Effect of G-CSF prophylaxis on the occurrence of neutropenia in men receiving cabazitaxel plus prednisone for the treatment of metastatic castration-resistant prostate cancer (mCRPC) in the TROPIC study

144^

Background: The phase III TROPIC study showed that cabazitaxel plus prednisone (CbzP) improves survival compared with mitoxantrone plus prednisone (MP) in men with mCRPC who progressed after docetaxel-based therapy (HR 0.70; p<0.001; Lancet 2010;376:1147). In this study, a higher percentage of men in the CbzP group had grade ≥3 neutropenia (81.7% versus 58.0%). We analyzed the effect of G-CSF use on the occurrence of grade ≥3 neutropenia.

Methods: 755 men with mCRPC who progressed during or after a docetaxel-containing regimen were randomized to receive 10 mg of oral prednisone daily and either 12 mg/m2 of mitoxantrone or 25 mg/m2 of cabazitaxel every 3 weeks. Primary prophylaxis with G-CSF was not permitted at cycle 1, but was allowed after the first occurrence of neutropenia either lasting ≥7 days or complicated by fever >38.5°C, or fever >38.1°C for three observations during a 24- hour period, or infection. We analyzed the effect of G-CSF use on the occurrence of neutropenia in cycles 2–10. G-CSF use was defined as either prophylactic (administered within 3 days of chemotherapy dose) or therapeutic (administered more than 3 days after chemotherapy dose).

Results: A total of3246 cycles (1881 CbzP; 1365 MP) were administered from cycle 2 onward. No G-CSF was used in 2,322 cycles (1144 CbzP; 1178 MP) and the percentage of these cycles with grade ≥3 neutropenia was similar between the groups (44.6% CbzP; 38.4% MP). G-CSF was used in more cycles in the CbzP group as prophylaxis (588 CbzP; 118 MP; chi-square P<0.0001) and therapeutically (149 CbzP; 69 MP; P=0.0013). The percentage of CbzP cycles with grade ≥3 neutropenia was lower when G-CSF was used early as prophylaxis versus using it later as a therapeutic modality (24.7% versus 57.7%; P<0.0001). A reduction in grade ≥3 neutropenia favoring prophylactic versus therapeutic G-CSF was also observed in the MP group (9.3% versus 33.3%; P<0.0001).

Conclusions: The appropriate and timely use of G-CSF as prophylaxis reduces the occurrence of neutropenia in men receiving CbzP for mCRPC. Adherence to current guidelines on the use of G-CSF is recommended to manage this predictable side effect.

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Everolimus in patients with metastatic renal cell carcinoma (mRCC) who are intolerant of or have progressed after prior vascular endothelial growth factor receptor–tyrosine kinase inhibitor (VEGFr-TKI) therapy: An international expanded access program (EAP)

314

Background: The mammalian target of rapamycin (mTOR) inhibitor everolimus is the first agent to show efficacy in a randomized, controlled phase III trial in patients with mRCC after progression on VEGFr-TKIs (RECORD-1). Progression-free survival (PFS) was significantly improved (4.9 vs 1.9 months) and the risk of disease progression was reduced by 67% with everolimus compared with placebo. To fulfill an unmet medical need, everolimus was offered globally in this EAP. Presented here are preliminary results on 605 patients.

Methods: The program began in July 2008 (ClinicalTrials.gov: NCT00655252 ; EudraCT: 2007-005460-28), and since then over 1,000 patients in 34 countries have been enrolled. Patients with clear cell and non–clear cell mRCC who failed or became intolerant of VEGFr-TKIs received daily oral doses of everolimus with investigator assessment every 3 months.

Results: Data were collected for 605 patients who had discontinued treatment as of January 15, 2010. Evaluable patients had a mean age of 63 years, and most (94%) had progressed after prior VEGFr-TKI therapy. The adverse event (AE) profile did not differ significantly from that reported in the RECORD-1 trial. Most frequently reported grade 3–4 AEs were anemia (6.1%), stomatitis (4.6%), fatigue (4.6%), hyperglycemia (4.0%), and infection (3.6%). Grade 3–4 noninfectious pneumonitis was reported in 2.8%. Best overall response was stable disease, which was evident in 42% of patients.

Conclusions: The EAP has allowed patients with mRCC access to everolimus before marketing approval. The rapid enrollment rate of this EAP confirms the unmet medical need after failure of VEGFr-TKIs. Everolimus has shown good tolerability, and no new safety issues have been identified. The investigator-assessed response rate is consistent with that reported in the RECORD-1 trial. The EAP provides an efficient framework for the development of other programs for innovative anticancer agents in patients without satisfactory therapeutic options.

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An open-label, randomized, phase III trial of zalutumumab, a human monoclonal EGF receptor (EGFr) antibody, versus best supportive care, in patients with noncurable squamous cell carcinoma (SCCHN) of the head and neck who have failed standard platinum-based chemotherapy (ZALUTE)

LBA5506

Background: Zalutumumab is a novel, fully human IgG1 mAb targeting the EGFr that has shown encouraging activity in SCCHN.

Methods: Patients with noncurable SCCHN with an ECOG PS of 0-2 and centrally documented radiographic progressive disease (PD) within 6 months after platinum-therapy were randomized between zalutumumab monotherapy and best supportive care (BSC) in a 2:1 ratio. Stratification parameter was ECOG PS. Methotrexate (MTX) was allowed in the BSC arm only. Individual dose-titration of zalutumumab was applied (max. exposure 16 mg/kg). The primary endpoint was overall survival (OS), with progression free survival (PFS) as the only secondary endpoint to be compared between groups, using log-rank test. 231 deaths were required to statistically differentiate OS between groups with 80% power.

