Radiographic Progression-free Survival Research Articles

QOL-26. A RANDOMIZED, DOUBLE-BLIND PHASE 3 STUDY OF VORASIDENIB VS PLACEBO IN PATIENTS WITH MUTANT IDH1/2DIFFUSE GLIOMA (INDIGO): ANALYSIS OF HEALTH-RELATED QUALITY OF LIFE, NEUROCOGNITION AND SEIZURES

Abstract INTRODUCTION The Phase 3 INDIGO study (NCT04164901) is a randomized, double-blind evaluation of vorasidenib, an oral, brain-penetrant inhibitor of mutant isocitrate dehydrogenase (mIDH) 1/2 enzymes, compared with placebo, in patients with grade 2 mIDH1/2 diffuse gliomas, whose only prior treatment was surgery. The primary endpoint, radiographic progression-free survival by blinded independent review committee, and the key secondary endpoint, time-to-next-intervention, were significantly improved with vorasidenib versus placebo. As these patients are young, with several years’ life expectancy, impact of treatments on health-related quality of life (HRQoL), cognition and symptomatic burden is of interest. METHODS HRQoL, assessed by Functional Assessment of Cancer Therapy-Brain (FACTBr) questionnaire, was a secondary endpoint. FACT-Br was collected at baseline, Cycles 2 and 3, then every 3 months. Scores were interpreted using an estimate of clinically meaningful deterioration change from baseline for each arm. Exploratory endpoints included neurocognitive function, assessed by a validated battery of cognitive performance instruments, and seizure frequency and severity, assessed using a subject diary. RESULTS 331 patients were randomized to vorasidenib (n = 168) or placebo (n = 163) (median age, 40.0 years; Karnofsky performance scale = 100, 53.5%; ongoing medical history of seizures, 54.1%). Median follow-up was 14.2 months. No clinically meaningful deterioration from baseline FACT-Br total score and subscales were observed at any timepoint through the median treatment duration (Cycle 13) in either arm. At baseline, active seizures (≥ 1 seizure in the previous 30 days) were reported in 20/168 (11.9%) vorasidenib patients and 20/163 (12.3%) placebo patients. On-treatment seizure frequencies and cognition outcomes will be presented by arm. CONCLUSION INDIGO is the first randomized Phase 3 study of targeted therapy in grade 2 mIDH1/2 diffuse glioma. HRQoL, as measured by FACT-Br, was maintained during treatment with vorasidenib. These data support the clinical benefit of vorasidenib in this patient population for whom chemotherapy and radiotherapy are being delayed.

CTNI-51. A RANDOMIZED DOUBLE-BLIND PHASE 3 STUDY OF VORASIDENIB VS PLACEBO IN PATIENTS WITH MUTANT IDH1/2 DIFFUSE GLIOMA (INDIGO): EXPLORATORY ANALYSIS OF VARIANT ALLELE FREQUENCY AND PROGRESSION-FREE SURVIVAL

Abstract INTRODUCTION Vorasidenib is an oral, brain-penetrant, inhibitor of mutant isocitrate dehydrogenase (mIDH) 1/2 enzymes. The INDIGO study (NCT04164901) showed significantly improved radiographic progression-free survival (PFS) by blinded independent review committee (BIRC) with vorasidenib, compared with placebo, in patients with mIDH1/2 adulttype diffuse glioma (hazard ratio [HR] 0.39, 95% CI 0.27–0.56; one-sided P = 0.000000067 [Mellinghoff N Engl J Med 2023]). The key secondary endpoint of time-to-next-intervention was also met. METHODS In this double-blind Phase 3 study, patients aged ≥ 12 years with residual/recurrent grade 2 mIDH1/2 oligodendroglioma or astrocytoma, measurable non-enhancing disease, and no prior treatment for glioma were randomized 1:1 to receive vorasidenib 40 mg or placebo daily in 28-day cycles. An investigational clinical trial assay centrally confirmed IDH1 R132H/C/G/S/L or IDH2 R172K/M/W/S/G mutation variants. Pretreatment (archival) tumor tissue was analyzed by next-generation sequencing for CDKN2A/B homozygous deletion and other co-mutations (ACE Extended Cancer Panel). RESULTS As of Sep 6, 2022 (preplanned second interim analysis), 168 patients were randomized to vorasidenib and 163 to placebo (median age, 40.0 years; Karnofsky performance scale = 100, 53.5%; oligodendroglioma, 172; astrocytoma, 159; mIDH1, 315; mIDH2, 16). Two patient subgroups were defined by baseline IDH1/2 variant allele frequency (VAF): lower/higher than the median value (0.377). The median PFS results favored vorasidenib over placebo in both subgroups (low VAF, one-sided P = 0.0116; high VAF, one-sided P < 0.0001). Vorasidenib and placebo groups had similar and a low number of co-mutations in known/likely oncogenic genes at baseline (median number of co-mutations across both groups was 4). CDKN2A homozygous deletion was detected in only two participants (both in the placebo group). Additional data will be presented. CONCLUSION In the first randomized Phase 3 study of a targeted therapy in grade 2 mIDH1/2 glioma, vorasidenib prolonged median PFS by BIRC, relative to placebo, irrespective of IDH1/2 VAF.

