Retrospective studies suggest that p53 alteration is prognostic for recurrence in patients with urothelial bladder cancer and predictive for benefit from combination methotrexate, vinblastine, doxorubicin, and cisplatin (MVAC) adjuvant chemotherapy.
Patients and Methods
Patients with pT1/T2N0M0 disease whose tumors demonstrated ≥ 10% nuclear reactivity on centrally performed immunohistochemistry for p53 were offered random assignment to three cycles of adjuvant MVAC versus observation; p53-negative patients were observed. By using a log-rank test with one-sided α = .05 and β = .10, 190 p53-positive patients were planned to be randomly assigned to detect an absolute improvement in probability of recurring by 3 years from 0.50 to 0.30.
A total of 521 patients were registered, 499 underwent p53 assessment, 272 (55%) were positive, and 114 (42%) were randomly assigned. Accrual was halted on the basis of the data and safety monitoring board review of a futility analysis. Overall 5-year probability of recurring was 0.20 (95% CI, 0.16 to 0.24) with no difference on the basis of p53 status. Only 67% of patients randomly assigned to MVAC received all three cycles with 12 patients receiving no treatment. There was no difference in recurrence in the randomly assigned patients (hazard ratio, 0.78; 95% CI, 0.29 to 2.08; P = .62).
Neither the prognostic value of p53 nor the benefit of MVAC chemotherapy in patients with p53-positive tumors was confirmed, but the high patient refusal rate, lower than expected event rate, and failures to receive assigned therapy severely compromised study power.
The randomized discontinuation trial (RDT) design is an enrichment-type design that has been used in a variety of diseases to evaluate the efficacy of new treatments. The RDT design seeks to select a more homogeneous group of patients, consisting of those who are more likely to show a treatment benefit if one exists. In oncology, the RDT design has been applied to evaluate the effects of cytostatic agents, that is, drugs that act primarily by slowing tumor growth rather than shrinking tumors. In the RDT design, all patients receive treatment during an initial, open-label run-in period of duration T. Patients with objective response (substantial tumor shrinkage) remain on therapy while those with early progressive disease are removed from the trial. Patients with stable disease (SD) are then randomized to either continue active treatment or switched to placebo. The main analysis compares outcomes, for example, progression-free survival (PFS), between the two randomized arms. As a secondary objective, investigators may seek to estimate PFS for all treated patients, measured from the time of entry into the study, by combining information from the run-in and post run-in periods. For t ≤ T, PFS is estimated by the observed proportion of patients who are progression-free among all patients enrolled. For t > T, the estimate can be expressed as Ŝ(t) = p̂OR × ŜOR(t − T) + p̂SD × ŜSD(t − T), where p̂OR is the estimated probability of response during the run-in period, p̂SD is the estimated probability of SD, and ŜOR(t − T) and ŜSD(t − T) are the Kaplan–Meier estimates of subsequent PFS in the responders and patients with SD randomized to continue treatment, respectively. In this article, we derive the variance of Ŝ(t), enabling the construction of confidence intervals for both S(t) and the median survival time. Simulation results indicate that the method provides accurate coverage rates. An interesting aspect of the design is that outcomes during the run-in phase have a negative multinomial distribution, something not frequently encountered in practice.
Confidence limits; Enrichment design; Negative multinomial distribution; Phase II clinical trials
To improve future drug development efficiency in renal cell carcinoma (RCC), a disease progression model was developed with longitudinal tumor size data from a phase III trial of sorafenib in RCC. The best fit model was externally evaluated on 145 placebo-treated patients in a phase III trial of pazopanib, and incorporated baseline tumor size, a linear disease progression component, and an exponential drug effect parameter. With the model-estimated effect of sorafenib on RCC growth we calculated the power of randomized phase II trials between sorafenib and hypothetical comparators over a range of effects. A hypothetical comparator with 80% greater drug effect than sorafenib would have 82% power (one-sided α = 0.1) with 50 patients per arm. Model-based quantitation of treatment effect with CT imaging offers a scaffold on which to develop new, more efficient, phase II trial endpoints and analytic strategies for RCC.
