Outcomes of patients with metastatic clear-cell renal cell carcinoma treated with second-line VEGFR-TKI after first-line immune checkpoint inhibitors

BACKGROUND

Immune checkpoint inhibitors (ICIs) are being increasingly utilised in the front-line (1L) setting of metastatic clear-cell renal cell carcinoma (mccRCC). Limited data exist on responses and survival on second-line (2L) vascular endothelial growth factor-receptor tyrosine kinase inhibitor (VEGFR-TKI) therapy after 1L ICI therapy.

PATIENTS AND METHODS

This is a retrospective study of mccRCC patients treated with 2L VEGFR-TKI after progressive disease (PD) with 1L ICI. Patients were treated at MD Anderson Cancer Center or Memorial Sloan Kettering Cancer Center between December 2015 and February 2018. Objective response was assessed by blinded radiologists' review using Response Evaluation Criteria in Solid Tumours v1.1. Descriptive statistics and Kaplan-Meier method were used.

RESULTS

Seventy patients were included in the analysis. Median age at mccRCC diagnosis was 59 years; 8 patients (11%) had international metastatic database consortium favourable-risk disease, 48 (69%) had intermediate-risk disease and 14 (20%) had poor-risk disease. As 1L therapy, 12 patients (17%) received anti-programmed death ligand-1 (PD-(L)1) monotherapy with nivolumab or atezolizumab, 33 (47%) received nivolumab plus ipilimumab and 25 (36%) received combination anti-PD-(L)1 plus bevacizumab. 2L TKI therapies included pazopanib, sunitinib, axitinib and cabozantinib. On 2L TKI therapy, one patient (1.5%) achieved a complete response, 27 patients (39.7%) a partial response and 36 patients (52.9%) stable disease. Median progression-free survival (mPFS) was 13.2 months (95% confidence interval: 10.1, NA). Forty-five percent of subjects required a dose reduction, and twenty-seven percent of patients discontinued treatment because of toxicity.

CONCLUSIONS

In this retrospective study of patients with mccRCC receiving 2L TKI monotherapy after 1L ICI, we observed 2L antitumour activity and tolerance comparable to historical data for 1L TKI.

Integrating cytokines and angiogenic factors and tumour bulk with selected clinical criteria improves determination of prognosis in advanced renal cell carcinoma

Background:

In two clinical trials of the vascular endothelial growth factor (VEGF) receptor inhibitor pazopanib in advanced renal cell carcinoma (mRCC), we found interleukin-6 as predictive of pazopanib benefit. We evaluated the prognostic significance of candidate cytokines and angiogenic factors (CAFs) identified in that work relative to accepted clinical parameters.

Methods:

Seven preselected plasma CAFs (interleukin-6, interleukin-8, osteopontin, VEGF, hepatocyte growth factor, tissue inhibitor of metalloproteinases (TIMP-1), and E-selectin) were measured using multiplex ELISA in plasma collected pretreatment from 343 mRCC patients participating in the phase 3 registration trial of pazopanib vs placebo (NCT00334282). Tumour burden (per sum of longest diameters (SLD)) and 10 other clinical factors were also analysed for association with overall survival (OS; based on initial treatment assignment).

Results:

Osteopontin, interleukin-6, and TIMP-1 were independently associated with OS in multivariable analysis. A model combining the three CAFs and five clinical variables (including SLD) had higher prognostic accuracy than the International Metastatic Renal Cell Carcinoma Database Consortium criteria (concordance-index 0.75 vs 0.67, respectively), and distinguished two groups of patients within the original intermediate risk category.

Conclusions:

A prognostic model incorporating osteopontin, interleukin-6, TIMP-1, tumour burden, and selected clinical criteria increased prognostic accuracy for OS determination in mRCC patients.

A randomized phase 2 study of MK-2206 versus everolimus in refractory renal cell carcinoma

Background

Activation of the phosphoinisitide-3 kinase (PI3K) pathway through mutation and constitutive upregulation has been described in renal cell carcinoma (RCC), making it an attractive target for therapeutic intervention. We performed a randomized phase II study in vascular endothelial growth factor (VEGF) therapy refractory patients to determine whether MK-2206, an allosteric inhibitor of AKT, was more efficacious than the mammalian target of rapamycin inhibitor everolimus.