Pembrolizumab and Enzalutamide in Patients with Abiraterone Acetate–Pretreated Metastatic Castration-Resistant Prostate Cancer: Cohort C of the Phase 1b/2 KEYNOTE-365 Study

BackgroundLimited responses have been observed in patients treated with enzalutamide after disease progression on abiraterone for metastatic castration-resistant prostate cancer (mCRPC), but androgen receptor signaling impacts T-cell function. ObjectiveTo evaluate the efficacy and safety of pembrolizumab plus enzalutamide in mCRPC. Design, setting, and participantsPatients in cohort C of the phase 1b/2 KEYNOTE-365 study, who received ≥4 wk of treatment with abiraterone acetate in the prechemotherapy mCRPC state and experienced treatment failure or became drug-intolerant, were included. InterventionPembrolizumab 200 mg intravenously every 3 wk plus enzalutamide 160 mg orally once daily. Outcome measurements and statistical analysisThe primary endpoints were safety, the confirmed prostate-specific antigen (PSA) response rate, and the objective response rate (ORR) according to Response Evaluation Criteria in Solid Tumors version 1.1 on blinded independent central review (BICR). Secondary endpoints included radiographic progression-free survival (rPFS) on BICR and overall survival (OS). Results and limitationsA total of 102 patients received pembrolizumab plus enzalutamide. Median follow-up was 51 mo (interquartile range 37–56). The confirmed PSA response rate was 24% (95% confidence interval [CI] 16–33%). The confirmed ORR was 11% (95% CI 2.9–25%; 4/38 patients; two complete responses). Median rPFS was 6.0 mo (95% CI 4.1–6.3). Median OS was 20 mo (95% CI 17–24). Treatment-related adverse events (TRAEs) occurred in 94 patients (92%); grade 3–5 TRAEs occurred in 44 patients (43%). The incidence of treatment-related rash was higher with combination therapy than expected from the safety profile of each drug. One patient (1.0%) died of a TRAE (cause unknown). Study limitations include the single-arm design. ConclusionsPembrolizumab plus enzalutamide had limited antitumor activity in patients who received prior abiraterone treatment without previous chemotherapy for mCRPC, with a safety profile consistent with the individual profiles of each agent. Patient summaryPembrolizumab plus enzalutamide showed limited antitumor activity and manageable safety in patients with metastatic castration-resistant prostate cancer.The KEYNOTE-365 trial is registered on ClinicalTrials.gov as NCT02861573.

Nephron-sparing ureteroscopic surgery vs. radical nephroureterectomy: comparable survival-outcomes in upper tract urothelial carcinoma.

This study investigates the utility of ureteroscopic surgery (URS) as an alternative to radical nephroureterectomy (RNU) in managing upper tract urothelial carcinoma (UTUC), with a focus on survival outcomes and re-evaluation of current the European Association of Urology guidelines criteria. We conducted a retrospective, multi-institutional review of 143 UTUC patients treated with URS (n = 35) or RNU (n = 108). Clinicopathological factors were analyzed, and survival outcomes were assessed using Kaplan-Meier analysis and Cox proportional-hazards models. The median follow-up period was 27months. Overall survival (OS) and radiographic progression-free survival (rPFS) were comparable between the URS and RNU groups (OS: HR 2.42, 95% CI 0.63-9.28, P = 0.0579; rPFS: HR 1.82, 95% CI 0.60-5.47, P = 0.1641). URS conferred superior renal function preservation. In patients characterized by factors such as radiographically invisible lesions, negative cytology, pTa stage, low-grade tumors, and multiple lesions, the OS outcomes with URS were comparable to those with RNU as follows: radiographically invisible lesions (P = 0.5768), negative cytology (P = 0.7626), pTa stage (P = 0.6694), low-grade tumors (P = 0.9870), and multiple lesions (P = 0.8586). URS offers survival outcomes similar to RNU, along with better renal function preservation, especially in low-risk UTUC patients. These findings underscore the urgency of re-evaluating the current EAU guidelines and encourage further research into determining the ideal patient selection for URS in UTUC treatment.

Real-world prostate-specific antigen reduction and survival outcomes of metastatic hormone-sensitive prostate cancer patients treated with apalutamide: An observational, retrospective, and multicentre study.

Backgroundetastatic hormone-sensitive prostate cancer (mHSPC) treatment has changed drastically during the last years with the emergence of androgen receptor–targeted agents (ARTAs). ARTA combined with androgen deprivation therapy has demonstrated better oncological and survival outcomes in these patients. However, the optimal choice among different ARTAs remains uncertain due to their analogous efficacy. ObjectivesThe objective of this study was to describe prostate-specific antigen (PSA) response and oncological outcomes of patients with mHSPC treated with apalutamide. Material and methodsMedical records from three different hospitals in Spain were used to conduct this study. Patients diagnosed with mHSPC and under apalutamide treatment were included between March 2021 and January 2023. Data regarding PSA response, overall survival (OS), and radiographic progression-free survival (rPFS) were collected and stratified by metastasis volume, timing, and stating. Results193 patients were included; 34.2% of patients were de novo mHSPC, and the majority was classified as m1b. The 18-month OS and rPFS were 92.5% and 88.9%, respectively. Patients with PSA levels ≤0.2 ng/ml showcased an 18-month OS rate of 98.7%, contrasting with 65.3% for those with PSA >0.2 ng/ml. Similar trends emerged for rPFS (97.4% and 53.7%, respectively). When differentiating between low-volume and high-volume metastasis, the OS rate stood at 98.4% and 80.7%, respectively, while the rPFS rates were 93% and 81.6%, respectively. No significant differences were found between groups stratified by metastasis timing. ConclusionThis real-world study on patients with mHSPC treated with apalutamide plus androgen deprivation therapy revealed robust oncological outcomes, aligning with the emerging evidence. The study's hallmark finding highlights the significance of rapid and deep PSA response as a predictor of improved oncological and survival outcomes.

