Diagnostic utility and therapeutic impact of PET/CT [18F]F-Fluoromethylcholine -Choline in the biochemical recurrence of prostate cancer

OBJECTIVE

To assess the diagnostic capability of PET/CT with [¹⁸F]F-Fluoromethylcholine in prostate cancer (PC) with biochemical recurrence and its therapeutic impact.

MATERIAL AND METHODS

We included 108 patients, diagnosed with PC with biochemical criteria for recurrence. A PET/CT Choline scan was performed by dynamic pelvic and whole body study at 60min post-tracer injection. The relationship between the positive studies and the PSA value was analysed by classifying patients into three groups (<1.2/1.2-2/>2ng/ml), and the diagnostic capacity was assessed with respect to pelvic MRI and the impact on the therapeutic decision.

RESULTS

The location of recurrence was identified in 85 of 108 patients (78.7%): 34 local, 47 pelvic lymph nodes and 58 distant lesions, including retroperitoneal, mediastinal lymph nodes and distant organ lesions (bone and lung). Second tumors were diagnosed in 4 patients. No significant differences were found in the percentage of positive studies depending on primary treatment. Patients with PSA>2ng/ml showed a higher percentage of disease detection than patients with a lower PSA level, with significant differences (p<0.0001). PET/CT [¹⁸F]F-Choline was able to detect local disease, not previously known from MRI, in 29.41% of patients. PET/CT Choline had an impact on therapeutic management in 67 of 108 patients (62%).

CONCLUSIONS

PET/CT with [¹⁸F]F-Fluoromethylcholine is a useful tool in the detection of locoregional and disseminated disease of PC treated with suspicion of recurrence, providing a change in therapeutic management in 62% of patients.

Evolving development of PD-1 therapy: Cetrelimab (JNJ-63723283) from monotherapy to combination with erdafitinib

3055

Background: Cetrelimab (CET) is an investigational checkpoint inhibitor (CI). In part 1 of a first-in-human (FIH) trial (LUC1001; NCT02908906), pts with advanced solid tumors with ≥1 prior treatment received CET 80–800 mg Q2W or 480 mg Q4W. Response rates and safety profiles were similar to other CIs. Based on preclinical and clinical data, a phase 1/2 study (NORSE; NCT03473743) of CET + erdafitinib (ERD) in metastatic urothelial carcinoma (mUC) + FGFR alterations (alt) was initiated and is ongoing. Methods: In LUC1001 Part 2, pts with nonsmall cell lung cancer (NSCLC), melanoma (MEL), or MSI-H/dMMR colorectal cancer (CRC) received CET IV 240 q2w. Overall response rates (ORR = % complete response + partial response [PR] confirmed) were assessed as per RECIST v1.1. Adverse events (AEs) were assessed for all patients receiving CET IV 240 q2w in parts 1 and 2. Results: As of July 1, 2019, 122 pts with NSCLC (n=30); MEL (n=50); or CRC (n= 42) had been treated in Part 2. Median age ranged from 58 to 64 yrs (overall range, 23–86 yrs). Duration of treatment was 8.1 mos (range, 0.0-24.7) for NSCLC; 5.5 mos (range, 0.0-25.0) for MEL; and for 3.0 mos (0.0-16.1) for CRC. ORR was 37% in NSCLC; 53% in PD-L1+ NSCLC (≥50% by IHC), 28% in MEL; 32% in non-uveal MEL, 14% in CRC and 24% in centrally confirmed MSI-high CRC. In all CET IV 240 q2w treated pts in the FIH study (N= 162), treatment-related grade ≥3 and serious AEs were reported in 15% and 12% of pts, respectively. All grade and grade ≥3 immune-related (ir) AEs were reported in 41% and 8% of pts, respectively Most common ir AE: hypothyroidism (8%), asthenia (6%), diarrhea (4%), rash (4%), hyperthyroidism (4%), dyspnea (3%), pruritis (3%) and pneumonitis (3%). There was 1 treatment-related death due to myasthenia gravis. In the phase 1 combination study (NORSE), pts with mUC + FGFR alt (n=17) received fixed-dose CET IV 240 q2w + ERD 6mg, 8 mg or 8mg + up titration (UpT) to 9 mg to establish the RP2D for the combination as CET + ERD 8mg + UpT. In the RP2D group (n=10), 60% had treatment-related grade ≥3 AEs. ORR (all confirmed PR) was 50% in the all treated response-evaluable group (n=16). Conclusions: CET is a CI with efficacy and safety profiles in advanced solid tumors similar to approved CIs. In NORSE phase 1, CET+ ERD demonstrated antitumor activity in mUC with an acceptable safety profile. NORSE phase 2 is evaluating this combination as first-line therapy in pts with mUC with FGFR alt. References: Rutkowski, et al J Clin Oncol.2019; 37 (8 suppl): 31-31. Moreno, et al. ASCO-GU Genitourinary Cancers Symposium. February 13-15, 2020. San Francisco, CA. Clinical trial information: NCT02908906 and NCT03473743 .

