The 4th Annual Ontario Thoracic Cancer Conference at Niagara-on-the-Lake

The 4th annual Ontario Thoracic Cancer Conference at Niagara-on-the-Lake focused on the themes of innovations in the management of lung cancer, controversies in the management of esophageal cancer, and molecular targeted therapies in lung cancer. This conference summary highlights the presentations and provides clinicians with a referenced update on these topics.

The 4th Annual Ontario Thoracic Cancer Conference at Niagara-on-the-Lake

The 4th annual Ontario Thoracic Cancer Conference at Niagara-on-the-Lake focused on the themes of innovations in the management of lung cancer, controversies in the management of esophageal cancer, and molecular targeted therapies in lung cancer. This conference summary highlights the presentations and provides clinicians with a referenced update on these topics.

A phase II study of once-daily dasatinib for patients with castration-resistant prostate cancer (CRPC) (CA180085)

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Background: Dasatinib is a potent oral SRC family kinase inhibitor that also inhibits c-KIT and PDGFR in vitro. The anti-proliferative/anti-metastatic activity as well as osteoclast inhibitory function of dasatinib in pre-clinical models supports its potential as a targeted therapy for prostate cancer. Previously we presented results on BID dosing of dasatinib in the treatment of CRPC (ASCO. 2008 Abstract 5156). A second group of patients (pts) was enrolled to investigate the activity, safety and bone effects of 100 mg once daily dosing. Methods: Male pts with progressive metastatic CRPC, rising PSA, castrate levels of testosterone (< 50 ng/dL) and no prior chemotherapy were enrolled. Dasatinib dose was 100 mg QD. Continuation of bisphosphonates was permitted. Primary endpoint was a composite of: PSA responses, bone scans and disease control by RECIST. Urinary N-telopeptide (uNTX) and bone alkaline phosphatase (BAP) were determined Q 4-weeks as indicators of bone metabolism. Results: 47 pts were treated (median treatment duration was 2.3 months). 11 patients were evaluable by RECIST; of these 64% achieved SD. The composite response rate was (8/47) 17%. Of 22 pts with bone scans, 50% were stable at 12 weeks and 3/9 (33%) were stable at 24 weeks. A prolonged PSA doubling time was observed in 32 of 39 pts (82%), including one pt with a PSA response. Of the pts with evaluable bone markers, including those who continued on bisphosphonate therapy, 20/41 (49%) had a ≥ 35% decrease in uNTX and 21/42 (50%) had a decrease from baseline in BAP. Grade 3/4 adverse events (AEs) were experienced by 13% of pts (diarrhea, asthenia, and pleural effusion [n=1]). Grade 1/2 AEs (≥ 15% of pts) were diarrhea, nausea, headache, fatigue, asthenia, anorexia and dyspnea. Conclusions: Fewer and less severe AEs were observed in all categories for the QD dosing group compared to the previously reported BID dosing cohort. In addition, preliminary clinical activity (tumor and PSA response; decreasing bone turnover [uNTX, BAP]), is now confirmed to be similar in pts treated with 100mg QD and BID dosing. These data support the relevance of further studies of dasatinib in metastatic CRPC.

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Mature results of a randomized phase II study of OGX-011 in combination with docetaxel/prednisone versus docetaxel/prednisone in patients with metastatic castration-resistant prostate cancer

