Efficacy of chemotherapy and atezolizumab in patients with non-small-cell lung cancer receiving antibiotics and proton pump inhibitors: pooled post hoc analyses of the OAK and POPLAR trials

BACKGROUND

Preclinical data have shown that proton pump inhibitors (PPI) can modulate the microbiome, and single-arm studies suggested that antibiotics (ATB) may decrease the efficacy of immune checkpoint inhibitors (ICI), but randomized controlled trial data are lacking. This pooled analysis evaluated the effect of ATB and PPI on outcome in patients randomized between ICI and chemotherapy.

PATIENTS AND METHODS

This retrospective analysis used pooled data from the phase II POPLAR (NCT01903993) and phase III OAK (NCT02008227) trials, which included 1512 patients with previously treated non-small-cell lung cancer (NSCLC) randomly assigned to receive atezolizumab (n = 757) or docetaxel (n = 755). The main objective of this analysis was to assess the impact of ATB and PPI use on overall survival (OS) and progression-free survival (PFS).

RESULTS

A total of 169 (22.3%) patients in the atezolizumab group and 202 (26.8%) in the docetaxel group received ATB, and 234 (30.9%) and 260 (34.4%), respectively, received PPI. Multivariate analysis in all patients revealed that ATB were associated with shorter OS [hazard ratio (HR) 1.20, 95% confidence interval (CI) 1.04-1.39], as was PPI (HR 1.26, 95% CI 1.10-1.44). Within the atezolizumab population, OS was significantly shorter in patients who received ATB (8.5 versus 14.1 months, HR 1.32, 95% CI 1.06-1.63, P = 0.01) or PPI (9.6 versus 14.5 months, HR 1.45, 95% CI 1.20-1.75, P = 0.0001). PPI use was associated with shorter PFS in the atezolizumab population (1.9 versus 2.8 months, HR 1.30, 95% CI 1.10-1.53, P = 0.001). There was no association between ATB and PPI use and PFS or OS within the docetaxel population.

CONCLUSION

In this unplanned analysis from two randomized trials, data suggest that ATB or PPI use in patients with metastatic NSCLC is associated with poor outcome and may influence the efficacy of ICI.

Phase I study of the halichondrin B analogue eribulin mesylate in combination with cisplatin in advanced solid tumors

BACKGROUND

Eribulin mesylate is a synthetic macrocyclic ketone analogue of Halichondrin B that has demonstrated high antitumor activity in preclinical and clinical settings. This phase I study aimed to determine the maximum tolerated dose (MTD), dose-limiting toxicities (DLTs), and pharmacokinetics in combination with cisplatin (CP) in patients with advanced solid tumours.

METHODS

Thirty-six patients with advanced solid tumours received eribulin mesylate 0.7-1.4 mg m(-2) and CP 60-75 mg m(-2). Eribulin mesylate was administered on days 1, 8, and 15 in combination with CP day 1 every 28-day cycle. The protocol was amended after dose level 4 (eribulin mesylate 1.4 mg m(-2), CP 60 mg m(-2)) when it was not feasible to administer eribulin mesylate on day 15 because of neutropenia; the treatment schedule was changed to eribulin mesylate on days 1 and 8 and CP on day 1 every 21 days.

RESULTS

On the 28-day schedule, three patients had DLT during the first cycle: grade (G) 4 febrile neutropenia (1.0 mg m(-2), 60 mg m(-2)); G 3 anorexia/fatigue/hypokalemia (1.2 mg m(-2), 60 mg m(-2)); and G 3 stomatitis/nausea/vomiting/fatigue (1.4 mg m(-2), 60 mg m(-2)). On the 21-day schedule, three patients had DLT during the first cycle: G 3 hypokalemia/hyponatremia (1.4 mg m(-2), 60 mg m(-2)); G 4 mucositis (1.4 mg m(-2), 60 mg m(-2)); and G 3 hypokalemia (1.2 mg m(-2), 75 mg m(-2)). The MTD and recommended phase II dose was determined as eribulin mesylate 1.2 mg m(-2) (days 1, 8) and CP 75 mg m(-2) (day 1), on a 21-day cycle. Two patients had unconfirmed partial responses (PR) (pancreatic and breast cancers) and two had PR (oesophageal and bladder cancers).

