Autologous Hematopoietic Stem Cell Transplantation for Male Germ Cell Tumors: Improved Outcomes Over 3 Decades

The curative potential of autologous hematopoietic cell transplantation (autoHCT) for male germ cell tumors (GCTs) is well established. The optimal timing and number (single transplant [ST] versus tandem transplants [TT] versus triple transplants) of autoHCT are controversial, with wide practice variations. We examined survival trends among 2395 recipients of autoHCT for male GCTs between 1990 and 2015 reported to the Center for International Blood and Marrow Transplant Research. Trends and outcomes were analyzed by year of transplantation for intervals 1990 to 1994 (N = 288), 1995 to 1999 (N = 351), 2000 to 2004 (N = 376), 2005 to 2009 (N = 509), and 2010 to 2015 (N = 871). Multivariate analysis was restricted to the subset from 2000 to 2015 with research-level data (n = 267). The median duration of follow-up was 51 months. The median age at autoHCT was 31 years; 633 patients (26%) had primary extragonadal GCT, and 1167 (49%) underwent TT. The 3-year progression-free (PFS) and overall survival (OS) improved from 24% (95% confidence interval [CI], 18% to 31%) and 35% (95% CI, 29% to 40%), respectively, in 1990 to 1994 to 47% (95% CI, 43% to 50%) and 54% (95% CI, 50% to 57%), respectively, in 2010 to 2015 (P < .0001). TT recipients were more likely than ST recipients to undergo autoHCT as first salvage treatment. The proportion of TTs increased from 38% of all autoHCTs in 2000 to 2004 to 77% in 2010 to 2015. Nonseminoma histology, residual disease at autoHCT, >1 line of pretransplantation chemotherapy, and ST versus TT were associated with inferior PFS and OS. Post-transplantation survival has improved significantly over time for relapsed/refractory male GCT and is associated with the increased use of TTs (compared with STs) and performance of autoHCT earlier in the disease course.

Mobilization and Collection of Peripheral Blood Stem Cells in Adults: Focus on Timing and Benchmarking

Peripheral blood stem cells (PBSCs) are preferentially used as a hematopoietic stem cell source for autologous blood stem cell transplantation (ABSCT) upon high-dose chemotherapy (HDT) in a variety of hemato-oncologic diseases. As a prerequisite, hematopoietic stem cells have to be mobilized into the peripheral blood (PB) and collected by leukapheresis (LP). Despite continuous improvements, e.g., the introduction of plerixafor, current challenges are the further optimization regarding the leukapheresis procedure, preventing collection failures, as well as benchmarking and harmonization of mobilization approaches between institutions.This chapter summarizes the current PBSC mobilization and collection approaches and is focusing on timely orchestration of mobilization therapy, granulocyte colony-stimulating factor (G-CSF) application, and peripheral blood (PB) CD34⁺ cell assessment. Moreover, strategies for prediction and performance assessment of the PBSC collection yield are discussed.

Orchestration of Chemomobilization and G-CSF Administration for Successful Hematopoietic Stem Cell Collection

Successful collection of peripheral blood stem cells (PBSCs) depends on the optimal orchestration of mobilization chemotherapy, granulocyte colony stimulating factor (G-CSF) application, and CD34⁺ cell number assessment in the peripheral blood (PB). However, determining the optimal timing in accordance to the applied chemomobilization regimen can be challenging. Although most centers apply their own local timing schedules, a reliable timetable including the currently most often used mobilization regimens is lacking. We present a comprehensive analysis of the timing modalities for 11 of the most commonly used chemomobilization regimens. A retrospective analysis was performed on the clinical and PBSC collection parameters (including duration of G-CSF application, time point of CD34⁺ assessment, PB CD34⁺ cell count, number of leukapheresis [LP] sessions, processed blood volume, and CD34⁺ collection results) of 91 representatively selected patients who had undergone stem cell mobilization at 2 collection centers. Six to 10 patients were analyzed per regimen with a variety of diagnoses, including multiple myeloma, malignant lymphoma, and sarcoma. No collection failures (<2 × 10⁶ CD34⁺ cells/kg body weight) were observed. All analyzed patients successfully reached their individual collection goal in adherence to the given schedule of chemotherapy, application of G-CSF, measurement of CD34⁺ cells, and subsequent LP. The presented data on the timing of chemomobilization, G-CSF application, and stem cell collection may be helpful in clinical decision making and contribute to a more transparent and predictable treatment process.

Immunotherapy advances in uro-genital malignancies

Immunotherapy for the treatment of cancer has made significant progresses over the last 20 years. Multiple efforts have been attempted to restore immune-mediated tumor elimination, leading to the development of several targeted immunotherapies. Data from recent clinical trials suggest that these agents might improve the prognosis of patients with advanced genito-urinary (GU) malignancies. Nivolumab has been the first immune checkpoint-inhibitor approved for pre-treated patients with metastatic renal cell carcinoma. Pembrolizumab and atezolizumab have shown promising results in both phase I and II trials in urothelial carcinoma. Brentuximab vedotin has demonstrated early signals of clinical activity and immunomodulatory effects in highly pre-treated patients with testicular germ cell tumors. In this review, we have summarized the major clinical achievements of immunotherapy in GU cancers, focusing on immune checkpoint blockade as well as the new immunomodulatory monoclonal antibodies (mAbs) under clinical evaluation for these malignancies.