Antineoplastic Agents; Antiangiogenic Agents; Carcinoma; Renal/drug therapy; Decision Making; Drugs; Investigational; Humans; Models; Statistical; Renal Neoplasms/drug therapy
The mTOR (mammalian target of rapamycin) inhibitor, everolimus, affects tumor growth by targeting cellular metabolic proliferation pathways and delays renal cell carcinoma (RCC) progression. Preclinical evidence suggests that baseline elevated tumor glucose metabolism as quantified by FDG-PET ([18F] fluorodeoxy-glucose positron emission tomography) may predict antitumor activity. Metastatic RCC (mRCC) patients refractory to vascular endothelial growth factor (VEGF) pathway inhibition were treated with standard dose everolimus. FDG-PET scans were obtained at baseline and 2 weeks; serial computed tomography (CT) scans were obtained at baseline and every 8 weeks. Maximum standardized uptake value (SUVmax) of the most FDG avid lesion, average SUVmax of all measured lesions and their corresponding 2-week relative changes were examined for association with 8-week change in tumor size. A total of 63 patients were enrolled; 50 were evaluable for the primary endpoint of which 48 had both PET scans. Patient characteristics included the following: 36 (72%) clear cell histology and median age 59 (range: 37–80). Median pre- and 2-week treatment average SUVmax were 6.6 (1–17.9) and 4.2 (1–13.9), respectively. Response evaluation criteria in solid tumors (RECIST)-based measurements demonstrated an average change in tumor burden of 0.2% (−32.7% to 35.9%) at 8 weeks. Relative change in average SUVmax was the best predictor of change in tumor burden (all evaluable P = 0.01; clear cell subtype P = 0.02), with modest correlation. Baseline average SUVmax was correlated with overall survival and progression-free survival (PFS) (P = 0.023; 0.020), but not with change in tumor burden. Everolimus therapy decreased SUVs on follow-up PET scans in mRCC patients, but changes were only modestly correlated with changes in tumor size. Thus, clinical use of FDG-PET-based biomarkers is challenged by high variability.
In this phase II trial, FDG-PET was explored as a predictive biomarker for response to everolimus (mTOR inhibition) in metastatic renal cell carcinoma. Everolimus therapy decreased SUVs on follow-up FDG-PET scans in these patients. SUV changes were modestly correlated with changes in tumor size and baseline average SUVmax values were correlated with overall survival.
Kidney carcinoma; mTOR protein; pharmacological biomarkers; positron emission tomography
Many clinical trials of oncology drugs now include at least a consideration of pharmacogenomics, the study of germline or acquired genetic factors governing a drug's response and toxicity. Besides the potential benefit to patients from the consideration of personalized pharmacogenomic information when making treatment decisions, there is a clear incentive for oncology drug developers to incorporate pharmacogenomic factors in the drug development process since pharmacogenomic biomarkers may allow predictive characterization of sub-populations within a disease that may particularly respond, or may allow preidentification of patients at highest risk for adverse events. There is, however, a lack of agreement in actual practice as to where in the oncology clinical drug development process pharmacogenomic studies should be incorporated. In this article, we examine the recent growth of pharmacogenomics in oncology clinical trials, especially in early phase studies, and examine several critical questions facing the incorporation of pharmacogenomics in early oncologic drug development. We show that phase II clinical trials in particular have a favorable track record for demonstrating positive pharmacogenomic signals, worthy of additional follow-up and validation, and that the phase II setting holds significant promise for potentially accelerating and informing future phase III trials. We conclude that phase II trials offer an ideal “sweet spot” for routine incorporation of pharmacogenomic questions in oncology drug development.
phase II; oncology; clinical trials; pharmacogenomics; biomarker development
A randomized, placebo-controlled study based on preclinical and clinical data that supports the potential role of vascular endothelial growth factor in prostate cancer was performed to evaluate the addition of bevacizumab to standard docetaxel and prednisone therapy in patients with metastatic castration-resistant prostate cancer (mCRPC).
Patients and Methods
Patients with chemotherapy-naive progressive mCRPC with Eastern Cooperative Oncology Group performance status ≤ 2 and adequate bone marrow, hepatic, and renal function were randomly assigned to receive docetaxel 75 mg/m2 intravenously (IV) over 1 hour for 21 days plus prednisone 5 mg orally twice per day (DP) with either bevacizumab 15 mg/kg IV every 3 weeks (DP + B) or placebo. The primary end point was overall survival (OS), and secondary end points were progression-free survival (PFS), 50% decline in prostate-specific antigen, objective response (OR), and toxicity.
In total, 1,050 patients were randomly assigned. The median OS for patients given DP + B was 22.6 months compared with 21.5 months for patients treated with DP (hazard ratio, 0.91; 95% CI, 0.78 to 1.05; stratified log-rank P = .181). The median PFS time was superior in the DP + B arm (9.9 v 7.5 months, stratified log-rank P < .001) as was the proportion of patients with OR (49.4% v 35.5%; P = .0013). Grade 3 or greater treatment-related toxicity was more common with DP + B (75.4% v 56.2%; P ≤ .001), as was the number of treatment-related deaths (4.0% v 1.2%; P = .005).