ERDAFITINIB in locally advanced or metastatic urothelial carcinoma (mUC): Long-term outcomes in BLC2001

5015

Background: Erdafitinib (JNJ-42756493; ERDA) is the only pan-FGFR kinase inhibitor with US FDA approval for treatment of adults with mUC with susceptible FGFR3/2 alterations (alt) and who progressed on ≥ 1 line of prior platinum-based chemotherapy (chemo). Approval was based on data from the primary analysis of the pivotal BLC2001 trial1. Here we report long-term efficacy and safety data from the 8 mg/d continuous dose regimen in BLC2001. Methods: BLC2001 (NCT02365597) is a global, open-label, phase 2 trial of pts with measurable mUC with prespecified FGFR alt, ECOG 0-2, and progression during/following ≥ 1 line of prior chemo or ≤ 12 mos of (neo)adjuvant chemo, or were cisplatin ineligible, chemo naïve. The optimal schedule of ERDA determined in the initial part of the study was 8 mg/d continuous ERDA in 28-d cycles with uptitration to 9 mg/d (ERD 8 mg UpT) if a protocol-defined target serum phosphate level was not reached and if no significant treatment-related adverse events (TRAEs) occurred. Primary end point was the confirmed objective response rate (ORR=% complete response + % partial response). Key secondary end points were progression-free survival (PFS), duration of response (DOR) and overall survival (OS). Results: Median follow-up for 101 patients treated with ERDA 8 mg UpT was ~24 months. Confirmed ORR was 40%. Median DOR was 5.98 mos; 31% of responders had DOR ≥ 1 yr. Median PFS was 5.52 mos, median OS was 11.3 mos. 12-mos and 24-mos survival rates were 49% and 31%, respectively. Median treatment duration was 5.4 mos. The ERDA safety profile was consistent with the primary analysis. No new TRAEs were seen with longer follow-up. Central serous retinopathy (CSR) events occurred in 27% (27/101) of patients; 85% (23/27) were Grade 1 or 2; dosage was reduced in 13 pts, interrupted for 8, and discontinued for 3. On the data cut-off date, 63% (17/27) had resolved; 60% (6/10) of ongoing CSR events were Grade 1. There were no treatment-related deaths. Conclusions: With a median follow-up of 2 yrs, ERDA in mUC + FGFR alt showed a manageable safety profile and consistent efficacy, with median OS of 11.3 mos. 31% had a DOR ≥12 mos and 31% were alive at 24 mos. ERDA monotherapy vs. immune checkpoint inhibitor (PD-1) or chemo is being further analyzed in a randomized control study (THOR; NCT03390504).Reference: Loriot Y, et al. N Engl J Med. 2019;381:338-48. Clinical trial information: NCT02365597 .