Comparative efficacy of olaparib in combination with or without novel antiandrogens for treating metastatic castration-resistant prostate cancer.

Studies using novel antiandrogens (NAA) in patients with metastatic castration-resistant prostate cancer (mCRPC) have shown overall survival benefit. As patients develop resistance to NAA therapy, the poly(ADP-ribose) polymerase inhibitor (PARPi) olaparib in combination with NAA may become a promising therapy. However the overall benefit of olaparib monotherapy or combination therapy still needs to be evaluated. Therefore, we performed a network meta-analysis to assess the efficacy and toxicity between olaparib, olaparib combined with abiraterone and NAA. We searched PubMed, EMBASE, the Cochrane Library and American Society of Clinical Oncology (ASCO) University Meeting abstracts for randomized controlled trials reporting olaparib and NAA from 2010 up to March, 2023. Network meta-analysis using Stata 16.0 and R 4.4.2, hazard ratios (HR) with 95% confidence intervals (CI) were used to assess the results. Four trials reported olaparib, olaparib plus abiraterone and apalutamide plus abiraterone. radiographic progression-free survival (rPFS) was significantly lower in patients on apalutamide plus abiraterone compared to olaparib (HR, 1.43; 95% CI, 1.06-1.93). rPFS was similar for olaparib plus abiraterone and olaparib (HR, 1.35; 95% CI, 0.99-1.84); likewise, olaparib plus abiraterone and apalutamide plus abiraterone were similar (HR, 1.06; 95% CI, 0.83-1.35). In addition, there was no significant difference between the three interventions for OS. But olaparib has the highest probability of being a preferred treatment for improving rPFS and OS. rPFS was in favor of olaparib compared with apalutamide plus abiraterone. But there were no difference between olaparib plus abiraterone and either olaparib or apalutamide plus abiraterone. Apalutamide plus abiraterone might be the most preferred intervention in cases where AEs are involved. https://inplasy.com, identifier INPLASY2023100072.

Phase II Trial Evaluating Olaparib Maintenance in Patients with Metastatic Castration-Resistant Prostate Cancer Responsive or Stabilized on Docetaxel Treatment: SOGUG-IMANOL Study.

The SOGUG-IMANOL trial was a phase 2, uncontrolled, Spanish multicenter study to assess the effect of maintenance treatment with olaparib on radiographic progression-free survival (PFS) in patients with metastatic castration-resistant prostate cancer (mCRPC) who achieved partial or complete response or disease stabilization on docetaxel treatment and had a documented germline/somatic mutation in any of the homologous recombination repair (HRR) genes. Patients received olaparib 300 mg orally twice daily. From the screened population (n = 134), 26 (19.4%) somatic mutations were found, and 14 patients were included in the study. The median radiographic PFS was 11.1 (95%CI, 5.7 to 16.5) months. The median PSA-PFS was 3.5 (95%CI, 1.0 to 6.0) months, and the median clinical PFS was 14.7 (95%CI, 1.8 to 27.5 months). Clinical benefit was observed in 12 patients (85.7%, 95%CI 67.4% to 100%), including two patients with partial response and 10 with stable disease. Six patients reported grade 3-5 adverse events: asthenia (n = 3), anemia (n = 2) and neutropenia (n = 1). In this setting, olaparib has been shown to be an efficacious maintenance treatment in terms of radiographic PFS and clinical benefit, becoming a therapeutic option for some patients harboring an HRR gene mutation and in scenarios where further investigation is needed.

Olaparib plus Abiraterone for Metastatic Castration-resistant Prostate Cancer: Pharmacokinetics Data from the PROpel Trial

PROpel (NCT03732820) was a positive phase 3 trial that demonstrated a clinically significant improvement in radiographic progression-free survival with olaparib plus abiraterone versus placebo plus abiraterone in first-line metastatic castration-resistant prostate cancer. For a subset of PROpel patients, steady-state concentrations of olaparib, abiraterone, and Δ4-abiraterone were measured in blood samples collected before and at several time points after dose administration. The pharmacokinetics (PK) for each drug and metabolite were evaluated to determine whether any clinically relevant drug-drug interactions between olaparib and abiraterone occurred. The results demonstrate that steady-state PK parameters for olaparib and abiraterone in PROpel were comparable with those in monotherapy trials. Abiraterone steady-state exposures were similar between treatment arms. Δ4-Abiraterone had slightly lower steady-state exposures when abiraterone was administered in combination with olaparib. These results are consistent with a previous phase 2 study, supporting the conclusion that no clinically relevant PK-based drug-drug interactions occurred when olaparib and abiraterone were given in combination at their full monotherapy doses. Patient summaryWhen drugs are administered in combination, a key consideration is whether there are any interactions between the drugs that may affect their activity. We analyzed blood concentrations of olaparib and abiraterone in a subset of patients with prostate cancer from the PROpel trial to determine if there were interactions between these two drugs. We found that there was no significant effect on the profile of either drug when they were given together at the same doses used when each drug is given individually.

