDDP refractory GCT patients. Initially HDCT was performed with autologous bone marrow transplantation in heavily treated patients. However, the clinical outcome was not good and the treatment-related death rate was not ignorable. Therefore, earlier introduction of HDCT with peripheral blood stem cell transplantation was preferable as it renders HDCT more effective and less toxic, and multicycle HDCT is feasible. The durable free rate of recent HDCT for refractory GCT patients is 32-65%. HDCT is also performed as first line chemotherapy for poor prognosis GCT patients. Induction chemotherapy followed by multicycles of HDCT was tried. The durable free rate of recent HDCT as first line chemotherapy is 43-73%. Although previous reports suggest the superiority of HDCT, one recent randomized controlled trial (RCT) failed to show an improvement with one cycle of HDCT followed by three cycles of standard-dose chemotherapy (SDCT) compared with four cycles of SDCT. Ongoing RCT comparing multicycles of HDCT with SDCT for poor prognostic GCT patients will clarify the role of HDCT. Recently, new regimens of HDCT containing paclitaxel have been devised. In this review, the history, current status and future of HDCT for advanced or refractory GCT will be discussed.

Paclitaxel-based high-dose chemotherapy with autologous stem cell rescue for relapsed germ cell cancer

We evaluated the antitumor activity of tandem cycles of high-dose chemotherapy with autologous peripheral stem cell transplantation (aPSCT) in relapsed germ cell tumors by using high-dose paclitaxel, carboplatin, etoposide, and ifosfamide. Thirty-three patients were entered, and 31 underwent protocol therapy. Paclitaxel 350 mg/m2 (5 patients) or 425 mg/m2 (26 patients) by 24-hour continuous intravenous infusion was followed by 3 daily doses of carboplatin and either etoposide (cycle 1) or ifosfamide/mesna (cycle 2). The carboplatin dose had a calculated area under the curve of 7 mg-min/mL, and the daily dose of etoposide was 20 mg/kg (cycle 1). Ifosfamide 3 g/m2/d for 3 days (with mesna uroprotection) was substituted for etoposide in cycle 2. Each cycle was supported by granulocyte colony-stimulating factor-mobilized peripheral blood stem cells. Thirty-one patients were evaluable for response, toxicity, and long-term disease control. Two patients did not undergo aPSCT because of rapid disease progression. Nineteen patients received both cycles of aPSCT, 8 progressed after cycle 1, 3 refused the second cycle, and 1 died of fungal infection during cycle 1. Twelve patients remain relapse free at a median of 67 months from the initiation of therapy. Whereas the International Germ Cell Cancer Collaborative Group category at the time of initial diagnosis did not seem to predict outcome, the patient's probability of achieving durable remission was significantly associated with the Beyer prognostic score at the time of protocol entry. Regimens containing the most active agents in relapsed nonseminomatous germ cell tumors, including high-dose paclitaxel, are well tolerated and have promising activity even in patients with poor-risk features who do not achieve durable remissions with standard therapy. The Beyer prognostic system is a valuable predictor for patients undergoing aPSCT.

Combination of paclitaxel, ifosfamide, and cisplatin is an effective second-line therapy for patients with relapsed testicular germ cell tumors

PURPOSE

The efficacy of paclitaxel was evaluated in combination with ifosfamide and cisplatin as second-line chemotherapy for patients with relapsed testicular germ cell tumors (GCTs).

PATIENTS AND METHODS

Forty-six patients with progressive metastatic GCTs were treated with paclitaxel and ifosfamide plus cisplatin (TIP) as second-line therapy. Eligibility required that patients have both a testis primary tumor site and a prior complete response (CR) to a first-line chemotherapy program, which had been identified previously as favorable prognostic factors to conventional-dose salvage chemotherapy.

RESULTS

Thirty-two (70%) of 46 patients achieved a CR to treatment. Three patients (7%) who achieved a CR relapsed after TIP chemotherapy. Twenty-nine patients are continuously disease free at a median follow-up time of 69 months, resulting in a 63% durable CR rate and a 2-year progression-free survival rate of 65% (95% CI, 51% to 79%).

CONCLUSION

Four cycles of TIP as second-line therapy achieved a durable CR rate in a high proportion of patients with relapsed testicular GCT. The high CR rate emphasizes the importance of patient selection according to prognostic factors to achieve a favorable outcome to conventional-dose salvage therapy.

Germ cell tumors: An update of recent data and review of active protocols in stage I and metastatic disease

Germ cell tumors are highly curable malignancies even when metastatic. Investigations currently focus on curtailing toxicity in low-risk patients and improving cure rates in poor-risk individuals. Reduced dose radiation schedules and short-course chemotherapy regimens have been evaluated in stage I disease. In metastatic disease, several new nonplatinum agents offer promise for patients with poor risk or relapsed disease. In addition, high-dose chemotherapy regimens with autologous stem cell transplant provide potential for further improvements in survival. This review will highlight recent developments and currently active clinical trials pertinent to the treatment of patients with germ cell tumors.