Despite an improvement in PFS and OR, the addition of bevacizumab to docetaxel and prednisone did not improve OS in men with mCRPC and was associated with greater toxicity.
The best phase II design and endpoint for growth inhibitory agents is controversial. We simulated phase II trials by resampling patients from a positive (sorafenib vs. placebo; TARGET) and a negative (AE941 vs. placebo) phase III trial in metastatic renal cancer to compare the ability of various designs and endpoints to predict the known results.
770 and 259 patients from TARGET and the AE 941 trial, respectively, were resampled (5,000 replicates) to simulate phase II trials with alpha = 0.10 (one-sided). Designs/endpoints: single arm, two-stage with response rate (RR) by RECIST (37 patients); and randomized, two arm (20–35 patients/arm) with RR by RECIST, mean log ratio of tumor sizes (log ratio), PFS rate at 90 days (PFS-90), and overall PFS.
Single arm trials were positive with RR by RECIST in 55% and 1% of replications for sorafenib and AE 941, respectively. Randomized trials versus placebo with 20 patients per arm were positive with RR by RECIST in 55% and 7%, log ratio in 88% and 25%, PFS-90 in 64% and 15%, and overall PFS in 69% and 9% of replications for sorafenib and AE 941, respectively.
Compared with the single arm design and the randomized design comparing PFS, the randomized phase II design with the log ratio endpoint has greater power to predict the positive phase III result of sorafenib in renal cancer, but a higher false positive rate for the negative phase III result of AE 941.
resampling; phase II; randomized; single arm; tumor size
The androgen pathway remains biologically relevant even in castration resistant prostate cancer (CRPC). In preclinical models, androgen therapy for CRPC leads to growth arrest, apoptosis, and tumor shrinkage. This study determined the toxicity and feasibility of a testosterone therapy in early CRPC.
Prostate cancer patients with progressive disease following androgen ablation, antiandrogen therapy and withdrawal, with none to minimal metastatic disease were randomized to treatment with transdermal testosterone, at 2.5, 5.0 or 7.5 mg/day. Toxicity, PSA, imaging, quality of life, and strength were monitored. Treatment was discontinued for significant toxicity, clinical progression, or a 3-fold increase in PSA.
Fifteen men, median age 73 (62–92), median PSA 11.1 ng/ml (5.2–63.6), were treated. Testosterone increased from castrate, to median concentrations of 305, 308, 297 ng/dL for 2.5mg (n=4), 5.0mg (n=5), and 7.5mg (n=5) doses, respectively. One patient was taken off study at 53 weeks due to grade 4 cardiac toxicity. There were no other grade 3 or 4 toxicities related to the study medication, and the grade 2 toxicities were minimal. Only one patient experienced symptomatic progression, and 3 (20%) demonstrated a decrease in PSA (largest =43%). Median time to progression was 9 weeks (range 2–96), with no detectable difference in the three dose cohorts. There was no significant change in QOL or hand-grip strength with treatment.
Testosterone is a feasible and reasonably well tolerated therapy for men with early CRPC. A larger, randomized trial is underway to further characterize efficacy and impact on QOL measures.
Cilengitide (EMD121974) is a cyclized pentapeptide that is a potent and selective integrin antagonist which has shown activity in malignant gliomas. In all previous studies, cilengitide has been administered in an intermittent fashion. However, cilengitide has a short half-life of 3-5 hours with no evidence of drug accumulation. These data prompted the initiation of this phase I study of continuous infusion cilengitide.
Cilengitide was administered as a continuous infusion without break in 4-week cycles. Plasma samples for pharmacokinetic studies were obtained weekly in cycle 1 immediately prior to and 2 hours after infusion bag change.
Thirty-five patients were treated (median age 56; 23 males) at dose levels of 1, 2, 4, 8, 12, 18, 27, and 40 mg/hr. Toxicities were limited to grade ≤ 2 and showed no relation to dose. Fatigue was most common (17%), while all other toxicities were reported in <10% of patients. No dose-limiting toxicities were observed, and therefore the maximum tolerated dose was not reached. Pharmacokinetic analysis showed that values for clearance and volume of distribution were comparable across dose levels, and the steady-state concentration increased proportionally with dose.
Cilengitide can be safely administered as a continuous infusion at doses up to at least 40 mg/hr, which represents the maximum feasible dose due to drug solubility and delivery limitations. The pharmacokinetics of continuous infusion cilengitide are linear and consistent with the results obtained using a twice weekly infusion.
