Vascular endothelial growth factor (VEGF) receptor-mediated signaling contributes to ovarian cancer pathogenesis. Elevated VEGF expression is associated with poor clinical outcomes. We investigated ramucirumab, a fully human anti-VEGFR-2 antibody, in patients with persistent or recurrent epithelial ovarian, fallopian tube, or primary peritoneal carcinoma. Primary endpoints were progression-free survival at 6 months (PFS-6) and confirmed objective response rate (ORR).
Women who received ≥ 1 platinum-based chemotherapeutic regimen and had a platinum-free interval of < 12 months with measurable disease were eligible. Patients received 8 mg/kg ramucirumab intravenously every 2 weeks.
Sixty patients were treated; one patient remained on study as of September 2013. The median age was 62 years (range: 27–80), and median number of prior regimens was 3. Forty-five (75%) patients had platinum refractory/resistant disease. Thirty-nine patients (65.0%) had serous tumors. PFS-6 was 25.0% (n = 15/60, 95% CI: 14.7–37.9%). Best overall response was: partial response 5.0% (n = 3/60), stable disease 56.7% (n = 34/60), and progressive disease 33.3% (n = 20/60). The most common treatment-emergent adverse events possibly related to study drug were headache (65.0%; 10.0% Grade ≥ 3), fatigue (56.7%; 3.3% Grade ≥ 3), diarrhea (28.3%; 1.7% Grade ≥ 3), hypertension (25.0%; 3.3% Grade ≥ 3), and nausea (20.0%; no Grade ≥ 3). Two patients experienced intestinal perforations (3.3% Grade ≥ 3). Pharmacodynamic analyses revealed changes in several circulating VEGF proteins following initial ramucirumab infusion, including increased VEGF-A, PlGF and decreased sVEGFR-2.
Although antitumor activity was observed, the predetermined efficacy endpoints were not met.
Angiogenesis; Antiangiogenic; VEGF; Clear cell; Resistant
Mammalian target of rapamycin (mTOR) represents a key downstream intermediate for a myriad of oncogenic receptor tyrosine kinases. In the case of the insulin-like growth factor (IGF) pathway, the mTOR complex (mTORC1) mediates IGF-1 receptor (IGF-1R)-induced estrogen receptor alpha (ERα) phosphorylation/activation and leads to increased proliferation and growth in breast cancer cells. As a result, the prevalence of mTOR inhibitors combined with hormonal therapy has increased in recent years. Conversely, activated mTORC1 provides negative feedback regulation of IGF signaling via insulin receptor substrate (IRS)-1/2 serine phosphorylation and subsequent proteasomal degradation. Thus, the IGF pathway may provide escape (e.g. de novo or acquired resistance) from mTORC1 inhibitors. It is therefore plausible that combined inhibition of mTORC1 and IGF-1R for select subsets of ER-positive breast cancer patients presents as a viable therapeutic option.
Using hormone-sensitive breast cancer cells stably transfected with the aromatase gene (MCF-7/AC-1), works presented herein describe the in vitro and in vivo antitumor efficacy of the following compounds: dalotuzumab (DALO; “MK-0646”; anti-IGF-1R antibody), ridaforolimus (RIDA; “MK-8669”; mTORC1 small molecule inhibitor) and letrozole (“LET”, aromatase inhibitor).
With the exception of MK-0646, all single agent and combination treatment arms effectively inhibited xenograft tumor growth, albeit to varying degrees. Correlative tissue analyses revealed MK-0646 alone and in combination with LET induced insulin receptor alpha A (InsR-A) isoform upregulation (both mRNA and protein expression), thereby further supporting a triple therapy approach.
These data provide preclinical rationalization towards the combined triple therapy of LET plus MK-0646 plus MK-8669 as an efficacious anti-tumor strategy for ER-positive breast tumors.
Electronic supplementary material
The online version of this article (doi:10.1186/s12885-016-2847-3) contains supplementary material, which is available to authorized users.