CONCLUSIONS

On the 21-day cycle, eribulin mesylate 1.2 mg m(-2), administered on days 1 and 8, in combination with CP 75 mg m(-2), administered on day 1 is well tolerated and showed preliminary anticancer activity.

KRAS mutations in non-small-cell lung cancer and colorectal cancer: implications for EGFR-targeted therapies

BACKGROUND

KRAS mutations are associated with diverse biologic functions as well as prognostic and predictive impact in non-small cell-lung cancer (NSCLC) and colorectal cancer (CRC). In CRC, benefit from monoclonal antibody therapies targeting EGFR is generally limited to patients whose tumors have wild-type (WT) KRAS, whereas data suggest that this association is not present for NSCLC. We hypothesized that the unique tobacco-related carcinogenesis of NSCLC results in a divergence of KRAS MT genotype compared with CRC, contributing to differences in outcomes from EGFR-targeted therapies.

MATERIAL AND METHODS

Tumor from 2603 patients (838 CRC and 1765 NSCLC) was analyzed for KRAS mutations. DNA was extracted from microdissected formalin-fixed-paraffin-embedded specimens (FFPE) and 7 different base substitutions in codons 12 and 13 of KRAS were determined.

RESULTS

KRAS mutation genotype differed significantly between NSCLC and CRC in frequency (25% vs. 39%; p<0.001), smoking-associated G>T transversions (73% versus 27%; p<0.001), and ratio of transversions to transitions (3.5 vs. 0.79; p<0.001). In NSCLC GLY12Cys mutations, resulting from a codon 12 GGT>TGT substitution, were observed in 44% compared to 10% for CRC. In contrast, codon 12 or 13 GLY>ASP substitutions (resulting in a G>A transition) were more frequent in CRC (42%) compared with NSCLC (21%).

CONCLUSION

In this large dataset, KRAS mutation patterns are quantitatively and qualitatively distinct between NSCLC and CRC, reflecting in part differences in tobacco-related carcinogenesis. In light of differences in predictive value for EGFR-directed monoclonal antibody therapy and prognosis for specific KRAS mutations between NSCLC and CRC, these data provide an underlying biologic rationale.

A phase 0 microdosing trial to identify chemoresistance in bladder cancer

264

Background: DNA damage is the critical step in cancer cell response to platinum (Pt) chemotherapy. We hypothesize that low levels of Pt-induced DNA damage are predictive of chemoresistance. Accelerator mass spectrometry (AMS) is an ultrasensitive method for measuring radiocarbon. By measuring 14C bound to DNA, AMS can detect carboplatin-induced DNA damage after patients receive one subtoxic microdose of 14C-labeled carboplatin.

Methods: Cancer cells and mice bearing tumor xenografts were treated with one microdose (1/100th of the therapeutic dose) or one therapeutic dose of [14C]carboplatin. Carboplatin-DNA adducts and other relevant parameters such as drug influx/efflux, intracellular drug inactivation, and repair of DNA damage, were measured and correlated with response to chemotherapy.

Results: AMS detected Pt-DNA damage when cancer cells and mice with tumor xenografts were exposed to one microdose of [14C]carboplatin. The levels of microdose-induced DNA damage were linearly proportional to the DNA damage caused by the therapeutic drug dose (R2=0.92, p<0.001); and these levels of DNA damage correlated with chemoresistance. Low DNA damage predicts chemoresistance. Measuring drug uptake/efflux, intracellular inactivation and DNA repair allowed insight into some resistance mechanisms. We have opened a phase 0 microdosing trial to study patients with bladder cancer who are scheduled to receive Pt-based chemotherapy. One subtoxic microdose of 14C-carboplatin will be administered to these patients before biopsy. Pt-induced DNA damage and repair in left-over tumor biopsy specimens and other relevant parameters will be measured and correlated with the response and toxicity of chemotherapy. Molecular analysis of genes such as ERCC1 and RRM1 will be analyzed and compared with this phase 0 results. We have opened a similar phase 0 trial in dog patients with bladder cancer.