Patients and methods

A total of 43 patients were randomized in a 2:1 distribution, with 29 patients assigned to the MK-2206 arm and 14 to the everolimus arm. Progression-free survival (PFS) was the primary endpoint.

Results

The trial was closed at the first futility analysis with an observed PFS of 3.68 months in the MK-2206 arm and 5.98 months in the everolimus arm. Dichotomous response rate profiles were seen in the MK-2206 arm with one complete response and three partial responses in the MK-2206 arm versus none in the everolimus arm. On the other hand, progressive disease was best response in 44.8% of MK2206 versus 14.3% of everolimus-treated patients. MK-2206 induced significantly more rash and pruritis than everolimus, and dose reduction occurred in 37.9% of MK-2206 versus 21.4% of everolimus-treated patients. Genomic analysis revealed that 57.1% of the patients in the PD group had either deleterious TP53 mutations or ATM mutations or deletions. In contrast, none of the patients in the non-PD group had TP53 or ATM defects. No predictive marker for response was observed in this small dataset.

Conclusions

Dichotomous outcomes are observed when VEGF therapy refractory patients are treated with MK-2206, and MK-2206 does not demonstrate superiority to everolimus. Additionally, mutations in DNA repair genes are associated with early disease progression, indicating that dysregulation of DNA repair is associated with a more aggressive tumor phenotype in RCC.

Integrating chemohormonal therapy and surgery in known or suspected lymph node metastatic prostate cancer

BACKGROUND

Prostate cancer persisting in the primary site after systemic therapy may contribute to emergence of resistance and progression. We previously demonstrated molecular characteristics of lethal cancer in the prostatectomy specimens of patients presenting with lymph node metastasis after chemohormonal treatment. Here we report the post-treatment outcomes of these patients and assess whether a link exists between surgery and treatment-free/cancer-free survival.

METHODS

Patients with either clinically detected lymph node metastasis or primaries at high risk for nodal dissemination were treated with androgen ablation and docetaxel. Those responding with PSA concentration <1 ng ml(-1) were recommended surgery 1 year from enrollment. ADT was withheld postoperatively. The rate of survival without biochemical progression 1 year after surgery was measured to screen for efficacy.

RESULTS

Forty patients were enrolled and 39 were evaluable. Three patients (7.7%) declined surgery. Of the remaining 36, 4 patients experienced disease progression during treatment and 4 more did not reach PSA <1. Twenty-six patients (67%) completed surgery, and 13 (33%) were also progression-free 1 year postoperatively (8 with undetectable PSA). With a median follow-up of 61 months, time to treatment failure was 27 months in the patients undergoing surgery. The most frequent patterns of first disease recurrence were biochemical (10 patients) and systemic (5).

CONCLUSIONS

Half of the patients undergoing surgery were off treatment and progression-free 1 year following completion of all therapy. These results suggest that integration of surgery is feasible and may be superior to systemic therapy alone for selected prostate cancer patients presenting with nodal metastasis.

Circulating cytokines and monocyte subpopulations as biomarkers of outcome and biological activity in sunitinib-treated patients with advanced neuroendocrine tumours

BACKGROUND

Sunitinib is approved worldwide for treatment of advanced pancreatic neuroendocrine tumours (pNET), but no validated markers exist to predict response. This analysis explored biomarkers associated with sunitinib activity and clinical benefit in patients with pNET and carcinoid tumours in a phase II study.

METHODS

Plasma was assessed for vascular endothelial growth factor (VEGF)-A, soluble VEGF receptor (sVEGFR)-2, sVEGFR-3, interleukin (IL)-8 (n=105), and stromal cell-derived factor (SDF)-1α (n=28). Pre-treatment levels were compared between tumour types and correlated with response, progression-free (PFS), and overall survival (OS). Changes in circulating myelomonocytic and endothelial cells were also analysed.

RESULTS

Stromal cell-derived factor-1α and sVEGFR-2 levels were higher in pNET than in carcinoid (P=0.003 and 0.041, respectively). High (above-median) baseline SDF-1α was associated with worse PFS, OS, and response in pNET, and high sVEGFR-2 with longer OS (P⩽0.05). For carcinoid, high IL-8, sVEGFR-3, and SDF-1α were associated with shorter PFS and OS, and high IL-8 and SDF-1α with worse response (P⩽0.05). Among circulating cell types, monocytes showed the largest on-treatment decrease, particularly CD14+ monocytes co-expressing VEGFR-1 or CXCR4.

