A phase I/II trial of intensity modulated radiation (IMRT) dose escalation with concurrent fixed-dose rate gemcitabine (FDR-G) in patients with unresectable pancreatic cancer

PURPOSE

Local failure in unresectable pancreatic cancer may contribute to death. We hypothesized that intensification of local therapy would improve local control and survival. The objectives were to determine the maximum tolerated radiation dose delivered by intensity modulated radiation with fixed-dose rate gemcitabine (FDR-G), freedom from local progression (FFLP), and overall survival (OS).

METHODS AND MATERIALS

Eligibility included pathologic confirmation of adenocarcinoma, radiographically unresectable, performance status of 0-2, absolute neutrophil count of ≥ 1,500/mm(3), platelets ≥ 100,000/mm(3), creatinine <2 mg/dL, bilirubin <3 mg/dL, and alanine aminotransferase/aspartate aminotransferase ≤ 2.5 × upper limit of normal. FDR-G (1000 mg/m(2)/100 min intravenously) was given on days -22 and -15, 1, 8, 22, and 29. Intensity modulated radiation started on day 1. Dose levels were escalated from 50-60 Gy in 25 fractions. Dose-limiting toxicity was defined as gastrointestinal toxicity grade (G) ≥ 3, neutropenic fever, or deterioration in performance status to ≥ 3 between day 1 and 126. Dose level was assigned using TITE-CRM (Time-to-Event Continual Reassessment Method) with the target dose-limiting toxicity (DLT) rate set to 0.25.

RESULTS

Fifty patients were accrued. DLTs were observed in 11 patients: G3/4 anorexia, nausea, vomiting, and/or dehydration (7); duodenal bleed (3); duodenal perforation (1). The recommended dose is 55 Gy, producing a probability of DLT of 0.24. The 2-year FFLP is 59% (95% confidence interval [CI]: 32-79). Median and 2-year overall survival are 14.8 months (95% CI: 12.6-22.2) and 30% (95% CI 17-45). Twelve patients underwent resection (10 R0, 2 R1) and survived a median of 32 months.

CONCLUSIONS

High-dose radiation therapy with concurrent FDR-G can be delivered safely. The encouraging efficacy data suggest that outcome may be improved in unresectable patients through intensification of local therapy.

Abstract 1463: PARP inhibition reverses radiation resistance conferred by ETS fusions in prostate cancer

Background: ETS gene fusions, which are found in approximately half of all prostate cancers, result in overexpression of ETS transcription factors, of which ERG is the prototype. We previously discovered that ERG interacts with the DNA damage response protein poly (ADP-ribose) polymerase 1 (PARP1). Therefore, we hypothesized that the ERG-PARP1 interaction may confer radiation resistance by increasing DNA repair efficiency, and this radioresistance can be reversed with PARP1 inhibition. Methods: We used lentiviral approaches to establish isogenic models of ERG overexpression in PC3 and DU145 prostate cancer cell lines. We then assessed the role of ERG overexpression on 1) PARP1 activity (via immunoblots for poly ADP-ribose (PAR) formation), 2) DNA repair (via COMET assays and immunofluorescent microscopy for gamma-H2aX foci), and 3) clonogenic survival, before and following radiation +/− the PARP1 inhibitor olaparib. We also created ERG mutants with a point mutation (Y373) which disrupted the ERG-PARP interaction, and assessed the role of this interaction on radiation response. Finally, we established xenografts from ERG-overexpressing and control PC3 cells, and treated these xenografts with radiation +/− PARP1 inhibition. Results: In both PC3 and DU145 cells, ERG overexpression resulted in increased PARP1 activity and quicker repair of DNA damage, both of which were reversed with olaparib. ERG overexpression resulted in a 1.3 fold increase in clonogenic survival following radiation, consistent with radioresistance. PARP1 inhibition with olaparib preferentially radiosensitized ERG-positive cells, by a factor of 1.5 relative to ERG-negative cells (p&lt;0.05). Additionally, disruption of ERG-PARP interaction via point mutation reversed the ERG-mediated increase in clonogenic survival following radiation. Within PC3 xenografts, ERG overexpression also conferred radioresistance which was reversed with PARP1 inhibition. Conclusions: In these prostate cancer cell models, ERG overexpression confers radiation resistance via increased efficiency of DNA repair following radiation. This radioresistance is dependent on the ERG-PARP1 interaction, and can be reversed via inhibition of PARP1 both in vitro and in vivo. These novel findings motivate the use of PARP1 inhibitors as radiosensitizers in patients with localized ETS fusion-positive prostate cancers.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1463. doi:1538-7445.AM2012-1463