TP53 structure-function relationships in metastatic castrate-sensitive prostate cancer and the impact of APR-246 treatment.

Despite well-informed work in several malignancies, the phenotypic effects of TP53 mutations in metastatic castration-sensitive prostate cancer (mCSPC) progression and metastasis are not clear. We characterized the structure-function and clinical impact of TP53 mutations in mCSPC. We performed an international retrospective review of men with mCSPC who underwent next-generation sequencing and were stratified according to TP53 mutational status and metastatic burden. Clinical outcomes included radiographic progression-free survival (rPFS) and overall survival (OS) evaluated with Kaplan-Meier and multivariable Cox regression. We also utilized isogenic cancer cell lines to assess the effect of TP53 mutations and APR-246 treatment on migration, invasion, colony formation in vitro, and tumor growth in vivo. Preclinical experimental observations were compared using t-tests and ANOVA. Dominant-negative (DN) TP53 mutations were enriched in patients with synchronous (vs. metachronous) (20.7% vs. 6.3%, p < 0.01) and polymetastatic (vs. oligometastatic) (14.4% vs. 7.9%, p < 0.01) disease. On multivariable analysis, DN mutations were associated with worse rPFS (hazards ratio [HR] = 1.97, 95% confidence interval [CI]: 1.31-2.98) and overall survival [OS] (HR = 2.05, 95%CI: 1.14-3.68) compared to TP53 wild type (WT). In vitro, 22Rv1 TP53 R175H cells possessed stronger migration, invasion, colony formation ability, and cellular movement pathway enrichment in RNA sequencing analysis compared to 22Rv1 TP53 WT cells. Treatment with APR-246 reversed the effects of TP53 mutations in vitro and inhibited 22Rv1 TP53 R175H tumor growth in vivo in a dosage-dependent manner. DN TP53 mutations correlated with worse prognosis in prostate cancer patients and higher metastatic potential, which could be counteracted by APR-246 treatment suggesting a potential future therapeutic avenue.

Breaking through resistance in mCRPC: Enzalutamide analogues as effective anticancer agents for enhanced male survival

To alleviate metastatic castration-resistant prostate cancer (mCRPC), enzalutamide, a non-steroidal antiandrogen, is employed. Following androgen deprivation therapy or anti-androgen treatment, compensatory mechanisms in prostate cancer have been identified, leading to increased expression and function of steroidal receptors. Comparative studies involving individuals with CRPC have demonstrated enzalutamide's superior efficacy compared to its predecessor, bicalutamide. Currently, there are four nonsteroidal antiandrogens approved by the US Food and Drug Administration, with two investigational medications undergoing clinical trials. Enzalutamide effectively slowed prostate cancer growth by preventing nuclear translocation and gene expression that are dependent on the AR, according to preclinical research. Its effectiveness in metastatic hormone-sensitive prostate cancer was supported by clinical trials like ARCHES, which also showed an improvement in radiographic progression-free survival with an acceptable safety profile. Resistance to enzalutamide can occur due to the F786L mutation. Recent research has shown that analogues of enzalutamide can overcome this resistance, enhancing anticancer activity and improving male survival rates. We will explore various enzalutamide analogues, including those with trifluoromethyl, trifluoromethoxy, diarylhydantoin, benzothiazole or benzoxazole, and 1-hydroxy-2,2,2-trifluoro-1-ethyl moieties, primarily used to address the resistance issue. Additionally, we will highlight the structural activity relationships of these analogues, which may enhance their antiproliferative effects and increase male survival rates. Notably, imidazolidine derivatives exhibit the most significant antiproliferative activity.

Health-related quality of life of metastatic prostate cancer patients treated with prostate Radiotherapy

BackgroundThe impact of prostate radiotherapy on patient-reported health-related quality of life (HRQoL) significantly influences the outcomes of metastatic prostate cancer. We measured and compared HRQoL of metastatic prostate cancer patients who received cytoreductive prostate radiotherapy.MethodsBetween November 23, 2020, and November 21, 2022, we recruited 70 metastatic prostate cancer patients at the Department of Clinical Oncology at Suez Canal University Hospital. Patients were eligible if they had synchronous and metachronous histopathological confirmed metastatic adenocarcinoma and an Eastern Cooperative Oncology Group performance status ≤ 2. Random allocation was performed for either definitive local radiotherapy concurrent with the standard androgen deprivation therapy (ADT) or to the standard ADT alone. Definitive radiotherapy was delivered conventionally (70 Gy/35 fractions) or through the hypofractionated regimen (55 Gy/20 fractions). Patients completed the comprehensive European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-PR25) at baseline, then at three-month intervals for one year. The primary endpoint was patient-reported HRQoL, with secondary endpoints including toxicity and radiographic progression-free survival (rPFS). Mean HRQoL scores between groups were compared using the independent samples t-test.ResultsWe observed clinically significant improvements in urinary and bowel functions between baseline, 3-month, 6-month, and 12-month intervals after receiving definitive prostate radiotherapy. Patients in the radiotherapy group had significantly lower urinary symptoms scores than the control group. However, sexual activity and functioning showed significant deterioration.ConclusionCytoreductive prostate radiotherapy in metastatic prostate cancer patients significantly improved urinary functioning, preserved bowel functioning but was associated with worsening of sexual functioning.Trial RegistrationThis trial was registered on (27/04/2023) with pactr.samrc.ac.za, PACTR202305854600529, URL: https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=25510.