Use of plasma androgen receptor (AR) testing to optimize docetaxel chemotherapy in castration-resistant prostate cancer (CRPC): A multicenter biomarker study

5546

Background: Plasma AR status has been identified as a potential biomarker of response in CRPC patients receiving docetaxel or the AR-targeted therapies abiraterone or enzalutamide. However, the relevance of plasma AR in the overall management of CRPC patients (pts) receiving docetaxel at different dose due to the toxicity profiles and physician-patient preferences is unknown. Methods: This was a multi-institution study of associations between baseline plasma AR-copy-number status assessed by droplet digital PCR and outcome in 325 CRPC pts. Between September 2011 and July 2019 pts started treatment with docetaxel administered at standard regimen 75mg/m2 every three weeks or adapted regimen (75-80% of standard recommended dose or 30mg/m2 weekly administration) at the discretion of the treating physician. Patients were assigned randomly into 2 sets with a ratio 2:1 to either training (n=217) and internal validation (n=108) cohorts. Results: In our study, adapted regimen of docetaxel was administered in 68 (31.3%) and 35 (32.4%) of training and validation cohorts, respectively. Based on plasma AR status, 67 (30.9%) and 39 (36.1%) validation and training set pts were classified as AR gain, respectively. In men treated with standard docetaxel regimen, no difference in progression-free/overall survival (PFS/OS) was seen between plasma AR normal and gain in both cohorts. In patients treated with adapted docetaxel regimen, we observed a significantly shorter median PFS (3.9 vs. 6.4 months, HR 4.77, 95%CI 1.48-3.80, p=0.0003) and median OS (11.2 vs . 20.4 months, HR 2.87, 95%CI 1.73-2.13, p=0.0008) in the training cohort. This finding was confirmed in the validation cohort (median PFS: 4.8 vs. 7.4 months, HR 2.54, 95%CI 1.40-4.58, p=0.005, and median OS: 11.8 vs. 26.4 months, HR 5.00, 95%CI 2.59-9.65, p<0.0001). In addition, AR-gained patients were less likely than AR normal to have a PSA decline when receiving an adapted regimen in both cohorts (p=0.010 e p=0.003, respectively). Conclusions: This study suggests that plasma AR may improve clinical decision making in choosing not only between AR-directed therapies and taxanes, but also between adapted and standard regimen of docetaxel in first- and subsequent-therapy lines, providing promising clinical implications to select the proper timing and dose of docetaxel. Prospective trials to validate these findings are warranted.

Single nucleotide polymorphisms (SNPs) as predictors of efficacy of cabazitaxel in patients with metastatic castration-resistant prostate cancer (mCRPC)

e17582

Background: Cabazitaxel is a semi-synthetic derivative of a natural taxoid approved for the treatment of mCRPC patients (pts) after failure to docetaxel. Despite its proven efficacy, there is variability in the response, progression-free survival (PFS) and overall survival (OS) of pts. Changes in the genetic constitution of the individual such as the SNPs could explain this variability. The aim of this study was to evaluate the impact of certain SNPs in cabazitaxel activity. Methods: Clinical data from 67 mCRPC pts treated with cabazitaxel between March 2011 and October 2016 were collected. DNA was isolated from formalin fixed paraffin-embedded tumor samples. 56 SNPs in 5 genes related with metabolism and/or mechanism of action of cabazitaxel (CYP3A4, CYP3A5, ABCB1, TUBB1, CYP2C8) were chosen based on their Minor Allele Frequency, linkage disequilibrium and information from dbSNP and analyzed by TaqMan OpenArray (Lifetech). The presence/absence of mutant alleles of the selected SNPs was correlated with clinical features, progression free survival (PFS) and overall survival (OS) of prostate cancer. Chi-square test and Kaplan-Meier with log-rank test were used for statistical analyses. Results: The median age was 61 years (range 44-82). 56.7% (n = 38) had a Gleason score ≥8 and 94% had received docetaxel in first line. Type of response to cabazitaxel was associated with median OS (Partial response = 24.35 months, Stable disease = 11.16 months, Progression disease = 5.8 months; p= 0.045). Univariate analysis, showed worsed OS at 1 year for wild type status of SNP rs151352 (OR = 4, 95%CI 1.27-12.58, p= 0.029). In addition, two SNPs (rs11773597, rs1202186) were associated with radiological response to cabazitaxel ( p= 0.031 and p= 0.030 respectively). Other 7 SNPs (rs11773597, rs2235040, rs1045642, rs1419745, rs1202170, rs6949448, rs11572093) were associated ( p<0.05) with Gleason score, pain, PSA doubling time, febrile neutropenia and asthenia. Conclusions: A particular SNP profile could be predictive of efficacy and related with toxicity in mCRPC population treated with cabazitaxel after progression to docetaxel. These outcomes become particularly relevant in patient selection given the recent results of the CARD trial.