Sorafenib is an antiangiogenic agent with activity in renal cancer. We conducted a randomized trial to investigate dynamic contrast magnetic resonance imaging (DCE-MRI) as a pharmacodynamic biomarker.
Patients and Methods
Patients were randomly assigned to placebo or 200 or 400 mg twice per day of sorafenib. DCE-MRI was performed at baseline and 4 weeks. DCE-MRI parameters, area under the contrast concentration versus time curve 90 seconds after contrast injection (IAUC90), and volume transfer constant of contrast agent (Ktrans) were calculated for a metastatic site selected in a blinded manner. Primary end point was change in Ktrans.
Of the 56 assessable patients, 48 underwent two MRIs; 44 MRIs were assessable for study end points. Mean Ktrans log ratios were 0.131 (standard deviation [SD], 0.315), −0.148 (SD, 0.382), −0.271 (SD, 0.499) in placebo, 200- and 400-mg cohorts, respectively (P = .0077 for trend) corresponding to changes of +14%, −14%, and −24%. IAUC90 log ratios were 0.041 (SD, 0.197), −0.040 (SD, 0.132), −0.356 (SD, 0.411), respectively (P = .0003 for trend), corresponding to changes of +4%, −4%, and −30%. Using a log-rank test, IAUC90 and Ktrans changes were not associated with progression-free survival (PFS). Patients with high baseline Ktrans had a better PFS (P = .027).
IAUC90 and Ktrans are pharmacodynamic biomarkers for sorafenib, but variability is high and magnitude of effect is less than previously reported. Changes in DCE-MRI parameters after 4 weeks of sorafenib are not predictive of PFS, suggesting that these biomarkers are not surrogate end points. The value of baseline Ktrans as a prognostic or predictive biomarker requires additional study.
Advanced renal cell cancer (RCC) continues to have a poor overall prognosis despite new FDA-approved therapies. Although taxane-based therapies are generally ineffective in RCC, research into the role of the von Hippel-Lindau protein has shown an association with microtubule dynamics. Mitotic kinesins are a class of molecular motors that also interact with microtubules and are required for proper mitotic function. SB-715992 is a new agent that inhibits the function of a mitotic kinesin known as kinesin spindle protein and leads to cell death.
Patients and Methods
Twenty previously treated advanced RCC patients were enrolled in this phase II trial of SB-715992, with response rate as a primary endpoint.
No patients responded with complete or partial remission. Six patients had stable disease, and one patient continues on therapy after 12 cycles. Common toxicities included anemia (80%), elevated creatinine (70%), lymphopenia (45%), fatigue (50%), hyperglycemia (50%), and dyspnea (45%). Reported grade 3/4 toxicities included dyspnea, fatigue, neutropenia with skin infection, dizziness, hyperuricemia, and hypertension.
This dose and schedule of SB-715992 does not appear to have a significant cytotoxic effect for patients with previously treated advanced RCC.
Kinesin spindle inhibitor; Multidrug resistance–associated protein 2; von Hippel-Lindau protein
Locally advanced upper tract urothelial carcinoma has a poor prognosis. While surgery represents the only potentially curable therapeutic intervention, recurrences are common and typically systemic in nature. It is thus reasonable to consider perioperative chemotherapy in an effort to decrease the risk of recurrence. There are very little direct data providing clinical guidance in this scenario. For urothelial cancer of the bladder, there are randomized phase III data demonstrating a survival advantage with neoadjuvant cisplatin-based combination chemotherapy. Although arguments favoring adjuvant chemotherapy could be made for upper tract urothelial cancer, the loss of renal function that occurs with nephrectomy can complicate administration of appropriate perioperative treatment. Therefore, by analogy to urothelial carcinoma of the lower tract, it is argued that cisplatin-based neoadjuvant chemotherapy should be the standard of care for patients with locally advanced upper tract urothelial cancer.
Randomized data have supported the use of long-term androgen deprivation therapy (ADT) combined with radiotherapy (RT) for men with high-risk prostate cancer. The present study reviewed the outcomes of intermediate- and high-risk men treated with RT and short-term ADT.
Materials and Methods
A total of 184 men with any single risk factor of prostate-specific antigen ≥10 ng/mL, clinical Stage T2b or greater, or Gleason score ≥7 were treated with primary external beam RT for nonmetastatic adenocarcinoma of the prostate. The median radiation dose was 74 Gy; 55% were treated with intensity-modulated RT. All patients received ADT for 1 to 6 months (median, 4), consisting of a gonadotropin-releasing hormone analog. Univariate and multivariable analyses were performed for risk factors, including T stage, Gleason score, radiation dose, and prostate-specific antigen level.
