PURPOSE Translational studies have shown that CDK12 mutations may delineate an immunoresponsive subgroup of prostate cancer, characterized by high neo-antigen burden. Given that these mutations may define a clinically distinct subgroup, we sought to describe outcomes to standard drugs and checkpoint inhibitors (CPI). PATIENTS AND METHODS Clinical data from consecutive patients with CDK12 mutations were retrospectively collected from 7 centers. Several clinical-grade sequencing assays were used to assess CDK12 status. Descriptive statistics included PSA50 response rate (≥ 50% decline in prostate-specific antigen from baseline) and clinical/radiographic progression-free survival (PFS). RESULTS Of 52 patients with CDK12-mutated prostate cancer, 27 (52%) had detected biallelic CDK12 alterations. At diagnosis, 44 (88%) had Gleason grade group 4-5, 52% had T3-T4, and 14 (27%) had M1 disease. Median follow-up was 8.2 years (95% CI, 5.6 to 11.1 years), and 49 (94%) developed metastatic disease. Median overall survival from metastasis was 3.9 years (95% CI, 3.2 to 8.1 years). Unconfirmed PSA50 response rates to abiraterone and enzalutamide in the first-line castration-resistant prostate cancer setting were 11 of 17 (65%) and 9 of 12 (75%), respectively. Median PFS on first-line abiraterone and enzalutamide was short, at 8.2 months (95% CI, 6.6 to 12.6 months) and 10.6 months (95% CI, 10.2 months to not reached), respectively. Nineteen patients received CPI therapy. PSA50 responses to CPI were noted in 11%, and PFS was short; however, the estimated 9-month PFS was 23%. PFS was higher in chemotherapy-naïve versus chemotherapy-pretreated patients (median PFS: not reached v 2.1 months, P = .004). CONCLUSION CDK12 mutations define an aggressive prostate cancer subgroup, with a high rate of metastases and short overall survival. CPI may be effective in a minority of these patients, and exploratory analysis supports using anti–programmed cell death protein 1 drugs early. Prospective studies testing CPI in this subset of patients with prostate cancer are warranted.

BackgroundLow-density lipoprotein receptor-related protein 1b (encoded by LRP1B) is a putative tumor suppressor, and preliminary evidence suggests LRP1B-mutated cancers may have improved outcomes with immune checkpoint inhibitors (ICI).MethodsWe conducted a multicenter, retrospective pan-cancer analysis of patients with LRP1B alterations treated with ICI at Duke University, Johns Hopkins University (JHU) and University of Michigan (UM). The primary objective was to assess the association between overall response rate (ORR) to ICI and pathogenic or likely pathogenic (P/LP) LRP1B alterations compared with LRP1B variants of unknown significance (VUS). Secondary outcomes were the associations with progression-free survival (PFS) and overall survival (OS) by LRP1B status.ResultsWe identified 101 patients (44 Duke, 35 JHU, 22 UM) with LRP1B alterations who were treated with ICI. The most common tumor types by alteration (P/LP vs VUS%) were lung (36% vs 49%), prostate (9% vs 7%), sarcoma (5% vs 7%), melanoma (9% vs 0%) and breast cancer (3% vs 7%). The ORR for patients with LRP1B P/LP versus VUS alterations was 54% and 13%, respectively (OR 7.5, 95% CI 2.9 to 22.3, p=0.0009). P/LP LRP1B alterations were associated with longer PFS (HR 0.42, 95% CI 0.26 to 0.68, p=0.0003) and OS (HR 0.62, 95% CI 0.39 to 1.01, p=0.053). These results remained consistent when excluding patients harboring microsatellite instability (MSI) and controlling for tumor mutational burden (TMB).ConclusionsThis multicenter study shows significantly better outcomes with ICI therapy in patients harboring P/LP versus VUS LRP1B alterations, independently of TMB/MSI status. Further mechanistic and prospective validation studies are warranted.

Background The identification of biomarkers to select patients with metastatic renal cell carcinoma (mRCC) most likely to respond to combination immunotherapy (IO) is needed. We sought to investigate an association of the baseline neutrophil-to-eosinophil ratio (NER) with outcomes to nivolumab plus ipilimumab for patients with mRCC. Methods We performed a retrospective review of patients with clear cell mRCC treated with nivolumab plus ipilimumab from Vanderbilt-Ingram Cancer Center and Duke Cancer Institute. Patients with prior receipt of immunotherapy and those without available baseline complete blood count with differential were excluded. Patients were divided into groups by the median baseline NER and analyzed for overall survival (OS), progression free survival (PFS), and objective response rate (ORR). Patients were also divided by median baseline neutrophil-to-lymphocyte ratio (NLR) and analyzed for clinical outcome. Further analyses of patients above/below the median NER and NLR were performed in subgroups of IMDC intermediate/poor risk, IMDC favorable risk, and treatment naïve patients. Results A total of 110 patients were included: median age was 61 years and 75% were treatment naïve. The median NER (mNER) at baseline was 26.4. The ORR was 40% for patients with <mNER compared to 21.8% among patients with >mNER (OR 2.39, p = 0.04). The median PFS for patients with <mNER was significantly longer at 8.6 months (mo) compared to 3.2 mo for patients with >mNER (HR 0.50, p < 0.01). Median OS was not reached (NR) for patients with <mNER compared with 27.3 mo for patients with >mNER (HR 0.31, p < 0.01). The median NLR (mNLR) was 3.42. While patients with <mNLR showed improvement in OS (HR 0.42, p = 0.02), PFS and ORR did not differ compared with patients in the >mNLR group. Conclusions A lower baseline NER was associated with improved clinical outcomes (PFS, OS, and ORR) in patients with mRCC treated with nivolumab plus ipilimumab, and prospective validation of the baseline NER as a predictive biomarker for response to immunotherapy-based combinations in mRCC is warranted.