A randomized phase II study of nivolumab plus ipilimumab versus standard of care in previously untreated and advanced non-clear cell renal cell carcinoma (SUNIFORECAST)

TPS5103

Background: Non-clear cell renal cell carcinomas (nccRCC) are a heterogeneous group of tumors accounting for approximately 25% of RCC patients (pts.). Since most clinical trials focus on clear-cell RCC (ccRCC) only, data on treatment strategies for nccRCC are limited. The combination of Nivolumab and Ipilimumab (IO/IO) has recently been approved for treatment in RCC showing a significant improvement in overall response rate (ORR), progression free (PFS), and overall survival (OS) in intermediate and high-risk pts. compared to sunitinib in a phase-III trial. Furthermore retrospective analysis in nccRCC patients have shown promising results for IO/IO as well in these entities. Methods: In this prospective randomized phase-II multicenter European trial adults with advanced or metastatic nccRCC without prior systemic therapy are eligible. Other key inclusion criteria include: available tumor tissue, Karnofsky > 70% and measurable disease per RECIST 1.1. All histological diagnoses are reviewed by a central pathologist. The study plans to randomize ~306 pts. stratified for papillary or non-papillary non-clear cell histology and by the International Metastatic RCC Database Consortium (IMDC) risk score. Pts. will be randomized 1:1 to either i) Nivolumab 3mg/kg intravenously (IV) plus Ipilimumab 1mg/kg IV every 3 weeks for 4 doses followed by Nivolumab fixed dose 240mg IV every 2 weeks or ii) standard of care therapy according to the approved schedule. Treatment will be discontinued in case of unacceptable toxicity or withdrawal of informed consent. Pts may continue treatment beyond progression, if clinical benefit is achieved and treatment is well tolerated. Primary endpoint is the OS rate at 12 months. Secondary endpoints include OS rate at 6 and 18 months, median OS, PFS, ORR and quality of life. The trial is in progress and 122 patients (78 pts with papillary, 37 pts with non-papillary histology) have been enrolled until now. Clinical trial information: NCT03075423 .

Atezolizumab (atezo) therapy for locally advanced/metastatic urinary tract carcinoma (mUTC) in patients (pts) with poor performance status (PS): Analysis of the prospective global SAUL study

5035

Background: Pts with PS > 1 have a poor prognosis and are often excluded from clinical trials. The single-arm SAUL study (NCT02928406) evaluated atezo in a ‘real-world’ population. Overall, safety and efficacy were consistent with prior trials. However, ECOG PS 2 pts had worse overall survival (OS) but fewer adverse events (AEs) than ECOG PS 0/1 pts [Sternberg, 2019], likely reflecting shorter treatment duration and warranting exploration. Methods: Pts with mUTC received atezo 1200 mg q3w until loss of clinical benefit or unacceptable toxicity. The primary endpoint was safety. Post hoc analyses compared baseline factors, AEs and efficacy in pts with ECOG PS 2 vs 0/1. In this analysis, AE incidences were restricted to the first 45 days of atezo to adjust for differing treatment exposure. Results: None of the baseline factors explored was significantly associated with worse OS or disease control rate (DCR) in ECOG PS 2 pts. However, pts with visceral metastases and ECOG PS 2 had particularly poor outcomes. Safety appeared similar between subgroups. Conclusions: ECOG PS 2 pts have a dismal prognosis. The higher proportion with poor prognostic factors despite similar age in ECOG PS 2 vs 0/1 pts may suggest that poor PS was related to disease rather than comorbidities. Risk/benefit should be considered especially carefully when treating pts with ECOG PS 2 due to high-burden/visceral disease. Clinical trial information: NCT02928406 . [Table: see text]