With a median follow-up of 51 months, the 4-year freedom from biochemical failure (FFBF) using the nadir plus 2 ng/mL definition was 83% for all patients. Clinical Stage T3 disease was the only variable tested associated with FFBF on univariate (4-year FFBF rate, 46% vs. 87% for Stage T1-T2c disease; p = .0303) and multivariable analysis (hazard ratio, 3.9; p = .0016). On a subset analysis of high-risk patients (National Comprehensive Cancer Network criteria), those with clinical Stage T3 disease (4-year FFBF rate, 46% vs. 80%; p = .0303) and a radiation dose <74 Gy (4-year FFBF rate, 64% vs. 80%) had a poorer outcome on univariate analysis. However, clinical Stage T3 disease and radiation dose were not significant on multivariable analysis, although a statistical multivariable trend was seen for both (p = .0650 and p = .0597, respectively).
Short-term ADT and RT might be acceptable for men with intermediate- and high-risk prostate cancer, especially for clinically localized disease treated with doses of ≥74 Gy.
Prostate cancer; radiotherapy; hormonal therapy
Evaluation of clinical activity and safety of IPI-504 (retaspimycin hydrochloride) in patients with castration-resistant prostate cancer (CRPC).
A single arm trial was conducted in two cohorts: Group A (chemotherapy-naïve), Group B (docetaxel-treated). IPI-504 was administered intravenously at 400 mg/m2 on Days 1, 4, 8, and 11 of a 21-day cycle. Trial expansion was planned if at least one prostate specific antigen (PSA) or radiographic response was noted per cohort. Pharmacokinetic samples were collected following the first dose; safety was assessed throughout.
Nineteen patients were enrolled (4 in Group A; 15 in Group B), with a median age of 66 years (range 49-78). Group B had received a median of 2 prior chemotherapy regimens. All Group B patients had bone metastases; 66% had measurable soft tissue or visceral metastases. One Group A patient remained on trial for 9 cycles; PSA declined 48% from baseline. No PSA responses were observed in other patients. Adverse events reported in >25% of the study population included nausea (47%), diarrhea (42%), fatigue (32%), anorexia (26%), and arthralgia (26%). Two patients in Group B died on study, involving study drug-related events of hepatic failure and ketoacidosis, respectively.
In this study, Hsp90 inhibition with IPI-504 administered as a single agent had a minimal effect on PSA or tumor burden and was associated with unacceptable toxicity in several patients; therefore, further evaluation in CRPC patients is not warranted. IPI-504 is being investigated at less intensive doses and schedules in other tumor types.
Castration-resistant prostate cancer; CRPC; Hsp90 inhibition; chemotherapy
Given the multitude of novel anticancer drugs and the limited resources available to study them, phase II trials should identify drugs with the highest probability of succeeding in subsequent phase III trials. Currently, single-arm phase II trial results are interpreted relative to historical control subjects, introducing selection bias and confounding that may limit the validity of the conclusions. The rate of success (defined as a statistically significant difference between arms) in phase III oncology trials is only 40%, suggesting that current phase II trials are insufficiently informative. However, simulation studies suggest that randomized phase II trials would have lower error rates and greater predictive power for phase III results. Randomized phase II trials may also be more informative than single-arm phase II trials because of the hypotheses being tested, the variety of possible endpoints, and the opportunities for biomarker discovery. There are a wide variety of randomized phase II designs that can be used, including the randomized discontinuation design, the delayed-start design, adaptive (Bayesian) designs, selection designs, and phase II/III designs. The barriers to widespread adoption of randomized phase II trials include time to completion, sample size considerations, and ethical concerns, but none are insurmountable. We conclude that randomized phase II trials are a worthy investment considering finite patient and financial resources and should be the rule rather than the exception for evaluating novel therapies in oncology.
Early androgen deprivation therapy (ADT) has no proven survival advantage in older men with biochemical recurrence (BCR) of prostate cancer (PCa), and it may contribute to geriatric frailty; we tested this hypothesis.
We conducted a case-control study of men aged 60+ with BCR on ADT (n=63) versus PCa survivors without recurrence (n=71). Frailty prevalence, “obese” frailty, Short Physical Performance Battery (SPPB) scores and falls were compared. An exploratory analysis of frailty biomarkers (CRP, ESR, hemoglobin, albumin, and total cholesterol) was performed. Summary statistics, univariate and multivariate regression analyses were conducted.
