Antitumor activity, and antiangiogenic activity of nanoparticle albumin-bound nab-rapamycin in combination with nab-paclitaxel

Abstract #3125

Background: Rapamycin inhibits downstream signals from the mammalian target of rapamycin (mTOR), a known kinase member of a signaling pathway that promotes tumor growth. Rapamycin's poor aqueous solubility and poor chemical stability have limited its development as an intravenous (IV) anticancer agent. Nab-rapamycin utilizes the albumin-bound technology to allow for IV administration of rapamycin and has demonstrated dose-linear pharmacokinetics and safety up to 90 mg/kg with effective antitumor activity at 40 mg/kg against a human panel of tumor xenografts. This study investigated the efficacy of combined therapy with nab-paclitaxel (Abraxane®) utilizing invasive human breast (MDA-MB-231) and colon (HT29) cancer xenograft models.
 Material and Methods: Xenograft transplants using luciferase-tagged MDA-MB-231 cells were implanted into mammary fatpad of SCID mice and allowed to reach 460 mm3 in size prior to IV administration of saline (vehicle, n = 9); nab-rapamycin, 3x wkly for 2 wks at 40 mg/kg (nab-rap-2W; n = 8); nab-rapamycin, 3x wkly for 4 wks at 40 mg/kg (nab-rap-4W; n = 8); Abraxane, qdx5 at 30 mg/kg (ABX; n = 8); nab-rap-2W + ABX (n = 9); or nab-rap-4W + ABX (n = 8). HT29 xenografts were also treated with nab-rap-4W (n = 8) and nab-rap-4W + ABX (10 mg/kg, qdx5, IP, n = 8). The in vivo antiangiogenic effect of nab-rapamycin was evaluated using the standard in vivo chick chorioallantoic membrane (CAM) assay with 3-day old embryos (n = 18).
 Results: Relative to vehicle controls, nab-rap-2W (P < 0.00011), nab-rap-4W (P < 0.0001), and ABX (P < 0.0001) were effective against MDA-MB-231 tumor xenograft models with tumor growth inhibition (TGI) of 60%, 66%, and 73% respectively. Additive antitumor effects were observed with combination of nab-rapamycin + ABX with TGI of 81% and 86% for nab-rap-2W + ABX and nab-rap-4W + ABX groups, respectively. For HT29 tumors, the combination of ABX and nab-rapamycin also showed greater TGI (89%) compared to nab-rapamycin alone (81%). In the chick CAM assay, nab-rapamycin demonstrated antiangiogenic efficacy at doses of 10 µg and above without affecting embryo viability.
 Conclusions: Combination therapy of nab-rapamycin and Abraxane was more effective at inhibiting breast and colon xenograft tumor growth than single therapy of either drug. The enhanced antitumor activity seen with combined nab-rapamycin-Abraxane may in part be due to the observed antiangiogenic activity of nab-rapamycin.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3125.

Preliminary progression free survival and SPARC tumor correlatives from a phase II neoadjuvant trial of gemcitabine, epirubicin, and nab paclitaxel

