Multiplex KRASG12/G13 mutation testing of unamplified cell-free DNA from the plasma of patients with advanced cancers using droplet digital polymerase chain reaction

Background

Cell-free DNA (cfDNA) from plasma offers easily obtainable material for KRAS mutation analysis. Novel, multiplex, and accurate diagnostic systems using small amounts of DNA are needed to further the use of plasma cfDNA testing in personalized therapy.

Patients and methods

Samples of 16 ng of unamplified plasma cfDNA from 121 patients with diverse progressing advanced cancers were tested with a KRASG12/G13 multiplex assay to detect the seven most common mutations in the hotspot of exon 2 using droplet digital polymerase chain reaction (ddPCR). The results were retrospectively compared to mutation analysis of archival primary or metastatic tumor tissue obtained at different points of clinical care.

Results

Eighty-eight patients (73%) had KRASG12/G13 mutations in archival tumor specimens collected on average 18.5 months before plasma analysis, and 78 patients (64%) had KRASG12/G13 mutations in plasma cfDNA samples. The two methods had initial overall agreement in 103 (85%) patients (kappa, 0.66; ddPCR sensitivity, 84%; ddPCR specificity, 88%). Of the 18 discordant cases, 12 (67%) were resolved by increasing the amount of cfDNA, using mutation-specific probes, or re-testing the tumor tissue, yielding overall agreement in 115 patients (95%; kappa 0.87; ddPCR sensitivity, 96%; ddPCR specificity, 94%). The presence of ≥ 6.2% of KRASG12/G13 cfDNA in the wild-type background was associated with shorter survival (P = 0.001).

Conclusion(s)

Multiplex detection of KRASG12/G13 mutations in a small amount of unamplified plasma cfDNA using ddPCR has good sensitivity and specificity and good concordance with conventional clinical mutation testing of archival specimens. A higher percentage of mutant KRASG12/G13 in cfDNA corresponded with shorter survival.

Abstract P3-14-02: Targeting the PI3K/AKT/mTOR pathway for the treatment of mesenchymal triple-negative breast cancer (TNBC): Evidence of efficacy and proof of concept from a phase I trial with dose expansion of mTOR inhibition in combination with liposomal doxorubicin and bevacizumab

Background: Approximately 30% of TNBCs are characterized by microarray as claudin-low, mesenchymal or mesenchymal stem cell-like and, unlike basal TNBCs, these tumors frequently harbor aberrations in the PI3K/AKT/mTOR axis, raising the possibility of targeting this axis to enhance chemotherapy response. Assays to clinically identify mesenchymal TNBCs are under development, but published results confirm that up to 30% are metaplastic breast cancers (MpBCs), a chemo-refractory group of tumors that contain a mixture of epithelial and mesenchymal components, making them identifiable by microscopy. As such, MpBCs serve as surrogates of response for potential regimens to treat mesenchymal TNBC.

Methods: Patients (pts) with advanced TNBC (N=64) were treated with liposomal doxorubicin (D), bevacizumab (A) and the mTOR inhibitors temsirolimus (T) or everolimus (E). D and A were administered IV on day 1 with T (IV on days 1, 8 and 15) or E (continuous daily oral administration) using 21 day cycles. Response was assessed every 6 weeks using RECIST. When available, archived tissue was evaluated for aberrations in the PI3K pathway using standard assays.

Results: Fifty-two MpBC pts were treated with DAT (N=39) or DAE (N=13). Median age was 58 (range 37-79); median # of prior regimens for metastatic disease was 1 (range 0-5). The objective response rate (ORR) was 21% [complete response (CR)=4 (8%); partial response (PR)=7 (13%)] and 10 (19%) pts had stable disease (SD)≥6 months for a clinical benefit rate (CBR) of 40%. Tissue was available for testing in 43 pts and 32 (74%) had a PI3K pathway activating aberration (Table 1).

