Despite remarkable results with salvage standard-dose or high-dose chemotherapy ∼15% of patients with relapsed germ-cell tumors (GCT) are incurable. Immune checkpoint inhibitors have produced significant remission in multiple tumor types. We report the first study of immunotherapy in patients with GCT. Single arm phase II trial investigating pembrolizumab 200 mg i.v. Q3weeks until disease progression in patients with relapsed GCT and no curable options. Patients age ≥18 with GCT who progressed after first-line cisplatin-based chemotherapy and after at least one salvage regimen (high-dose or standard-dose chemotherapy) were eligible. Centrally assessed programmed death-ligand 1 (PD-L1) on tumor and infiltrating immune cells was scored. Primary end point was overall response rate using immune-related response criteria. Simon two-stage design with type I error 20% and power 80% was utilized. Twelve male patients were enrolled. Median age was 38 years. All patients had nonseminoma. Primary site was testis (11) or mediastinum (1). Median AFP 615 (range 1–32, 760) and hCG 4 (range 0.6–37, 096). Six patients had late relapse (>2 years). Median number of previous chemotherapy regimens was 3. Six patients received prior high-dose chemotherapy. Two patients had positive PD-L1 staining (H-score 90 and 170). Median number of pembrolizumab doses was 2 (range 1–8). There were six grade 3 adverse events. No immune-related adverse events were reported. No partial or complete responses were observed. Two patients achieved radiographic stable disease for 28 and 19 weeks, respectively; both had continued rising AFP level despite radiographic stability and had negative PD-L1 staining. This is the first reported trial evaluating immune checkpoint inhibitors in GCT. Pembrolizumab is well tolerated but does not appear to have clinically meaningful single-agent activity in refractory GCT. NCT02499952.

Purpose: Patients with relapsed metastatic germ cell tumor (GCT) can be cured with second-line and even third-line regimens. We report survival outcomes of patients treated with high-dose chemotherapy (HDCT) and peripheral-blood stem-cell transplantation (PBSCT) at Indiana University between 2004 and 2014. Patients and Methods: We conducted a retrospective analysis of 364 consecutive patients with GCT who progressed after cisplatin-based combination chemotherapy and were subsequently treated with HDCT and PBSCT. Three hundred forty-one patients received two consecutive courses of HDCT consisting of 700 mg/m² carboplatin and 750 mg/m² etoposide, each for 3 consecutive days, and each followed by PBSCT. Twenty-three patients received only a single course of HDCT because of progressive disease or toxicity. Cox proportional hazards models were used to test predictors of disease progression. Results: The median age was 32 years (range, 17 to 70 years). With a median follow-up of 3.3 years, the 2-year progression-free survival (PFS) was 60% (95% CI, 55% to 65%) and the 2-year overall survival was 66% (95% CI, 60% to 70%). Three hundred three patients received HDCT as second-line therapy with a 2-year PFS of 63% (95% CI, 57% to 68%), and 61 patients received HDCT as third-line or later therapy with a 2-year PFS of 49% (95% CI, 36% to 61%). In a multivariable analysis, factors associated with disease progression included use of HDCT as third-line or later therapy, platinum-refractory disease, mediastinal primary tumor site, nonseminoma histology, intermediate- or poor-risk disease at the time of GCT diagnosis, and human chorionic gonadotropin ≥ 1,000 mIU/mL at initiation of HDCT. There were nine treatment-related deaths. Secondary leukemia developed in five patients. Conclusion: This large single-institution study demonstrates that patients with relapsed metastatic GCT are curable by HDCT plus PBSCT even when used in third-line or later therapy.