Does escalation results from phase Ib/II Norse study of erdafitinib (ERDA) + PD-1 inhibitor JNJ-63723283 (Cetrelimab [CET]) in patients (pts) with metastatic or locally advanced urothelial carcinoma (mUC) and selected fibroblast growth factor receptor (FGFR) gene alterations

511

Background: ERDA, an oral pan-FGFR inhibitor, is approved by the US FDA for pts with metastatic urothelial carcinoma (mUC) with susceptible FGFR3/2 gene alterations and progressed after ≥1 line of prior platinum-containing chemotherapy (PCC).1 CET, an IgG4, binds to anti-programmed cell death proteins (PD-1) and has shown activity in solid tumors.2 ERDA+CET may demonstrate complementary mechanisms as neoantigen release by ERDA may prime the tumor microenvironment for response. NORSE is a phase 1b/2 study to evaluate ERDA+CET in pts with mUC. Methods: Adult mUC pts with specific FGFR alterations who have progressed after ≥1 prior systemic therapy and no prior FGFR or PD-1/PD(L)-1 inhibitors enrolled in 3 dose levels (DL) of ERDA (DL1: 6 mg, DL2A: 8 mg, DL2: 8 mg with uptitration [UPT] to 9 mg) + CET (IV, 240 mg). Cohorts enrolled until dose limiting toxicity (DLT) or RP2D was identified. Primary endpoints: DLT and adverse events (AEs). Results: Of 15 pts (DL1: 4, DL2A: 3, DL2: 8), 11 continued on treatment at the time of the data cut. 14/15 pts experienced AEs; 3 experienced serious unrelated AEs (urinary tract infection, urosepsis, and large intestinal obstruction) all in DL1, 2 led to death; 10 experienced Grade >3 AEs and 2 experienced AEs of special interest, considered related to ERDA (Table). No DLTs were observed in any cohorts, 8 mg with UPT + CET was established as the RP2D. At data cut-off, investigator-assessed best overall response rate (CR+PR+uCR+uPR) in pts treated with the RP2D was 71% and disease control rate was 100% for RECIST 1.1 evaluable pts (n=7). Conclusions: 8 mg ERDA with UPT+240 mg CET was well tolerated and established as the RP2D. The combination of ERDA+CET is being further explored in the ongoing randomized phase 2 study in first-line cisplatin-ineligible mUC pts (NCT03473743). Clinical trial information: 2017-001980-19. [Table: see text]

Association of neuroendocrine (NE) mRNA expression profiling in hormone-sensitive tumors samples with adverse clinical outcome in castration-resistant prostate cancer (CRPC) patients

165

Background: NE dedifferentiation is associated to clinical aggressiveness and resistance to androgen receptor inhibition in prostate cancer. We investigated impact of a NE expression signature in the clinical outcome of mCRPC patients treated with taxanes. Methods: This is a multicenter retrospective study. A customized panel of 45 NE-related gene signature was tested in total RNA from formalin-fixed paraffin-embedded hormone-sensitive tumor samples, by the nCounter platform (Nanostring Technologies). Patients were grouped according to their molecular profile by unsupervised clustering. Expression levels were correlated with taxanes response and clinical outcome. Independent association with survival was evaluated by multivariate Cox modeling. Results: Eighty seven patients were included in the study, 79 were treated with docetaxel and 8 with cabazitaxel. Median age was 64.8 (44-88.3) years and median follow-up was 20.7 (1.17-74.4) months. High expression of the NE signature was associated with a shorter time of CRPC development (N=60, median 12.8 vs 21.6, HR 2.4, 95%CI 1.3-4.3, P=0.003) and shorter OS from CRPC diagnosis (median 24.1 vs 41.33, HR 2.3, 95%CI 1.4-3.8, P=0.001). Moreover, according to the outcome to taxanes, high NE signature correlated with lower PSA-PFS (median 6.6 vs 10.1 mo P=0.047, HR 1.6, 95%CI 1-2.7, P=0.05) and OS (median 19 vs 22 mo, HR 1.8, 95%CI 1.1-2.8, P=0.014), and it was independently associated to a lower OS (HR 1.9, 95%CI 1.1-3.2, P=0.016). Conclusions: NE-related gene expression in hormone-sensitive tumor samples is associated with adverse clinical outcome and lower taxane benefit in metastatic CRPC patients. Thus, molecular characterization of primary tumors may be useful to guide treatment strategies in metastatic prostate cancer.