Response According to PI3K Pathway AberrationPI3K Pathway AberrationN (%)CRPRSD≥6monthsCBRORRAny PI3K Pathway Aberration*32 (74)46444%31%PIK3CA Mutation19 (59)23447%26%p.H1047R12 (38)21350%25%p.E545K6 (19)02150%33%p.G1007R1 (3)010100%100%p.E545A1 (3)0000%0%p.H1047Y1 (3)0000%0%p.K111E1 (3)0000%0%p.E542K1 (3)0000%0%PIK3CA Amplification1 (3)010100%100%PTEN Mutation5 (16)0000%0%PTEN Loss5 (16)02040%40%AKT1 p.E17K Mutation2 (6)0000%0%AKT2 Amplification1 (3)100100%100%PIK3R1 Mutation2 (6)01050%50%NF2 Mutation1 (3)100100%100%No PI3K Pathway Aberration11 (26)00545%0%*Some tumors had >1 aberration detected

PI3K pathway activation was associated with a significant improvement in ORR (31 vs 0%; P=0.043) but not CBR (44 vs 45%; P=1.000) or progression-free survival (median 5.1 vs 2.9 months; P=0.352). A pt with 5 year+ durable CR (on maintenance everolimus) had a mutation in NF2. To emphasize the importance of pt selection, it is notable that 12 pts with non-metaplastic TNBC were also treated with DAT, and only 1 pt had a response (CR/PR=1; SD≥6 months=0), for a CBR that was significantly worse than pts with MpBC (8 vs 40%; P=0.045).

Conclusions: Using MpBC as a surrogate of response, DAT/DAE has significantly better activity in mesenchymal compared to non-selected TNBC. Response is enhanced in pts with PI3K pathway activation. DAT/DAE should be tested in non-metaplastic, mesenchymal TNBC once a diagnostic assay is available.

Citation Format: Basho RK, Gilcrease M, Murthy RK, Helgason T, Booser DJ, Karp DD, Meric-Bernstam F, Wheler JJ, Valero V, Albarracin C, Litton J, Chavez-MacGregor M, Ibrahim NK, Murray JL, Koenig KB, Hong D, Subbiah V, Kurzrock R, Janku F, Moulder S. Targeting the PI3K/AKT/mTOR pathway for the treatment of mesenchymal triple-negative breast cancer (TNBC): Evidence of efficacy and proof of concept from a phase I trial with dose expansion of mTOR inhibition in combination with liposomal doxorubicin and bevacizumab. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-14-02.

Retreatment with anti-EGFR based therapies in metastatic colorectal cancer: impact of intervening time interval and prior anti-EGFR response

BACKGROUND

This retrospective study aims to investigate the activity of retreatment with anti-EGFR-based therapies in order to explore the concept of clonal evolution by evaluating the impact of prior activity and intervening time interval.

METHODS

Eighty-nine KRAS exon 2-wild-type metastatic colorectal patients were retreated on phase I/II clinical trials containing anti-EGFR therapies after progressing on prior cetuximab or panitumumab. Response on prior anti-EGFR therapy was defined retrospectively per physician-records as response or stable disease ≥6 months. Multivariable statistical methods included a multiple logistic regression model for response, and Cox proportional hazards model for progression-free survival.

RESULTS

Retreatment anti-EGFR agents were cetuximab (n = 76) or cetuximab plus erlotinib (n = 13). The median interval time between prior and retreatment regimens was 4.57 months (range: 0.46-58.7). Patients who responded to the prior cetuximab or panitumumab were more likely to obtain clinical benefit to the retreatment compared to the non-responders in both univariate (p = 0.007) and multivariate analyses (OR: 3.38, 95 % CI: 1.27, 9.31, p = 0.019). The clinical benefit rate on retreatment also showed a marginally significant association with interval time between the two anti-EGFR based therapies (p = 0.053). Median progression-free survival on retreatment was increased in prior responders (4.9 months, 95 % CI: 3.6, 6.2) compared to prior non-responders (2.5 months, 95 % CI, 1.58, 3.42) in univariate (p = 0.064) and multivariate analysis (HR: 0.70, 95 % CI: 0.43-1.15, p = 0.156).

CONCLUSION

Our data lends support to the concept of clonal evolution, though the clinical impact appears less robust than previously reported. Further work to determine which patients benefit from retreatment post progression is needed.