Patients with muscle-invasive bladder cancer who are ineligible for cisplatin-based chemotherapy proceed directly to radical cystectomy with pelvic lymph-node dissection. Perioperative therapy may improve outcomes in this population. In this phase 3, open-label trial, participants with muscle-invasive bladder cancer who were ineligible for or declined cisplatin-based chemotherapy were randomly assigned to perioperative (neoadjuvant and adjuvant) enfortumab vedotin, an antibody-drug conjugate directed at nectin-4, plus pembrolizumab and surgery (9 total cycles of enfortumab vedotin [1.25 mg per kilogram of body weight on days 1 and 8] plus 17 total cycles of pembrolizumab [200 mg on day 1 every 3 weeks], with surgery after 3 cycles) or surgery alone (control). The primary end point was event-free survival. Key secondary end points were overall survival and pathological complete response (absence of viable tumor after surgical resection). Other secondary end points included safety. A total of 344 participants underwent randomization (170 in the enfortumab vedotin-pembrolizumab group and 174 in the control group). At data cutoff, median follow-up was 25.6 months (range, 11.8 to 53.7). Surgery was performed in 87.6% of participants in the enfortumab vedotin-pembrolizumab group and in 89.7% in the control group. At 2 years, estimated event-free survival was 74.7% in the enfortumab vedotin-pembrolizumab group and 39.4% in the control group (hazard ratio for an event or death, 0.40; 95% confidence interval [CI], 0.28 to 0.57; two-sided P<0.001); estimated overall survival was 79.7% and 63.1% (hazard ratio for death, 0.50; 95% CI, 0.33 to 0.74; two-sided P<0.001). A pathological complete response had occurred in 57.1% and 8.6% of the participants (estimated difference, 48.3 percentage points; 95% CI, 39.5 to 56.5; two-sided P<0.001). Adverse events occurred in all participants in the enfortumab vedotin-pembrolizumab group (grade ≥3, 71.3%; grade ≥3 drug-related, 45.5%) and in 64.8% in the control group (grade ≥3, 45.9%). Perioperative enfortumab vedotin plus pembrolizumab and surgery led to significantly better event-free and overall survival outcomes and a greater percentage of participants with pathological complete response than surgery alone in a predominantly cisplatin-ineligible population with muscle-invasive bladder cancer. Safety was also assessed. (Funded by Merck Sharp and Dohme, a subsidiary of Merck [Rahway, NJ]; KEYNOTE-905 ClinicalTrials.gov number, NCT03924895.).

PURPOSE: The long-term toxicities of chemotherapy and radiotherapy can represent a significant burden to testicular cancer survivors. Retroperitoneal lymph node dissection (RPLND) is an established treatment for testicular germ cell tumors with minimal late morbidity although little data exist on its efficacy in early metastatic seminoma. Surgery in early metastatic seminoma is a prospective phase II single-arm, multi-institutional trial of RPLND as first-line treatment for testicular seminoma with clinically low-volume retroperitoneal lymphadenopathy. PATIENTS AND METHODS: Twelve sites in the United States and Canada prospectively enrolled adult patients with testicular seminoma and isolated retroperitoneal lymphadenopathy (1-3 cm). Open RPLND was performed by certified surgeons with a primary end point of 2-year recurrence-free survival (RFS). Complication rates, pathologic up/downstaging, recurrence patterns, adjuvant therapies, and treatment-free survival were assessed. RESULTS: A total of 55 patients were enrolled, with a median (IQR) largest clinical lymph node size of 1.6 cm (1.3-1.9). RPLND pathology demonstrated a median (IQR) largest lymph node size of 2.3 cm (0.9-3.5); nine patients (16%) were pN0, 12 (22%) pN1, 31 (56%) pN2, and 3 (5%) pN3. One patient received adjuvant chemotherapy. With a median (IQR) follow-up of 33 months (12.0-61.6), 12 patients experienced recurrence, with a 2-year RFS of 81% and a recurrence rate of 22%. Of the patients who experienced recurrence, 10 were treated with chemotherapy and two underwent additional surgery. At last follow-up, all patients who experienced a recurrence were disease-free and the 2-year overall survival was 100%. Four patients (7%) experienced short-term complications, and four patients experienced long-term complications including incisional hernia (1) and anejaculation (3). CONCLUSION: RPLND is a treatment option for testicular seminoma with clinically low-volume retroperitoneal lymphadenopathy and is associated with low long-term morbidity.