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Background: Clusterin is a cytoprotective chaperone protein associated with CRPC progression. OGX is a 2'-methoxyethyl antisense that potentiates chemotherapy in xenografts and inhibits clusterin expression at doses of <640 mg. Methods: Pts with CRPC and chemo-naive received docetaxel (DOC) 75mg/m2 q3w + OGX 640mg IV weekly + prednisone (Arm A) or DOC + prednisone (Arm B) in a single stage randomized phase II design. Primary endpoint was PSA response rate (RR). Progression-free survival (PFS) and overall survival (OS) were secondary endpoints. Planned sample size was 40/arm: Arm A the hypotheses (PSA RR<40% vs. >60%) could be tested at 10% β and 10% α, Arm B the true PSA RR could be estimated with half-width of the 90% CI<13% if PSA RR=40%. Results: 82 pts (41 Arm A, 41 Arm B) were randomized from 09/05–12/06. At this analysis time, all pts are off therapy and 49 have died. One pt was ineligible but included in ITT survival analysis. Baseline characteristics were similar: median age 69 (49–87), PSA >100 μg/L in 51%, Hgb ≥100 g/L in 98%, alk phos >ULN in 44%, LDH >ULN in 36%, ECOG performance status (PS) 0:1 in 51%:49%, bone/lymph node/visceral metastases in 69%/50%/28%. Median cycles for Arm A and B was 9 and 7. Adverse events associated with OGX included fatigue, fever, rigors, diarrhea and rash. Mean serum clusterin change on day 1 cycle 2 was -18% in Arm A and +8% in Arm B (p = 0.0005). PSA RR was 58% (Arm A) and 54% (Arm B). PSA declines at 12 weeks of any/>30%/>50% was observed in 87%/65%/45% (Arm A) and 68%/58%/34% (Arm B). PSA/objective disease progression as best response occurred in 0%/4% (Arm A), and 3%/17% (Arm B). PFS for Arms A and B was 7.3 (5.3–8.8) and 6.1 months (3.7–8.6). Median OS for Arms A and B was 27.5 (19.2-∞) and 16.9 months (12.7–26.0) (unadjusted HR = 0.60 [0.34–1.06], p = 0.07). Variables predictive of OS on multivariate analysis: PS 0 vs 1 (p = 0.0002), presence of visceral metastasis (p = 0.006) and treatment assignment (HR = 0.54 [0.29–0.97], p = 0.04). Conclusions: The PSA RR in both arms met criterion for further study. OGX reduced serum clusterin and OS appears superior with DOC/OGX. This combination warrants further evaluation. Supported by a grant from the NCI-Canada/Canadian Cancer Society.

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Impact of positron emission tomography (PET) in stage III non-small cell lung cancer (NSCLC): A prospective randomized trial (PET START)

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Background: Patients with stage III NSCLC are potentially curable using combined modality therapy (CMT) with chemotherapy and radical radiation (RT). The use of PET-CT rather than conventional imaging (CI) may better identify patients for CMT by enhanced tumor staging and improved definition of RT treatment volumes. Methods: Patients with stage III NSCLC (based on histology/cytology, brain CT/MRI, CT thorax, CT/US abdomen, and bone scan) who were considered candidates for CMT were randomized to either PET-CT or CT for RT treatment planning. The primary outcome was the proportion of patients who did not receive CMT because their tumor was upstaged to Stage 4 or their intrathoracic tumor was too extensive for radical RT. Overall survival (OS) and alteration of RT treatment planning volume were secondary outcomes. Target sample size was 400 patients based on a hazard rate reduction of 30% in OS at 2 years in favor of PET-CT with 2-sided alpha = 0.05 and 80% power. We also postulated that 200 patients would be required to detect a 20% difference between arms for the primary endpoint. 5 centers in Ontario participated. Results: The trial commenced in August 2004. In November 2008 after a planned interim analysis for the primary outcome, the Data Safety Monitoring Board recommended stopping recruitment because of superior efficacy with PET-CT. 304 patients were randomized and 289 had analyzable data. 25 patients were unsuitable for CMT: 21 in the PET-CT arm (16 upstaged to Stage 4 and 5 unsuitable for radical RT) and 4 in the CT arm (unsuitable for radical RT). Thus, 21 of 140 (15%) patients in the PET-CT arm achieved the primary outcome compared with 4 of 149 (2.7%) in the CT arm, P= 0.0002. Conclusions: This is the first randomized trial in stage III NSCLC showing that PET-CT is superior to CT planning alone in selecting appropriate patients for CMT. Longer patient follow-up will determine potential impact on OS.

No significant financial relationships to disclose.

Case report. Sclerosing liver haemangioma with pericapillary smooth muscle proliferation: atypical CT and MR findings with pathological correlation

We report a case of sclerosing liver haemangioma with pericapillary smooth muscle proliferation in a 63-year-old man who presented with abdominal pain. Because the tumour showed atypical features on CT and MRI, a correct diagnosis could not be made until surgery. In this report, the atypical radiological findings are illustrated and correlated with pathological findings.

