Androgen deprivation therapy (ADT) for metastatic and high-risk prostate cancer (PC) inhibits growth pathways driven by the androgen receptor (AR). Over time, ADT leads to the emergence of lethal castrate-resistant PC (CRPC), which is consistently caused by an acquired ability of tumors to re-activate AR. This has led to the development of second-generation anti-androgens that more effectively antagonize AR, such as enzalutamide (ENZ). However, the resistance of CRPC to ENZ develops rapidly. Studies utilizing preclinical models of PC have established that inhibition of the Jak2-Stat5 signaling leads to extensive PC cell apoptosis and decreased tumor growth. In large clinical cohorts, Jak2-Stat5 activity predicts PC progression and recurrence. Recently, Jak2-Stat5 signaling was demonstrated to induce ENZ-resistant PC growth in preclinical PC models, further emphasizing the importance of Jak2-Stat5 for therapeutic targeting for advanced PC. The discovery of the Jak2V617F somatic mutation in myeloproliferative disorders triggered the rapid development of Jak1/2-specific inhibitors for a variety of myeloproliferative and auto-immune disorders as well as hematological malignancies. Here, we review Jak2 inhibitors targeting the mutated Jak2V617F vs. wild type (WT)-Jak2 that are currently in the development pipeline. Among these 35 compounds with documented Jak2 inhibitory activity, those with potency against WT-Jak2 hold strong potential for advanced PC therapy.

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.