Receptor, IGF type 1; Receptor, Insulin; mTOR inhibitor; Drug resistance, Neoplasm; Breast neoplasms/drug therapy; Aromatase inhibitors/therapeutic use; Disease models, Animal
The many improvements in breast cancer therapy in recent years have so lowered rates of recurrence that it is now difficult or impossible to conduct adequately powered adjuvant clinical trials. Given the many new drugs and potential synergistic combinations, the neoadjuvant approach has been used to test benefit of drug combinations in clinical trials of primary breast cancer. A recent FDA-led meta-analysis showed that pathologic complete response (pCR) predicts disease-free survival (DFS) within patients who have specific breast cancer subtypes. This meta-analysis motivated the FDA's draft guidance for using pCR as a surrogate endpoint in accelerated drug approval. Using pCR as a registration endpoint was challenged at ASCO 2014 Annual Meeting with the presentation of ALTTO, an adjuvant trial in HER2-positive breast cancer that showed a nonsignificant reduction in DFS hazard rate for adding lapatinib, a HER-family tyrosine kinase inhibitor, to trastuzumab and chemotherapy. This conclusion seemed to be inconsistent with the results of NeoALTTO, a neoadjuvant trial that found a statistical improvement in pCR rate for the identical lapatinib-containing regimen. We address differences in the two trials that may account for discordant conclusions. However, we use the FDA meta-analysis to show that there is no discordance at all between the observed pCR difference in NeoALTTO and the observed HR in ALTTO. This underscores the importance of appropriately modeling the two endpoints when designing clinical trials. The I-SPY 2/3 neoadjuvant trials exemplify this approach.
The majority of ovarian cancer patients acquire resistance to standard platinum chemotherapy and novel therapies to reduce tumor burden and ascites accumulation are needed. Pregnancy-associated plasma protein-A (PAPP-A) plays a key role in promoting insulin-like growth factor (IGF) pathway activity, which directly correlates to ovarian cancer cell transformation, growth and invasiveness. Herein, we evaluate PAPP-A expression in tumors and ascites of women with ovarian cancer, and determine the anti-tumor efficacy of a neutralizing monoclonal PAPP-A antibody (mAb-PA) in ovarian cancer using primary patient ovarian tumorgrafts (“Ovatars”).
PAPP-A mRNA expression in patient ovarian tumors correlated with poor outcome and was validated as a prognostic surrogate in Ovatar tumors. Following confirmation of mAb-PA bioavailability and target efficacy in vivo, the anti-tumor efficacy of mAb-PA in multiple Ovatar tumor models was examined and the response was found to depend on PAPP-A expression. Strikingly, the addition of mAb-PA to standard platinum chemotherapy effectively sensitized platinum-resistant Ovatar tumors. PAPP-A protein in ascites was also assessed in a large cohort of patients and very high levels were evident across the entire sample set. Therefore, we evaluated targeted PAPP-A inhibition as a novel approach to managing ovarian ascites, and found that mAb-PA inhibited the development, attenuated the progression and induced the regression of Ovatar ascites.
Together, these data indicate PAPP-A as a potential palliative and adjunct therapeutic target for women with ovarian cancer.
Ovarian cancer; pregnancy-associated plasma protein-A; insulin-like growth factor; ascites; predictive biomarker; antibody therapy
Innovation in oncology drug development has been hindered by lack of preclinical models that reliably predict clinical activity of novel therapies in cancer patients. Increasing desire for individualize treatment of patients with cancer has led to an increase in the use of patient-derived xenografts (PDX) engrafted into immune-compromised mice for preclinical modeling. Large numbers of tumor-specific PDX models have been established and proved to be powerful tools in pre-clinical testing. A subset of PDXs, referred to as Avatars, establish tumors in an orthotopic and treatment naïve fashion that may represent the most clinical relevant model of individual human cancers. This review will discuss ovarian cancer (OC) PDX models demonstrating the opportunities and limitations of these models in cancer drug development, and describe concepts of clinical trials design in Avatar guided therapy.