Importance of continuous sequential chemotherapy and multimodal treatment for advanced testicular cancer: a high-volume Japanese center experience

Patients with "difficult-to-treat" advanced testicular cancer can require multiple therapies. We retrospectively assessed our patients with advanced germ cell tumors (GCTs) and characterized the clinical efficacy, outcomes, and factors affecting overall survival (OS).Two hundred fifty-three patients with advanced GCTs were treated at Kyoto Prefectural University of Medicine, Kyoto, Japan, from June 1998 to September 2013. Of 253 patients, 142 patients had salvage chemotherapy.As first-line therapy, bleomycin, etoposide, and cisplatin, and etoposide and cisplatin therapies were performed in 234 cases (92.5%). As second-line therapy, etoposide, ifosfamide, and cisplatin/vinblastine, ifosfamide, and cisplatin, and paclitaxel, ifosfamide, and cisplatin/paclitaxel, ifosfamide, and nedaplatin therapies were carried out in 44 and 59 cases, respectively. Furthermore, 111, 72, 44, and 28 cases had third, fourth, fifth, and sixth-or-later-line chemotherapy, respectively. Five-year OS rate stratified by chemotherapy line was 95.5% in the first line, 89.4% in the second line, 82.1% in the third line, 45.1% in the fourth line, and 58.9% in the fifth or after line. A statistical significant difference was found when comparing fourth-or-after-line versus first to third-line therapy. Additional procedures were performed, including retroperitoneal lymph node dissection (RPLND) (n = 168), extra-RPLN resection (n= 114), and external beam radiotherapy/stereotactic radiotherapy (n = 78).Multivariate analysis showed that factors predicting better outcomes were in serum tumor marker (STM) normalization, RPLND, and extra-RPLN resection.Good outcomes were obtained in patients who completed chemotherapy up to third line. After fourth-line chemotherapy, approximately 50% of "difficult-to-treat" patients could be cured with normalization of STM levels and residual mass resection. Continuous or sequential chemotherapy with multimodality therapy is important for patients with "difficult-to-treat" advanced GCTs. Effective chemotherapy after third line should be developed.

High-dose sequential chemotherapy (HDS) versus PEB chemotherapy as first-line treatment of patients with poor prognosis germ-cell tumors: mature results of an Italian randomized phase II study

BACKGROUND

In the late 1990s, the use of high-dose chemotherapy (HDCT) and stem-cell rescue held promise for patients with advanced and poor prognosis germ-cell tumors (GCT). We started a randomized phase II trial to assess the efficacy of sequential HDCT compared with cisplatin, etoposide, and bleomycin (PEB).

PATIENTS AND METHODS

Patients were randomly assigned to receive four cycles of PEB every 3 weeks or two cycles of PEB followed by a high-dose sequence (HDS) comprising HD-cyclophosphamide (7.0 g/m(2)), 2 courses of cisplatin and HD-etoposide (2.4 g/m(2)) with stem-cell support, and a single course of HD-carboplatin [area under the curve (AUC) 27 mg/ml × min] with autologous stem-cell transplant. Postchemotherapy surgery was planned on responding residual disease in both arms. The primary end point was progression-free survival (PFS). The study was designed to detect a 30% improvement of 5-year PFS (from 40% to 70%), with 80% power and two-sided α at 5%.

RESULTS

From December 1996 to March 2007, 85 patients were randomized: 43 in PEB and 42 in HDS arm. Median follow-up was 114.2 months [interquartile range (IQR): 87.7-165.8]. Complete or partial response with normal markers (PRm-) were obtained in 28 (65.1%) and 29 (69.1%) patients, respectively. Five-year PFS was 55.8% [95% confidence interval (CI) 42.8-72.8] and 54.8% (95% CI 41.6%-72.1%) in PEB and HDS arm, respectively (log-rank test P = 0.726). Five-year overall survival was 62.8% (95% CI 49.9-79.0) and 59.3% (95% CI 46.1-76.3). One toxic death (PEB arm) was recorded.

CONCLUSIONS

The study failed to meet the primary end point. Furthermore, survival estimates of conventional-dose chemotherapy higher than expected should be accounted for and will likely limit further improvements in the first-line setting. CLINICALTRIALS.GOV: NCT02161692.

Predictors of CD34+ cell mobilization and collection in adult men with germ cell tumors: implications for the salvage treatment strategy

BACKGROUND

High-dose chemotherapy with tandem or triple carboplatin and etoposide course is currently the first curative choice for relapsing GCT. The collection of an adequate amount of hematopoietic (CD34(+)) stem cells is a priority.

PATIENTS AND METHODS

We analyzed data of patients who underwent HDCT at 2 referral institutions. Chemotherapy followed by myeloid growth factors was applied in all cases. Uni- and multivariable models were used to evaluate the association between 2 prespecified variables and mobilization parameters. Analyses included only the first mobilizing course of chemotherapy and mobilization failures.

RESULTS

A total of 116 consecutive patients underwent a mobilization attempt from December 1995 to November 2012. Mobilizing regimens included cyclophosphamide (CTX) 7 gr/m(2) (n = 39), cisplatin, etoposide, and ifosfamide (PEI) (n = 42), paclitaxel, cisplatin, and gemcitabine (TPG) (n = 11), and mixed regimens (n = 24). Thirty-seven percent were treated in first-line, 50% (n = 58) in second-line, 9.5% (n = 11) and 3.4% (n = 4) in third- and fourth-line settings, respectively. Six patients did not undergo HDCT because they were poor mobilizers, 2 in first- and second-line (1.9%), and 4 beyond the second-line (26.7%). In the multivariable model, third-line or later setting was associated with a lower CD34(+) cell peak/μL (P = .028) and a lower total CD34(+)/kg collected (P = .008). The latter was also influenced by the type of mobilizing regimen (P < .001).

CONCLUSION

A decline in significant mobilization parameters was found, primarily depending on the pretreatment load. Results lend support to the role of CD34(+) cell mobilization in the therapeutic algorithm of relapsing GCT, for whom multiple HDCT courses are still an option, and potentially a cure.