Abstract #5116

Background: Neoadjuvant combinations of gemcitabine (G), anthracyclines and taxanes have demonstrated significant activity with pCR rates of 20-25% albeit with significant myelosuppression. Secreted protein acidic rich in cysteine (SPARC) is an albumin binding protein that mediates intratumoral accumulation of nab-paclitaxel (nab-P) via a SPARC-albumin specific binding activity. This study was designed to evaluate a biweekly schedule of neoadjuvant nab paclitaxel (nab-P) with gemcitabine and epirubicin (E). SPARC tumor assessments were performed in consenting patients (pts) with subsequent pathologic and survival correlatives.
 Methods: Eligibility: Clinical T1c-T4d and/or N0-3, M0 breast cancer (T1N0M0 excluded), ECOG PS 0-2, normal LVEF. ER/PR/HER2 obtained for all pts. Treatment: 6 cycles neoadjuvant G 2000 mg/m2, E 50 mg/m2, and nab-P 175 mg/m2 q14 days followed by surgery. Post operative therapy: 4 cycles G 2000 mg/m2 and nab-P 220 mg/m2 q14 days. Myeloid growth factors were mandated with all cycles. 2 antibody reagents were used to probe for SPARC expressions. For this study, level 3 immunohistochemical (IHC) SPARC staining was considered positive. Results: 123 pts have enrolled with pathologic responses available for 106. 82 pts consented to SPARC testing. Median age 51 (29-72). Median tumor size 4.5 cm. Histology: 81% ductal, 10% lobular, 9% other. 42% ER and PR negative. 55% clinical T3/T4 and 66% lymph node positive at presentation. G3/4 toxicity present in >5% of pts: neutropenia 16% (febrile neutropenia 1 pt), thrombocytopenia 9% with arthralgias 11%, fatigue 10%, and infection 7%. 20 pts did not complete study treatment for the following reasons: disease progression 7, toxicity 3, pt/MD request 5, and other 5. pCR was noted in 23 pts (22%) with PRs in 76 pts (71%), and 6 SD. SPARC IHC staining was available for 76 tumors. SPARC level 3 IHC staining was noted in 65 tumors (86%); 65% were associated with a PR or pCR. Median PFS was 23 months and overall survival at 24 months is 77%. Pts who relapsed ≤16 months from diagnosis were more likely to be triple negative (p = 0.04), or ER negative (p = 0.001), or PR negative (p = 0.0006). Conclusions: Neoadjuvant dose dense GEA is active and better tolerated than other gemcitabine/anthracycline/taxane combinations. The pCR rate of 22% compares favorably with other comparable neoadjuvant regimens albeit with minimal toxicity. Pts with early relapse defined as ≤16 months from diagnosis were more likely to demonstrate a triple negative phenotype or demonstrate estrogen or progesterone receptor negativity. SPARC tumor correlatives with progression free and overall survival are on ongoing and will be presented.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5116.

Mechanisms of nab-paclitaxel and bevacizumab cooperation in inhibition of breast tumor growth and metastasis

Abstract #1032

Background: Nab-paclitaxel, also known as Abraxane®, is paclitaxel formulated in nanoparticles that consist of human albumin encapsulating the hydrophobic drug moiety. This drug has shown numerous advantages including linear pharmacokinetics, significantly higher tumor retention, and increased maximal-tolerated dose due to reduced toxicity. We previously showed that combination of Abraxane and anti-VEGF-A antibody, bevacizumab, is significantly more efficacious in suppression of breast tumor xenografts and metastasis as compared to treatments with each of these drugs alone. We hypothesized that the mechanism underlying the therapeutic success of the combined therapy might include bevacizumab-dependent abrogation of the stress response elicited by paclitaxel in the tumor cells surviving chemotherapy.
 Materials and Methods: Cultured MDA-MB-231 cells were treated with 0, 2.5, 5, 10, and 30 nM of Abraxane followed by detection of angiogenic (VEGF-A), prosurvival (p42 & p44 kinase, bcl-2) and inflammatory (IL-6, IL-8, and TNF-α) proteins using Western blotting and ELISA. MDA-MB-231 tumors were extracted from mice upon cessation of intravenous (IV) Abraxane therapy (10 to 30 mg/kg, qdx5) followed by Western blot and immunohistochemical analyses.
 Results: In vitro, Abraxane treatment increased expression of VEGF-A, p42/44 kinase, bcl-2 as well as total and phosphorylated p65 subunit of NF-κB. Treated cells secreted 25- to 30-fold higher concentrations of inflammatory cytokines IL-6, IL-8, and TNF-α into conditioned media as compared with untreated control cells. Likewise, significant increases in bcl-2 and inflammatory cytokines were observed in tumors extracted immediately after paclitaxel therapy in vivo as confirmed by both Western blotting and immunohistochemical analyses.
 Discussion: These findings suggest that paclitaxel elicits VEGF-A dependent prosurvival and proinflammatory stress responses in tumor cells surviving the cytotoxic therapy. Activation of these pathways suggests that concurrent therapy with VEGF-A neutralizing antibody might significantly improve the efficacy of paclitaxel-based therapies by counteracting the stress responses in the therapy-spared tumor cells.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1032.