Ovarian cancer (OC); model systems; patient-derived xenografts (PDX); xenograft models; personalized medicine; clinical trial design
The mammalian target of rapamycin (mTOR) plays a critical role in promoting tumor cell growth and is frequently activated in breast cancer. In preclinical studies, the antitumor activity of mTOR inhibitors is attenuated by feedback up-regulation of AKT mediated in part by Insulin-like growth factor type 1 receptor (IGF-1R). We designed a phase I trial to determine the maximum-tolerated dose (MTD) and pharmacodynamic effects of the IGF-1R antibody Cixutumumab in combination with temsirolimus in patients with metastatic breast cancer refractory to standard therapies. A 3 + 3 Phase I design was chosen. Temsirolimus and Cixutumumab were administered intravenously on days 1, 8, 15, and 22 of a 4-week cycle. Of the 26 patients enrolled, four did not complete cycle 1 because of disease progression (n = 3) or comorbid condition (n = 1) and were replaced. The MTD was determined from the remaining 22 patients, aged 34–72 (median 48) years. Most patients (86 %) had estrogen receptor positive cancer. The median number of prior chemotherapy regimens for metastatic disease was 3. The MTD was determined to be Cixutumumab 4 mg/kg and temsirolimus 15 mg weekly. Dose-limiting toxicities (DLTs) included mucositis, neutropenia, and thrombocytopenia. Other adverse events included grade 1/2 fatigue, anemia, and hyperglycemia. No objective responses were observed, but four patients experienced stable disease that lasted for at least 4 months. Compared with baseline, there was a significant increase in the serum levels of IGF-1 (p < 0.001) and IGFBP-3 (p = 0.019) on day 2. Compared with day 2, there were significant increases in the serum levels of IGF-1 (p < 0.001), IGF-2 (p = 0.001), and IGFBP-3 (p = 0.019) on day 8. A phase II study in women with metastatic breast cancer is ongoing.
Cixutumumab; Temsirolimus; Metastatic breast cancer; IGF-1R; mTOR
Chemotherapy-induced peripheral neuropathy (CIPN) is a significant side effect of taxane and platinum based chemotherapy. Several studies have supported the potential benefit of glutathione for the prevention of platinum-induced CIPN. The current trial was designed to determine whether glutathione would prevent CIPN as a result of carboplatin/paclitaxel therapy.
185 patients undergoing treatment with paclitaxel and carboplatin were accrued between 12/04/2009 and 12/19/2011. Patients were randomized to receive either placebo (n=91) or 1.5 g/m2 glutathione (n=94) over 15 minutes immediately prior to chemotherapy. CIPN was assessed using the EORTC-CIPN20 sensory subscale and the NCI Common Terminology Criteria for Adverse Events (CTCAE), version 4.0.
There were no statistically significant differences between the two study arms with regard to 1) peripheral neurotoxicity, assessed utilizing both EORTC-QLQ-CIPN20 (p=0.21) and CTCAE scales (p=0.449 for grade 2+ neurotoxicity; p=0.039 for time to development of grade 2+ neuropathy, in favor of the placebo); 2) the degree of the paclitaxel acute pain syndrome (p=0.30 for patients who received every 3–4 week paclitaxel vs. p=0.002, in favor of the placebo, for patients who received weekly paclitaxel); 3) the time to disease progression (p=0.63); or 4) apparent toxicities. Subgroup analysis did not reveal any evidence of benefit in any particular subgroup.
This study does not support the use of glutathione for the prevention of paclitaxel/carboplatin-induced CIPN.
glutathione; chemotherapy induced peripheral neuropathy; prevention; paclitaxel; carboplatin
Ovarian carcinosarcoma is a rare subtype of ovarian cancer with poor clinical outcomes. The low incidence of this disease makes accrual to large clinical trials challenging. However, studies have shown that treatment responses in patient-derived xenograft (PDX) models correlate with matched-patient responses in the clinic, supporting their use for preclinical testing of standard and novel therapies. An ovarian carcinosarcoma PDX is presented herein and showed resistance to carboplatin and paclitaxel (similar to the patient) but exhibited significant sensitivity to ifosfamide and paclitaxel. The PDX demonstrated overexpression of EGFR mRNA and gene amplification by array comparative genomic hybridization (log2 ratio 0.399). EGFR phosphorylation was also detected. Angiogensis and insulin-like growth factor pathways were also implicated by overexpression of VEGFC and IRS1. In order to improve response to chemotherapy, the PDX was treated with carboplatin/paclitaxel with or without a pan-HER and VEGF inhibitor (BMS-690514) but there was no tumor growth inhibition or improved animal survival, which may be explained by a KRAS mutation. Resistance was also observed when the IGF-1R inhibitor BMS-754807 was combined with carboplatin/paclitaxel. Because poly (ADP-ribose) polymerase inhibitors have activity in ovarian cancer patients, with and without BRCA mutations, ABT-888 was also tested but found to have no activity. Pathogenic mutations were also detected in TP53 and PIK3CA. In conclusion, ifosfamide/paclitaxel was superior to carboplatin/paclitaxel in this ovarian carcinosarcoma PDX and gene overexpression or amplification alone was not sufficient to predict response to targeted therapy. Better predictive markers of response are needed.
