Targeted therapies in the treatment of germ cell tumors: The need for new approaches against “orphan” tumors

Targeted treatment approaches in refractory germ cell tumors

Germ cell tumors (GCTs) are the most common type of solid tumor amongst patients between 15 and 35 years of age. They are also one of the types of tumor with the highest cure rate, due to their high sensitivity to cisplatin based chemotherapy. Nonetheless, around 15-20% of metastatic patients will not have curative options after a relapse on the first and second line. This proves that new therapeutic options for these refractory GCTs patients need to be developed. This article offers a bibliographic review of all studies using targeted treatment or immunotherapy for refractory GCTs patients.

Activity of nintedanib in germ cell tumors

Germ cell tumors (GCTs) are the most frequent malignancy in male patients between 15 and 45 years of age. Cisplatin-based chemotherapy shows excellent cure rates, but patients with cisplatin-resistant GCTs have a poor prognosis. Nintedanib (BIBF 1120, Vargatef) inhibits the receptor classes vascular endothelial growth factor receptor, platelet derived growth factor receptor, and fibroblast growth factor receptor, and has shown activity against many tumors, as well as in idiopathic lung fibrosis and bleomycin-induced lung injury. Here, we investigated the antineoplastic and antiangiogenic properties of nintedanib in cisplatin-resistant and cisplatin-sensitive GCT cells, both alone and in combination with classical cytotoxic agents such as cisplatin, etoposide, and bleomycin. The half-maximal inhibitory concentration (IC50) of nintedanib was 4.5 ± 0.43 μmol/l, 3.1 ± 0.45 μmol/l, and 3.6 ± 0.33 μmol/l in cisplatin-sensitive NTERA2, 2102Ep, and NCCIT cells, whereas the IC50 doses of the cisplatin-resistant counterparts were 6.6 ± 0.37 μmol/l (NTERA2-R), 4.5 ± 0.83 μmol/l (2102Ep-R), and 6.1 ± 0.41 μmol/l (NCCIT-R), respectively. Single treatment with nintedanib induced apoptosis and resulted in a sustained reduction in the capacity of colony formation in both cisplatin-sensitive and cisplatin-resistant GCT cells. Cell cycle analysis showed that nintedanib induced a strong G0/G1-phase arrest in all investigated cell lines. Combination treatment with cisplatin did not result in additive, synergistic, or antagonistic effects. The in-vivo activity was studied using the chorioallantoic membrane assay and indicated the antiangiogenic potency of nintedanib with markedly reduced microvessel density. Topical treatment of inoculated tumor plaques resulted in a significant reduction of the tumor size. This indicates that nintedanib might be a promising substance in the treatment of GCT.

[Treatment of testicular cancer]

Germ-cell tumours (GCTs) are the most common type of cancer in young men. Since the late 1970s, disseminated GCT have been a paradigm for curable metastatic cancer and metastatic GCTs are highly curable with cisplatin-based chemotherapy followed by surgical resection of residual masses. Patients' prognosis is currently assessed using the International Germ-Cell Consensus Classification (IGCCC) and used to adapt the burden of chemotherapy. Approximately 20% of patients still do not achieve cure after first-line cisplatin-based chemotherapy, and need salvage chemotherapy (high dose or standard dose chemotherapy). Clinical stage I testicular cancer is the most common presentation and different strategies are proposed: adjuvant therapies, surgery or surveillance. During the last three decades, clinical trials and strong international collaborations lead to the development of a consensus in the management of GCTs.

Revisiting bleomycin from pathophysiology to safe clinical use

Bleomycin is a key component of curative chemotherapy regimens employed in the treatment of curable cancers, such as Hodgkin lymphoma (HL) and testicular germ-cell tumours (GCT), yet its use may cause bleomycin-induced lung injury (BILI), which is associated with significant morbidity and a mortality rate of 1-3%. Diagnosis of BILI is one of exclusion and physicians involved in the care of HL and GCT patients should be alerted. Pharmacogenomic studies could contribute towards the identification of molecular predictors of bleomycin toxicity on the aim to optimize individual use of bleomycin. We review all existing data on bleomycin's most recent integrated chemical biology, molecular pharmacology and mature clinical data and provide guidelines for its safe clinical use.