First-in-human study of pbi-05204, an oleander-derived inhibitor of akt, fgf-2, nf-κΒ and p70s6k, in patients with advanced solid tumors

BACKGROUND

PBI-05204, a Nerium oleander extract (NOE) containing the cardiac glycoside oleandrin, inhibits the α-3 subunit of Na-K ATPase, as well as FGF-2 export, Akt and p70S6K, hence attenuating mTOR activity. This first-in-human study determined the safety, pharmacokinetics (PK) and pharmacodynamics (PD) of PBI-05204 in patients with advanced cancer. Methods Forty-six patients received PBI-05204 by mouth for 21 of 28 days (3 + 3 trial design). Dose was escalated 100% using an accelerated titration design until grade 2 toxicity was observed. Plasma PK and mTOR effector (p70S6K and pS6) protein expressions were evaluated. Results Dose-limiting toxicities (grade 3 proteinuria, fatigue) were observed at dose level 8 (0.3383 mg/kg/day). Common possible drug-related adverse were fatigue (26 patients, 56.5%), nausea (19 patients, 41.3%) and diarrhea (15 patients, 32.6 %). Electrocardiogram monitoring revealed grade 1 atrioventricular block (N = 10 patients) and grade 2 supraventricular tachycardia (N = 1). The MTD was DL7 (0.2255 mg/kg) where no toxicity of grade ≥ 3 was observed in seven patients treated. Seven patients (15%) had stable disease > 4 months. Mean peak oleandrin concentrations up to 2 ng/mL were achieved, with area under the curves 6.6 to 25.5 μg/L*hr and a half-life range of 5-13 h. There was an average 10% and 35% reduction in the phosphorylation of Akt and pS6 in PBMC samples in 36 and 32 patients, respectively, tested between predose and 21 days of treatment. Conclusions PBI-05204 was well tolerated in heavily pretreated patients with advanced solid tumors. The recommended Phase II dose is 0.2255 mg/kg/day.

Abstract P1-08-18: PIK/AKT/MTOR pathway activation in triple negative breast cancer and outcomes with matched therapy in phase I clinical trials: Response in both patients with and without direct molecular alterations

Introduction

The PI3K/AKT/MTOR pathway is a known driver in triple negative breast cancers (TNBC). We analyzed patients with TNBC seen in our Phase I clinic including molecular subtyping and correlation with response to therapies targeting the PI3K/AKT/mTOR pathway.

Methods

Patients with advanced TNBC [negative (<1%) expression for estrogen and progesterone receptors and negative Her 2 (</ = 1+ by IHC or non-amplified by FISH)] whose tumors had undergone molecular profiling (including PIK3CA/PTEN mutation analysis and/or PTEN immunohistochemistry (IHC)). We evaluated sequential patients seen in the Phase I clinic at M.D. Anderson Cancer Center treated on at least one Phase I clinical trial and correlated molecular status with clinical outcomes on therapy. Molecular profiling methods including hotspot analysis, next generation sequencing and IHC.

Results

Forty-four patients (median age 56, range 27-81; all female; white race76%) with a median of 2 (0-7) prior therapies (40% received ≥3 prior systemic therapies) and 2 metastatic sites (range, 1-6) were included. Histology: invasive ductal carcinoma 29 (66%), metaplastic 12 (27%), other 3 (7%). Nine out of 42 patients tested (19%) had a PIK3CA mutation and, 11 out of 33 patients tested (33%) demonstrated PTEN loss on IHC and 2 patients had PTEN mutations. Altogether, 21 out of 44 patients had at least one alteration in the PI3K/AKT/mTOR pathway. Sixteen of these 21 patients received “matched” therapy consisting of at least one agent targeting the PI3K/AKT/mTOR pathway. Four out of 16 patients (25%) with at least one molecular alteration, treated with one or more regimens containing at least one agent targeting the PI3K/AKT/mTOR pathway (“matched” therapy), demonstrated clinical benefit: complete response (CR) (N = 1)/partial response (PR) (N = 1)/stable disease ≥ 6 months (SD) (N = 2). Similarly, three out of 12 patients (25%) who did not demonstrate a direct molecular alteration in the PI3K/AKT/mTOR pathway and who were treated with PI3K-directed therapy, had either CR (N = 1)/PR (N = 1)/SD ≥ 6 months (N = 1). Twenty-eight patients received PI3K/AKT/mTOR pathway directed therapy yielding CR (N = 2), PR (N = 3) and CR/PR/ SD ≥ 6 months (N = 1) while those who received other therapies had CR (N = 0), PR (N = 1) and CR/PR/SD>6mo (N = 3)and a median TTF of 3.1 (2.1-4.8) vs. 1.8 (1.4-2.5) months (p = 0.23).

Conclusions

A significant percentage of patients with TNBC demonstrate a direct alteration in the PI3K/AKT/mTOR pathway. Our data shows that PI3K-directed therapies benefit both those patients with and without direct molecular alterations in this pathway. Further molecular testing results will be presented. This data suggests that there may be additional molecular alterations that activate PI3K/AKT/mTOR in patients with TNBC.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-08-18.