CONCLUSIONS

Interleukin-8, sVEGFR-3, and SDF-1α were identified as predictors of sunitinib clinical outcome. Putative pro-tumorigenic CXCR4+ and VEGFR-1+ monocytes represent novel candidate markers and biologically relevant targets explaining the activity of sunitinib.

Sunitinib in combination with docetaxel and prednisone in chemotherapy-naive patients with metastatic, castration-resistant prostate cancer: a phase 1/2 clinical trial

BACKGROUND

This phase 1/2 study assessed sunitinib combined with docetaxel (Taxotere) and prednisone in chemotherapy-naive metastatic, castration-resistant prostate cancer (mCRPC) patients.

PATIENTS AND METHODS

To determine the recommended phase 2 dose (RP2D), 25 patients in four dose escalation cohorts received 3-week cycles of sunitinib (2 weeks on, 1 week off), docetaxel and prednisone, preceded by a 4-week sunitinib 50 mg/day lead in. RP2D was evaluated in 55 additional patients. The primary end point was prostate-specific antigen (PSA) response rate.

RESULTS

One phase 1 dose-limiting toxicity occurred (grade 3 hyponatremia). The RP2D was sunitinib 37.5 mg/day, docetaxel 75 mg/m(2) and prednisone 5 mg b.i.d. During phase 2, confirmed PSA responses occurred in 31 patients [56.4% (95% confidence interval 42.3-69.7)]. Median time to PSA progression was 9.8 months. Forty-one patients (75%) were treated >3 months, 12 (22%) completed the study (16 cycles) and 43 (78%) discontinued (36% for disease progression and 27% adverse events). The most frequent treatment-related grade 3/4 adverse events were neutropenia (53%; 15% febrile) and fatigue/asthenia (16%). Among 33 assessable patients, 14 (42.4%) had confirmed partial response. Median progression-free and overall survivals were 12.6 and 21.7 months, respectively.

CONCLUSION

This combination was moderately well tolerated, with promising response rate and survival benefit, justifying further investigation in mCRPC.

A cytokine and angiogenic factor (CAF) analysis in plasma for selection of sorafenib therapy in patients with metastatic renal cell carcinoma

BACKGROUND

We investigated cytokines and angiogenic factors (CAFs) in patients with metastatic renal cell carcinoma (mRCC) treated in a randomized phase II clinical trial of sorafenib versus sorafenib+ interferon-α (IFN-α) that yielded no differences in progression-free survival (PFS). We aimed to link the CAF profile to PFS and select candidate predictive and prognostic markers for further study.

METHODS

The concentrations of 52 plasma CAFs were measured pretreatment (n = 69), day 28, and day 56 using multiplex bead arrays and enzyme-linked immunosorbent assay. We investigated the association between baseline levels of CAFs with PFS and posttreatment changes.

RESULTS

Unsupervised CAF clustering analysis revealed two distinct mRCC patient groups with elevated proangiogenic or proinflammatory mediators. A six-marker baseline CAF signature [osteopontin, vascular endothelial growth factor (VEGF), carbonic anhydrase 9, collagen IV, VEGF receptor-2, and tumor necrosis factor-related apoptosis-inducing ligand] correlated with PFS benefit (hazard ratio 0.20 versus 2.25, signature negative versus positive, respectively; P = 0.0002). While changes in angiogenic factors were frequently attenuated by the sorafenib+ IFN combination, most key immunomodulatory mediators increased.

CONCLUSIONS

Using CAF profiling, we identified two mRCC patient groups, a candidate plasma signature for predicting PFS benefit, and distinct marker changes occurring with each treatment. This platform may provide valuable insights into renal cell carcinoma biology and the molecular consequences of targeted therapies.

Increased mobilisation of circulating endothelial progenitors in von Hippel-Lindau disease and renal cell carcinoma

Background:

Circulating endothelial cells (CECs) are a candidate biomarker for monitoring angiogenesis in cancer. Circulating endothelial cell subsets are mobilised by angiogenic mediators. Because of the highly angiogenic phenotype of renal cell carcinoma (RCC), we sought to assess the potential of CECs as a marker of RCC in patients with von Hippel-Lindau (VHL) disease and those with sporadic RCC.