Concurrent temozolomide and dose-escalated intensity-modulated radiation therapy in newly diagnosed glioblastoma

PURPOSE

To determine the maximum-tolerated dose (MTD) of radiation (RT) with concurrent temozolomide in patients with newly diagnosed glioblastoma (GBM), to estimate their progression-free (PFS) and overall survival (OS), and to assess the role of (11)C methionine PET (MET-PET) imaging in predicting recurrence.

EXPERIMENTAL DESIGN

Intensity-modulated RT (IMRT) doses of 66 to 81 Gy, assigned to patients by the time-to-event continual reassessment method, were delivered over 6 weeks with concurrent daily temozolomide (75 mg/m(2)) followed by adjuvant cyclic temozolomide (200 mg/m(2) d1-5 q28d ×6 cycles). Treatment was based on gadolinium-enhanced MRI. Pretreatment MET-PET scans were obtained for correlation with eventual sites of failure.

RESULTS

A total of 38 patients were analyzed with a median follow-up of 54 months for patients who remain alive. Late CNS grade ≥III toxicity was observed at 78 (2 of 7 patients) and 81 Gy (1 of 9 patients). None of 22 patients receiving 75 or less Gy developed RT necrosis. Median OS and PFS were 20.1 (14.0-32.5) and 9.0 (6.0-11.7) months, respectively. Twenty-two of 32 patients with pretreatment MET-PET uptake showed uptake beyond the contrast-enhanced MRI. Patients whose treatment did not include the region of increased MET-PET uptake showed an increased risk of noncentral failure (P < 0.001).

CONCLUSIONS

Patients with GBM can safely receive standard temozolomide with 75 Gy in 30 fractions, delivered using IMRT. The median OS of 20.1 months is promising. Furthermore, MET-PET appears to predict regions of high risk of recurrence not defined by MRI, suggesting that further improvements may be possible by targeting metabolically active regions.

Abstract 491: The roles of homologous recombination repair and cell cycle checkpoints in radiosensitization by the Chk1/2 inhibitor, AZD7762

The combination of gemcitabine and radiation is superior to gemcitabine alone for locally advanced pancreatic cancer however the median survival is only approximately one year. We have previously demonstrated that inhibition of Chk1 (checkpoint kinase 1) sensitizes pancreatic cancer cell lines, as well as patient-derived tumor xenografts, to both radiation and gemcitabine-radiation. The exact mechanism(s) for this sensitization, however, remains unclear. Based on the abilities of Chk1 to induce cell cycle arrest and promote HRR (homologous recombination repair) in response to DNA damage, we set out to determine the relevance of these mechanisms to radiosensitization by AZD7762, an AstraZenca Chk1/2 inhibitor currently in Phase I clinical trials. We tested the effects of AZD7762 on survival, cell cycle checkpoints, Rad51 focus formation and HRR activity in response to radiation and gemcitabine-radiation in two pancreatic cancer cell lines, Panc-1 and MiaPaCa-2. We began this study with the observation that AZD7762 sensitized MiaPaCa-2 cells to radiation and gemcitabine-radiation with enhancement ratios of 1.5 ± 0.08 (AZD7762), 1.2 ± 0.07 (50 nM gemcitabine), and 1.9 ± 0.16 (AZD7762 + 50 nM gemcitabine) but did not sensitize Panc-1 cells where enhancement ratios were 1.0 ± 0.03 (AZD7762), 1.5 ± 0.11 (100 nM gemcitabine), and 1.4 ± 0.05 (AZD7762 + 100 nM gemcitabine). AZD7762 inhibited Chk1 in both cell lines as evidenced by accumulation of Cdc25A and abrogation of the radiation-induced G2 arrest. To begin to determine the contribution of HRR to radiosensitization by AZD7762, we utilized a DR-GFP reporter assay which measures homology directed repair of an I-SceI endonuclease-induced DNA double strand break in an integrated GFP reporter gene in MiaPaCa-2 and Panc-1 cells. Treatment of cells expressing the DR-GFP reporter with 100 nM AZD7762 produced a 2- to 3-fold (P&lt;0.05) inhibition of HRR activity in MiaPaCa-2 cells but minimal to no inhibition in Panc-1 cells. Inhibition of HRR by AZD7762 was accompanied by a reduction in the number of MiaPaCa-2 cells which stained positive for Rad51 foci in response to radiation (32 ± 3% versus 9 ± 3%; P&lt;0.05). Taken together these results suggest that inhibition of HRR may play a role in the mechanism(s) of radiosensitization by Chk1 inhibition. It will be important in future studies to further decipher the contributions of cell cycle checkpoint abrogation and HRR inhibition to the mechanisms of radiosensitization by Chk1 inhibitors.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 491.