Randomized phase II study of docetaxel (D) + abiraterone acetate (AA) versus D after disease progression to first-line AA in metastatic castration-resistant prostate cancer (mCRPC): ABIDO-SOGUG Trial

95

Background: Abiraterone acetate (AA) improves OS and rPFS in first line mCRPC patients (pts). After AA progression D is commonly used as standard second line therapy. However, the value of maintaining AA in combination with D despite progression has not been tested beyond small exploratory studies (Tagawa ST, Eur Urol 2016) ABIDO is a randomized-phase II trial that evaluates efficacy and safety of D + AA vs D after first-line AA progression in mCRPC. Methods: Asymptomatic or minimally symptomatic mCRPC pts with no visceral metastases, ECOG PS 0-1, and adequate organ functions were included. The study has two stages: In stage I pts receive AA (1000 mg/d + prednisone (P) 10 mg qd) until radiological or unequivocal clinical progression. In stage II pts were randomized to D 75 mg/m2 q3wk in combination with AA 1000 mg/d (arm A) or without AA (arm B) The primary endpoint was rPFS and the secondary endpoints radiological response (RR), OS, PSA-response, PSA-PFS and safety. Results: 88 pts were randomized, (46 arm A, 42 Arm B). Median age was 69 y/o, 43% had ECOG 0 and 91%/11%/5% had bone, liver and lung metastases. Median rPFS was 11.4 months (m) in arm A vs 10.5 m in ARM B; 12-m rPFS was 43% vs 45%; Median PSA PFS was 6.2 vs 5.5 m and median OS was 17.3 vs 16.9 m. Twenty four pts (52%) in arm A and 19 (46%) in arm B achieve ≥50% PSA response. RR was achieved in 15% vs 7% of pts and disease control rate in 74% in both arms. No statistically significant differences were found in efficacy parameters. Half of pts received 10 cycles of D (median 7 and 8). D median dose intensity was 86% and 90% for each arm and 91% for AA. Eleven pts discontinued treatment due to non-hematological toxicity, 5 in arm A and 6 in arm B. Most frequent G3-4 toxicities per arm (A/B) were: neutropenia (57%/29%; P=0.027), febrile neutropenia (17%/10%), diarrhea (9%/7%), and asthenia (11%/10%). Conclusions: ABIDO trial was unable to demonstrate the significant clinical benefit of maintenance AA approach + D after AA first-line therapy. No differences were observed in RR, PSA PFS, rPFS and OS. In AA + D cohort, more frequent and severe hematological toxicity (neutropenia and febrile neutropenia) were reported. Clinical trial information: NCT02036060.

Association of high plasma glutamine levels with outcome in metastatic castration-resistant prostate (mCRPC) patients treated with taxanes

