Carboplatin plus weekly docetaxel as salvage chemotherapy in docetaxel-resistant and castration-resistant prostate cancer (DRPC)

172

Background: Cabacitaxel has recently been approved by the FDA as second-line chemotherapy for patients progressing during or after first-line docetaxel chemotherapy. However, cabacitaxel treatment is hampered by high costs and toxicity. Carboplatin in combination with docetaxel may also be effective in DRPC. Platinum(II)-complexes have been shown to lower testosterone levels by inhibiting 3β-hydroxysteroid dehydrogenase and 17α hydroxylase (Schertl et al. J Cancer Res Clin Oncol. 2007;133:153-67).

Methods: Docetaxel failure/resistance was defined according to the Prostate Cancer Working Group (PCWG2 2007) criteria. Since February 2005, 55 consecutive DRPC pts were treated with at least two cycles of carboplatin AUC5 iv for 30 min on day 1 every 4 weeks (q4w), docetaxel at a dose of 35 mg/m2 iv for one hour on days 1, 8, (15) plus prednisone 2×5mg/day orally after receiving informed consent until disease progression or occurrence of intolerable adverse effects. Efficacy measures were done following PCWG2 recommendations. Free testosterone levels were measured before and during carboplatin/docetaxel chemotherapy (n=25).

Results: Response of prostate-specific antigen (PSAR; ≥50% PSA) was observed in 28/55 (50.9%) patients. At the time of the current analysis the median follow-up time was 11.9 months and 32/55 patients had died. Median progression-free survival (PFS) for all patients was 7.5 months (CI 95% 5.7, 9.3) and median overall survival (OS) was 17.1 months (CI 95% 10.3, 23.9). In PSAR, PFS was 13.6 (CI 95% 7.8, 19.4) months versus 4.3 (CI 95% 2.9, 5.7) months in PSANR (p<0.001; hazard ratio HR 0.159) and OS was 24.4 months (CI 95% 18.1, 30.8) versus 8.1 (CI 95% 3.4, 12.8) months (p<0.001; HR 0.208). This regimen was reasonably well tolerated, with leukopenia/neutropenia as the most common reversible grade 3/4 toxicity (44.2/40.4%). Median free testosterone levels were 1.05 pg/ml before and 0.26 pg/ml during carboplatin/docetaxel treatment (p<0.01).

Conclusions: Our data suggest that carboplatin/docetaxel may be an important therapeutic second-line treatment option for DRPC patients by inferfering with the testosterone synthesis.

No significant financial relationships to disclose.

Preliminary safety results of an ongoing phase I/II clinical study of MGN1601, a tumor vaccine comprising allogeneic, gene-modified, and irradiated tumor cells in combination with an immunomodulator in patients with metastatic renal cell carcinoma (ASET study)

392

Background: MGN1601 is a cell-based RCC tumor vaccine MGN1601 consisting of two active pharmaceutical ingredients: genetically modified allogeneic (human) cells transfected with four different MIDGE vectors encoding IL-7, GM-CSF, CD80 and CD154 and a synthetic DNA-based immunomodulator dSLIM-30L1, a TLR-9 agonist. The vaccine is being developed for treatment of patients with advanced RCC. Its prophylactic and therapeutic anti-tumor activity has been shown in several in-vivo models. A good safety profile of MGN1601 was shown in a wide program of acute and chronic toxicity studies. Based on these promising data, this phase 1/2 study was started in patients with advanced RCC.

Methods: This multicentric open clinical study for the assessment of safety and efficacy of MGN1601 in patients with advanced RCC was initiated in October 2010. A total of 24 patients have to be recruited into the study. The treatment consists of 8 MGN1601 treatments administered as follows: the first 3 treatments are administered on a weekly basis, and the consecutive 5 treatments on a bi-weekly basis. The treatment dose contains 107 transfected tumor cells and 5 mg dSLIM per administration, which has been proven to be safe with a high safety margin in repeated toxicity studies. The efficacy and safety of the study treatment will be evaluated based on extensive immunological tests, radiological assessment, safety laboratory results and assessments of the quality of life. Here, the first safety data are presented.

