Evaluation of circulating tumor cell (CTC) enumeration as an efficacy response biomarker of overall survival (OS) in metastatic castration-resistant prostate cancer (mCRPC): Planned final analysis (FA) of COU-AA-301, a randomized, double-blind, placebo-controlled, phase III study of abiraterone acetate (AA) plus low-dose prednisone (P) post docetaxel

LBA4517

Background: A preplanned interim analysis of COU-AA-301 showed that AA, a selective androgen biosynthesis (CYP17) inhibitor, significantly improves OS in mCRPC. This is the first phase III study to prospectively assess CTC as a surrogate biomarker as part of a regulatory qualification process, here using updated OS data. Methods: 1,195 patients (pts) with mCRPC post docetaxel were randomized 2:1 to AA (1 g QD) + P (5 mg BID) (n = 797) or placebo + P (n = 398). CTCs (screening and baseline [BL]; post BL at weeks 4, 8 and 12) were enumerated (cells/7.5 mL) at MSKCC and The ICR using CellSearch and analyzed with other prognostic covariates as dichotomous and continuous variables using updated OS data at 775 events (prior to crossover from placebo to AA). CTC (as part of a biomarker panel - LDH, PSA, Hg, AlkPhos) was examined as a surrogate for OS. Multivariate (Cox model) analyses were conducted. Results: At median follow up (FU) of 20.2 mo, the difference in median OS between the 2 groups improved from 3.9 to 4.6 mo (AA 15.8 mo vs placebo 11.2 mo; HR = 0.74; p < .0001). CTC counts were evaluated in 972 pts at screening and BL, 838 at 4 wks, 783 at 8 wks and 723 pts at 12 wks. High concordance between screening and BL values was observed (r = 0.83). CTC conversion using standard definition for unfavorable (CTC ≥ 5) and favorable (CTC < 5) counts was predictive of OS as early as 4 wks after treatment and its inclusion significantly reduced the treatment effect at all post-treatment time points (HR: from 0.74 to 0.97). A reduced model incorporating CTCs and LDH was developed. Conclusions: The magnitude of the treatment effect of AA on OS increased with longer FU. Using standard definition of CTC conversion, the biomarker panel demonstrated a level of surrogacy for OS by correlating well with survival and in a model-adjusted analysis dramatically attenuating the treatment effect. BL CTCs and CTC conversion, along with LDH, were key predictors of OS. Future trials will further evaluate the CTC-based surrogate developed from COU-AA-301.

Clinical response of newly diagnosed HIV seropositive & seronegative pulmonary tuberculosis patients with the RNTCP Short Course regimen in Pune, India

BACKGROUND & OBJECTIVES

In the Revised National Tuberculosis Control Programme (RNTCP) in India prior to 2005, TB patients were offered standard DOTS regimens without knowledge of HIV status. Consequently such patients did not receive anti-retroviral therapy (ART) and the influence of concomitant HIV infection on the outcome of anti-tuberculosis treatment remained undetermined. This study was conducted to determine the results of treatment of HIV seropositive pulmonary tuberculosis patients with the RNTCP (DOTS) regimens under the programme in comparison with HIV negative patients prior to the availability of free ART in India.

METHODS

Between September 2000 and July 2006, 283 newly diagnosed pulmonary TB patients were enrolled in the study at the TB Outpatient Department at the Talera Hospital in the Pimpri Chinchwad Municipal Corporation area at Pune (Maharashtra): they included 121 HIV seropositive and 162 HIV seronegative patients. They were treated for tuberculosis as per the RNTCP in India. This study was predominantly conducted in the period before the free ART become available in Pune.

RESULTS

At the end of 6 months of anti-TB treatment, 62 per cent of the HIV seropositive and 92 per cent of the HIV negative smear negative patients completed treatment and were asymptomatic; among smear positive patients, 70 per cent of the HIV-seropositive and 81 per cent of HIV seronegative pulmonary TB patients were cured. Considering the results in the smear positive and smear negative cases together, treatment success rates were substantially lower in HIV positive patients than in HIV negative patients, (66% vs 85%). Further, 29 per cent of HIV seropositive and 1 per cent of the HIV seronegative patients expired during treatment. During the entire period of 30 months, including 6 months of treatment and 24 months of follow up, 61 (51%) of 121 HIV positive patients died; correspondingly there were 6 (4%) deaths among HIV negative patients.