Dual HER2 inhibition in combination with anti-VEGF treatment is active in heavily pretreated HER2-positive breast cancer

BACKGROUND

Preclinical data indicate that dual HER2 inhibition overcomes trastuzumab resistance and that use of an HER2 inhibitor with an anti-angiogenic agent may augment responses.

PATIENTS AND METHODS

We conducted a dose-escalation, phase I study of a combination of trastuzumab, lapatinib and bevacizumab. The subset of patients with metastatic breast cancer was analyzed for safety and response.

RESULTS

Twenty-six patients with metastatic breast cancer (median = 7 prior systemic therapies) (all with prior trastuzumab; 23 with prior lapatinib; one with prior bevacizumab) received treatment on a range of dose levels. The most common treatment-related grade 2 or higher toxicities were diarrhea (n = 11, 42%) and skin rash (n = 2, 8%). The recommended phase 2 dose was determined to be the full Food and Drug Administration (FDA) approved doses for all the three agents (trastuzumab 8 mg/kg loading dose, 6 mg/kg maintenance dose, intravenously every 3 weeks; lapatinib 1250 mg daily, bevacizumab 15 mg/kg intravenously every 3 weeks). The overall rate of stable disease (SD) ≥6 months and partial or complete remission (PR/CR) was 50% (five patients with SD ≥6 months; seven PRs (including one unconfirmed); one CR). The rate of SD ≥6 months/PR/CR was not compromised in patients who had previously received study drugs, those with brain metastases, and patients treated at lower dose levels.

CONCLUSIONS

The combination of trastuzumab, lapatinib and bevacizumab was well-tolerated at maximally approved doses of each drug, and its activity in heavily pretreated patients with metastatic breast cancer suggests that it warrants further investigation.

CLINTRIALSGOV ID

NCT00543504.

Aberrations in the epidermal growth factor receptor gene in 958 patients with diverse advanced tumors: implications for therapy

BACKGROUND

Epidermal growth factor receptor (EGFR) mutations are associated with the response to EGFR inhibitors in patients with non-small-cell lung cancer (NSCLC). We sought to investigate EGFR aberrations in patients with diverse advanced cancers.

PATIENTS AND METHODS

Patients referred to the phase I clinic were evaluated for the presence of EGFR mutations and response to therapy.

RESULTS

EGFR aberrations were detected in 34 of 958 patients (3.5%). Though EGFR mutations were most frequent in NSCLC (21 of 131, 16%), they were also present in a variety of other solid tumors (13 of 827 patients, 1.6%) including adrenocortical (1/10 patients), skin (1/24), breast (1/55), carcinoid (1/8), cholangiocarcinoma (1/20), head and neck (1/61), ovarian (1/84), parathyroid (1/1), salivary gland (1/20), renal (1/17), sarcoma (2/38), and thymic carcinomas (1/7). Of the 13 EGFR aberration-positive non-NSCLC patients (median number of prior systemic therapies = 3), 6 had treatment with an EGFR inhibitor. Two patients (diagnosis = parathyroid tumor and basal cell carcinoma) achieved stable disease (SD), lasting 6 and 7 months, respectively.

CONCLUSION

We found EGFR aberrations in 1.6% of a large group of patients with diverse tumors other than NSCLC, and treatment with an EGFR inhibitor could be associated with prolonged SD.

Electrocardiograms (ECGs) in phase I anticancer drug development: the MD Anderson Cancer Center experience with 8518 ECGs

BACKGROUND

Cardiac sequelae from oncologic drugs are important in early cancer drug development. Prolongation of the corrected QT interval (QTc) by noncardiac drugs is the most common cause of drug development delays, nonapprovals and postmarketing withdrawals by the US Food and Drug Administration.

PATIENTS AND METHODS

We analyzed 8518 electrocardiograms (ECGs) in 525 consecutive cancer patients enrolled in 22 industry-sponsored phase I clinical trials, starting 1 January 2006.