Conclusions: The levels of DNA damage induced by nontoxic microdosing carboplatin can potentially predict chemoresistance in cancer cell lines. The clinical data of the phase 0 trial will be presented.

No significant financial relationships to disclose.

Final results of a University of Chicago phase II consortium trial of sorafenib (SOR) in patients (pts) with imatinib (IM)- and sunitinib (SU)-resistant (RES) gastrointestinal stromal tumors (GIST)

4

Background: GIST pts who develop resistance to IM and SU have few therapeutic options. SOR inhibits KIT, VEGFR, PDGFR-β, and BRAF kinases. In preclinical models, SOR has activity against several IM-RES mutations that are resistant to SU (Heinrich. ASCO 2009).

Methods: We performed a multi-center, phase II trial of SOR in unresectable, KIT-expressing GIST pts who had disease progression on IM by RECIST. After FDA approval of SU for IM-RES GIST, the study was amended in 2/07 to require progression after both IM and SU. Pts received SOR 400 mg orally twice daily. CT scans were obtained Q2 28-day cycles. The primary endpoint was objective response rate. A Simon minimax 2-stage design required 1 response in 18 pts to proceed to a second stage, and 4 responses in 32 IM/SU RES pts for further investigation.

Results: 38 pts (6 IM-RES, 32 IM/SU-RES) enrolled 1/06-9/09 at 6 centers. Median follow-up for survivors: 31 months (mo). Pt characteristics: male 55%; median age 57 (range 42-85); PS 0/1/2: 47%/47%/6%. Median cycles: 4 (range 1-37). 63% pts had at least 1 dose reduction. Partial response (PR): 13% (1 IM-RES, 4 IM/SU-RES); stable disease (SD): 55% (3 IM-RES, 18 IM/SU-RES). Disease control rate (PR + SD): 68%. Median progression-free survival: 5.2 mo (95% CI: 3.4, 7.4). Median overall survival 11.6 mo (95% CI: 8.8, 18.0); 1-year survival 50%; 2-year survival 29%. Three pts remain on trial receiving study drug (1 PR at 34 mo; 2 SD at 18 and 37 mo). Grade 3/4 toxicities (% pts): hand-foot syndrome 45%, hypertension 21%, diarrhea 8%, hypophosphatemia 8%, GI bleed 5%, rash 5%, thrombosis 3%, GI perforation 3%, fatigue 3%, anemia 3%.

Conclusions: SOR is active in IM-and SU-resistant GIST. Some pts treated with SOR experience prolonged disease control. SOR is well-tolerated in GIST pts, but dose reductions are often required. SOR warrants further investigation in GIST. Supported by NCI grant N01-CM-62201.

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Phase I evaluation of lapatinib and everolimus in patients with advanced malignancies: Southwest Oncology Group trial S0528