INTERPRETATION & CONCLUSIONS

The HIV seropositive TB patients responded poorly to the RNTCP regimens as evidenced by lower success rates with chemotherapy and high mortality rates during treatment and follow up. There is a need to streamline the identification and management of HIV associated TB patients in the programme with provision of ART to achieve high cure rates for TB, reducing mortality rates and ensuring a better quality of life.

Genomic analysis of circulating tumor cells to evaluate predictive biomarkers

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Background: To estimate the association between molecular biomarkers detected in circulating tumor cells (CTC) and tumor sensitivity to treatment, robust assays are needed before qualification in prospective clinical trials.

Methods: To address the limitations of the current FDA cleared technology, we focused on improving our ability to isolate more purified CTC populations based on fluorescence-activated cell sorting (FACS) to capture EpCAM+, CD45−, DAPI− cells from patients with castration-resistant prostate cancer (CRPC). Androgen receptor (AR) and genes frequently mutated in CRPC have been selected from the integrative genomic profiling at MSK. We optimized the RainDance microfluidic PCR followed by targeted sequencing in low number of cancer cells, before proceeding to clinical samples.

Results: On blood samples from124 patients with progressive CRPC, FACS method isolates an average 100-fold more EpCAM+ events compared to the current FDA cleared CellSearch assay. By FACS, >10 or >50 events were isolated in 88% or 58% of patients, compared to 32% or 10% of patients by CellSearch, respectively. FACS isolated cells express prostate-specific mRNAs (PSA, AR, TMPRSS2-ERG), as detected by an analytically validated multiplex RT-PCR, indicating that these EpCAM+ events are bona fide CTC. For genomic profiling, sufficient high quality DNA was obtained from as little as 50 CTC, with a recovery rate of 89% from FACS sorted samples and adequate sequencing coverage, and 1:4 detection threshold in a heterogeneous cell population. Selected missense mutations in AR, PIK3CA and TP53 found in CTC but not in WBC from same patient are further analyzed.

Conclusions: Molecular alterations in CTC can potentially serve as predictive markers of sensitivity and clinical outcomes as surrogate tissue in clinical practice. We established standard operating procedures for specimen processing, and confirmed the sequencing coverage and polymorphism detection thresholds in a heterogeneous cell population. In the context of available samples collected from patients enrolled on AR-targeted therapies, we will generate data to qualify CTC as biomarkers under the Oncology Biomarker Qualification Initiative.

[Table: see text]

Antitumor activity of MDV3100 in pre- and post-docetaxel advanced prostate cancer: Long-term follow-up of a phase I/II study

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Background: MDV3100 is a novel androgen receptor (AR) antagonist selected for potent AR activity and devoid of partial agonist effects. A preliminary report of the phase I/II study described anti-tumor activity and adverse events (Scher HI et al. Lancet. 2010;375:1437). This abstract provides long-term follow-up on time to PSA and radiographic progression in this trial.

Methods: Patients (pts) with progressive castration resistant prostate cancer (CRPC) were enrolled in sequential cohorts of 3-6 pts at MDV3100 doses of 30, 60, 150, 240, 360, 480 and 600 mg/day. Once the tolerability of a dose was established, enrollment was expanded at doses ≥60 mg/day to include approximately 12 chemotherapy naïve (naïve) pts and 12 pts previously treated with docetaxel (post-chemo) per cohort.

Results: 140 pts were enrolled of which 18 (13%) pts continue on active treatment (16 naive and 2 post-chemo). The median time on treatment is 51 weeks for naïve and 17 weeks for post-chemo groups. Median time on treatment for the 18 patients still on study is 131 weeks. The median time to PSA progression, defined per-protocol as a ≥25% increase in PSA from baseline, was not met for naïve and was 33 weeks for post-chemo groups. Median time to PSA progression by Prostate Cancer Clinical Trials Working Group 2 criteria was 41 weeks for naïve and 20 weeks for post-chemo groups. Median time to radiographic progression was 56 weeks for naive and 24 weeks for post-chemo groups. Circulating tumor cell counts available for 128 of 140 pts showed 91% (70/77) with favorable pre-treatment counts (<5 cells/7.5 mL blood) remaining favorable post-treatment, while 49% (25/51) converted from unfavorable pre-treatment to favorable post-treatment.