This phase I, multicenter, open-label, single-arm, dose-escalation, and dose-expansion study evaluated the safety, tolerability, and antitumor activity of MEDI-573 in adults with advanced solid tumors refractory to standard therapy or for which no standard therapy exists.
Patients received MEDI-573 in 1 of 5 cohorts (0.5, 1.5, 5, 10, or 15 mg/kg) dosed weekly or 1 of 2 cohorts (30 or 45 mg/kg) dosed every 3 weeks. Primary end points included the MEDI-573 safety profile, maximum tolerated dose (MTD), and optimal biologic dose (OBD). Secondary end points included MEDI-573 pharmacokinetics (PK), pharmacodynamics, immunogenicity, and antitumor activity.
In total, 43 patients (20 with urothelial cancer) received MEDI-573. No dose-limiting toxicities were identified, and only 1 patient experienced hyperglycemia related to treatment. Elevations in levels of insulin and/or growth hormone were not observed. Adverse events observed in >10% of patients included fatigue, anorexia, nausea, diarrhea, and anemia. PK evaluation demonstrated that levels of MEDI-573 increased with dose at all dose levels tested. At doses >5 mg/kg, circulating levels of insulin-like growth factor (IGF)-I and IGFII were fully suppressed. Of 39 patients evaluable for response, none experienced partial or complete response and 13 had stable disease as best response.
The MTD of MEDI-573 was not reached. The OBD was 5 mg/kg weekly or 30 or 45 mg/kg every 3 weeks. MEDI-573 showed preliminary antitumor activity in a heavily pretreated population and had a favorable tolerability profile, with no notable perturbations in metabolic homeostasis.
Edmonston vaccine strains of measles virus (MV) have significant antitumor activity in mouse xenograft models of ovarian cancer. MV engineered to express the sodium iodide symporter gene (MV-NIS) facilitates localization of viral gene expression and offers a tool for tumor radiovirotherapy. Here, we report results from a clinical evaluation of MV-NIS in patients with taxol- and platinum-resistant ovarian cancer. MV-NIS was given intraperitoneally every 4 weeks for up to 6 cycles. Treatment was well tolerated and associated with promising median overall survival in these patients with heavily pretreated ovarian cancer; no dose-limiting toxicity was observed in 16 patients treated at high-dose levels (108–109 TCID50), and their median overall survival of 26.5 months compared favorably with other contemporary series. MV receptor CD46 and nectin-4 expression was confirmed by immunohistochemistry in patient tumors. Sodium iodide symporter expression in patient tumors after treatment was confirmed in three patients by 123I uptake on SPECT/CTs and was associated with long progression-free survival. Immune monitoring posttreatment showed an increase in effector T cells recognizing the tumor antigens IGFBP2 and FRα, indicating that MV-NIS treatment triggered cellular immunity against the patients' tumor and suggesting that an immune mechanism mediating the observed antitumor effect. Our findings support further clinical evaluation of MV-NIS as an effective immunovirotherapy.
Ovarian cancer has a high recurrence and mortality rate. A barrier to improved outcomes includes a lack of accurate models for preclinical testing of novel therapeutics.
Clinically-relevant, patient-derived tumorgraft models were generated from sequential patients and the first 168 engrafted models are described. Fresh ovarian, primary peritoneal, and fallopian tube carcinomas were collected at the time of debulking surgery and injected intraperitoneally into severe combined immunodeficient mice.
Tumorgrafts demonstrated a 74% engraftment rate with microscopic fidelity of primary tumor characteristics. Low-passage tumorgrafts also showed comparable genomic aberrations with the corresponding primary tumor and exhibit gene set enrichment of multiple ovarian cancer molecular subtypes, similar to patient tumors. Importantly, each of these tumorgraft models are annotated with clinical data and for those that have been tested, response to platinum chemotherapy correlates with the source patient.
Presented herein is the largest known living tumor bank of patient-derived, ovarian tumorgraft models that can be applied to the development of personalized cancer treatment.
Severe combined immunodeficient (SCID) mouse; xenograft; intraperitoneal; heterotransplantation; orthotopic; preclinical
Reduced CYP2D6 metabolism and low Z-endoxifen (ENDX) concentrations may increase the risk of breast cancer recurrence in tamoxifen (TAM)-treated women. Little is known regarding the differences between TAM and ENDX murine pharmacokinetics or the effect of administration route on plasma concentrations of each drug.