RESULTS

Seventy-four patients [14%, 95% confidence interval (CI) 11% to 17%] with normal QTc at baseline had QTc intervals above upper limit of normal after treatment initiation; 33 (6%, 95% CI 4% to 9%) had prolonged QTc intervals at baseline, and only one (3%, 95% CI 0% to 16%) worsened after dosing. Seven of 33 patients (21%, 95% CI 9% to 39%) with prolonged baseline QTc had normalization of QTc intervals after dosing. All QTc prolongations were clinically insignificant; study drugs were continued uneventfully. Two of 525 patients (0.4%, 95% CI 0% to 1%) experienced cardiac serious adverse events (myocardial infarction possibly related to drug and unstable atrial flutter related to metastatic disease). Both cardiac events were detected by clinical assessment, not surveillance ECGs.

CONCLUSION

Frequent ECG monitoring provided no clinically significant information in 525 patients in early phase trials.

Risk of serious toxicity in 1181 patients treated in phase I clinical trials of predominantly targeted anticancer drugs: the M. D. Anderson Cancer Center experience

BACKGROUND

This study assessed toxicity in advanced cancer patients treated in a phase I clinic that focuses on targeted agents.

PATIENTS AND METHODS

An analysis of database records of 1181 consecutive patients with advanced cancer who were treated in the phase I program starting 1 January 2006 was carried out.

RESULTS

All patients were treated on at least 1 of the 82 phase I clinical trials. Overall, 56 trials (68.3%) had only targeted agents, 13 (15.9%) only cytotoxics, and 13 (15.9%) targeted and cytotoxic agents. Rates of grade 3 and 4 toxicity that were at least possibly drug related were 7.1% and 3.2%, respectively, and 5 of the 1181 patients (0.4%) died from toxicity that was at least possibly drug related. The most common grade 3 or more toxic effects were neutropenia, thrombocytopenia, anemia, dehydration, infection, altered mental status, bleeding, vomiting, nausea, and diarrhea. Eastern Cooperative Oncology Group (ECOG) performance status greater than zero and use of a cytotoxic agent were selected as independent factors associated with serious toxicity.

CONCLUSION

Phase I trials of primarily targeted agents showed low rates of toxicity, with 10.3% of patients experiencing grade 3 or 4 toxicity and a 0.4% rate of death, at least possibly drug related.

PD09-01: Target-Based Therapeutic Matching in Early-Phase Clinical Trials in Patients with Advanced Breast Cancer and PIK3CA Mutations

Background: Therapeutic matching based on underlying molecular abnormalities showed promising results in early-phase clinical trials. PIK3CA mutations may predict response to therapies with PI3K/AKT/mTOR inhibitors.

Methods: Tumors from patients with breast cancer referred to the Clinical Center for Targeted Therapy (Phase I Program) were analyzed for PIK3CA mutations. Patients with PIK3CA mutations were treated, whenever feasible, with agents targeting the PI3K/AKT/mTOR pathway.

Results: Of 54 patients analyzed, 15 (28%) had PIK3CA mutations. PIK3CA mutations were found in 5/9 (56%) metaplastic, 3/8 (38%) HER2−positive, 7/29 (24%) hormone receptor-positive, and 0/8 (0%) triple negative (excluding metaplastic) breast cancers (P=0.07). Of the 15 patients with PIK3CA mutations, 12 (80%) were treated in clinical trials containing a PI3K/AKT/mTOR pathway inhibitor (median age, 54; median number of prior therapies, 3). Of these 12 patients, 3 (25%, 95% CI 0.09−0.53) had stable disease for more than 6 months (SD≥6 months; n=1) or a partial response (PR; n=2). Breast cancer patients without PIK3CA mutations treated on the same protocols had a rate of SD≥6 months/PR of 8% (1/12; 95% CI 0.01−0.35, p=0.6). Of the 4 patients with a H1047R mutation treated with agents targeting the PI3K/AKT/mTOR pathway, 3 (75%) had SD≥6 months (n=1) or a PR (n=2) compared to 0 of 8 patients (0%) with other PIK3CA mutations (P=0.045). Patients with H1047R mutations had a median progression-free survival (PFS) of 8.5 months compared to 2 months in patients with other PIK3CA mutations (p=0.13).

Conclusion: Heavily pretreated patients with PIK3CA-mutant advanced breast cancer had a SD≥6 months/PR rate of 25% on protocols incorporating PI3K/AKT/mTOR. Patients with mutation H1047R had significantly longer SD≥6 months/PR rate compared to those with other PIK3CA mutations. Our observations suggest that screening for PIK3CA mutations is warranted in larger numbers of patients with advanced breast cancer when treatment with PI3K/AKT/mTOR pathway inhibitors is planned.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr PD09-01.