More patients on ADT were obese (BMI >30; 46.2% vs. 20.6%; p=0.03). There were no statistical differences in SPPB (p=0.41) or frailty (p=0.20). Using a proposed “obese” frailty criteria, 8.7% in ADT group were frail and 56.5% were “prefrail”, compared with 2.9% and 48.8% of controls (p=0.02). Falls in the last year were higher in ADT group (14.3% vs. 2.8%; p=0.02). In analyses controlling for age, clinical characteristics, and comorbidities, the ADT group trended toward significance for “obese” frailty (p = 0.14) and falls (OR = 4.74, p = 0.11). Comorbidity significantly increased the likelihood of “obese” frailty (p=0.01) and falls (OR 2.02, p = 0.01).
Men with BCR on ADT are frailer using proposed modified “obese” frailty criteria. They may have lower performance status and more falls. A larger, prospective trial is necessary to establish a causal link between ADT use and progression of frailty and disability.
prostate cancer; biochemical recurrence; androgen deprivation therapy; frailty; older adults
The use of docetaxel prolongs survival for patients with castrate resistant prostate cancer (CRPC). Inhibition of vascular endothelial growth factor (VEGF) with bevacizumab may further enhance the anti-tumor effect of docetaxel and estramustine in patients with CRPC.
Patients and Methods
This cooperative group trial enrolled men with CRPC. Patients received oral estramustine 280 mg three times per day on days 1-5 of every cycle, with 70 mg/m2 of docetaxel and bevacizumab at 15 mg/kg on day 2, every three weeks. PSA values were monitored every cycle and imaging was performed every 3 cycles. The primary endpoint was progression free survival (PFS) with safety, prostate specific antigen decline, measurable disease response, and overall survival secondary objectives.
Seventy-nine patients were enrolled; 77 received a median of 8 cycles and were evaluable. A 50% PSA decline was observed in 58 patients (75%). Twenty-three of 39 patients with measurable disease had a partial response (59%) The median time of PFS was 8.0 months with an overall median survival of 24 months. Neutropenia without fever (69%), fatigue (25%), thrombosis\emboli (9%) were the most common severe toxicities. Twenty-four of 77 patients were removed from protocol treatment due to disease progression, 35/77 for physician or patient decision and 15 patients secondary to toxicity.
The combination of docetaxel, estramustine and bevacizumab was tolerable but complicated by toxicity. Although progression free survival did not meet the desired endpoint, encouraging anti-tumor activity and overall survival was observed. Further phase III evaluation of the role of bevacizumab in CRPC is ongoing.
Docetaxel; Bevacizumab; castrate resistant prostate cancer
MicroRNAs, small non-coding RNAs, may act as tumor suppressors or oncogenes, and each regulate their own transcription and that of hundreds of genes, often in a tissue-dependent manner. This creates a tightly interwoven network regulating and underlying oncogenesis and cancer biology. Although protein-coding gene signatures and single protein pathway markers have proliferated over the past decade, routine adoption of the former has been hampered by interpretability, reproducibility, and dimensionality, whereas the single molecule–phenotype reductionism of the latter is often overly simplistic to account for complex phenotypes. MicroRNA-derived biomarkers offer a powerful alternative; they have both the flexibility of gene expression signature classifiers and the desirable mechanistic transparency of single protein biomarkers. Furthermore, several advances have recently demonstrated the robust detection of microRNAs from various biofluids, thus providing an additional opportunity for obtaining bioinformatically derived biomarkers to accelerate the identification of individual patients for personalized therapy.
MicroRNA signatures; gene expression; biomarkers; bioinformatics; knowledge representations; uncertain reasoning and decision theory; languages and computational methods; prostate cancer; protein networks; pathway analysis; network modeling; machine learning; predictive modeling; statistical learning; privacy technology
The efficacy of systemic therapies for advanced urothelial cancer following failure of frontline platinum-based chemotherapy is limited. There is evidence that vascular endothelial growth factor (VEGF) is important in the pathophysiology of urothelial cancer. Aflibercept is a recombinant fusion protein that binds and neutralizes multiple VEGF isoforms.
Patients with measurable, metastatic or locally advanced urothelial cancer previously treated with one platinum-containing regimen were enrolled. Aflibercept was administered 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 patients 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.
22 patients were accrued. One partial response (PR) (4.5% RR, 95% CI: 0.1%-22.8%) was seen. Median PFS was 2.79 months (95% CI: 1.74-3.88). Attributable grade 3 toxicities included: fatigue, hypertension, proteinuria, pulmonary hemorrhage, pain, hyponatremia, anorexia and lymphopenia. There was no treatment attributable to grade 4+ toxicities.
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 urothelial carcinoma patients.