The pharmacokinetics of TAM and ENDX were characterized in female mice.
For subcutaneous [s.c.] and oral TAM (4, 10 and 20 mg/kg), TAM AUC increased in a linear manner, but concentrations of the active metabolites [ENDX and 4-hydroxytamoxifen (4HT)] remained low. For oral TAM (20 mg), 4HT concentrations were tenfold greater (>25 ng/ml) than achievable in TAM-treated humans. Both oral (10–200 mg/kg) and s.c. (2.5–25 mg/kg) ENDX·HCl resulted in a greater than dose-proportional increase in AUC, with eightfold greater ENDX concentrations than an equivalent TAM dose. ENDX accumulated in plasma after 5-day dosing of 25 or 100 mg/kg ENDX·HCl and exceeded target concentrations of 0.1 and 1.0 μM, respectively, by twofold to fourfold.
In murine models, oral ENDX yields substantially higher ENDX concentrations, compared to TAM. The low 4HT and ENDX concentrations observed in mice receiving s.c. TAM mirror the TAM pharmacokinetics in humans with impaired CYP2D6 metabolism. These data support the ongoing development of ENDX as a novel agent for the endocrine treatment of ER-positive breast cancer.
Endoxifen; Tamoxifen; Mouse; Pharmacokinetics; Estrogen receptor; MCF7
Type 1 insulin like growth factor receptor (IGF-1R) targeted therapies showed compelling pre-clinical evidence; however, to date, this has failed to translate into patient benefit in Phase 2/3 trials in unselected patients. This was further complicated by the toxicity, including hyperglycemia, which largely results from the overlap between IGF and insulin signaling systems and associated feedback mechanisms. This has halted the clinical development of inhibitors targeting IGF signaling, which has limited the availability of biopsy samples for correlative studies to understand biomarkers of response. Indeed, a major factor contributing to lack of clinical benefit of IGF targeting agents has been difficulty in identifying patients with tumors driven by IGF signaling due to the lack of predictive biomarkers. In this review, we will describe the IGF system, rationale for targeting IGF signaling, the potential liabilities of targeting strategies, and potential biomarkers that may improve success.
insulin receptor; insulin-like growth factor receptor; IGF binding proteins; biomarker discovery; IGF system and signaling; insulin receptor substrate proteins; endocrine system diseases; targeted therapies
Ovarian cancer mortality ranks highest among all gynecological cancers with growth factor pathways playing an integral role in tumorigenesis, metastatic dissemination and therapeutic resistance. The human epidermal growth factor receptor (HER) and vascular endothelial growth factor receptor (VEGFR) are both overexpressed and/or aberrantly activated in subsets of ovarian tumors. While agents targeting either the HER or VEGF pathways alone have been investigated, the impact of these agents have not led to overall survival benefit in ovarian cancer. We tested the hypothesis that co-targeting HER and VEGFR would maximize anti-tumor efficacy at tolerable doses. To this end, ovarian cancer xenografts grown intraperitoneally in athymic nude mice were tested in response to AC480 (pan HER inhibitor, “HERi”), cediranib (pan VEGFR inhibitor “VEGFRi”), or BMS-690514 (combined HER/VEGFR inhibitor “EVRi”). EVRi was superior to both HERi and VEGFRi in terms of tumor growth, final tumor weight and progression-free survival. Correlative tumor studies employing phosphoproteomic antibody arrays revealed distinct agent-specific alterations, with EVRi inducing the greatest overall effect on growth factor signaling. These data suggest that simultaneous inhibition of HER and VEGFR may benefit select subsets of ovarian cancer tumors. To this end, we derived a novel HER/VEGF signature that correlated with poor overall survival in high-grade, late stage, serous ovarian cancer patient tumors.