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Association of therapy with sunitinib and treatment-related hyperparathyroidism in renal cell carcinoma

e16023

Background: Targeted therapies have been thought to combine high potency with high specifity. With increasing experience with multitargeted tyrosine kinase inhibitors (MTKI) recent findings suggest various interactions with physiological organ functions. Here, we report on abnormalities of the mineral metabolism in patients with renal cell carcinoma (RCC) treated with MTKI. Methods: We identified a total of 61 patients with metastatic RCC and evaluable markers of bone metabolism, which were either treated at our institution (N=53) or followed (N=8) during March 2005 and December 2008. Chemistry and parathyroid hormone (PTH) tests were assessed retrospectively. Patients received either sunitinib (4 weeks on/2 weeks off schedule) or sorafenib (continuous dosing) for metastatic disease. PTH, calcium and phosphate were either determined prior to, during and in some cases after completion of therapy with MTKI. Statistical analyses included either student's t-test or one-way ANOVA. Results: Of 61 evaluable patients, 47 received sunitinib, 6 sorafenib, and 8 patients follow-up only. Mean phosphate levels significantly decreased during treatment from 1.151 (CI 1.077–1.224) to 0.9264 (CI 0.844–1.008) (P<0.0001), whereas mean calcium levels remained unchanged (2.37; CI 2.30–2.44 and 2.36; CI 2.28–2.43 mmol/l, respectively). Treatment with MTKI resulted in increased mean levels of PTH (118.3; CI 91.37–145.2), when compared to baseline 43.52 (CI 30.94–56.10) (P<0.0001). In 4 patients additional values after end of therapy were evaluable, which showed reversible PTH increase (42.7; CI 7.473–77.93). Increase of PTH remained significant for treatment with either sorafenib or sunitinib (P0.05). Conclusions: Treatment with MTKI is associated with dysregulated parathyroid axis, which may have clinical implications in a number of patients and therefore should be monitored throughout the treatment. The mechanism for hormone disturbances remains elusive, but may involve the PDGFR, which plays a major role in transmitting signaling of the bone metabolism.

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The effect of zoledronic acid on bone metastasis in patients suffering from renal cell cancer (RCC): A German prospective single-arm clinical trial

5107

Background: The incidence of RCC increased over the last decades and about 30% of patients will develop bone metastasis. These pts. face considerable skeletal morbidity e.g. bone pain, pathologic fractures, spinal cord compression or tumor induced hypercalcemia (TIH). A prospective trial was initiated in RCC metastatic to bone evaluating the SRE (skeletal related event) rate under therapy with zoledronic acid (ZA). Primary objective was the proportion of pts. with at least one SRE after 12 months. Methods: Patients with RCC must have had ≥1 bone metastasis and ≤2 prior applications of a bisphosphonate. Bone lesions were diagnosed by bone scan and ≥1 lesion was confirmed using X-ray, CT or MRI. Pts. passed a 12 months treatment period receiving 4 mg ZA every 3 weeks. Pts. were followed every 3 weeks for 54 weeks for development of SREs (radiation or surgery to bone, spinal cord compression, pathologic bone fractures) and TIH. A bone scan was done, if AP or LDH were >2xULN or symptoms occurred. Suspected SRE was confirmed by X-ray, CT or MRI. After end of treatment patients entered a survival follow-up. Results: 51 pts. participated in the study. Median age was 63 years and 2/3 were male. Proportions of MSKCC risk groups good/intermediate/poor for pretreated pts. were 8%, 56%, and 18%, respectively. 78% of pts. suffered from ≤6 bone metastases. 18% had already experienced at least one SRE before study entry. 26% obtained prior medications, mainly interferons (20%), interleukins (16%) and chemotherapy (16%). 25 pts. completed the 12 months treatment period. Based on a preliminary analysis 13 pts. (26%) experienced at least one SRE with an absolute number of 23 events. No TIH was observed. Bone lesions response was observed in 3 pts. (2 CR, 1 PR) out of 33 pts. currently available. Final efficacy and safety results of the 12 months treatment phase will be shown at presentation. Conclusions: Pts. with mRCC and bone metastases are at high risk for experiencing an SRE with a reported incidence of up to 74%. This is the first study prospectively evaluating SRE rate in patients with mRCC and bone lesions receiving ZA. A preliminary analysis indicates an SRE-rate of 26% and no TIH was observed. Final results of this trial could further support the use of ZA in mRCC.