Methods:

We performed multicolour flow cytometry to enumerate CECs in patients with RCC, patients with VHL disease with and without RCC, and normal subjects. Two subsets of CECs were evaluated: mature CECs (mCECs) and circulating endothelial progenitors (CEPs).

Results:

In patients with VHL disease and RCC and those with sporadic RCC (N=10), CEPs and the CEP:mCEC ratio were higher than in normal subjects (N=17) (median CEPs: 0.97 vs 0.19 cells μl⁻¹, respectively, P<0.01; median CEP:mCEC: 0.92 vs 0.58, respectively, P=0.04). However, in patients with VHL without RCC, CECs were not increased. In paired pre- and post-nephrectomy RCC patient samples (N=20), CEPs decreased after surgery (median difference 0.02 cells μl⁻¹, −0.06 to 1.2; P=0.05).

Conclusion:

Circulating endothelial progenitors were elevated in RCC, but not in patients with VHL without RCC. Circulating endothelial progenitor enumeration merits further investigation as a monitoring strategy for patients with VHL.

Neoadjuvant trial of sunitinib malate and androgen ablation (ADT) in patients with localized prostate cancer (PCa) at high risk for recurrence

143

Background: Presurgical ADT does not improve long-term outcomes in patients (pts) with high-risk localized PCa. Since the VEGF and PDGF signaling pathways have been implicated in PCa progression, and ADT results in endothelial cell apoptosis in the prostate by a VEGF-mediated mechanism, we hypothesized that combined treatment with sunitinib malate (SU), an oral inhibitor of the tyrosine kinases of VEGFR and PDGFR, might improve the efficacy of ADT in this pt population.

Methods: Pts with no radiological evidence of metastases and either PCa ≥ clinical (c)T3 disease or Gleason grade 8-10 or serum prostate-specific antigen (PSA) ≥ 20 ng/mL or cT2b-c and Gleason 7 and PSA ≥10 ng/mL (AJCC, 1992), received i.m. leuprolide and oral SU for three 30-day cycles followed by surgery. SU was administered continuously at 37.5 mg daily (25 mg daily in the initial 6 pts). The primary endpoint of this phase II trial was rate of pathologic complete response (pCR). Secondary endpoints included safety and time to progression (TTP). Unresectable pelvic nodal disease, confirmed post-operative PSA ≥ 0.2 ng/mL, or administration of post-operative radiation or ADT, defined treatment failure.

Results: Forty-four pts completed accrual, with a median age of 58 years (range 47-72); 34 Caucasian, 5 African-American, 4 Hispanic, and 1 Indian. High-risk criteria included cT3 (24/44), Gleason 8-10 (30/44), PSA ≥ 20 ng/mL (16/44). Two men were ineligible/declined therapy and one postponed surgery. No grade 4 toxicities or related discontinuations were observed. Thirty-five pts completed 3 months on 37.5 mg daily SU plus ADT and surgery with no unexpected complications. Of these, 2 pts experienced a pCR. Twenty (57%) pts have failed treatment or died, with a median TTP 27 months (95% CI: 12 – not estimable). The median follow-up of the remaining event-free pts is 35 months (range 23-41).

Conclusions: The 3-months preoperative combination of SU and ADT is safe and well tolerated in pts with high-risk primary PCa. We observed 2 complete remissions in 35 patients. Ongoing characterization of molecular changes in the epithelial and stromal compartments will help understand the mechanisms of SU activity in PCa.

[Table: see text]

Cytokine and angiogenic factor (CAF) profiling for identification of markers associated with response to cediranib in metastatic renal cell carcinoma (mRCC)

362

Background: Cediranib is a highly potent and selective signaling inhibitor of vascular endothelial growth factor (VEGF) receptors−1, −2, −3 and c-Kit. In a phase II trial, patients (pts) with mRCC were randomized 3:1 to treatment with cediranib or placebo to primarily assess the difference in change in tumor size at 12 weeks. Cediranib resulted in a significant reduction in tumor size vs. placebo (Mulders et al. ESMO. 2009). Here we investigated soluble biomarkers in serum and concentration changes during treatment.