Parametric response map as an imaging biomarker to distinguish progression from pseudoprogression in high-grade glioma

PURPOSE

To assess whether a new method of quantifying therapy-associated hemodynamic alterations may help to distinguish pseudoprogression from true progression in patients with high-grade glioma.

PATIENTS AND METHODS

Patients with high-grade glioma received concurrent chemoradiotherapy. Relative cerebral blood volume (rCBV) and blood flow (rCBF) maps were acquired before chemoradiotherapy and at week 3 during treatment on a prospective institutional review board-approved study. Pseudoprogression was defined as imaging changes 1 to 3 months after chemoradiotherapy that mimic tumor progression but stabilized or improved without change in treatment or for which resection revealed radiation effects only. Clinical and conventional magnetic resonance (MR) parameters, including average percent change of rCBV and CBF, were evaluated as potential predictors of pseudoprogression. Parametric response map (PRM), an innovative, voxel-by-voxel method of image analysis, was also performed.

RESULTS

Median radiation dose was 72 Gy (range, 60 to 78 Gy). Of 27 patients, stable disease/partial response was noted in 13 patients and apparent progression was noted in 14 patients. Adjuvant temozolomide was continued in all patients. Pseudoprogression occurred in six patients. Based on PRM analysis, a significantly reduced blood volume (PRM(rCBV)) at week 3 was noted in patients with progressive disease as compared with those with pseudoprogression (P < .01). In contrast, change in average percent rCBV or rCBF, MR tumor volume changes, age, extent of resection, and Radiation Therapy Oncology Group recursive partitioning analysis classification did not distinguish progression from pseudoprogression.

CONCLUSION

PRM(rCBV) at week 3 during chemoradiotherapy is a potential early imaging biomarker of response that may be helpful in distinguishing pseudoprogression from true progression in patients with high-grade glioma.

Adaptive trial of personalized radiotherapy for intrahepatic cancer

Primary liver cancer is a major health problem worldwide, with more than 500,000 new cases diagnosed yearly. Preliminary results suggest excellent local control rates of intrahepatic malignancies treated with stereotactic body radiation therapy (SBRT), but some patients have experienced life-threatening toxicity because the current approaches cannot accurately estimate residual liver function after treatment. An early-phase trial of SBRT in hepatocellular carcinoma patients, including those with compromised liver function, is described. Patients are treated with three fractions of SBRT, then treatment is paused for 4 weeks and liver function is evaluated by means of an indocyanine green assay. The size of the final two fractions of SBRT is determined based on the patient's indocyanine green assay after the first three fractions, so that the therapy is personalized to each patient's sensitivity to radiation. The sensitivity to the liver of the final two fractions of SBRT, compared with the first three fractions, is re-estimated using a Bayesian model throughout the trial, so this is an adaptive trial. The operating characteristics of the trial are described by Monte Carlo simulations.

Differential tumor and normal mucosa biomarker modulation by epidermal growth factor receptor (EGFR) inhibition using erlotinib in oral cavity squamous cell carcinoma (OCSCC)