Personalized medicine in a phase I clinical trials program: The M. D. Anderson Cancer Center Initiative

CRA2500

Background: We initiated a personalized medicine program hypothesizing that tumor molecular analysis and use of targeted therapy to counteract the effects of specific aberrations would improve the outcomes of affected patients. Methods: Molecular analysis was performed in the M. D. Anderson CLIA-certified pathology laboratory. Patients whose tumors had an aberration were treated in the Phase I Program with a matched targeted agent, when available. Results: Tumor molecular analysis was feasible in 852 (89%) of 955 consecutive patients with advanced cancer. Of 852 patients (median, age 56 yrs; prior therapies 4), 354 (41.5%) had ≥ 1 aberration: 10% of patients had a PIK3CA mutation; 19% KRAS; 8% NRAS; 19% BRAF; 3% EGFR; and 2% had a CKIT mutation; 21% had PTEN loss. Results are shown in the table. Median time to treatment failure (TTF) in 161 patients with 1 aberration treated with matched targeted therapy was 5.3 months (95%CI: 4.1, 6.6) vs 3.2 months (95%CI: 2.9 – 4.0) for their prior systemic antitumor therapy (prior to referral to phase I) (p= .0003). For patients with 1 aberration, the CR+PR rate was 29% with matched targeted therapy vs. 8% without matching (p = .0001). The CR+PR rate was 6% in 438 patients without molecular testing treated on the same studies. Conclusions: Preliminary results suggest that in early clinical trials matching patients with targeted drugs based on their molecular profile results in (a) longer TTF compared to their prior therapy and (b) higher rates of response, survival and TTF compared to those seen in patients treated without molecular matching. Support: 3UL1 RR024148 04 S1 and IPCT.

[Table: see text]

Clinical outcomes of patients with breast cancer in a phase I clinic: The M. D. Anderson Cancer Center experience

1054

Background: Patients with metastatic breast cancer refractory to standard therapy are eligible for phase I trials. We assessed prognostic factors and clinical outcomes for patients with breast cancer in a phase I clinic focused on targeted agents. Methods: We reviewed the medical records of sequential patients with metastatic breast cancer who presented to our phase I clinic from September 2004 to May 2008. We assessed the relationship between overall survival and patients’ demographic and clinical characteristics using both univariate and multivariate (Cox proportional hazard model) analyses. Results: Ninety-two patients were identified with median age of 53 years (range 28 to 83 years). The median number of prior therapies was 5 (range 1 to 16). The median follow-up of surviving patients is 7.4 months. The median overall survival is 6.7 (95% CI: 5.2, 9.7) months. In univariate analysis, factors predicting shorter survival were elevated Ca-125 (p = 0.001) (Ca27.29 was not significant), albumin < 3.5 g/dL (p = 0.002), worsening ECOG performance status (p = 0.004), absolute neutrophil count < 7.3 x 109/L (p = 0.004), ≥ 10 prior treatment regimens (p = 0.008), ≥ 5 prior chemotherapy-only regimens (p = 0.008), body mass index (BMI) < 25 (p = 0.018), and elevated platelet counts (p = 0.007). In multivariate analysis, independent factors predicting shorter survival were ≥10 prior treatments (vs. <10 prior treatments) (HR = 3.27; 95% CI 1.37, 7.81; p = 0.0077), ECOG performance status 2–3 (vs. 0–1) (HR = 2.92; 95% CI 1.28, 6.66; p = 0.01), and albumin < 3.5 g/dL (vs. > 3.5g/dL) (hazard ratio [HR] = 2.88; 95% CI; 1.41, 5.89; p = 0.004). Of 78 patients treated on a first phase I trial, 14 (18%) demonstrated stable disease (SD), with a median duration of 18 weeks (range 10–25). Of those 19 patients treated on a second phase I trial, 6 (32%) had SD with a median duration of 12 weeks (range 8–17). Two of 4 (50%) patients treated on a third phase I trial had SD with a median duration of 20 weeks (range 16–24). Conclusions: Patients with metastatic breast cancer referred for our phase I studies had a median survival of 6.6 months. In this preliminary analysis, independent factors predicting shorter survival were ≥ 10 prior treatments, worsening ECOG performance status and low albumin levels.

No significant financial relationships to disclose.