This was a phase I trial to determine the maximum tolerated dose and toxicity of deforolimus (AP23573, MK-8669), an inhibitor of mammalian target of rapamycin (mTOR). The pharmacokinetics, pharmacodynamics, and antineoplastic effects were also studied.
Deforolimus was administered intravenously over 30 min every 7 days according to a flat dosing schedule. Dose was escalated according to an accelerated titration design. Patients remained on study until disease progression as long as they tolerated the drug without significant toxicities.
Forty-six patients were enrolled on the study. Common side effects included fatigue, anorexia, and mucositis. The maximum tolerated dose was 75 mg and mucositis was the dose-limiting toxicity. Similar to other mTOR inhibitors, deforolimus exhibited nonlinear pharmacokinetics and a prolonged half-life. Among 34 patients evaluable for response, 1 patient had a partial response, 21 patients had stable disease, and 12 had progressed. Percent change in tumor size was significantly associated with AUC (P = 0.015). A significant association was also detected for maximum change in cholesterol within the first two cycles of therapy and change in tumor size (r = −0.38; P = 0.029).
Deforolimus was well tolerated on the schedule tested in this trial with toxicity and pharmacokinetic profiles that were similar to that of other mTOR inhibitors. Additional phase II studies are needed to determine if deforolimus is superior to other mTOR inhibitors in terms of efficacy. The change in serum cholesterol as a potential biomarker of activity should be studied further.
Uncovering the dominant molecular deregulation among the multitude of pathways implicated in aggressive prostate cancer is essential to intelligently developing targeted therapies. Paradoxically, published prostate cancer gene expression signatures of poor prognosis share little overlap and thus do not reveal shared mechanisms. The authors hypothesize that, by analyzing gene signatures with quantitative models of protein–protein interactions, key pathways will be elucidated and shown to be shared.
The authors statistically prioritized common interactors between established cancer genes and genes from each prostate cancer signature of poor prognosis independently via a previously validated single protein analysis of network (SPAN) methodology. Additionally, they computationally identified pathways among the aggregated interactors across signatures and validated them using a similarity metric and patient survival.
Using an information-theoretic metric, the authors assessed the mechanistic similarity of the interactor signature. Its prognostic ability was assessed in an independent cohort of 198 patients with high-Gleason prostate cancer using Kaplan–Meier analysis.
Of the 13 prostate cancer signatures that were evaluated, eight interacted significantly with established cancer genes (false discovery rate <5%) and generated a 42-gene interactor signature that showed the highest mechanistic similarity (p<0.0001). Via parameter-free unsupervised classification, the interactor signature dichotomized the independent prostate cancer cohort with a significant survival difference (p=0.009). Interpretation of the network not only recapitulated phosphatidylinositol-3 kinase/NF-κB signaling, but also highlighted less well established relevant pathways such as the Janus kinase 2 cascade.
SPAN methodolgy provides a robust means of abstracting disparate prostate cancer gene expression signatures into clinically useful, prioritized pathways as well as useful mechanistic pathways.
Prostate cancer; protein networks; systems biology; information theory; network modeling; Simulation of complex systems (at all levels: molecules to work groups to organizations); knowledge representations; Uncertain reasoning and decision theory; languages and computational methods; statistical analysis of large datasets; advanced algorithms; discovery and text and data mining methods; Natural-language processing; Automated learning; Ontologies
Cervical tumors of 38 cervix cancer patients were scanned by T1-weighted dynamic contrast enhanced (DCE) MRI and then by DCE-CT on the same day. Gadodiamide and iohexol were respectively used as the low-molecular-weight contrast agent in DCE-MRI and DCE-CT. Under an extended Tofts model, DCE-MRI data were analyzed using either individual arterial input functions estimated by a multiple reference tissue method or a population arterial input function by Parker et al., whereas DCE-CT data were analyzed using the arterial input function directly measured from the external iliac arteries. The derived quantitative parameters of cervical tumors were compared between DCE-MRI and DCE-CT. When using the individual multiple reference tissue method arterial input functions to analyze the DCE-MRI data, the correlation coefficients between DCE-MRI- and DCE-CT-derived parameters were, respectively, back-flux rate constant (r = 0.80), extravascular extracellular fractional volume (r = 0.73), contrast agent transfer rate (r = 0.62), and blood plasma volume (r = 0.32); when using the Parker population arterial input function, the correlation coefficients were back-flux rate constant (r = 0.79), extravascular extracellular fractional volume (r = 0.77), contrast agent transfer rate (r = 0.63), and blood plasma volume (r = 0.58). Tumor parametric maps derived by DCE-MRI and DCE-CT had very similar morphologies. However, the means of most derived quantitative parameters were significantly different between the two imaging methods. Close correlation of quantitative parameters derived from two independent imaging modalities suggests both are measuring similar tumor physiologic variables.
dynamic contrast enhanced MRI; dynamic contrast enhanced CT; quantitative analysis; correlation; tracer kinetic modeling; T1 MRI
Bevacizumab is an antibody that binds vascular endothelial growth factor and has activity in metastatic renal cell carcinoma (RCC). Interferon alfa (IFN-α) is the historic standard initial treatment for RCC. A prospective, randomized, phase III trial of bevacizumab plus IFN-α versus IFN-α monotherapy was conducted.