6077

Background: Targeted therapy may improve the therapeutic index in locally advanced head neck cancer if differential EGFR inhibition in tumors compared to the normal mucosa is demonstrated. Based on prior published data, EGFR degradation is an important biomarker of cytotoxicity in a preclinical model. The aim of this pilot study was to determine if there are differences in biomarker modulation between tumor and the normal mucosa and confirm our initial preclinical findings regarding EGFR degradation. Methods: Patients with primary OCSCC requiring surgical resection had normal mucosa and tumor biopsies prior to a test course of erlotinib. Patients received one week of erlotinib 150 mg qd. Repeat tumor and normal mucosal biopsies were obtained at the time of surgical resection to evaluate the effect of the EGFR inhibitor on both tumor and the normal mucosa. Changes in known preclinical markers of EGFR activity (phospho, total EGFR, AKT, STAT3) were measured by immunoblotting assays. In addition, changes in distribution of these biomarkers were analyzed by immunohistochemical analysis. Results: 12 pts were enrolled; 7 pts with paired tumor and normal mucosa biopsies. Tumor specimens showed over-expression of EGFR compared to the normal mucosa (p = 0.005). Erlotinib treatment led to marked inhibition of both pEGFR and EGFR protein (p = 0.004 and p = 0.007, respectively) in tumor biopsies. In contrast, we found heterogeneity in EGFR inhibition in the normal mucosa following erlotinib. (p = 0.1 [pEGFR], and p = 0.07 [EGFR)]) We noted dramatic reduced levels of pSrc and pSTAT3 following erlotinib in tumors compared to untreated matched tumor samples. In addition, levels of p27 were enhanced. Conclusions: Differential EGFR inhibition in tumors compared to the normal mucosa, may suggest that the addition of EGFR inhibitors to chemo-RT or accelerated RT, whose dose limiting toxicity is acute mucositis, may select patients who will benefit from targeted therapy. Our results demonstrate that EGFR inhibition by erlotinib led to marked reduction in EGFR protein levels. EGFR degradation may be an important biomarker in selecting patients predicted to have a response to TKI. These results need further validation.

No significant financial relationships to disclose.

The polished tri-tapered stem for cement-in-cement revision hip arthroplasty, a reliable and reproducible technique?

The object of this study was to determine the short to medium term outcome of cementing a highly polished tapered implant into the old cement mantle once damaged cement is removed at the time of revision hip surgery. A consecutive series of 36 patients underwent c-stem cement-in-cement revision hip arthroplasty between June 2000 and April 2006. The primary outcome measure was the validated shortened Western Ontario and McMaster Universities (WOMAC) score, secondary outcomes were the Orthowave company patient satisfaction survey, radiological analysis, and general complications. The follow-up period was between 12 and 84 months (average 48.86 months). The mean post op WOMAC score at latest follow-up was 10.89 (0 to 29). Two patients died with their hip in situ. Two patients had radiological signs of prosthesis loosening on follow-up. Complications included: one sacral plexus palsy which had a partial recovery and one intra-operative periprosthetic fracture. One patient underwent cup revision for recurrent dislocation. Cement within cement revision hip arthroplasty using a highly polished tapered stem in the short to medium term provides satisfactory functional outcomes and is associated with a low complication rate and good survivorship.

Reactive synovitis following hip resurfacing: a case presentation

We report a case of metal-on-metal hip resurfacing complicated by a reactive synovitis and a large effusion resulting in dislocation, peripheral oedema and groin discomfort. Histological analysis of the retrieved specimens revealed an intense lymphocytosis. Conversion to a traditional hip replacement resulted in resolution of the symptoms.

Molecularly targeted radiosensitization of human prostate cancer by modulating inhibitor of apoptosis

PURPOSE

The inhibitor of apoptosis proteins (IAP) are overexpressed in hormone-refractory prostate cancer, rendering the cancer cells resistant to radiation. This study aims to investigate the radiosensitizing effect of small-molecule IAP inhibitor both in vitro and in vivo in androgen-independent prostate cancer and the possible mechanism of radiosensitization.

EXPERIMENTAL DESIGN

Radiosensitization of SH-130 in human prostate cancer DU-145 cells was determined by clonogenic survival assay. Combination effect of SH-130 and ionizing radiation was evaluated by apoptosis assays. Pull-down and immunoprecipitation assays were employed to investigate the interaction between SH-130 and IAPs. DU-145 xenografts in nude mice were treated with SH-130, radiation, or combination, and tumor suppression effect was determined by caliper measurement or bioluminescence imaging. Nuclear factor-kappaB activation was detected by luciferase reporter assay and quantitative real-time PCR.