A first-in-human phase I trial of PBI-05204 (oleandrin), an inhibitor of Akt, FGF-2, NF-Kb, and p70S6K in advanced solid tumor patients

3537

Background: PBI-05204 contains oleandrin, a cardiac glycoside, which inhibits the α-3 subunit Na-K ATPase pump. Over-expression of the α-3 subunit in malignant cells correlates with the tumor proliferation. Oleandrin inhibits FGF- 2 export and activation of NF-Kβ and inhibits phosphorylation of Akt. PBI-05204 also inhibits p70S6K, decreasing mTOR activity. In this ongoing study of PBI-05204, we sought to determine the DLTs, MTD and recommended phase II dose in advanced solid tumors patients (pts) and to characterize its’ pharmacokinetics (PK) and pharmacodynamics (PD). Methods: This was a standard 3+3 phase I design. PBI-05240 was given orally for 21 days of 28 days. Dose was increased by 100% if no related grade 2 adverse event (AE) was observed and increased by 50% if a grade 2 AE occurred. If no other grade 2 AE were observed then subsequent dose escalation was resumed at 100%. In order to determine drug-mediated changes in pAkt, p70S6K, and S6 (mTOR effectors) expression as a surrogate marker of target effect, peripheral blood mononuclear cells (PBMCs) were obtained in addition to PKs. Results: To date 15 pts have received PBI-05204 at 5 dose levels (0.6 mg to 10.2 mg/day), 2 pts are currently active at dose level 5. No DLT has been observed thus far. 10 out of 15 pts (67%) experienced only grade 1 AEs, most common: fatigue and constipation (20%). No significant cardiac toxicities have been observed, only first degree AV block and grade 2 PVC's. Of the 15 evaluable pts, 3 had stable disease for > 4 months, with bladder, colorectal, and fallopian tube cancer pts having an 11, 16, and 10% reduction by RECIST respectively. PKs initially show dose-dependent peak plasma oleandrin concentrations are reached at 2–4 hr following administration with > 50% cleared in 6 hrs. Western blots of PBMCs showed PBI-05204 markedly reduced phosphorylation of Akt, p70S6K, and S6 in a time dependent manner in 4 pts (1 at dose level 2, and 3 and 2 at dose level 5). Reduction of these effectors was observed concomitantly with relatively higher levels of Na, K-ATPase α-3 subunit expression. Conclusions: PBI-05204 is tolerated up to 10.2/mg/day with very little AE's or cardiotoxicity. Initial response evaluation shows activity in diverse tumors with PD analysis suggesting target effect.

[Table: see text]

A phase I trial of liposomal doxorubicin (D), bevacizumab (A), and temsirolimus (T) in advanced malignancy

e13508

Background: Liposomal doxorubicin (D) and bevacizumab (A) are active drugs in multiple malignancies. Unfortunately, resistance mechanisms have been described for each that limit their efficacy following repeated exposure. These include aberrant activation of alternate signaling pathways, such as PI3K/AKT/mTOR and upregulation of hypoxia inducible factor (HIF-1α). We therefore added temsirolimus (T), an agent known to inhibit mTOR and to downregulate HIF-1α, to the combination of D and A. The objectives of this trial were to assess the safety of this combination, obtain preliminary efficacy data and to identify biologic correlates for treatment response. Methods: D, A and T were administered intravenously on a 21 day cycle. D, A and T were given day 1, and T was administered alone weeks 2 and 3. A standard 3+3 trial design was used for dose escalation; 6 dose levels are planned. Patient serum and biopsies were also collected pre- and post-treatment for batched analysis to assess biologic response correlates. Results: 6/12 treated patients are evaluable (remaining patients have not yet completed 1st restaging). 5 patients are male; median age (all patients) 53, range 12 to 59. Median number of prior treatments = 5, range 2 - 8. At first restaging, 2/2 patients with endometrial cancer were found to have ≥ 25% decrease in tumor size (RECIST), and one patient with colorectal carcinoma had a 15% decrease. 1 patient had stable disease. One of the patients with endometrial cancer and extensive intra-abdominal disease who showed rapid tumor regression (≥ 25% decrease at 2 months) developed an entero-colonic fistula, and chose hospice care. Grade 2 stomatitis and fatigue (CTCAEv3)have also been seen. The current doses being used are 20mg/m2 of D and 5mg/m2 of A every 21 days, and 25mg of T every 7 days (dose level 3). Conclusions: Preliminary data indicate that the combination of D, A and T has anti-tumor activity and is well tolerated at the doses used. Patients with intra-abdominal disease who experience rapid tumor regression may be at risk for fistula formation. Biomarker analysis for modulation of the mTOR signal (via PI3K mutations or other aberrations) and the HIF-1α pathway is ongoing.