Cytochrome P450 probe substrate metabolism kinetics in Sprague Dawley rats

The objective of the current study was to investigate the metabolism of cytochrome P450 (CYP) probe substrates in male Sprague Dawley rat liver microsomes and to determine their substrate specificities. Time and microsomal protein concentrations were varied to determine the linear conditions for each reaction. Appropriate substrate concentrations were chosen to determine the apparent K(m) and V(max) for 17 different reactions under initial rate conditions of protein and reaction time. All reactions appeared to follow Michaelis-Menten kinetics. Subsequently, each substrate was incubated at one to two times K(m) with each of 14 baculovirus cDNA-expressed rat CYP enzymes to determine the specificity of the reaction monitored. Of the 14 enzymes tested, seven were seen as the major rat CYP enzymes responsible for the majority of the substrate metabolism tested. Testosterone 2alpha- and 16alpha-hydroxylation reactions were conducted primarily by CYP2C11, and midazolam 4-hydroxylation and triazolam 1'-hydroxylation were preferentially catalyzed by CYP3A1/2, but specificity was otherwise generally poor. The results presented herein clearly indicate that care must be taken in interpretation of metabolism results obtained in rats using standard probe substrates, especially in extrapolation of those results to humans.

Improvement in patient-reported outcomes in a rituximab trial in patients with severe rheumatoid arthritis refractory to anti-tumor necrosis factor therapy

OBJECTIVE

To assess the effects of treatment with rituximab plus methotrexate on patient-reported outcomes in patients with active rheumatoid arthritis (RA) who experienced inadequate response to anti-tumor necrosis factor therapy.

METHODS

Patients with active RA were randomly assigned to rituximab (1,000 mg on days 1 and 15) or placebo. The primary end point was the proportion of patients with an American College of Rheumatology 20% response at week 24. Additional goals were to assess treatment effects on pain, fatigue, functional disability, health-related quality of life, and disease activity by comparing mean changes between groups. The analysis was conducted in the intent-to-treat population. The proportion of patients who achieved the minimum clinically important difference on the Health Assessment Questionnaire (HAQ) disability index (DI), Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F), and Short Form 36 (SF-36) was determined.

RESULTS

Rituximab patients had statistically significantly greater pain relief. The FACIT-F showed significantly greater improvement in rituximab patients than placebo patients from weeks 12 through 24. Mean improvement from baseline in functional disability (measured by the HAQ DI) was significantly greater in rituximab patients from weeks 8 to 24. The mean +/- SD change from baseline for the SF-36 Physical Component Score was 6.64 +/- 8.74 for rituximab patients and 1.48 +/- 7.32 for placebo patients (P < 0.0001). The mean change from baseline for the SF-36 Mental Component Score was 5.32 +/- 12.41 for rituximab patients and 2.25 +/- 12.23 for placebo patients (P = 0.0269).

CONCLUSION

Rituximab produced rapid, clinically meaningful, and statistically significant improvements in patient-reported pain, fatigue, functional disability, health-related quality of life, and disease activity. These effects were sustained throughout the study.

Poster - Thurs Eve-40: The potential of using SPECT ventilation information with IMRT for functional lung avoidance in radiotherapy of non small cell lung cancer

We have investigated the feasibility of using ventilation scans obtained from single photon emission computed tomography (SPECT) in intensity-modulated radiation therapy (IMRT) planning in lung cancer radiotherapy to avoid well functioning lung. We fused SPECT ventilation scans acquired at GE Hawkeye SPECT-CT of ten stage-III lung radiotherapy patients with planning CT in treatment planning system (Pinnacle v8.0, Philips Medical Systems). We automatically segment out 50% and 70% ventilated volumes. For each patient, we generated IMRT plans using nine equally spaced beams with and without avoiding well ventilated volume. They were compared with three beam IMRT plans with beam directions chosen to minimize the mean dose to the ventilated lung volumes, while keeping cord dose below tolerance and dose uniformity in the target. The plans generated using functional lung avoidance information reduces the doses to the functioning lung. With both IMRT avoidance plans, we could not obtain better functional avoidance or lower V-20Gy (volume receiving 20Gy or more) for total lung when the planning target volume (PTV) was surrounded by functional lung volumes. We were able to achieve better ventilated lung avoidance and lower total lung V-20Gy when the PTV is close to, but not surrounded by functioning lung volumes. For patients with the PTV that is far from 50% and 70% functional lung volumes, three-field IMRT spare the ventilated lung as well as nine-field IMRT ventilation avoidance plan, with a lower total lung V20-Gy.