Multi-Institutional Analysis of Metastasis Directed Therapy with or without Androgen Deprivation Therapy in Oligometastatic Castration Sensitive Prostate Cancer.

Several prospective trials in oligometastatic castration sensitive prostate cancer (omCSPC) have shown metastasis-directed therapy (MDT) can delay time to progression and initiation of androgen deprivation therapy (ADT) compared to observation. However, the optimal integration of ADT with MDT remains unclear. Here we report a multi-national, multi-institutional retrospective cohort of omCSPC treated with MDT to characterize the long-term outcomes of patients treated with MDT alone or in combination with ADT. Patients with a controlled primary site and omCSPC (defined as ≤ 5 lesions on conventional imaging) treated with MDT with or without concurrent ADT and with at least 36 months follow-up were retrospectively screened across 13 institutions. The primary endpoints included biochemical progression free survival (bPFS) and radiographic progression free survival (rPFS) calculated using Kaplan-Meier method and stratified by treatment group (MDT alone vs MDT + ADT). Multivariable Cox regression was performed adjusted for variables found to be prognostic on univariate analysis. Among 414 patients screened, a total of 263 patients treated between 2003 and 2018 met inclusion criteria and included. Of these, 105 received MDT alone and 158 received MDT+ADT, with median follow-up of 49.5 and 54.5 months, respectively. The majority were metachronous (90%) and had bone lesions (60%). Median ADT duration was 21.3 months (IQR 12.0- 31.9). Patients who received ADT vs. no ADT had poorer prognostic features including 23% vs. 1% synchronous (p<0.001), and 55% vs 40% Gleason 8-10 (p = 0.012). ADT use was associated with a better 5-year bPFS 24% vs 11% (p<0.0001) and rPFS 41% vs 29% (p<0.001). On multivariable Cox regression adjusting for post-MDT PSA nadir and salvage therapy, ADT use maintained significance for both bPFS (HR 0.51 (0.36, 0.71), p<0.001) and rPFS (HR 0.67, 95% CI 0.46-0.96, p = 0.03). Long-term outcomes with MDT alone suggest a small proportion of patients experience sustained disease control. The addition of ADT appears to improve rPFS, however prospective studies are needed in order to allow for personalization of care in patients with omCSPC.

The Impact of TP53 Mutations and Use of the TP53-Mutation-Reactivating Agent APR-246 on Metastatic Castrate-Sensitive Prostate Cancer.

TP53 mutations appear to be enriched over the spectrum of metastatic castration-sensitive prostate cancer (mCSPC) and are associated with worse survival outcomes. We chose to further explore the impact of dominant negative (DN) TP53 mutations on mCSPC progression and pro-metastatic behaviors in addition to studying the ability of APR-246, a small molecule targeting TP53 mutants, to blunt pro-metastatic behaviors. We retrospectively analyzed 531 mCSPC patients who underwent next-generation sequencing. Patients were stratified by metastasis timing (synchronous if metastasis present at diagnosis or metachronous if arising after definitive treatment of localized disease) and the number of metastatic lesions (oligometastatic ≤5 or polymetastatic >5 lesions). Tumors were classified based on TP53 mutation status (missense, truncating, or wild-type [WT]) and dominant negativity, which was defined as the production of a mutant protein that reduces the residual WT protein's transcriptional activity according to the World Health Organization TP53 database. Clinical outcomes were radiographic progression-free survival (rPFS) and overall survival (OS), evaluated with Kaplan-Meier and multivariable Cox regression. To verify the impact of TP53 mutation on metastasis, we created isogenic 22Rv1 prostate cancer cell lines that carried either TP53 WT or TP53 R175H and tested this mutation for migration, invasion, and anchorage-independent growth. APR-246 (25-80 µM) was tested for anti-metastatic properties in vitro and anti-tumor growth in 22Rv1 xenografted nude mice. In our cohort, 155 (29.2%) had a TP53 mutation, which mostly occurred in the DNA-binding domain (85.16%). DN TP53 mutations were associated with more aggressive disease states: DN TP53 mutations were enriched in patients with synchronous (vs. metachronous: 20.7% vs. 6.3%, p < 0.01) and polymetastatic disease (vs. oligometastatic: 14.4% vs. 7.9%, p < 0.01). On multivariable analysis, DN TP53 mutations were correlated with shorter rPFS (HR = 1.97, 95% CI: 1.31-2.98, p < 0.01) and OS (HR = 2.05, 95% CI: 1.14-3.68, p = 0.02) compared to those with TP53 WT. In vitro, 22Rv1 cells with DN TP53 R175H mutation had increased abilities to migrate, invade, and form colonies compared to TP53 WT. APR-246 treatment of TP53 R175H mutants blunted the pro-metastatic effects of the cell line in vitro (p < 0.01 for all assays by unpaired t-test). Interestingly, APR-246 also inhibited xenograft tumor growth of 22Rv1 TP53 R175H mutants (p < 0.0001 by two-way ANOVA). DN TP53 mutations were associated with poorer survival outcomes for mCSPC patients. DN TP53 mutations also promoted prostate cancer pro-metastatic behaviors in vitro, which was effectively counteracted by APR-246, making it a promising treatment option that should be explored further in early-phase clinical studies.