164

Background: Cancer cells may metabolize glutamine to fulfill their metabolic needs. In prostate cancer it has been shown that androgen receptor signaling promotes glutamine metabolism by increasing the expression of the glutamine transporters, and that stromal glutamine may promote tumor growth. Methods: We retrospectively tested glutamine levels in frozen plasma samples from mCRPC patients treated with taxanes, which were included in a prospective biomarker study in our institution. Glutamine levels were determined by a bioluminescent assay. Optimal cut-offs for glutamine levels were assessed using maximally selected log-rank statistics to determine low and high level groups. Pre-treatment glutamine level was correlated with taxanes response and clinical outcome. Independent association with survival was evaluated by multivariate Cox modeling. Results: Seventy eight mCRPC patients treated with taxanes were included. Median age was 70.3 (55.8-83.5) years and median follow-up was 13.1 (0.2-53.9) months. Glutamine was tested in 88 plasma samples: 69 from pre-docetaxel and 19 pre-cabazitaxel treatment (10 patients had both samples). High glutamine levels significantly correlated with worst PSA-progression-free survival (PFS) (median 2.8 vs 4.7 months, hazard ratio [HR] 1.8, 95%CI 1.1-2.7, P= 0.012) and overall survival (OS) (median 12.4 vs 20.4, HR 2, 95%CI 1.2-3.3, P= 0.006). In a multivariate analysis, high plasma glutamine levels were independently associated with shorter PSA-PFS (HR 2.3, 95%CI 1.4-3.7, P< 0.001) and OS (HR 2.2, 95%CI 1.3-3.7, P= 0.003). Patients with high glutamine levels were more likely to present PSA progression to taxanes than those with low levels (odds ratio [OR] 3, 95%CI 1.2-7.7, P= 0.016). Moreover, samples from patients treated with abiraterone or enzalutamide before taxanes (51 samples from 43 patients) had significantly higher glutamine levels (T-test, P= 0.014) than those without these prior therapies. Conclusions: Glutamine can be detected in plasma of mCRPC patients and higher levels are associated with adverse clinical outcome, supporting the relevance of metabolism in prostate cancer progression.

Response to immunotherapy, platinum-based chemotherapy or their combination in metastatic urothelial carcinoma (MUC) with or without FGFR-3 alterations: Single cohort experience

560

Background: Fibroblast growth factor receptor-3 (FGFR-3) is a promising target therapy in metastatic urothelial carcinoma. Its role in patient’s clinical outcome and treatment response is unclear. We present data for overall survival (OS) and response to platinum-based treatment, immunotherapy and combination (platinum plus immunotherapy) in MUC. Methods: Enrolled patients were diagnosed with muscle-invasive urothelial cancer (MIUC) between 2/2009-6/2019 at Clinic Hospital of Barcelona, Spain. All have been screened for FGFR-3 alterations using next-generation sequencing or qualitative real-time polymerase chain reaction-based assays in tumour or blood. Demographic, pathology, treatments and treatment response were collected retrospectively. Results: 101 patients with MIUC were screened, 99% had progressed to metastatic stage. At diagnosis 32.67% were metastatic. 77% were man and median age was 68y (38-85y). Median follow-up (FU) since metastatic disease was 16.25 months (1.2-89.72m) with 69.31% of patients had died at cut-off. 32% presented FGFR-3 alteration (fusion =1 and mutation=31). FGFR-3 altered more frequently had papillary histology than FGFR-3 wild type tumours (69 vs 26%, p<0.05). No statistical differences were detected between both groups for gender, age, stage at diagnosis, median FU, primary tumour site (upper vs lower tract) or previous history of non-invasive urothelial carcinoma. 58% patients received 1st line platinum-based chemotherapy, 25% immunotherapy and 8% the combination of both (9% with other therapies). FGFR-3 altered tended to present more benefit (complete, partial response or stable disease) with platinum-based chemotherapy than FGFR-3 wild type (81% vs 62%) but without reach statistical significance. No differences were detected for immunotherapy or combination therapies. Moreover, OS was similar for FGFR-3 altered (median 14.6m) and FGFR-3 wild- type (median 17.1 m) (HR 0.76, p=0.3). Conclusions: In our series, no significant differences related to response to first line therapy or survival was observed.

Association between PD1 mRNA and response to anti-PD1 monotherapy across multiple cancer types

Background

We hypothesized that the abundance of PD1 mRNA in tumor samples might explain the differences in overall response rates (ORR) observed following anti-PD1 monotherapy across cancer types.

Patients and methods

RNASeqv2 data from 10 078 tumor samples representing 34 different cancer types was analyzed from TCGA. Eighteen immune-related gene signatures and 547 immune-related genes, including PD1, were explored. Correlations between each gene/signature and ORRs reported in the literature following anti-PD1 monotherapy were calculated. To translate the in silico findings to the clinical setting, we analyzed the expression of PD1 mRNA using the nCounter platform in 773 formalin-fixed paraffin embedded (FFPE) tumor samples across 17 cancer types. To test the direct relationship between PD1 mRNA, PDL1 immunohistochemistry (IHC), stromal tumor-infiltrating lymphocytes (sTILs) and ORR, we evaluated an independent FFPE-based dataset of 117 patients with advanced disease treated with anti-PD1 monotherapy.