3553

Background: Anti-tumor activity of Her inhibitors including lapatinib, an oral inhibitor of Her1 and Her 2, appears to correlate with their ability to down regulate PI3/Akt pathway. Everolimus, an oral inhibitor of mTOR, a serine/threonine kinase downstream of Akt, has shown enhanced efficacy when combined with Her inhibitors in pre-clinical studies. This phase I study is being conducted to determine the maximum tolerated dose (MTD) and pharmacokinetics (PK) of the combination of lapatinib and everolimus. Methods: Pts with advanced tumors, for which there was no effective therapy, were eligible. The study consists of two parts. In Part I dose escalation to define MTD was performed with both drugs being given together. MTD was defined by dose limiting toxicities (DLT) in the first cycle (each cycle is of 4 weeks duration). In Part II, PK of both drugs are being analyzed in patients treated at MTD and randomized to either cohort A- everolimus alone for a week followed by both drugs, or cohort B- lapatinib alone for a week followed by both drugs. 12 PK eligible pts will be accrued to each cohort to detect the influence of one drug over the other drug's PK. Results: 26 pts were enrolled in Part I of the study, 23 were evaluable for DLT. Median age- 63 (29–76); males/females- 20/6. Common tumors were breast (4), lung cancer (3), adenoid cystic (3). 79 cycles (median 2, range 1–15) have been administered to date. 6 pts developed DLTs: pneumonitis, rash, diarrhea, stomatitis (2), and fatigue (2). The MTD of the combination is lapatinib 1250mg and everolimus 5mg, daily. None of the pts had a response but 11 pts (2 liver, 1 breast, 1 renal, 1 sarcoma, 2 adenoid cystic, 1 melanoma, 1 bladder, 1 NSCLC, 1 colorectal) had stable disease for 8 weeks or longer. Conclusions: The MTD of the combination is lapatinib 1250 mg and everolimus 5 mg. The dose limiting toxicities observed were diarrhea, stomatitis and fatigue. Accrual to Part II is ongoing and pharmacokinetic analysis is pending.

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SWOG S0342 and S0536: Expression of EGFR protein and markers of epithelial-mesenchymal transformation (EMT) in cetuximab/chemotherapy-treated non-small cell lung cancer (NSCLC)

11076

Background: High EGFR gene copy number is associated with efficacy in NSCLC patients (pts) receiving combined chemotherapy and cetuximab (S0342). EGFR protein is typically overexpressed in tumors with high copy number but no consistent association has yet been demonstrated between EGFR protein expression and outcome in pts treated with chemotherapy plus cetuximab. EMT is associated with aggressive biological behavior and resistance to anti-EGFR TKI therapy in NSCLC. Our objective was to identify any association between EGFR protein and EMT and to correlate findings with pt outcomes from cetuximab/chemotherapy in SWOG trials S0342 (paclitaxel [P]-carboplatin [CB] plus sequential or concurrent cetuximab [CX]) and S0536 (P-CB-CX + bevacizumab). Methods: Paraffin sections were stained by immunoperoxidase methods using monoclonal antibodies against EGFR and the EMT markers vimentin, E-cadherin and Zeb1. Sections were scored on continuous scale ranging from 0–300 based on the H score (sum of % positive at each intensity from 0–3). Results were compared to outcome by Kaplan-Meier plot. Results: 79 samples from S0342 were evaluated for EGFR and EMT markers. 67 samples from S0536 were assessed for EGFR only. Mean EGFR H score was 153 and 137 for S0342 and S0536 respectively. At all cut points tested (scores 0, <100, <300) no association between EGFR H score and response or progression-free survival (PFS) was detected in either trial. There was a trend for overall survival and EGFR level at each cutpoint in S0536 but the results did not achieve statistical significance (15 vs 11 mos, p=0.14; 15 vs 11 mos, p=0.20 and 14 mos vs not reached, p=0.10, respectively). Vimentin (6 positive pts) was associated with a shorter PFS, HR=2.60 (1.10–6.14), p=0.03. ECAD and Vimentin were significantly inversely correlated with one another (Spearman p-value<0.01) Conclusions: EGFR protein level by IHC does not significantly correlate with efficacy parameters in chemotherapy/cetuximab-treated NSCLC pts. Patients with vimentin producing tumors (and possible other EMT markers) had shorter PFS, suggesting possible relative resistance to EGFR blockade from cetuximab.