Targeted therapy; EVRi; ovarian cancer; VEGF; HER; erbB; AC480; BMS-690514; cediranib
IGF-1R inhibitors arrived in the clinic accompanied by optimism based on preclinical activity of IGF-1R targeting, and recognition that low IGF bioactivity protects from cancer. This was tempered by concerns about toxicity to normal tissue IGF-1R and cross-reactivity with insulin receptor (InsR). In fact, toxicity is not a show-stopper; the key issue is efficacy. While IGF-1R inhibition induces responses as monotherapy in sarcomas and with chemotherapy or targeted agents in common cancers, negative Phase 2/3 trials in unselected patients prompted the cessation of several Pharma programs. Here, we review completed and on-going trials of IGF-1R antibodies, kinase inhibitors and ligand antibodies. We assess candidate bio-markers for patient selection, highlighting the potential predictive value of circulating IGFs/IGFBPs, the need for standardized assays for IGF-1R, and preclinical evidence that variant InsRs mediate resistance to IGF-1R antibodies. We review hypothesis-led and unbiased approaches to evaluate IGF-1R inhibitors with other agents, and stress the need to consider sequencing with chemotherapy. The last few years were a tough time for IGF-1R therapeutics, but also brought progress in understanding IGF biology. Even failed studies include patients who derived benefit; they should be investigated to identify features distinguishing the tumors and host environment of responders from non-responders. We emphasize the importance of incorporating biospecimen collection into trial design, and wording patient consents to allow post hoc analysis of trial material as new data become available. Such information represents the key to unlocking the potential of this approach, to inform the next generation of trials of IGF signalling inhibitors.
IGF; Type 1 IGF receptor; IGF-1R cancer therapy; Therapeutic antibody; Tyrosine kinase inhibitor; Predictive biomarker
In the era of targeted therapies, patients with gynecological malignancies have not yet been major beneficiaries of this new class of agents. This may reflect the fact that the main tumor types, ovarian, uterine and cervical cancers, are a highly heterogeneous group of cancers, with variable response to standard chemotherapies. This is also likely due to poor model development in which to study the diversity of these cancers. Cancer-derived cell lines fail to adequately recapitulate molecular hallmarks of specific cancer subsets and complex microenvironments, which may be critical for sensitivity to targeted therapies. Patient derived xenografts (PDX), using fresh human tumor without prior in vitro culture, combined with whole genome expression, gene copy number and sequencing analyses, could dramatically aid novel therapy development in gynecological malignancies. Gynecological tumors can be engrafted in immunodeficient mice with a high rate of success and within a reasonable time frame. The resulting PDX accurately recapitulate the patient’s tumour in histological, molecular and in vivo treatment response characteristics. Orthotopic PDX develop complications relevant for the clinic, such as ascites and bowel obstruction, providing opportunities for understanding the biology of these clinical problems. Thus, PDX have great promise for delivering improved understanding of gynecological malignancies, serve as better models for designing novel therapies and clinical trials and could underpin individualized, directed therapy for patients from whom PDX models have been established.
ovarian cancer; cervical cancer; model systems
New approaches to drug development are critically needed to lessen the time, cost, and resources necessary to identify and optimize active agents. Strategies to accelerate drug development include testing drugs earlier in the disease process, such as the neoadjuvant setting. The U.S. Food and Drug Administration (FDA) has issued guidance designed to accelerate drug approval through the use of neoadjuvant studies in which the surrogate short-term endpoint, pathologic response, can be used to identify active agents and shorten the time to approval of both efficacious drugs and biomarkers identifying patients most likely to respond. However, this approach has unique challenges. In particular, issues of patient safety are paramount, given the exposure of potentially curable patients to investigational agents with limited safety experience. Key components to safe drug development in the neoadjuvant setting include defining a study population at sufficiently poor prognosis with standard therapy to justify exposure to investigational agents, defining the extent and adequacy of safety data from phase I, detecting potentially harmful interactions between investigational and standard therapies, improving study designs, such as adaptive strategies, that limit patient exposure to ineffective agents, and intensifying safety monitoring in the course of the trial. The I-SPY2 trial is an example of a phase II neoadjuvant trial of novel agents for breast cancer in which these issues have been addressed, both in the design and conduct of the trial. These adaptations of phase II design enable acceleration of drug development by reducing time and cost to screen novel therapies for activity without compromising safety.
Insulin-like growth factor (IGF) signaling has been implicated in the resistance to hormonal therapy in breast cancer. Using a model of postmenopausal, estrogen-dependent breast cancer, we investigated the antitumor effects of the dual IGF-1R/InsR tyrosine kinase inhibitor BMS-754807 alone and in combination with letrozole or tamoxifen. BMS-754807 exhibited antiproliferative effects in vitro that synergized strongly in combination with letrozole or 4-hydroxytamoxifen and fulvestrant. Similarly, combined treatment of BMS-754807 with either tamoxifen or letrozole in vivo elicited tumor regressions not achieved by single-agent therapy. Notably, hormonal therapy enhanced the inhibition of IGF-1R/InsR without major side effects in animals. Microarray expression analysis revealed downregulation of cell-cycle control and survival pathways and upregulation of erbB in response to BMS-754807 plus hormonal therapy, particularly tamoxifen. Overall, these results offer a preclinical proof-of-concept for BMS-754807 as an antitumor agent in combination with hormonal therapies in hormone-sensitive breast cancer. Cooperative cell-cycle arrest, decreased proliferation, and enhanced promotion of apoptosis may contribute to antitumor effects to be gauged in future clinical investigations justified by our findings.