Activated effector and memory T cells contribute to circulating sCD30: potential marker for islet allograft rejection

T-cell activation up-regulates CD30 resulting in an increase in serum soluble CD30 (sCD30). CD4+ T cells, a major source for sCD30, play a significant role in the pathogenesis of rejection. In this study, sCD30 was measured pre- and posttransplant in mouse islet allograft models and human islet allograft recipients. sCD30 was measured by ELISA in diabetic C57BL/6, CD4Knockout (KO) and CD8KO islet allograft recipients. sCD30 increased significantly prior to rejection (1.8 +/- 1 days) in 80% of allograft recipients. Sensitization with donor splenocytes, or a second graft, further increased sCD30 (282.5 +/- 53.5 for the rejecting first graft vs. 374.6 +/- 129 for the rejecting second graft) prior to rejection suggesting memory CD4+ T cells contribute to sCD30. CD4KO failed to reject islet allograft and did not demonstrate sCD30 increase. CD8KO showed elevated (227 +/- 107) sCD30 (1 day) prior to rejection. High pretransplant sCD30 (>20 U/ml) correlated with poor outcome in human islet allograft recipients. Further, increase in sCD30 posttransplant preceded (3-4 months) loss of islet function. We conclude that sCD30 is released from activated CD4 T cells prior to islet allograft rejection and monitoring sCD30 can be a valuable adjunct in the follow-up of islet transplant recipients.

Choices: a study of preferences for end-of-life treatments in patients with advanced heart failure

BACKGROUND

The purpose of this study is to describe the treatment preferences of patients with heart failure among three distinct treatment options--optimal medical management, oral inotropes or left ventricular device (LVAD) support--to determine if there were differences in preferences between patients with mild heart failure (New York Heart Association [NYHA] Class II) and severe heart failure (NYHA Class IV), and also to determine whether quality of life, perceived severity of symptoms and overall health influenced treatment preferences.

METHODS

We enrolled 91 patients who completed the Minnesota Living with Heart Failure Questionnaire (MLHFQ); visual analog scales for depicting their perceived severity of overall health, dyspnea and fatigue; and a treatment trade-off tool.

RESULTS

The most preferred treatment options were oral inotropes, LVAD and standard medical management. There were no differences in treatment preferences between NYHA II and NYHA IV patients. Patient preferences correlated poorly with MLHFQ, symptom and overall health scores. Although not statistically significant, there was a trend toward patients with worse quality of life and symptom scores preferring more aggressive treatment.

CONCLUSIONS

The results of our study identified two distinct groups of patients: one group preferring treatments that prolonged survival time and another group that favored strategies that improved quality of life but reduced survival time. Treatment preferences were independent of functional or symptom status, suggesting that preferences may be decided early in the course of illness.

Myotonic dystrophy in a patient of celiac disease: a new association?

Celiac disease (CD) has long been known to be associated with neurological and psychiatric manifestations; its in association with myotonic dystrophy however has not yet been reported. We report the case of a 27-year old female patient who presented to us with diarrhoea, weight loss, easy fatigability, irritability and alopecia of 8 months duration and was diagnosed to have celiac disease and put on gluten free diet. 8 weeks later she developed neurological symptoms and was found to have myotoni dystrophy in addition. At six month follow up patient had gained 5 kg, but the neurological symptoms remained the same. Treatment of neurological symptoms associated with gluten hypersensitivity depends on the type of neurological syndrome associated. Only exceptionally do these symptoms improve with gluten restriction and, in some patients, the neurological manifestations even progress despite resolution of both pathologic findings and intestinal symptoms.