Erdafitinib versus pembrolizumab in pretreated patients with advanced or metastatic urothelial cancer with select FGFR alterations: cohort 2 of the randomized phase III THOR trial

BACKGROUND

Erdafitinib is an oral pan-fibroblast growth factor receptor (FGFR) tyrosine kinase inhibitor approved to treat locally advanced/metastatic urothelial carcinoma (mUC) in patients with susceptible FGFR3/2 alterations (FGFRalt) who progressed after platinum-containing chemotherapy. FGFR-altered tumours are enriched in luminal 1 subtype and may have limited clinical benefit from anti-programmed death-(ligand) 1 [PD-(L)1] treatment. This cohort in the randomized, open-label phase III THOR study assessed erdafitinib versus pembrolizumab in anti-PD-(L)1-naive patients with mUC.

PATIENTS AND METHODS

Patients ≥18 years with unresectable advanced/mUC, with select FGFRalt, disease progression on one prior treatment, and who were anti-PD-(L)1-naive were randomized 1 : 1 to receive erdafitinib 8 mg once daily with pharmacodynamically guided uptitration to 9 mg or pembrolizumab 200 mg every 3 weeks. The primary endpoint was overall survival (OS). Secondary endpoints included progression-free survival (PFS), objective response rate (ORR), and safety.

RESULTS

The intent-to-treat population (median follow-up 33 months) comprised 175 and 176 patients in the erdafitinib and pembrolizumab arms, respectively. There was no statistically significant difference in OS between erdafitinib and pembrolizumab [median 10.9 versus 11.1 months, respectively; hazard ratio (HR) 1.18; 95% confidence interval (CI) 0.92-1.51; P = 0.18]. Median PFS for erdafitinib and pembrolizumab was 4.4 and 2.7 months, respectively (HR 0.88; 95% CI 0.70-1.10). ORR was 40.0% and 21.6% (relative risk 1.85; 95% CI 1.32-2.59) and median duration of response was 4.3 and 14.4 months for erdafitinib and pembrolizumab, respectively. 64.7% and 50.9% of patients in the erdafitinib and pembrolizumab arms had ≥1 grade 3-4 adverse events (AEs); 5 (2.9%) and 12 (6.9%) patients, respectively, had AEs that led to death.

CONCLUSIONS

Erdafitinib and pembrolizumab had similar median OS in this anti-PD-(L)1-naive, FGFR-altered mUC population. Outcomes with pembrolizumab were better than assumed and aligned with previous reports in non- FGFR-altered populations. Safety results were consistent with the known profiles for erdafitinib and pembrolizumab in this patient population.

Associations between KIR/KIR-ligand genotypes and clinical outcome for patients with advanced solid tumors receiving BEMPEG plus nivolumab combination therapy in the PIVOT-02 trial

Bempegaldesleukin (BEMPEG), a CD122-preferential IL2 pathway agonist, has been shown to induce proliferation and activation of NK cells. NK activation is dependent on the balance of inhibitory and excitatory signals transmitted by NK receptors, including Fc-gamma receptors (FCγRs) and killer immunoglobulin-like receptors (KIRs) along with their KIR-ligands. The repertoire of KIRs/KIR-ligands an individual inherits and the single-nucleotide polymorphisms (SNPs) of FCγRs can influence NK function and affect responses to immunotherapies. In this retrospective analysis of the single-arm PIVOT-02 trial, 200 patients with advanced solid tumors were genotyped for KIR/KIR-ligand gene status and FCγR SNP status and evaluated for associations with clinical outcome. Patients with inhibitory KIR2DL2 and its ligand (HLA-C1) observed significantly greater tumor shrinkage (TS, median change -13.0 vs. 0%) and increased PFS (5.5 vs. 3.3 months) and a trend toward improved OR (31.2 vs. 19.5%) compared to patients with the complementary genotype. Furthermore, patients with KIR2DL2 and its ligand together with inhibitory KIR3DL1 and its ligand (HLA-Bw4) had improved OR (36.5 vs. 19.6%), greater TS (median change -16.1 vs. 0%), and a trend toward prolonged PFS (8.4 vs. 3.6 months) as compared to patients with the complementary genotype. FCγR polymorphisms did not influence OR/PFS/TS.These data show that clinical response to BEMPEG plus nivolumab treatment in the PIVOT-02 trial may be associated with the repertoire of KIR/KIR-ligands an individual inherits. Further investigation and validation of these results may enable KIR/KIR-ligand genotyping to be utilized prospectively for identifying patients likely to benefit from certain cancer immunotherapy regimens.