1803P Phase I/II study of bavdegalutamide, a PROTAC androgen receptor (AR) degrader in metastatic castration-resistant prostate cancer (mCRPC): Radiographic progression-free survival (rPFS) in patients (pts) with AR ligand-binding domain (LBD) mutations

1803P Phase I/II study of bavdegalutamide, a PROTAC androgen receptor (AR) degrader in metastatic castration-resistant prostate cancer (mCRPC): Radiographic progression-free survival (rPFS) in patients (pts) with AR ligand-binding domain (LBD) mutations

OCT4‑positive circulating tumor cells may predict a poor prognosis in patients with metastatic castration‑resistant prostate cancer treated with abiraterone plus prednisone therapy.

Octamer-binding transcription factor 4 (OCT4) and circulating tumor cells (CTCs) are key factors associated with tumor metastasis and drug resistance in cancer. The present prospective study aimed to investigate the prevalence of OCT4-positive (OCT4+) CTCs and the potential association with the clinical features and survival of patients with metastatic castration-resistant prostate cancer (mCRPC) treated with abiraterone + prednisone. In total, 70 patients with mCRPC treated with abiraterone + prednisone were enrolled in the present study and peripheral blood samples were collected prior to treatment initiation to determine CTC count via a Canpatrol system. RNA in situ hybridization was performed for OCT4+ CTC quantification. Lactate dehydrogenase (LDH) was detected by automatic biochemical analyzer (AU54000, OLYMPUS). Results demonstrated that 34 (48.6%), 21 (30.0%) and 15 (21.4%) patients harbored OCT4+ (CTC+/OCT4+) or OCT4-negative CTCs (CTC+/OCT4-) or were CTC-negative (CTC-), respectively. Notably, CTC+/OCT4+ occurrence was associated with visceral metastasis and high levels of LDH. In addition, radiographic progression-free survival [rPFS; median, 15.0, 95% confidence interval (CI), 9.6-20.4 vs. not reached vs. median, 29.5, 95% CI, 18.6-40.4 months; P=0.001] and overall survival (OS) were significantly decreased (median, 27.3, 95% CI, 20.1-34.5 vs. not reached vs. not reached; P=0.016) in CTC+/OCT4+ compared with CTC+/OCT4- and CTC- patients. Subsequently, the adjustment was performed by multivariate Cox regression models, which revealed that CTC+/OCT4+ (vs. CTC+/OCT4- or CTC-) was independently associated with decreased rPFS [hazard ratio (HR), 3.833; P<0.001] and OS (HR, 3.938; P=0.008). In conclusion, OCT4+ CTCs were highly prevalent in patients with mCRPC and associated with visceral metastasis and increased levels of LDH. Thus, the presence of OCT4+ CTCs may serve as an independent prognostic factor for patients with mCRPC treated with abiraterone + prednisone.

Initial-to-nadir Prostate-specific Antigen Ratio Predicts Response to First-line Enzalutamide in Metastatic Castration-resistant Prostate Cancer.

No practical biomarkers predict the response to enzalutamide in chemotherapy-naïve metastatic castration-resistant prostate cancer (mCRPC). The present study aimed to evaluate the prognostic value of the initial-to-nadir prostate-specific antigen (PSA) ratio (I/N PSA) in primary hormone therapy for metastatic hormone-naïve prostate cancer associated with the response to first-line enzalutamide in mCRPC. Twenty-eight patients with mCRPC received first-line enzalutamide to determine the associations between I/N PSA in combined androgen blockade and clinical outcomes. The PSA response was defined as ≥90% decline from baseline in patients with mCRPC. The optimal cutoff I/N PSA value for PSA response was 1,219 (sensitivity=71.4%, specificity=92.9%, area under the receiver operating characteristic curve=0.85). The PSA response was 90.9% in the high I/N PSA group and 23.5% in the low I/N PSA group. The median overall survival, prostate cancer-specific survival, and radiographic progression-free survival after initiation of enzalutamide were statistically greater for the high I/N PSA group than the low group. Multivariable analysis showed that I/N PSA was an independent predictor of overall survival (hazard ratio=0.23; p=0.026). In chemotherapy-naïve patients with mCRPC, I/N PSA was a predictive and prognostic biomarker for first-line enzalutamide. The I/N PSA can enable optimization of individual treatment in real-world clinical practice.