Ovarian cancer is the sixth most common cancer worldwide among women in developed countries and the most lethal of all gynecologic malignancies. There is a critical need for the introduction of targeted therapies to improve outcome. Epidemiological evidence suggests a critical role for steroid hormones in ovarian tumorigenesis. There is also increasing evidence from in vitro studies that estrogen, progestin, and androgen regulate proliferation and invasion of epithelial ovarian cancer cells. Limited clinical trials have shown modest response rates; however, they have consistently identified a small subset of patients that respond very well to endocrine therapy with few side effects. We propose that it is timely to perform additional well-designed trials that should include biomarkers of response.
Activation of EGFR can stimulate proliferative and survival signaling through mTOR. Preclinical data demonstrates synergistic activity of combined EGFR and mTOR inhibition. We undertook a phase I trial of temsirolimus (T, an mTOR inhibitor) and EKB-569 (E, an EGFR inhibitor) to determine the safety and tolerability.
The primary aim was to determine the maximally tolerated dose (MTD) of this combination in adults with solid tumors. Following the dose-escalation phase, (Cohort A), two subsequent cohorts were used to assess any pharmacokinetic (PK) interaction between the agents.
Forty eight patients were enrolled. The MTD of this combination was E, 35 mg daily and T, 30 mg on days 1–3 and 15–17 using a 28-day cycle. The most common toxicities were nausea, diarrhea, fatigue, anorexia, stomatitis, rash, anemia, neutropenia, thrombocytopenia, and hypertriglyceridemia. Sixteen patients (36%) had at least one grade 3 toxicity. The most frequent grade 3/4 toxicities were diarrhea, dehydration, and nausea and vomiting (19% each). No grade 5 events were seen. Four patients had a partial response and 15 had stable disease. Clinical benefit was seen across a range of tumor types and in all cohorts. PK analysis revealed no significant interaction between E and T.
This combination of agents is associated with tolerable toxicities at doses that induced responses. PK studies revealed no interaction between the drugs. Further investigations of this targeting strategy may be attractive in renal cell carcinoma, non-small cell lung cancer, alveolar sarcoma, and carcinoid tumor.
CCI-779; EKB-569; Temsirolimus; Phase I; Pharmacokinetics; Solid tumors
The development of predictive biomarkers for IGF targeted anti-cancer therapeutics remains a critical unmet need. The insulin receptor A isoform (InsR-A) has been identified as a possible biomarker candidate but quantification of InsR-A in widely available formalin fixed paraffin embedded (FFPE) tissues is complicated by its similarities with the metabolic signaling insulin receptor isoform B (InsR-B). In the present study, qPCR based assays specific for InsR-A, InsR-B and IGF-1R were developed for use in FFPE tissues and tested for feasible use in clinical archived FFPE estrogen receptor (ER) + and ER− breast cancer tumors.
FFPE compatible primer sets were designed with amplicon sizes of less than 60 base pairs and validated for target specificity, assay repeatability and amplification efficiency. FFPE tumors from ER+ (n=83) and ER− (n=64) primary untreated breast cancers, and ER+ hormone refractory (HR ER+) (n=61) breast cancers were identified for feasibility testing. The feasible use of InsR-A and InsR-B qPCRs were tested using all tumor groups and the feasibility of IGF-1R qPCR was determined using HR ER+ tumors.
All qPCR assays were highly reproducible with amplification efficiencies between 96–104% over a 6 log range with limits of detection of 4 or 5 copies per reaction. Greater than 90% of samples were successfully amplified using InsR-A, InsR-B or IGF-1R qPCR primer sets and greater than 88% of samples tested amplified both InsR isoforms or both isoforms and IGF-1R. InsR-A was the predominant isoform in 82% ER+, 68% ER− and 100% HR ER+ breast cancer. Exploratory analyses demonstrated significantly more InsR-A expression in ER+ and HR ER+ groups compared to InsR-B (ER+ p< 0.05, HR ER+ p< 0.0005) and both groups had greater InsR-A expression when compared to ER− tumors (ER+ p< 0.0005, HR ER+ p< 0.05). IGF-1R expression of HR ER+ tumors was lower than InsR-A (p<0.0005) but higher than InsR-B (p<0.0005). The InsR-B expression of HR ER+ tumors was significantly reduced compared other tumor subgroups (ER+ and ER−, p< 0.0005) and lead to a significant elevation of HR ER+ InsR-A:InsR-B ratios (ER+ and ER−, p< 0.0005).