Gemcitabine, paclitaxel, and doxorubicin for patients (pts) with urothelial carcinoma (UC) and renal insufficiency: Preliminary results of a multicenter phase II study

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Background: The role of cisplatin-based chemotherapy for the treatment of locally advanced or metastatic UC is well established. Pts with impaired renal function cannot receive cisplatin, however, and substitution with carboplatin yielded inferior results. We initiated a phase II study to assess the efficacy of gemcitabine, paclitaxel, and doxorubicin (GTA) treatment for UC in pts with renal insufficiency.

Methods: Eligible pts had metastatic or unresectable UC of bladder, urethra, or upper tract, no prior chemotherapy, glomerular filtration rate < 60 ml/min, ECOG performance status ≤ 2, left ventricular ejection fraction > 40%, and adequate hematopoietic and hepatic function. Pts were excluded if they had brain metastasis, peripheral neuropathy ≥ grade 2, significant heart disease within 6 months of enrollment, or required hemodialysis. Outpatient treatment consisted of 900 mg/m2 gemcitabine, 135 mg/m2 paclitaxel, and 40 mg/m2 doxorubicin on day 1 every 2 weeks. Pegfilgrastim 6 mg sc was given immediately after GTA on day 1, or on day 2 if requested by the pt. Tumor evaluation was repeated every 3 cycles (6 weeks); treatment duration was limited to 9 cycles. A Simon 2-stage design was chosen to detect a target overall response rate of 40% and to reject a response rate of 25% or less.

Results: Twenty-five pts enrolled and 21 could be assessed for response. Median (range) age was 72.8 years (53.4, 89.3) and 8 pts (32.0%) were female. RECIST responses occurred in 12 pts (4 complete; 8 partial), for an overall response rate of 57.1% (95% CI 34.0-78.2). Notable grade 3 and 4 toxicities were anemia (9 pts), thrombocytopenia (3 pts), neutropenia (2 pts), dyspnea (1 pt), mucositis (1 pt), and sepsis (1 pt). No adverse events were attributed to same-day pegfilgrastim and there were no treatment-related deaths. Eleven pts (44.0%) died of progressive disease; the median (range) follow-up time for 14 surviving pts was 5.5 months (2.3, 17.5).

Conclusions: GTA has been well-tolerated in the setting of renal insufficiency, with an observed response rate in advanced UC exceeding the targeted response. The study will continue to a maximum of 72 pts.

[Table: see text]

A phase II randomized four-regimen selection trial incorporating response for sequential chemotherapy in metastatic, unresectable urothelial cancer: Final results from the M. D. Anderson Cancer Center

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Background: We developed a clinical trial incorporating response into the treatment algorithm. Patients meeting a certain threshold of response continued with the same treatment; those with insufficient response were switched to alternative chemotherapy. We now report on final results from this trial. Methods: Patients were randomly assigned to one of four regimens: ifosfamide, doxorubicin, gemcitabine; ifosfamide, paclitaxel, cisplatin; gemcitabine, cisplatin; or cisplatin, gemcitabine, and ifosfamide. To continue with chemotherapy, patients must have had at least a 40% response after the first 6-week interval, and a >90% response after the second 6 weeks. Otherwise, they were re-randomized to alternate chemotherapy. Overall success (OSX) was defined as patients with a >90% response with either front-line or second-line therapy. Surgical consolidation was offered to patients at the discretion of their treating physician. Results: Median overall survival (OS) for 120 patients was 19.1 mo. (3 and 5-yr survival: 33% and 20%). OSX was achieved in 41 patients (median OS: 51 mo.); the median OS in the other 79 patients was 15 mo. (p = 0.0001), with a 5-yr survival of 42% and 10% respectively. Surgical consolidation was performed in 35 patients: 23 with nodal metastases to pelvic and/or RPLN, 6 with cT4b tumors, and an additional 6 patients with distant metastases. Their median OS from surgery was 23.7 months, (5-yr survival: 31%). Surgical consolidation in the setting of OSX was associated with a 42% 5-yr survival as compared to 11% in those undergoing surgery in the absence of OSX. Visceral metastases and poor performance status were associated with a worse prognosis. Conclusions: With sequential therapy, 34% of patients had a >90% response (OSX). A potential benefit in long-term survival was seen in patients who had surgical consolidation in the setting of OSX. This trial design provides a novel method for assessing the benefits of sequential chemotherapy, and enhancing the population of patients who may be offered surgical consolidation in the setting of initially unresectable, or metastatic urothelial cancer.