Methods: Pts received cediranib 45 mg/day PO or placebo for the first 12 weeks on treatment. At that time (or upon progression if earlier), treatment was unblinded and pts on placebo were given the option of receiving cediranib. Serum was collected from 61 pts at baseline (BL; cediranib 46, placebo 15), from 50 pts on day (D) 28, and from 45 pts on D84. Multiplex bead suspension arrays and ELISA were used to measure CAF concentrations including VEGF, placental growth factor (PlGF), sVEGFR-2, PDGFbb, HGF, MMP-9, multiple chemokines and interleukins (IL). The objectives of this exploratory analysis were to assess whether baseline CAFs were associated with changes in tumor size after 12 weeks of treatment and whether CAF levels changed while on treatment.

Results: Of 39 CAFs available at BL, lower than median (‘low') concentrations of IL-10, VEGF, PlGF, stem cell factor (SCF), and monokine-induced by interferon-gamma (MIG) were associated with larger decreases in tumor size than high concentrations (independent of treatment arm), whereas the opposite trend was observed for IL-5 and TRAIL. Consistent with inhibition of VEGF signaling, cediranib treatment resulted in changes over time in VEGF (increase), sVEGFR-2 (decrease) and PlGF (increase) concentrations. In addition, SCF, a c-Kit ligand and M-CSF decreased, while VCAM-1 and TRAIL increased during cediranib treatment.

Conclusions: Candidate CAFs associated with response to cediranib in mRCC such as IL-10 and VEGF were identified. Patients treated with cediranib showed distinct CAF changes compared with placebo. These results require independent validation in a larger trial.

[Table: see text]

Plasma cytokine and angiogenic factors (CAFs) predictive of clinical benefit and prognosis in patients (Pts) with advanced or metastatic renal cell cancer (mRCC) treated in phase III trials of pazopanib (PAZO)

334

Background: PAZO is a multikinase inhibitor approved for the treatment of mRCC. From phase II study of PAZO in mRCC (VEG102616), plasma CAF analysis from 3 different platforms (cross platform correlation r >0.70) revealed several candidate CAFs including HGF, IL-6, IL-8, TIMP-1, VEGF, E-Selectin and OPN were found to be significantly correlated with clinical benefit (Tran ASCO 2010, #4522). To validate these findings, plasma were analyzed for CAFs from mRCC pts enrolled in phase III randomized, placebo controlled trial with PAZO where progression-free survival (PFS) of 9.2 months of PAZO and 4.2 months of placebo (hazard ratio:0.46 p<.0001) and overall response rate 30% was observed (Sternberg, JCO, 2010).

Methods: Plasma samples (n=344) from phase III randomized, placebo-controlled trial (VEG105192) were analyzed for candidate CAFs by a CLIA-certified laboratory (Aushon Biosystems, MA). These markers of PAZO and placebo arms were correlated with PFS by Cox regression and plotted in Kaplan Meier by using median concentration of each marker as a cutoff.

Results: Higher levels of IL-8 (p<0.006), HGF (p<0.01), OPN (p<0.001) and TIMP-1 (p<0.006) were associated with shorter PFS in PAZO treated pts. Higher levels of all these markers except HGF were also associated with shorter PFS in the placebo arm (IL-8 (p<0.002), OPN (p<0.001), IL-6 (<0.001), TIMP-1 borderline at p= 0.052) and were therefore prognostic. Only IL-6 was predictive of PFS benefit; pts with high IL-6 had a greater relative benefit from PAZO compared to placebo with a HR of 0.32 in the high IL-6 group and 0.57 in the low IL-6 group (p value for interaction 0.009).

Conclusions: This study validated HGF, IL-8, OPN, and TIMP-1 as markers associated with clinical benefit with PAZO treatment. IL-8 and OPN were confirmed as prognostic markers in the placebo arm and IL-6 was both a prognostic marker and predictive marker for pazopanib therapy.