INDIGO: A GLOBAL, RANDOMIZED, DOUBLE-BLINDED, PHASE 3 STUDY OF VORASIDENIB VERSUS PLACEBO IN PATIENTS WITH RESIDUAL OR RECURRENT GRADE 2 GLIOMA WITH AN IDH1/2 MUTATION

Abstract AIMS Current treatments grade 2 gliomas are not curative and can be associated with short- and long-term toxicities. Vorasidenib (VOR), an oral, brain-penetrant, dual inhibitor of mutant (m)IDH1/2 enzymes, has shown a tolerable safety profile and preliminary clinical activity in phase 1 studies. METHOD In the phase 3 INDIGO study (NCT04164901), patients (pts) were randomized 1:1 to receive VOR 40 mg daily or placebo (PBO) daily in 28-day cycles. Patients were stratified by 1p19q status and baseline tumor size. Key eligibility criteria included: age ≥12; KPS &amp;gt;80; residual or recurrent grade 2 IDH1m or IDH2m oligodendroglioma or astrocytoma; measurable non-enhancing disease; no prior treatment for glioma with most recent surgery 1-5 years from randomization; and not in immediate need of chemotherapy/radiation. Primary endpoint: radiographic progression-free survival (PFS) by blinded independent radiology committee (BIRC). Key secondary endpoint: time to next intervention (TTNI). RESULTS As of 06 Sep2022, 331 pts were randomized across 10 countries: 168 to VOR and 163 to PBO. Median PFS by BIRC was 27.7 mos with VOR and 11.1 with PBO (HR, 0.39; 95% CI, 0.27, 0.56; 1-sided P=0.000000067). Median TTNI was not reached with VOR and 17.8 mos with PBO (HR, 0.26; 95% CI, 0.15, 0.43; 1-sided P=0.000000019). All-grade adverse events (AEs) occurring in &amp;gt;20% pts receiving VOR vs PBO were alanine aminotransferase increased, COVID-19, fatigue, aspartate aminotransferase increase, headache, diarrhea, nausea. Common grade ≥3 AEs (&amp;gt;5%): ALT increased (9.6% vs 0%). CONCLUSIONS VOR significantly improved PFS by BIRC versus PBO with a manageable safety profile. © 2023 American Society of Clinical Oncology, Inc. Reused with permission. This abstract was accepted and previously presented at the 2023 ASCO Annual Meeting. All rights reserved.

Olaparib plus abiraterone versus placebo plus abiraterone in metastatic castration-resistant prostate cancer (PROpel): final prespecified overall survival results of a randomised, double-blind, phase 3 trial

PROpel met its primary endpoint showing statistically significant improvement in radiographic progression-free survival with olaparib plus abiraterone versus placebo plus abiraterone in patients with first-line metastatic castration-resistant prostate cancer (mCRPC) unselected by homologous recombination repair mutation (HRRm) status, with benefit observed in all prespecified subgroups. Here we report the final prespecified overall survival analysis. This was a randomised, double-blind, phase 3 trial done at 126 centres in 17 countries worldwide. Patients with mCRPC aged at least 18 years, Eastern Cooperative Oncology Group performance status 0-1, a life expectancy of at least 6 months, with no previous systemic treatment for mCRPC and unselected by HRRm status were randomly assigned (1:1) centrally by means of an interactive voice response system-interactive web response system to abiraterone acetate (orally, 1000 mg once daily) plus prednisone or prednisolone with either olaparib (orally, 300 mg twice daily) or placebo. The patients, the investigator, and study centre staff were masked to drug allocation. Stratification factors were site of metastases and previous docetaxel at metastatic hormone-sensitive cancer stage. Radiographic progression-free survival was the primary endpoint and overall survival was a key secondary endpoint with alpha-control (alpha-threshold at prespecified final analysis: 0·0377 [two-sided]), evaluated in the intention-to-treat population. Safety was evaluated in all patients who received at least one dose of a study drug. This study is registered with ClinicalTrials.gov, NCT03732820, and is completed and no longer recruiting. Between Oct 31, 2018 and March 11, 2020, 1103 patients were screened, of whom 399 were randomly assigned to olaparib plus abiraterone and 397 to placebo plus abiraterone. Median follow-up for overall survival in patients with censored data was 36·6 months (IQR 34·1-40·3) for olaparib plus abiraterone and 36·5 months (33·8-40·3) for placebo plus abiraterone. Median overall survival was 42·1 months (95% CI 38·4-not reached) with olaparib plus abiraterone and 34·7 months (31·0-39·3) with placebo plus abiraterone (hazard ratio 0·81, 95% CI 0·67-1·00; p=0·054). The most common grade 3-4 adverse event was anaemia reported in 64 (16%) of 398 patients in the olaparib plus abiraterone and 13 (3%) of 396 patients in the placebo plus abiraterone group. Serious adverse events were reported in 161 (40%) in the olaparib plus abiraterone group and 126 (32%) in the placebo plus abiraterone group. One death in the placebo plus abiraterone group, from interstitial lung disease, was considered treatment related. Overall survival was not significantly different between treatment groups at this final prespecified analysis. Supported by AstraZeneca and Merck Sharp & Dohme.

KS02.6.A INDIGO: A GLOBAL, RANDOMIZED, DOUBLE-BLINDED, PHASE III STUDY OF VORASIDENIB VERSUS PLACEBO IN PATIENTS WITH RESIDUAL OR RECURRENT GRADE 2 GLIOMA WITH AN IDH1/2 MUTATION