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Cisplatin + irinotecan versus cisplatin + etoposide in extensive stage small cell lung cancer (E-SCLC): Final “common arm”: Comparative outcomes analysis of JCOG 9511 and SWOG 0124

8027

Background: S0124 was a large North American phase III trial (n=651) that failed to confirm a survival benefit for cisplatin/irinotecan over cisplatin/etoposide in patients with E-SCLC, contrary to the results of J9511, a phase III trial exclusively in Japanese patients (n=154). As S0124 and J9511 protocols used identical treatment regimens and similar eligibility criteria, we compared demographics, toxicity, and outcomes using patient-level data and a “common arm” analysis to explore potential reasons for the divergent results. Methods: In both trials, patients with documented E-SCLC and adequate end-organ function were randomized to receive either cisplatin 60 mg/m2 day 1 + irinotecan 60 mg/m2 days 1, 8, & 15 Q 4 weeks or cisplatin 80 mg/m2 day 1 + etoposide 100 mg/m2 days 1–3 Q 3 weeks. Demographics and outcomes data were compared among 805 patients enrolled in J9511 and S0124 receiving identical treatment using a logistic model adjusted for age, sex, and performance status. Results: Of 671 patients in S0124, 651 were eligible. Patient characteristics (J9511 & S0124, respectively): Mean age - 61 & 62 years; Male sex - 132 (86%) & 370 (57%), p<0.001; Performance status 0 - 19 (12%) & 211 (32%), p<0.001. Efficacy and toxicity comparisons are summarized below. Conclusions: Significant differences in patient demographics, toxicity, and efficacy exist between J9511 and S0124 populations. These results, relevant in the current era of clinical trials globalization, warrant 1) consideration of differential patient characteristics and outcomes amongst populations receiving identical therapy; 2) utilization of the “common arm” model in prospective trials; and 3) inclusion of pharmacogenomic correlates in cancer trials where ethnic/racial differences in drug disposition are expected.

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Phase II study of aflibercept (VEGF-Trap) in patients (pts) with recurrent or metastatic transitional cell carcinoma (TCC) of the urothelium: A California Cancer Consortium trial

e16030

Background: The role and efficacy of subsequent systemic therapies for advanced TCC following failure of frontline platinum-based chemotherapy is unclear. There is evidence that vascular endothelial growth factor (VEGF) is important in the pathophysiology of TCC. Aflibercept is a recombinant fusion protein that binds and neutralizes multiple VEGF isoforms. Methods: Pts with measurable, metastatic or locally advanced urothelial TCC previously treated with one platinum-containing regimen were entered. Aflibercept was given at 4 mg/kg IV q 2 weeks. Response rate (RR) and progression free survival (PFS) were assessed in a 2-stage accrual design (22+18). A maximum of 40 pts were to be accrued to rule out a null hypothesized RR of 4% and PFS of 3 months versus alternative of 15% RR and 5.4 months PFS with α=0.12 and β=0.19. Results: 22 pts were accrued between 11/06–2/08. Pt characteristics: M/F 15/7; Median age 67 years (45–79); 18 had bladder primary. One partial response (4.5% RR) was seen in a pt with nodal metastasis. Median PFS was 3.5 months (95% CI: 1.8–4.1). Attributable grade 3 toxicities included: hypertension (2), proteinuria (1), pulmonary hemorrhage (1), back pain (1), upper GI bleed (1), hyponatremia (1), anorexia (1) and fatigue (1). There were no attributable grade 4+ toxicities Conclusions: Aflibercept was well tolerated with toxicities similar to those seen with other VEGF pathway inhibitors, however it has limited single agent activity in platinum-pretreated TCC pts.