[Table: see text]

A cytokine and angiogenic factor (CAF) plasma signature for selection of sorafenib (SR) therapy in patients (pts) with metastatic renal cell carcinoma (mRCC)

5114

Background: SR, an oral inhibitor of Raf kinase, RET-receptor (R), VEGFR-1, 2, and 3, PDGFR-β, FLT-3, and c-KIT tyrosine kinases, has been shown to prolong progression-free survival (PFS) in mRCC after cytokine failure. In a phase II trial, mRCC pts were randomized to first line treatment with SR vs. SR plus interferon (IFN) to assess whether combination therapy improved PFS. Both treatment arms showed similar outcomes (Tannir et al, ASCO. 2008). Here we investigated predictive and prognostic biomarkers in plasma. Methods: Pts received SR 400 mg PO BID or same dose SR plus IFN 0.5 MU SC BID. Plasma was collected from 69 pts at baseline (BL; SR 34, SR+IFN 35), 59 on day (D) 28, and 57 pts on D56. We used multiplex bead suspension arrays to measure concentrations of 54 CAFs, including VEGF, PDGFbb, EGF, HGF, MMP-9, and multiple chemokines and interleukins (IL). Osteopontin (OPN), soluble carbonic anhydrase 9 (sCA9), placental growth factor (PlGF), collagen type IV (ColIV) and sVEGFR-2 were measured by ELISA. The primary objective of this analysis was to establish a CAF signature based on a set of individual markers at BL with a significant and differential impact on the association between treatment arm and PFS. Results: Among 52 CAFs available at BL, higher than median EGF concentrations associated with poor outcome independently of treatment arm, whereas low IL-2 had the opposite effect (p = 0.003 for both). Only OPN showed a significant treatment by factor interaction at BL (p < 0.01), suggesting that OPN has a differential effect on PFS in the two arms. Pts with high OPN benefitted more from single agent SR (7.74 vs. 3.93 mos for the combination; p = 0.007), but no differences were found for those with low OPN. Lower than median on-treatment increases in sCA9 (D28, p = 0.01) and GRO-alpha (D56, p = 0.04) on SR only were also associated with a better outcome. A 6-marker CAF signature at BL containing OPN, sCA9, VEGF, sVEGFR-2, ColIV, and TRAIL demonstrated predictive value on PFS. Conclusions: A CAF signature showed potential value in predicting differential benefit from single agent SR vs. SR+IFN in mRCC. Broad-based screening of circulating CAFs may identify predictive and prognostic biomarkers in the context of clinical trials.

[Table: see text]

Sunitinib in combination with docetaxel and prednisone in patients (pts) with metastatic hormone-refractory prostate cancer (mHRPC)

5166

Background: Overexpression of VEGF and PDGF has been implicated in prostate cancer progression and bone metastases. Sunitinib is an oral, multitargeted inhibitor of VEGFRs, PDGFRs, and other tyrosine kinases which may improve the efficacy of chemotherapy in pts with mHRPC. We performed a multicenter phase I/II study of sunitinib in combination with docetaxel and prednisone as first-line therapy in pts with mHRPC. The combination dose was established in phase I (Zurita et al, ECCO. 2007). Final results from phase II will be reported. Methods: Pts received treatment in a 21-day cycle: sunitinib 37.5 mg/d on days 1–14, docetaxel 75 mg/m2 on day 1, and prednisone 5 mg BID on days 1–21. Dose reductions were permitted for treatment-related toxicity. The primary endpoint was PSA response rate (PSA Working Group Criteria). Secondary endpoints included tumor response rate (RECIST), safety and patient-reported outcomes. Results: Fifty-five pts were enrolled and 13 remained on study at the time of the data cutoff (1 Oct 08). Thirty-six discontinued from the study due to disease progression (16), adverse events (AEs; 13), consent withdrawal (6) and other (1). Six pts completed the study (16 cycles) and continued treatment on another protocol. Pts received a median of 23 weeks of therapy (range, 2–84). The most common treatment-related grade 3–4 AEs were neutropenia (75%), febrile neutropenia (15%), fatigue (15%), stomatitis (7%), and anorexia (7%). Sunitinib dose reduction to 25 mg/d was required in 14 pts (26%), and 3 pts (6%) had a further dose reduction to 12.5 mg/d. Docetaxel dose reduction to 60 mg/m2 was required in 18 pts (33%). PSA responses occurred in 31 pts (56%), with a preliminary median time to PSA progression of 42.1 weeks. Out of 33 pts with measurable disease, thirteen (39%) had a confirmed partial response (PR) and another 7 (21%) had an initial PR. The median progression-free and overall survivals have not been reached, but the probability of survival at 48 weeks is 92.4% (95% CI: 77.5, 97.6). Patient-reported assessments of pain and quality of life will be reported. Conclusions: Sunitinib in combination with docetaxel and prednisone is tolerated and has antitumor activity in pts with mHRPC, as indicated by both PSA and RECIST-defined tumor responses.