Nasopharyngeal liposarcoma MRI imaging features and a review of the literature

We present a case of liposarcoma in a 37-year-old female with a chronic history of nasal stuffiness. MR imaging revealed a fatty lesion in the nasopharynx. Subsequent tissue sampling and histopathology demonstrated features consistent with a liposarcoma.

A randomized phase II study of OGX-011 in combination with docetaxel and prednisone or docetaxel and prednisone alone in patients with metastatic hormone refractory prostate cancer (HRPC)

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Background: Clusterin, a cytoprotective chaperone protein that promotes cell survival, is associated with androgen independent progression and overexpressed in HRPC. OGX-011 (OGX, developed by OncoGenex Technologies/Isis Pharmaceuticals) is a 2’- methoxyethyl modified phosphorothioate antisense that inhibits clusterin expression in humans at doses of ≤640 mg and potentiates chemotherapy activity in prostate xenografts. The objective of this study was to determine the anti-tumor activity of OGX in combination with docetaxel (DOC) in patients (pts) with HRPC. Methods: Chemo-naive pts with metastatic HRPC were randomized to receive DOC 75mg/m2 q3 weeks + OGX 640mg weekly as a 2-hour IV infusion (Arm A) + prednisone or DOC + prednisone (Arm B). Serum levels of clusterin were assessed serially. A single stage randomized phase II design was employed with PSA response rate (RR) as the primary endpoint (Bubley et al, J Clin Oncol 1999;17:3461). Planned sample size was 40 per arm: Arm A the hypotheses (H0:PSA RR<40% vs. H1:PSA RR>60%) could be tested at 10% β and 10% a, Arm B the true PSA RR could be estimated with half-width of the 90% confidence interval <13% if observed PSA RR was 40%. Results: 82 pts (41/arm) were enrolled from September 2005 to December 2006 at 12 centers. Baseline characteristics are similar in both arms (available to date for 63 pts): median age 67 (range: 49–84), PSA 110 μg/L (5.6–1261), hemoglobin 128 g/L (96–158), alkaline phosphatase 133 U/L (47–1294), LDH 193 U/L (120–741). ECOG performance status was 0 in 49% and 1 in 51%; 67% had bone/nodal disease only and 33% had other metastatic sites. To date, 56 pts have received ≥2 cycles. Toxicity due to OGX included grade 1/2 fevers and rigors in 37% and 67% pts respectively, but other adverse events were similar in both arms. PSA response has occurred in 43%, progression in 9%, and 48% have not yet met criteria for response or progression. Conclusions: Combined docetaxel and OGX is well tolerated in pts with metastatic HRPC and PSA responses have been observed. Pt treatment, follow-up and analysis of serum clusterin levels continue. Results by arm will be available by June 2007. Supported by a grant from the NCI-Canada/Canadian Cancer Society.

No significant financial relationships to disclose.

Spinal metastasis from endolymphatic sac tumor

We describe a case of endolymphatic sac tumor with drop metastasis to the spine. Our review of the literature showed that this is only the 2nd reported case of such an occurrence.

3D thoracoscopic ultrasound volume measurement validation in an ex vivo and in vivo porcine model of lung tumours

The purpose of this study was to validate the accuracy and reliability of volume measurements obtained using three-dimensional (3D) thoracoscopic ultrasound (US) imaging. Artificial "tumours" were created by injecting a liquid agar mixture into spherical moulds of known volume. Once solidified, the "tumours" were implanted into the lung tissue in both a porcine lung sample ex vivo and a surgical porcine model in vivo. 3D US images were created by mechanically rotating the thoracoscopic ultrasound probe about its long axis while the transducer was maintained in close contact with the tissue. Volume measurements were made by one observer using the ultrasound images and a manual-radial segmentation technique and these were compared with the known volumes of the agar. In vitro measurements had average accuracy and precision of 4.76% and 1.77%, respectively; in vivo measurements had average accuracy and precision of 8.18% and 1.75%, respectively. The 3D thoracoscopic ultrasound can be used to accurately and reproducibly measure "tumour" volumes both in vivo and ex vivo.