Abstract BACKGROUND Grade 2 gliomas are slowly progressive, malignant brain tumours with a poor long-term prognosis. Current treatments (surgery followed by observation or adjuvant radiation and chemotherapy) are not curative and can be associated with short- and long-term toxicities. Mutations in isocitrate dehydrogenase (IDH) 1 or 2 occur in approximately 80% and 4% of grade 2 gliomas, respectively, and are a disease-defining characteristic in the World Health Organization (WHO) 2021 definition. Vorasidenib (VOR) - an oral, brain-penetrant, dual inhibitor of mutant (m)IDH1/2 enzymes - has shown a tolerable safety profile and preliminary clinical activity in Phase I studies. MATERIAL AND METHODS In this randomized, double-blind, placebo (PBO)-controlled Phase III study (NCT04164901), patients (pts) were randomized 1:1 to receive VOR 40 mg daily or PBO daily in 28-day cycles. Patients were stratified by 1p19q status and baseline tumour size. Key eligibility criteria included: age ≥12; Karnofsky performance scale (KPS) &amp;gt;80; residual or recurrent grade 2 IDH1m or IDH2m oligodendroglioma or astrocytoma; measurable non-enhancing disease; no prior treatment for glioma with most recent surgery 1-5 years from randomization; and not in immediate need of chemotherapy/radiation. Primary endpoint: radiographic progression-free survival (PFS) by blinded independent radiology committee (BIRC). Key secondary endpoint: time to next intervention (TTNI). RESULTS As of 6 Sep 2022 (2nd planned interim analysis data cutoff), 331 pts were randomized across 10 countries: 168 to VOR and 163 to PBO. Of the 331 pts: median age: 40.4 years (range, 16-71); KPS =100: 53.5%; histological subtype: oligodendroglioma (172) and astrocytoma (159); median time from last surgery until randomization: 2.4 years. Two hundred twenty-six (68.3%) pts remained on treatment (VOR: 131; PBO: 95). PFS by BIRC was statistically significant in favour of the VOR arm (HR 0.39, 95% CI 0.27-0.56; P=0.000000067). Median PFS: VOR: 27.7 months (mo); PBO: 11.1 mo. TTNI was statistically significant in favour of the VOR arm (HR 0.26, 95% CI 0.15-0.43; P=0.000000019). Median TTNI: PBO: 17.8 mo; VOR: not reached. All reported P values are one sided. All-grade adverse events (AEs) occurring in &amp;gt;20% pts receiving VOR vs PBO were alanine aminotransferase (ALT) increased (38.9 vs 14.7%); COVID-19 (32.9 vs 28.8%); fatigue (32.3 vs 31.9%); aspartate aminotransferase increase (28.7 vs 8.0%); headache (26.9 vs 27.0%); diarrhoea (24.6 vs 16.6%); nausea (21.6 vs 22.7%). Common grade ≥3 AEs (&amp;gt;5%): ALT increased (9.6% vs 0%). CONCLUSION This is the first prospective, randomized Phase III study of a targeted therapy in grade 2 mIDH glioma. VOR significantly improved PFS by BIRC, compared with PBO, with a manageable safety profile. These data demonstrate the clinical benefit of VOR in this pt population for whom chemotherapy and radiotherapy are being delayed.

NRG-GU012: randomized phase II stereotactic ablative radiation therapy (SABR) for metastatic unresected renal cell carcinoma (RCC) receiving immunotherapy (SAMURAI)

Abstract Background Background: It is estimated that a significant number of patients presenting with metastatic RCC are either ineligible, not recommended for, or refuse surgery. There remains no well-established method for addressing the primary tumor in such patients. Stereotactic ablative radiotherapy (SABR) is a highly effective modality for the treatment of the primary tumor in RCC. Our study seeks to evaluate SABR as an alternative approach to treat the primary tumor in patients with metastatic RCC receiving immunotherapy, who are not recommended for surgery, or who decline surgery. The primary objective of the study is to determine whether the addition of SABR to the primary tumor in combination with immunotherapy improves outcomes compared to immunotherapy alone in patients with metastatic, unresected, renal cell carcinoma (RCC). The primary endpoint is nephrectomy and radiographic progression-free survival (nrPFS) with progression determined as per iRECIST criteria. Patients are eligible if they are not recommended for upfront surgery, have a primary tumor treatable with SABR, and are candidates for immunotherapy. Immunotherapy is physician’s choice and will include either two different immunotherapy regimens (IO-IO) or immunotherapy in combination with a VEGF inhibitor (IO-VEGF). Methods 240 patients will be randomized in a 2:1 ratio favoring SABR plus immunotherapy (n=160) as compared to standard of care immunotherapy alone (n=80). The sample size will provide 90% power at a one-sided alpha level of 0.05 to detect a hazard ratio for nrPFS of 0.61, i.e., a 40% reduction in the rate of events. One-year PFS in the nivolumab plus ipilmumab arm was 50% (n=550, intermediate/poor risk population). Checkmate 9ER (Choueiri 2021) showed a one-year PFS rate in patients receiving nivolumab plus Cabozantinib (n=323) of 45-58% (intermediate/poor risk population). We have therefore estimated a one-year nrPFS rate of 50% in the control (immunotherapy alone) arm for SAMURAI. We expect nephrectomies to contribute only a small fraction to the total nrPRS events. To detect a hazard ratio of 0.62, which corresponds under exponential distribution assumptions to an absolute 15% improvement in one-year nrPFS from 50% in the control group to 65% in the experimental arm (SABR plus immunotherapy), a total sample size of 240 patients will be enrolled. This design will provide 90% power, based on a one-sided logrank test at the 0.05 alpha level, with three years of accrual and two further years of follow-up. The expected number of nrPFS events is E=175. The calculations allow for a 10% non-eligible/early dropout rate. The trial is currently open and accruing through the NRG oncology cooperative group (NCT05327686).