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KRAS mutation analysis in cetuximab-treated advanced stage non-small cell lung cancer (NSCLC): SWOG experience with S0342 and S0536

8022

Background: KRAS mutations occur in NSCLC with a frequency of 15–25% and have been associated with a poor response to EGFR tyrosine kinase inhibitors. In colorectal cancer, benefit from the EGFR-targeted monoclonal antibody cetuximab is largely limited to patients (pts) whose tumors are KRAS wild-type (WT). However, in cetuximab-treated NSCLC, a predictive role for KRAS mutations has not been established. We evaluated KRAS status in specimens from two cetuximab-based front-line multicenter SWOG phase II trials in advanced NSCLC. Methods: DNA extracted from archival tumor and plasma specimens from S0342 (carboplatin-paclitaxel plus sequential vs. concurrent cetuximab) and S0536 (carboplatin-paclitaxel-cetuximab-bevacizumab) was analyzed for KRAS mutations by micro-dissection/sequencing and/or Scorpion-ARMS (DxS LTD). Results: For S0342, 45 archival tissues and 90 plasma specimens were analyzed. Combined, KRAS mutations were detected in 24% of pts. No differences between mutant and WT tumors were observed for response rate (p=0.62) or progression-free survival (PFS; p=0.65). Overall survival (OS) was non-significantly higher for pts with WT vs. mutant KRAS [median OS: 11 vs. 8 mo.; p=0.39]. When evaluated with EGFR copy number analysis conducted previously (JCO 10:3351, 2008), pts with both low EGFR copy number and mutant KRAS trended towards a worse OS [7 mo. vs. 17 mo. for all others, p=0.08, n=31]. For S0536, 6/26 pt specimens (23%) harbored KRAS mutations. In the limited sample set available from S0536, no associations were observed between KRAS status and clinical outcome [response rate: p=0.83; PFS: p=0.93; OS p=0.89]. Conclusions: These data suggest that KRAS mutations may not play a significant predictive role for cetuximab-based therapy in NSCLC, contrary to colorectal cancer. KRAS analysis in recently completed phase III trials of chemotherapy ± cetuximab will be of interest to confirm these observations. Trends in favorable OS in pts with WT KRAS may reflect prognostic effects of KRAS mutations.

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Randomized, double-blind, placebo-controlled phase II study of carboplatin and paclitaxel with or without vorinostat, a histone deacetylase inhibitor (HDAC), for first-line therapy of advanced non-small cell lung cancer (NCI 7863)

8004

Background: Vorinostat, a HDAC inhibitor, enhances paclitaxel and platinum-mediated anti-cancer activity in preclinical studies by enhanced tubulin acetylation and DNA fragmentation respectively. Promising activity with carboplatin (C), paclitaxel (P), and vorinostat in patients with advanced NSCLC in the phase I study (Ramalingam et al, Clin Cancer Res, 2007) prompted this placebo-controlled, randomized phase II study. Methods: Pts. with stage IIIB (wet) or IV NSCLC, performance status (PS) 0/1, no prior therapy and adequate bone marrow, renal and hepatic function were randomized (2:1) for therapy with PC with either vorinostat or placebo. Treatment consisted of C: AUC=6 mg/ml.min; and P 200 mg/m2 both given on day 3 along with either vorinostat (400 mg PO QD) or placebo on days 1–14 of each 3 wk cycle to a maximum of 6 cycles. The estimated sample size to demonstrate a 50% improvement in response rate for vorinostat over placebo was 93 pts. (one-sided P, type I error 10%). Results: Ninety-four pts. were enrolled (vorinostat-64; placebo-32). Pts. baseline characteristics were similar between the two arms (median age 64, male 60%, PS 0 40%, brain mets 16%). Median # cycles: vorinostat-3.5; placebo - 4. The confirmed response rate was superior with vorinostat over placebo (34% vs. 12.5%, P = 0.02). At the time of analysis, the preliminary median PFS for vorinostat and placebo were 5.75 and 4.1 m respectively (ITT). Follow up for survival is ongoing. Common grade 3/4 toxicities (vorinostat vs. placebo): neutropenia (44% vs. 47%); thrombocytopenia (33% vs. 16%); fatigue (13% vs. 3%); hyponatremia (21% vs. 6%); diarrhea (5% vs. 0). Discontinuation from study after cycle 1 was higher with vorinostat (27% vs. 16%). Biomarker studies on baseline tumor tissue and peripheral blood cells are ongoing. Conclusions: Administration of vorinostat with carboplatin and paclitaxel resulted in a significantly superior response rate for pts.with advanced NSCLC. HDAC inhibition is a novel therapeutic strategy for treatment of NSCLC. Supported by ASCO Career Development Award to S.S.Ramalingam, and NCI NO1-CM-62209, NO1-CM-62201, NO1-CM-62208.

