What treatment regimen would you recommend for young adults with platinum refractory relapsed germ cell tumors?

We assess the patient risk by IPFSG score, and if it is high score or has extragonadal primary site then we consider tandem high dose chemotherapy and autologous transplantation https://onlinelibrary.wiley.com/doi/full/10.1002/acg2.47

The data sometimes is unclear on the role of HDCT . 

- the largest single institution dataset is a retrospective review of 184 patients with progressive testicular cancer after initial cisplatin‐based combination chemotherapy who underwent two consecutive cycles of high‐dose carboplatin and etoposide, each followed by auto‐HSC, which showed improved IS (Einhorn et al ; N Engl J Med. 2007;357(4):340‐348. ) 

- however the only randomized trial done comparing the conventional chemo vs high dose chemo strategies did not reveal a significant difference in either disease‐free survival or overall survival ( Pico J-L et al ; Ann Oncol Off J Eur Soc Med Oncol. 2005;16(7):1152‐1159.). The study however had several limitations. Only one cycle of HDCT/HSCT was administered, whereas favorable outcomes have been reported with two sequential cycles. Several patients did not receive the HDCT/HSCT which was scheduled to be administered after three cycles of standard dose chemotherapy, most likely due to toxicity or disease progression.

The conflicting data from these studies will hopefully be resolved by the TIGER trial, an international collaborative cooperative group study which aims to determine the optimal initial salvage chemotherapy approach in advanced GCT patients. This study randomly assigns patients to receive TIP for four cycles or ifosfamide plus paclitaxel for two cycles followed by high‐dose carboplatin and etoposide for three cycles. While awaiting the results of the TIGER trial, a risk‐based approach should define the decision to pursue HDCT/HSCT as initial salvage

At USC, we use a Gemcitabine-based regimen (Gemcitabine/Oxaliplatin/Paclitaxel) similar to what has been described by Bokemeyer et al., PMID 18006893. We designed a dose-dense form of GOT, cycled every 14 days, with paclitaxel 170 mg/m2 on day 1 (as compared to 80 mg/m2). We escalate the oxaliplatin dose from 100 mg/m2 in the first cycle to 125 mg/m2 in the second and subsequent cycles if the absolute neutrophil count is greater than 1,500, platelet counts are over 75,000, and patient has less than grade 2 neuropathy. We found a 6.7% CR rate, with 5 additional patients (total, 16.7%) becoming resectable, resulting in durable remission in a population with a median of 2 prior lines of therapy (https://ascopubs.org/doi/abs/10.1200/jco.2013.31.15_suppl.4531).