No significant financial relationships to disclose.

Final results from a phase II trial of systemic chemotherapy in a small cell urothelial cancer: Evidence supporting neoadjuvant chemotherapy from the M.D. Anderson Cancer Center

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Background: Previously reported retrospective data supported a potential role for neoadjuvant chemotherapy in small cell urothelial cancer (SCUC). We now report final results from a phase II clinical trial in SCUC. Methods: Since 2001, 30 patients with biopsy proven SCUC received alternating doublet chemotherapy with Ifosfamide + Doxorubicin, and Etoposide + Cisplatin. Patients with surgically resectable disease (<=cT4aN0M0) received a total of 4 cycles followed by cystectomy, while those with unresectable disease (>=cT4b, N+, or M+) received 2 cycles beyond maximal response. Results: Neoadjuvant chemotherapy was given in 18 patients (cT2:14, cT3:4), while 12 patients were treated for metastatic SCUC. For those receiving neoadjuvant therapy, the median OS is 58 months, with a 5-year survival of 48%; 8 remain alive and NED beyond 2.5 years. There have been only 5 deaths for the neoadjuvant group (3 SCUC, 1 post-op infection, 1 AML). For those with metastatic disease, the median OS is 14 months. Two were rendered resectable with chemotherapy (cT4b:1,N+:1); 1 died of recurrent SCUC, while the other is currently undergoing therapy for TCC of the ureter. Brain metastases developed in 7 patients (cT3b:2, initial M+:5). Chemotherapy has been well-tolerated with only 2 G4 toxicities (catheter infection and neutropenia). The most frequent G3 toxicities include transfusion (10), neutropenic fever (7), infection (5), and vomiting (3). There was only one post-surgical death; a case of sepsis in a patient with diverticulitis and abscess requiring sigmoid colon resection. Conclusions: These prospective results, which are consistent with our previously reported retrospective review, provide additional support for 4 cycles of neoadjuvant chemotherapy in the setting of SCUC. Unfortunately, once metastases are present, the prognosis remains poor with few long-term survivors. These results may also predict a patient subset for which prophylactic cranial irradiation may be potentially beneficial.

No significant financial relationships to disclose.

AG-013736, a novel VEGF receptor and PDGF receptor inhibitor with potent activity against human bladder carcinoma in vitro and in vivo

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The receptors for vascular endothelial growth factor and platelet-derived growth factor (VEGFR-2 and PDGFR) play essential and complementary roles in angiogenesis, and combined inhibition of these receptors may therefore result in potent antitumor activity in vivo. Here we characterized the effects of a small molecule tyrosine kinase inhibitor AG-013736 (Pfizer) in HUVEC and human bladder cancer cells. Previously, AG-013736 was reported to inhibit VEGFRs with picomolar potency and PDGFRs with nanomolar activity. All of the cell lines examined displayed cell surface VEGFR-2 and PDGFR α and β expression as measured by flow cytometry. Low nanomolar concentrations of AG-013736 blocked the HUVEC cell proliferation with inhibition of VEGF receptor 2 and PDGF receptor phosphorylation. AG-013736 caused regression of established subcutaneous human bladder cancer xenografts, effects that were associated with inhibition of VEGFR-2 and PDGFR β phosphorylation but not EGFR phosphorylation and reduction in tumor microvessel densities (MVDs). Our results demonstrate that AG-013736 has substantial anti-angiogenesis activity in preclinical models of human bladder cancer, which warrants further exploration either alone or with the combination of other pre-clinical drugs in bladder cancer treatment.

No significant financial relationships to disclose.