Conclusions: MDV3100 demonstrates durable anti-tumor activity in pts with CRPC both before and after chemotherapy. Based on these promising results MDV3100 is currently being evaluated in two global phase III studies in pts with metastatic CRPC, the AFFIRM study in pts previously treated with docetaxel and the PREVAIL study in chemotherapy-naïve pts who have progressed on androgen deprivation therapy.

[Table: see text]

A dose range finding study of novel oral insulin (IN-105) under fed conditions in type 2 diabetes mellitus subjects

AIM

The objective of the study was to establish the dose response of IN-105 tablets and explore a possible therapeutic window in type 2 diabetes subjects poorly controlled on metformin.

METHODS

The primary objective was to examine the effect of sequential single ascending doses of IN-105 on the plasma glucose concentration under fed conditions. All subjects received, sequentially, matching placebo, 10, 15, 20 and 30 mg IN-105 tablets in five consecutive periods. Tablets were administered 20 min prior to meal in all the periods. Plasma levels of immunoreactive insulin, C-peptide and glucose were measured up to 180 min from the time of dosing. The changes in postprandial glucose levels at 120 min in response to IN-105 administration were also compared against those of placebo.

RESULTS

Changes in glucose from baseline (mean +/- s.d.) at 140 min (2 h postprandial) were 94.84 +/- 22.3, 79.45 +/- 43.00, 70.68 +/- 35.71, 63.47 +/- 42.75 and 53.06 +/- 47.27 mg/dL, respectively, and exhibited linear dose-response. The insulin C(max) values were found to be 50.8 +/- 26.0 mU/L for placebo, 100.3 +/- 66.7 with 10 mg IN-105, 177.69 +/- 150.3 with 15 mg IN-105, 246.2 +/- 245.2 with 20 mg IN-105 and 352.5 +/- 279.3 mU/L with 30 mg of IN-105.

CONCLUSIONS

IN-105 absorption is proportional to the dose administered. The 2-h postprandial glucose excursion was reduced in a dose proportional manner. Circulating C-peptide levels were found to be suppressed in proportion to the IN-105 exposure. IN-105 reduces glucose excursion despite lower endogenous insulin secretion. IN-105 seems to have a wide therapeutic window as no clinical hypoglycaemia was observed at any of the doses studied.

A comparison of early and delayed arthroscopically-assisted reconstruction of the anterior cruciate ligament using hamstring autograft

Delayed rather than early reconstruction of the anterior cruciate ligament is the current recommended treatment for injury to this ligament since it is thought to give a better functional outcome. We randomised 105 consecutive patients with injury associated with chondral lesions no more severe than grades 1 and 2 and/or meniscal tears which only required trimming, to early (< two weeks) or delayed (> four to six weeks) reconstruction of the anterior cruciate ligament using a quadrupled hamstring graft. All operations were performed by a single surgeon and a standard rehabilitation regime was followed in both groups. The outcomes were assessed using the Lysholm score, the Tegner score and measurement of the range of movement. Stability was assessed by clinical tests and measurements taken with the KT-1000 arthrometer, with all testing performed by a blinded uninvolved experienced observer. A total of six patients were lost to follow-up, with 48 patients assigned to the delayed group and 51 to the early group. None was a competitive athlete. The mean interval between injury and the surgery was seven days (2 to 14) in the early group and 32 days (29 to 42) in the delayed group. The mean follow-up was 32 months (26 to 36).

The results did not show a statistically significant difference for the Lysholm score (p = 0.86), Tegner activity score (p = 0.913) or the range of movement (p = 1). Similarly, no distinction could be made for stability testing by clinical examination (p = 0.56) and measurements with the KT-1000 arthrometer (p = 0.93).

Reconstruction of the anterior cruciate ligament gave a similar clinical and functional outcome whether performed early (< two weeks) or late at four to six weeks after injury.