[Table: see text]

Distinct patterns of PSA modulation by single-agent sunitinib before combination with docetaxel and prednisone in patients with metastatic castrate-resistant prostate cancer (CRPCa)

5134

Background: We are conducting a phase I study of the oral, multitargeted tyrosine kinase inhibitor sunitinib malate in patients with CRPCa as a single agent lead-in, followed by combination with docetaxel and prednisone, to determine the optimal dose, safety, efficacy and pharmacokinetic profile of the combination. The lead-in with sunitinib alone was included to evaluate whether PSA is modulated differently than with imatinib (Mathew et al. JCO 2004;22:3323–9), and if this is predictive of response and toxicity to the combination. In addition to blocking PDGF signaling (imatinib), sunitinib also blocks VEGF. Preliminary safety and efficacy were previously reported (ASCO Prostate Symposium 2007). Here we present PSA modulation results. Methods: All patients receive a lead-in of daily sunitinib 50 mg for 4 weeks (wks) on, 2 wks off, prior to starting combination therapy. To date, 3 successive cohorts have received 60 mg/m2 docetaxel every 3 wks combined with prednisone 5 mg bid and escalating sunitinib doses (12.5, 37.5 or 50 mg/d) on a 2/1 schedule (2 wks on, 1 wk off). An ongoing cohort is receiving 75 mg/m2 docetaxel + 37.5 mg/d sunitinib. Dose-limiting toxicities (DLTs) are evaluated over the first 3-wk cycle. Results: PSA results are available for 21 patients (pts) enrolled across the 4 cohorts (median age 68 yrs, PSA 42 ng/mL, Gleason score 8). Preliminary data showed 3 patterns of sunitinib-induced PSA modulation during the lead-in: PSA reduction (6 pts; mean decrease 37.8%; >50% in 2 pts), initial increase followed by drop during the off-sunitinib period (10 pts; mean decrease 32.5%), and PSA increase (5 pts; mean increase 61%). Conclusions: Single-agent sunitinib induces PSA decline in a subset of patients with CRPCa in contrast to that observed with agents targeting PDGF or VEGF alone. The predictive value of the “lead-in PSA kinetics” in determining later response to the sunitinib plus docetaxel and prednisone combination will require completion of the study. These data support the hypothesis that blocking VEGFR may alter the phenotype of CRPCa and be synergistic with blocking PDGFR.

[Table: see text]

Lung resistance-related protein as a predictor of clinical outcome in advanced testicular germ-cell tumours

This study was undertaken to investigate the expression and predictive value for outcome of multidrug resistance-associated (MDR) proteins P-glycoprotein (Pgp), MRP1, BCRP, and LRP, in advanced testicular germ-cell tumours (TGCT). Paraffin-embedded sections from 56 previously untreated patients with metastatic TGCT were immunostained for Pgp, MRP1, BCRP, and LRP. All patients received platinum-based chemotherapy after orchidectomy. Immunostaining was related to clinicopathological parameters, response to chemotherapy, and outcome. Strong and intermediate expressions of the different MDR-related proteins were: 27 and 41% (Pgp), 54 and 37% (MRP1), 86 and 7% (BCRP), and 14 and 29% (LRP). P-glycoprotein and MRP1 associated, respectively, to low AFP (P=0.026) and high LDH levels (P=0.014), whereas LRP expression associated with high beta-hCG levels (P=0.003) and stage IV tumours (P=0.029). No correlation was found between Pgp, MRP1, and BCRP expression and response to chemotherapy and survival. In contrast, patients with LRP-positive tumours (strong or intermediate expression) had shorter progression-free (P=0.0006) and overall survival (P=0.0116) than LRP-negative patients, even after individual log-rank adjustments by statistically associated variables. Our data suggest that a positive LRP immunostaining at the time of diagnosis in metastatic TGCT is associated with an adverse clinical outcome.