Patients and Methods
Patients with previously untreated, metastatic clear cell RCC were randomly assigned to receive either bevacizumab (10 mg/kg intravenously every 2 weeks) plus IFN-α (9 million units subcutaneously three times weekly) or the same dose and schedule of IFN-α monotherapy in a multicenter phase III trial. The primary end point was overall survival (OS). Secondary end points were progression-free survival (PFS), objective response rate, and safety.
Seven hundred thirty-two patients were enrolled. The median OS time was 18.3 months (95% CI, 16.5 to 22.5 months) for bevacizumab plus IFN-α and 17.4 months (95% CI, 14.4 to 20.0 months) for IFN-α monotherapy (unstratified log-rank P = .097). Adjusting on stratification factors, the hazard ratio was 0.86 (95% CI, 0.73 to 1.01; stratified log-rank P = .069) favoring bevacizumab plus IFN-α. There was significantly more grade 3 to 4 hypertension (HTN), anorexia, fatigue, and proteinuria for bevacizumab plus IFN-α. Patients who developed HTN on bevacizumab plus IFN-α had a significantly improved PFS and OS versus patients without HTN.
OS favored the bevacizumab plus IFN-α arm but did not meet the predefined criteria for significance. HTN may be a biomarker of outcome with bevacizumab plus IFN-α.
Men experience a decrease in lean muscle mass and strength during the first year of androgen deprivation therapy (ADT). The prevalence of falls and physical and functional impairment in this population have not been well described.
A total of 50 men aged 70 years and older (median 78) receiving ADT for systemic prostate cancer (80% biochemical recurrence) underwent functional and physical assessments. The functional assessments included Katz’s Activities of Daily Living (ADLs) and Lawton’s Instrumental Activities of Daily Living (IADLs). Patients completed the Vulnerable Elder’s Survey-13, a short screening tool of self-perceived functional and physical performance ability. Physical performance was assessed using the Short Physical Performance Battery. The history of falls was recorded. Of the 50 patients, 40 underwent follow-up assessment with the same instruments 3 months after the initial assessment.
Of the 50 men, 24% had impairment in the ADLs, 42% had impairment in the IADLs, 56% had abnormal Short Physical Performance Battery findings, and 22% reported falls within the previous 3 months. Within the Short Physical Performance Battery, deficits occurred within all subcomponents (balance, walking, and chair stands). On univariate analysis, age, deficits in ADLs and IADLs, and abnormal cognitive and functional screen findings were associated with an increased risk of abnormal physical performance. ADL deficits, the use of an assistive device, and abnormal functional screen findings were associated with an increased risk of falling.
The results of our study have shown that older men with prostate cancer receiving long-term ADT exhibit significant functional and physical impairment and are at risk of falls that is greater than that for similar-aged cohorts. Careful assessment of the functional and physical deficits in older patients receiving ADT is warranted.
To determine the baseline prevalence of cognitive impairment in older men treated with ADT and to assess changes in cognitive performance over time.
Methods and results
Thirty-two patients (median age of 71 years, range 51–87) were administrated an extensive neuropsychological testing battery prior to ADT initiation, with 21 (65%) completing post-treatment evaluations 6 months later. At baseline, 45% scored >1.5 standard deviations below the mean on ≥2 neuropsychological measures. Using standardized inferential statistics, no change in cognition was documented following treatment. The Reliable Change Index revealed that, on a case-by-case basis, 38% demonstrated a decline in measures of executive functioning and 48% showed improvement on measures of visuospatial abilities. Within exploratory analyses, patients who scored below expectation at baseline displayed no change in cognition, while patients with average or better scores at baseline displayed improvements in visuospatial planning and timed tests of phonemic fluency.
We found a high prevalence of lower than expected cognitive performance among a sample of patients just starting ADT for prostate cancer. Assessment of baseline cognitive function should be taken into account for future research and to inform clinical management.
Cognition; Androgen deprivation; Prostate; Elderly