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Multicenter phase II study of cetuximab plus docetaxel in 84 patients with recurrent or metastatic, platinum-pretreated SCCHN

6048

Background: Cetuximab and docetaxel are both active in squamous cell carcinoma of the head and neck (SCCHN). We investigated the efficacy of cetuximab plus docetaxel as second-line treatment in platinum-pre-treated patients with recurrent and or metastatic SCCHN. Methods: 84 patients were enrolled and received cetuximab (initial dose of 400 mg/m2, followed by subsequent weekly doses of 250 mg/m2) and docetaxel (35 mg/m2 on days 1, 8, 15 of a 4-week cycle) for a maximum of 6 cycles. Patients with stable disease continued to receive cetuximab until disease progression or unacceptable toxicity. The primary endpoint was the objective response rate according to RECIST criteria. Secondary endpoints were response rate in relation to platinum sensitivity, progression-free survival, overall survival, and toxicity. Results: According to RECIST there were 10 PR (12%) and 23 SD (27%), resulting in a disease control rate of 39%. Response to protocol treatment was unrelated to previous platinum sensitivity. Median progression-free survival was 4 months (95% CI, 2.9 to 5.1) and median overall survival was 7 months (95% CI, 5.5 to 8.5). The duration on protocol treatment exceeded 12 months in 6 (8%) patients. Grade III/IV toxicities included gastric perforation (n = 1), pneumonia (n = 7), mucositis and skin toxicities. Conclusions: Cetuximab plus docetaxel was an active second-line treatment regimen with acceptable toxicity in patients with platinum-pretreated SCCHN. The responsiveness was independent of previous platinum sensitivity.

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A phase II open-label study of cetuximab in unresectable hepatocellular carcinoma: Final results

4598

Background: Hepatocellular carcinoma (HCC) express the epidermal growth factor receptor (EGFR), and EGFR-targeting therapies are known to block tumor growth. We tested the activity of cetuximab (CET) in HCC and evaluated serial tumor biopsies for biomarker analyses. Methods: Patients (pts) with advanced or metastatic HCC with ECOG = 2 and adequate organ function were eligible. Prior therapy was permitted. CET was given iv weekly (400 mg/m2 loading dose, 250 mg/m2 thereafter). The primary endpoint was the rate of progression-free survival (PFS) at 24 wks. Serial tumor biopsies were performed prior to treatment, after 4 wks and at time of progression. 32 pts were enrolled. 27 pts are evaluable for tumor response. Results: Stable disease (SD) was achieved in 44.4% (12 pts) for at least 8 weeks of treatment. 55.6% failed to respond to CET (15 pts). The median time to progression (TTP) for all pts was 8.0 wks. Pts, which were stable for more than 8 wks achieved a median TTP of 22.5 wks (11–48 wks) compared to a median TTP of 6.0 wks (3–8 wks) in progressive pts. No treatment-related severe adverse events were noted throughout the study. Preliminary evaluation of surrogate markers showed no correlation with cytogenetic abnormalities based on FISH analyses for chromosome 1 and 8. Furthermore, only 5 of 21 tumor specimens were positive for EGFR expression without gene amplification, evaluated by FISH analyses. Serial tumor specimens are available in 5 responding and in 7 non-responding pts for changes of p27 and p21 expression. p27 and p21 were upregulated simultaneously in 60% (3/5 pts) of responding pts, whereas in pts with treatment failure p27 and p21 expression was detectable in 14% (1/7 pts) only. Conclusions: Cytogenetic aberrations of chromosome 1 and 8 failed to predict response to CET. In a subgroup of pts with SD >8 weeks, induction of p21 and p27 were associated with prolonged TTP >20 wks. Further evaluation of p21 and p27 as early molecular tumor response is warranted to identify pts, which benefit from anti-EGFR therapies.