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A phase II study of the halichondrin B analog, E7389, in patients (pts) with advanced non-small cell lung cancer (NSCLC) previously treated with a taxane. A California Consortium/University of Pittsburgh/University of Chicago NCI/CTEP sponsored trial

8056

Background: E7389 is a structurally simplified synthetic macrocyclic ketone analog of halichondrin B and has a unique mechanism of microtubule binding and interaction, distinct from other agents in this class. Thus, it was our hypothesis that pts with prior taxane based therapy would respond to this agent. We conducted a phase II trial of E7389 in prior taxane-treated NSCLC pts. Methods: Eligible pts included: histologically confirmed advanced NSCLC, previous treatment with platinum-based therapy and a taxane, no more than 2 prior regimens, measurable disease, Zubrod performance status ≤ 2. Pts were classified by taxane-sensitivity status: taxane sensitive (TS) (progression >90 days after taxane) or taxane resistant (TR) (progression during or ≤90 days after taxane). Treatment: E7389 1.4 mg/m2 intravenously over 1–2 minutes on day 1 and 8 of a 21 day schedule until disease progression or unacceptable toxicity. Results: 41 pts were entered. There were 3 (15%) objective responses (7.2+, 8.5+, 10.6 mo) of 20 TS pts; and no response of 21 TR pts. Stable disease rate was 60% and 24% in TS and TR pts. respectively. Median progression free survival (PFS) is 6.3 mos TS pts. 95%CI (2.5–8.6 mos) and 1.2 mos TR pts. 95%CI (1.1–4.1 mos). Median number of cycles (range): TS 4 (1–14); TR 2 (1–7). Major toxicity included: 19 pts (46%) with grade 3 or 4 hematologic toxicity including only 1 episode of febrile neutropenia and 8 pts (20%) with grade 3 or 4 non-hematologic toxicity attributable to drug including: fatigue (1), dehydration (2), nausea (2), constipation (2). Only 1 pt developed grade 3 neuropathy (course 9). Conclusions: E7389 was well tolerated with encouraging objective response, PFS and disease control rate in the TS cohort. This cohort will be expanded, using a 2-stage design, to accrue up to another 25 pts.

No significant financial relationships to disclose.