Results: 286 patients (34F, 252M) were randomized. The median age was 57 years (range 18-78), 65% had distant metastasis and 17% were ECOG PS 2, all similar between groups. 78% of patients in BSC arm received MTX. Although a median OS of 6.7 months was observed in the zalutumumab group compared to 5.2 in the BSC group, this was not statistically significant (p=0.065). A clear improvement in PFS (P=0.001) was demonstrated. Zalutumumab showed a safety profile as expected within this drug class.

Conclusions: This is the first controlled study to demonstrate that an EGFr-targeted antibody given as monotherapy induces a clinically meaningful improvement in PFS in patients with SSCHN who have failed platinum-based chemotherapy.

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Phase II study of sunitinib in patients with recurrent and/or metastatic squamous head and neck carcinoma: The GORTEC 2006–01 study

6024

Background: Up to 90% of head and neck squamous cell carcinoma (HNSCC) express the vascular endothelial growth factor (VEGF) or the VEGF receptors (VEGFR) 1–3. Angiogenic factors could have prognostic implication making anti-angiogenic therapies an attractive treatment modality. Sunitinib inhibits multiple tyrosine kinase receptors including VEGFR1–3 and PDGFR. Methods: Palliative HNSCC in PD after platinum therapy received sunitinib 37.5 mg/day continuously. The primary endpoint was the disease control rate (SD, PR, CR) at 6–8 wks. A two-stage design was used (Simon; a = 0.15,b = 0.10, H0 = 10%, H1 = 25%) meaning that at least 6 patients out of 37 should achieve a SD. Dynamic contrast enhanced (DCE) magnetic resonance (MR) perfusion-weighted imaging before and 6 wks after treatment initiation was performed on a 3T system. Results: 37 pts (M/F:28/9;PS 0/1:5/32) were included.11 pts were not evaluable by imaging due to rapid clinical PD (7 pts) or toxicity (4 pts) and were considered in PD.PR was found in 1 pts, SD in 18, and PD in 18 (RECIST). Among the SD, 6 had a minor response and 5 had an unconfirmed PR (maximum % reduction in sum of the largest diameters: 2%, 4%, 7%, 10%, 16%, 17%, 30%, 45%, 48%, 65%, 73%). PR could not be confirmed due to PD within 4 wks (3 pts) or treatment termination due to toxicity (2 pts). 4 pts had MR DCE monitoring. In 3, a significant decrease in the volume transfer constant Ktrans measuring the tumor perfusion and endothelial permeability was found during sunitinib treatment. The main Gr3–4 toxicities (N pts) were fatigue (12), tumor bleedings (2), LVEF decrease (2), hypertension (2). Gr5 tumor bleedings occurred in 4 pts. Other local complications included apparition/worsening of tumor skin ulceration or tumor fistula in 15 pts. Conclusions: This trial met its primary endpoint with modest activity of sunitinib in HNSSC. The rate of complications (i.e., fatal bleedings) outlines the importance of a better patient selection. DCE-MRI may be useful to predict response.

No significant financial relationships to disclose.

Phase III trial of docetaxel (D), estramustine (E), and prednisone versus docetaxel plus prednisone in patients with metastatic hormone-refractory prostate cancer (HRPC)

5067

Background: D alone or in combination with E improves survival of pts with metastatic HRPC. Whether E is necessary in combination with D is controversial. Preclinical data suggest a synergistic activity between D and E. Phase II as well as small randomized trials support this hypothesis, although indirect comparisons between the large phase III studies are not in favor of D/E combination. We conducted a randomized, prospective, multicentric study to compare D versus D/E. Methods: 150 metastatic HRPC were randomized (minimisation, stratification parameters: PSA level, ECOG, previous E use (38 pts), and center) between D (35 mg/m2 on day 2 and 9, every 3 wks) and D in combination with E (280 mg PO tid on days 1 to 5 and 8 to 12, coumadin 1mg/d). E was the only difference between the two treatment arms. All the pts received prednisone (10 mg/d). The primary endpoint was PSA response rate (decrease in PSA > 50% from baseline) and the study was powered to detect a 25% difference in PSA response rate. Results: No significant difference was found for PSA response (D/E: 50/68 (73%); D: 48/69 (69%)), time to PSA progression (median 205 days for D/E and 210 days for D), duration of PSA response (median 185 days for D/E and 220 days for D), progression-free survival (median 186 days for D/E and 195 days for D), response rate according to RECIST, and overall survival (median 617 days for D/E and 629 days for D). PSA < 4 ngr/mL occurred in 28/68 pts (41%) in D/E and in 17/69 (25%) in D (p=0.04). More pts had at least one grade 3/4 NCI-CTC toxicity in D/E (33/75 pts; 45%) compared to D (16/75 pts; 21%) (p=0.003). The main difference was grade 3/4 digestive toxicity (D/E:15% and D:4%; p=0.017). Serious adverse events were reported more frequently in D/E than D: 20 vs 9 (p=0.03). In D/E, the most frequent grade 3/4 toxicities were digestive (15%) and venous thrombosis (12%). In D, the most frequent grade 3/4 toxicity was anemia (9%) and venous thrombosis (8%). Conclusions: Our study did not show any clinically relevant advantage in term of efficacy for the addition of E to D. Both regimens were well-tolerated although the toxicity profile was in favor of D without E. Our study does not support the addition of E to D to treat pts with HPRC.

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