The validated, highly sensitive InsR-A and InsR-B qPCR based assays presented here are the first to demonstrate the feasible amplification of InsR isoforms in FFPE tissues. Quantification data generated from this feasibility study indicating InsR-A is more predominant than InsR-B in breast cancer support the use of these assays for further investigation of InsR-A and InsR-B as predictive biomarkers for IGF targeted therapeutics.
Real-time; qPCR; breast cancer; receptor; insulin; receptor; IGF Type 1; monoclonal antibodies; therapeutic use; protein kinase inhibitors
To improve the significance of insulin-like growth factor binding protein 5 (IGFBP-5) as a prognostic and potentially predictive marker in breast cancer patients.
Increased IGFBP-5 expression was identified in MCF-7 cells resistant (MCF-7R4) to the IGF-1R/InsR inhibitor, BMS-536924 and its role examined by targeted knockdown and overexpression in multiple experimental models. Protein expression of IGFBP-5 was measured by immunohistochemistry in a cohort of 76 breast cancer patients to examine correlative associations with invasive tumor fraction and outcome. The utility of a combined IGFBP-5/IGFBP-4 (BPR) expression ratio was applied to predict anti-IGF-1R/InsR response in a panel of breast cancer lines and outcome in multiple breast tumor cohorts.
IGFBP-5 knockdown decreased BMS-536924 resistance in MCF-7R4 cells, while IGFBP-5 overexpression in MCF-7 cells conferred resistance. When compared to pathologically normal reduction mammoplasty tissue, IGFBP-5 expression levels were upregulated in both invasive and histologically normal adjacent breast cancer tissue. In both univariate and multivariate modeling, metastasis-free survival (MFS), recurrence free survival (RFS), and overall survival (OS) were significantly associated with high IGFBP-5 expression. Prognostic power of IGFBP-5 was further increased with the addition of IGFBP-4 where tumors were ranked based upon IGFBP-5/IGFBP-4 expression ratio (BPR). Multiple breast cancer cohorts confirm that BPR (high vs. low) was a strong predictor of RFS and OS.
IGFBP-5 expression is a marker of poor outcome in breast cancer patients. An IGFBP-5/IGFBP-4 expression ratio may serve as a surrogate biomarker of IGF pathway activation and predict sensitivity to anti-IGF-1R-targeting.
IGFBP; breast cancer; poor outcome
To evaluate the efficacy and biological effects of the gemcitabine/tanespimycin combination in patients with advanced ovarian and peritoneal cancer. To assess the effect of tanespimycin on tumor cells, levels of the chaperone proteins HSP90 and HSP70 were examined in peripheral blood mononuclear cells (PBMC) and paired tumor biopsy lysates.
Two-cohort phase II clinical trial. Patients were grouped according to prior gemcitabine therapy. All participants received tanespimycin 154 mg/m2 on days 1 and 9 of cycle 1 and days 2 and 9 of subsequent cycles. Patients also received gemcitabine 750 mg/m2 on day 8 of the first treatment cycle and days 1 and 8 of subsequent cycles.
The tanespimycin/gemcitabine combination induced a partial response in 1 gemcitabine naïve patient and no partial responses in gemcitabine resistant patients. Stable disease was seen in 6 patients (2 gemcitabine naïve and 4 gemcitabine resistant). The most common toxicities were hematologic (anemia and neutropenia) as well as nausea and vomiting. Immunoblotting demonstrated limited upregulation of HSP70 but little or no change in levels of most client proteins in PBMC and paired tumor samples.
Although well tolerated, the tanespimycin/gemcitabine combination exhibited limited anticancer activity in patients with advanced epithelial ovarian and primary peritoneal carcinoma, perhaps because of failure to significantly downregulate the client proteins at clinically achievable exposures.
Phase I/II Trials; Tanespimycin; gemcitabine; ovarian cancer; peritoneal cancer; heat shock protein 90