ABT-869 in non-small cell lung cancer (NSCLC): Interim results

8074

Background: ABT-869 is a novel orally active, potent and specific inhibitor of vascular endothelial growth factor and platelet derived growth factor receptor tyrosine kinases. Methods: This ongoing, open-label, randomized, multicenter phase 2 trial of ABT-869 at 0.10 mg/kg daily (Arm A) and 0.25 mg/kg daily (Arm B) until progressive disease (PD) or intolerable toxicity, was initiated to assess antitumor activity and toxicity of ABT-869 in patients (pts) with NSCLC. Eligibility criteria included locally advanced or metastatic NSCLC; ≥ 1 prior systemic treatment, and ≥1 measurable lesion by RECIST criteria. The primary endpoint was the progression free (PF) rate at 16 wks. Secondary endpoints were objective response rate (ORR), time to progression (TTP), progression free survival (PFS) and overall survival (OS). CT scans were assessed by the investigator and centrally; central assessment results are provided. Results: 138 patients (pts) were enrolled from 08/07–10/08 from 27 centers with interim data available for 94 pts (Arm A, n=43; Arm B; n=51). Median age was 64 years and 62 years in Arm A and B respectively. For the interim analysis population (Arm A, n=24; Arm B, n=24), 16 (33.3%) pts were PF at 16 wks: 7 (29.2%) in Arm A and 9 (37.5%) in Arm B. The ORR in Arm A (n=30) was 0% and 7.3% in Arm B (n=41). The median TTP and median PFS were 110 and 109 days, and 112 days and 108 days in Arm A and B, respectively. The most common adverse events (AEs) in Arm A were fatigue (35%), nausea (21%), and anorexia (21%), and in Arm B were hypertension (51%), fatigue (51%), diarrhea (43%), anorexia (41%), nausea (31%), proteinuria (31%) and vomiting (26%). The most common grade 3/4 toxicities in the Arm A were fatigue (7%), ascites (5%), dehydration (5%), pleural effusion (5%), and in the Arm B were hypertension (23%), fatigue (8%), PPE syndrome (8%), dyspnoea (6%) and stomatitis (6%). Most AE's were mild/moderate and reversible with interruptions/dose reduction/or discontinuation of ABT-869. Conclusions: ABT-869 demonstrates an acceptable safety profile and appears to be active in NSCLC patients.

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Dual epidermal growth factor receptor (EGFR) inhibition: Phase I study combining cetuximab (C225) and erlotinib (E) in advanced solid tumors

3552

Background: The EGFR pathway is implicated in lung tumorigenesis by aberrantly regulating cell proliferation, apoptosis, and invasion. Maximal blockade of the EGFR can be achieved by dually inhibiting the extracellular and intracellular domain with the monoclonal antibody C225 and the tyrosine kinase inhibitor, E. Given preclinical synergy of C225 and E, we hypothesized this combination would be feasible and result in improved therapeutic benefit. Methods: Patients (pts) with advanced solid tumors were enrolled using a standard phase I dose escalation design. C225 was administered IV weekly, with no loading dose, and E given orally daily on a 28-day cycle. Four dose levels were studied: C225 150 mg/m2, E 100 mg; C225 200 mg/m2, E 100 mg; C225 250 mg/m2, E 100 mg; and C225 250 mg/m2, E 150 mg. Dose limiting toxicity (DLT) was defined as: grade (Gr) 4 platelets, Gr 3 platelets with bleeding, febrile neutropenia, ≥ Gr 3 ANC with documented infection, or clinically significant > Gr 3 non-hematologic toxicity. Gr 3 rash based solely on pain or Gr 3 hypersensitivity infusion reactions were not considered DLTs. Results: 18 pts were treated: 13 NSCLC, 3 H&N, 1 pancreas, and 1 invasive thymoma. Characteristics: Age range 41–80, median 62.5; Gender: 7 M; ECOG PS ≤1 = 17; Prior chemo ≤1 = 10. Planned dose escalation was completed without reaching the MTD. The highest dose level was expanded to 6 pts. A single DLT for Gr 3 diarrhea was observed at the second dose level (C225 200 mg/m2, E 100 mg). Gr 3/4 toxicities were: lymphopenia (3), acneiform rash (3), nausea/vomiting (3), pruritis (1), fatigue (1), diarrhea (1), confusion (1), hypomagnesemia (1), hypocalcemia (1), hyponatremia (1), hyperkalemia (1), and anemia (1). Of 13 evaluable pts, 1 PR (NSCLC) and 4 with SD (2 NSCLC, 2 H&N). Median cycles: 2 (1–14) with one NSCLC pt on therapy for 8 cycles and one H&N pt receiving 14 cycles. Biomarker analysis of EGFR polymorphisms, gene copy number via FISH, and protein expression will be presented, along with the mutation status of EGFR and KRAS. Conclusions: 1) Dual EGFR inhibition with C225 250 mg/m2 weekly and E 150 mg daily is feasible, well tolerated, and the recommended phase II dose. 2) Efficacy of this combination in NSCLC is being evaluated in a phase II trial.

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