Purpose: Safety and efficacy of acapatamab, a prostate-specific membrane antigen (PSMA) x CD3 bispecific T-cell engager were evaluated in a first-in-human study in metastatic castration-resistant prostate cancer (mCRPC). Patients and Methods: Patients with mCRPC refractory to androgen receptor pathway inhibitor therapy and taxane-based chemotherapy received target acapatamab doses ranging from 0.003 to 0.9 mg in dose exploration (seven dose levels) and 0.3 mg (recommended phase II dose) in dose expansion intravenously every 2 weeks. Safety (primary objective), pharmacokinetics, and antitumor activity (secondary objectives) were assessed. Results: In all, 133 patients (dose exploration, n = 77; dose expansion, n = 56) received acapatamab. Cytokine release syndrome (CRS) was the most common treatment-emergent adverse event seen in 97.4% and 98.2% of patients in dose exploration and dose expansion, respectively; grade ≥ 3 was seen in 23.4% and 16.1%, respectively. Most CRS events were seen in treatment cycle 1; incidence and severity decreased at/beyond cycle 2. In dose expansion, confirmed prostate-specific antigen (PSA) responses (PSA50) were seen in 30.4% of patients and radiographic partial responses in 7.4% (Response Evaluation Criteria in Solid Tumors 1.1). Median PSA progression-free survival (PFS) was 3.3 months [95% confidence interval (CI): 3.0–4.9], radiographic PFS per Prostate Cancer Clinical Trials Working Group 3 was 3.7 months (95% CI: 2.0–5.4). Acapatamab induced T-cell activation and increased cytokine production several-fold within 24 hours of initiation. Treatment-emergent antidrug antibodies were detected in 55% and impacted serum exposures in 36% of patients in dose expansion. Conclusions: Acapatamab was safe and tolerated and had a manageable CRS profile. Preliminary signs of efficacy with limited durable antitumor activity were observed. Acapatamab demonstrated pharmacokinetic and pharmacodynamic activity.

Purpose: Deleterious germline/somatic homologous recombination repair mutations (HRRm) are present in ∼25% of patients with metastatic castration-resistant prostate cancer (mCRPC). Preclinically, poly(ADP-ribose) polymerase (PARP) inhibition demonstrated synergism with androgen receptor pathway (ARP)–targeted therapy. This trial evaluated the efficacy of ARP inhibitor versus PARP inhibitor versus their combination as first-line therapy in patients with mCRPC with HRRms. Patients and Methods: BRCAAway is a biomarker preselected, randomized, phase 2 trial. Patients with BRCA1/2 and/or ATM alterations were randomized 1:1:1 to Arm1: abiraterone (1,000 mg)/prednisone (5 mg BID) (Abi/pred), Arm2: olaparib (300 mg BID) (Ola), or Arm3: abiraterone/prednisone + olaparib (Abi/pred + Ola). Single-agent arms could cross over at progression. Exploratory Arm4 patients with other HRRms received olaparib alone. The primary endpoint was progression-free survival (PFS), and secondary endpoints were objective response, PSA response, and safety. Results: Sixty-one of 165 eligible patients had BRCA1/2 or ATM mutations: median age: 67 (IQR, 62–73) years. Mutations: BRCA1 n = 3, BRCA2 n = 46, ATM n = 11, and multiple n = 1; 33 germline and 28 somatic mutations. Median PFS [95% confidence interval (CI)]: Abi/pred, 8.6 months (m; 2.9, 17), Ola, 14 m (8.4, 20), and Abi/pred + Ola, 39 m [22, not reached (NR)]. There were no G4/5 adverse events; 8/19 patients on Abi/pred treatment crossed over to Ola, and 8/21 vice versa. Median PFS (95% CI) from crossover: Ola-after-Abi/pred, 8.3 m (5.5, 15) and Abi/pred-after-Ola, 7.2 m (2.8, NR). Median PFS (95% CI) from randomization: Ola-after-Abi/pred, 16 m (7.8, 25) and Abi/pred-after-Ola, 16 m (11, NR). Seventeen of 165 patients with other HRRms received olaparib: median PFS (95% CI): 5.5 m (2, 11). Conclusions: In patients with mCRPC with BRCA1/2 or ATM HRRm, Abi/pred + Ola was well tolerated and demonstrated longer PFS versus either agent alone or sequentially.