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No significant financial relationships to disclose.

A non-comparative phase II study of bendamustine hydrochloride in patients with pretreated soft tissue sarcoma (German Sarcoma Group-AIO 001)

9525

Background: To assess the efficacy and safety of bendamustine hydrochloride, a nucleoside analogue with alkylating activity, in patients with adult type soft tissue sarcoma (STS) who have failed anthracyline-based chemotherapy. Methods: Pts with a ECOG performance status 0–2, measurable disease and adequate organ functions were eligible. All patients had inoperable locally advanced or metastatic disease and had progressive disease during or after first-line chemotherapy prior to study entry. Bendamustine was administered at a dose of 100 mg/sqm on day 1 and 2 every four weeks for a maximum of 6 cycles with tumour assessment every two cycles. The primary endpoint was overall response rate as defined by RECIST. The secondary endpoint was toxicity. A two-stage design was used (1st step: 14 pts, at least 1 PR in order to succeed with 2nd step; p0 = 5%, p1 = 25%, alpha = beta = 0.1). Results: 32 patients, median age 56 yrs (range, 18–74) with STS were recruited (3 pts not evaluable for efficacy analysis). In general the drug was well tolerated. Grade 3 toxicity was granulocytopenia in 9% and febrile neutropenia/fever in 3% of pts. No toxic death was seen in a total of 89 cycles administered. A single pt experienced a clinically significant allergic reaction (3%). Anti-tumour activity: 1 confirmed partial response (3%). A further 10 patients had progression arrest by cycle two (34%). Conclusions: The confirmed objective response rate is low. However, the incidence of progression arrest in pretreated adult type STS is in the range of other agents considered active in STS. The observed toxicity profile is favorable. Further investigation in STS appears warranted.

No significant financial relationships to disclose.

A phase II open-label study of cetuximab in unresectable hepatocellular carcinoma

14079

Background: The majority of hepatocellular carcinomas (HCC) express the epidermal growth factor receptor (EGFR). The monoclonal anti-EGFR antibody cetuximab blocks EGFR activation. In the current study, we tested the activity of cetuximab in this disease. Methods: Pts with advanced or metastatic HCC and measurable disease with adequate renal, hematologic and hepatic function (bilirubin <2×UNL; AST/ALT <3×UNL) were eligible. Prior regional or systemic therapy was permitted. A total of 15 pts have been enrolled to date. Primary endpoint: rate of progression free survival (PFS) at 24 weeks of treatment. Secondary endpoints: overall survival (OS), objective response rate (ORR), tolerability and identification of surrogate markers. Tumor biopsies were performed prior to treatment, after 4 wks and at time of progression. Specimens were analyzed for genetic instability (FISH analyses) and cell cycle regulation (p27Kip1, skp2, EGFR) by immunohistochemistry. Cetuximab was administered 400 mg/m2 iv week 1, and 250 mg/m2 weekly thereafter until disease progression. Demographics: male 14, female 1, age 46–78 yrs (median 65), cirrhosis 13/15 pts, liver transplantion 2/15pts, Childs-Pugh class A: 14/15, B:1/15; distant metastases 6/15; risk factors: hepatitis C virus (HCV) 2/15, HBV 1/15. Contrast enhanced ultrasound examinations were performed on all pts at −2, 4, and at the time of progression to evaluate tumor blood flow. Results: At the time of the first tumor evaluation (8 wks) 2/15 pts (13%) achieved stable disease (SD). Tumor specimens showed a significant increase in copy numbers for centromeric probes against chromosome 1 and 8 in patients with progressive disease. Toxicity: all pts developed skin rash: Grade (Gr) 1 in 12/15 pts, Gr 2 in 3/15. Allergic reaction Gr 1 was seen in 1 pt. 2 pts required dose reduction for drug-related toxicity Conclusions: Cetuximab is well tolerated in pts HCC and liver cirrhosis, without additional toxicity. To date only modest activity has been detected in these unfavorably advanced pts. Accrual will continue to 35 pts total. At time of disease progression tumor specimens showed chromosomal instability with an increase in copy numbers of chr. 1 and 8. Updated results will be presented at the meeting.

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