No significant financial relationships to disclose.

Hypoxia-inducible factor-1α (HIF-1α) modulation in combination with anti-angiogenic therapy

3555

Background: HIF-1α mediates adaptive responses to hypoxic conditions induced by anti-angiogenic therapy. Bortezomib has demonstrated the ability to inhibit transcriptional activity of HIF-1α. We hypothesized that the addition of bortezomib to bevacizumab would augment response, and we performed this phase I trial to assess safety, MTD, and correlative studies of anti-angiogenic activity. Methods: Patients with advanced malignancy refractory to standard therapy were eligible. Cohorts of 6 patients received bevacizumab and bortezomib on a 3-week cycle, with a stair-step dose escalation design. Pharmacodynamic assessment included plasma VEGF, VEGFR2, 20S proteasome inhibition, DCE-MRI, and tumor expression of HIF-1α, VEGF, VEGFR2, and polymorphisms of VEGF and VEGFR2. Results: 71 patients were treated, and the MTD was identified at the highest dose level (bevacizumab 15 mg/kg, bortezomib 1.3 mg/m2). Two partial responses were observed in patients with renal cell carcinoma (RCC) (Total patients with RCC = 6). Minor responses or stable disease lasting ≥4 months was achieved in 8 patients, including RCC (1), breast (1), leiomyosarcoma (1), nasopharyngeal (2), hepatocellular (1), neuroendocrine (1), lacrimal gland adenocystic carcinoma (1). The most common drug-related toxicities observed included hypertension (36%), fatigue (34%), thrombocytopenia (29%), and myalgia (19%). 22 patients (31%) experienced no drug-related toxicities greater than grade 1. 56 patients (79%) experienced no drug-related toxicities greater than grade 2. One DLT (G5 bleeding) was observed at the MTD. Plasma VEGF levels demonstrated decreases at 1 and 4 hours post-infusion, followed by increases to levels above baseline on days 2, 3, and at the end of cycle 1. DCE-MRI analysis demonstrated decreases in Ktrans on days 2 and 3. Analysis of HIF-1α expression in biopsies is underway. Conclusions: Combination bevacizumab and bortezomib is well-tolerated and has demonstrated clinical activity in patients with previously treated, advanced malignancy. Pharmacodynamic assessment with biomarkers and DCE-MRI suggests that inhibition of angiogenic activity was achieved. Updated clinical and biomarker data will be presented.

No significant financial relationships to disclose.

High expression of the chemokine receptor CXCR4 is associated with estrogen receptor-negative breast cancer

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Background: Chemokine receptor CXCR4 and its ligand CXCL12 (SDF-1alpha) are important in the metastatic spread of breast cancer. Previous studies have shown that CXCR4 is overexpressed in breast cancers as compared to normal breast tissue and that estradiol increases levels of CXCL12. The association between CXCR4 and estrogen receptor (ER) status is unclear. Methods: We performed genome-wide molecular analysis of 61 primary breast cancer tissue samples. Total RNA was extracted and hybridized to Affymetrix HG-U133 oligonucleotide microarrays, and differentially expressed genes between groups were identified using a Welch t-test. CXCR4 protein expression was evaluated by immunohistochemistry (IHC) using a monoclonal antibody (R&D Systems, Minneapolis, MN). We characterized CXCR4 nuclear staining as high vs low-medium. Several clinico-pathologic variables were correlated with CXCR4 expression. Results: A predominantly nuclear staining pattern was noted for CXCR4. Of 61 primary tumors, 15 had high nuclear expression and 46 had low-medium expression. High levels of nuclear CXCR4 expression were significantly correlated with ER-negativity (p =0.0005). CXCR4 protein expression had no association with Her-2 status (gene copy number or IHC 3+), tumor size, or lymph node status. Using p<0.001, protein expression of CXCR4 was associated with 105 significantly differentially expressed genes including relative under expression of ER and ER-related genes and over expression of VEGF. Conclusion: High nuclear protein expression levels of CXCR4 in primary breast cancers are significantly associated with ER-negativity and with low differential expression of ER and ER-related genes. Since estrogen may play a role in CXCR4 activation, further investigation of the association of high CXCR4 expression and ER-negativity is planned.

No significant financial relationships to disclose.