Results

In pan-cancer TCGA, PD1 mRNA expression was found strongly correlated (r > 0.80) with CD8 T-cell genes and signatures and the proportion of PD1 mRNA-high tumors (80th percentile) within a given cancer type was variable (0%-84%). Strikingly, the PD1-high proportions across cancer types were found strongly correlated (r = 0.91) with the ORR following anti-PD1 monotherapy reported in the literature. Lower correlations were found with other immune-related genes/signatures, including PDL1. Using the same population-based cutoff (80th percentile), similar proportions of PD1-high disease in a given cancer type were identified in our in-house 773 tumor dataset as compared with TCGA. Finally, the pre-established PD1 mRNA FFPE-based cutoff was found significantly associated with anti-PD1 response in 117 patients with advanced disease (PD1-high 51.5%, PD1-intermediate 26.6% and PD1-low 15.0%; odds ratio between PD1-high and PD1-intermediate/low = 8.31; P < 0.001). In this same dataset, PDL1 tumor expression by IHC or percentage of sTILs was not found associated with response.

Conclusions

Our study provides a clinically applicable assay that links PD1 mRNA abundance, activated CD8 T-cells and anti-PD1 efficacy.

Interim analysis of the fierce-21 phase 2 (P2) study of vofatamab (B-701), a selective inhibitor of FGFR3, as salvage therapy in metastatic urothelial carcinoma (mUC)

4547

Background: Patients (pts) with mUC with FGFR3 mutations who have failed platinum-based chemotherapy have a poor prognosis. Their response to immune checkpoint inhibitors appears diminished 10% or less compared to WT pts. 20% of mUC pts harbor FGFR3 mutations or fusions (M/F). Vofatamab is a fully human monoclonal antibody against FGFR3 that blocks activation of the wildtype and genetically activated receptor. FIERCE-21 is a Phase 1b/2 study designed to evaluate vofatamab monotherapy (VFM) or in combination with docetaxel (VFD). Methods: The P2 expansion enrolled mUC pts with FGFR3 M/F+ tumor (identified with FoundationONE CDx™), who failed ≥ 1 prior line of chemotherapy (including prior taxane for pts receiving VFM) or recurred ≤ 12 months of (neo)adjuvant chemotherapy. Pts had measurable disease and ECOG ≤ 1. Treatment consisted of vofatamab at 25 mg/kg alone and in combination with docetaxel at 75 mg/m2 q3w. Efficacy was assessed by investigators (RECIST 1.1). Primary objectives were safety and objective response-rate (ORR). Results: In the P2, 21 pts each received VFM and VFD. 57% of VFD pts had received at least 2, and 71% of VFM at least 3 prior lines of therapy. Best response to prior therapy was PD for 67% of VFD and 38% of VFM. The safety profile is consistent with previously reported data. TEAEs occurring in > 20% of pts were decreased appetite, diarrhea, pyrexia, asthenia, anemia, dyspnea, and fatigue. Most common vofatamab-related TEAEs in > 10% of pts were asthenia, diarrhea, decreased appetite and rash; all were Grade 1 or 2. In VFM, only 1 pt had a grade 3 TEAE and no pt discontinued treatment due to an AE. There were no cases of hyperphosphatemia, ocular or nail toxicity; 1 pt reported grade 2 skin toxicity. For pts receiving VM, median age was 70 yrs, ECOG 1 = 67%, Hgb < 10 g/dL 5%, liver metastases 19%. Responses have been seen in 7 pts to date including those receiving both VFM and VFD. Conclusions: Vofatamab both alone and combined with D in a q3w schedule are well tolerated with a low frequency of grade 3 TEAEs. Both VFM and VFD have demonstrated efficacy in terms of ORR. PFS/OS and DOR data will be presented at 7+ months for VFD and 9+ months for VFM. Clinical trial information: NCT02401542.