RESULTS

SH-130 potently enhanced radiation-induced caspase activation and apoptosis in DU-145 cells. Both X-linked IAP and cIAP-1 can be pulled down by SH-130 but not by inactive SH-123. Moreover, SH-130 interrupted interaction between X-linked IAP/cIAP-1 and Smac. In a nude mouse xenograft model, SH-130 potently sensitized the DU-145 tumors to X-ray radiation without increasing systemic toxicity. The combination therapy suppressed tumor growth more significantly than either treatment alone, with over 80% of complete tumor regression. Furthermore, SH-130 partially blocked tumor necrosis factor-alpha- and radiation-induced nuclear factor-kappaB activation in DU-145 cells.

CONCLUSIONS

Our results show that small-molecule inhibitors of IAPs can overcome apoptosis resistance and radiosensitize human prostate cancer with high levels of IAPs. Molecular modulation of IAPs may improve the outcome of prostate cancer radiotherapy.

Natural BH3 mimetic (-)-gossypol chemosensitizes human prostate cancer via Bcl-xL inhibition accompanied by increase of Puma and Noxa

Antiapoptotic members of the Bcl-2 family proteins are overexpressed in prostate cancer and are promising molecular targets for modulating chemoresistance of prostate cancer. (-)-Gossypol, a natural BH3 mimetic, is a small-molecule inhibitor of Bcl-2/Bcl-xL/Mcl-1 currently in phase II clinical trials as an adjuvant therapy for human prostate cancer. Our objective is to examine the chemosensitization potential of (-)-gossypol in prostate cancer and its molecular mechanisms of action. (-)-Gossypol inhibited cell growth and induced apoptosis through mitochondria pathway in human prostate cancer PC-3 cells and synergistically enhanced the antitumor activity of docetaxel both in vitro and in vivo in PC-3 xenograft model in nude mouse. (-)-Gossypol blocked the interactions of Bcl-xL with Bax or Bad in cancer cells by fluorescence resonance energy transfer assay and overcame the Bcl-xL protection of FL5.12 model cells on interleukin-3 withdrawal. Western blot and real-time PCR studies showed that a dose-dependent increase of the proapoptotic BH3-only proteins Noxa and Puma contributed to the cell death induced by (-)-gossypol and to the synergistic effects of (-)-gossypol and docetaxel. The small interfering RNA knockdown studies showed that Noxa and Puma are required in the (-)-gossypol-induced cell death. Taken together, these data suggest that (-)-gossypol exerts its antitumor activity through inhibition of the antiapoptotic protein Bcl-xL accompanied by an increase of proapoptotic Noxa and Puma. (-)-Gossypol significantly enhances the antitumor activity of chemotherapy in vitro and in vivo, representing a promising new regime for the treatment of human hormone-refractory prostate cancer with Bcl-2/Bcl-xL/Mcl-1 overexpression.

Full-Dose Gemcitabine With Concurrent Radiation Therapy in Patients With Nonmetastatic Pancreatic Cancer: A Multicenter Phase II Trial

Purpose

Gemcitabine is effective in the treatment of pancreatic cancer and is a potent radiosensitizer. This study assessed safety and efficacy of full-dose gemcitabine administered before and during concurrent three-dimensional conformal radiation (3D-CRT) in patients with nonmetastatic pancreatic cancer.

Patients and Methods

During cycles 1 and 3, patients received gemcitabine at 1,000 mg/m2on days 1 and 8 of each 21-day cycle. Cycle 2 included the same dose of gemcitabine on days 1, 8, and 15 of a 28-day cycle with concurrent 3D-CRT at 36 Gy, administered in 15 fractions of 2.4 Gy, over 3 weeks. Resectable patients underwent surgery 4 to 6 weeks after treatment. The primary objective was evaluation of toxicity. Tumor response, CA 19-9, and 1-year survival were also assessed.

Results

Forty-one patients enrolled at six institutions between April 2002 and October 2003. Among the 39 treated patients, the most common toxicities were grade 3 neutropenia (12.8%), grade 3 nausea (10.3%), and grade 3 vomiting (10.3%). The response rate was 5.1% and disease control rate was 84.6%. Mean post-treatment CA 19-9 levels (228 ± 347 U/mL) were significantly (P = .006) reduced compared with pretreatment levels (1,241 ± 2,124 U/mL). Thirteen (81%) of 16 patients initially judged resectable, three (33%) of nine borderline-resectable patients, and one (7%) of 14 unresectable patients underwent resection after therapy. One-year survival rates were 73% for all patients, 94% for resectable patients, 76% for borderline-resectable patients, and 47% for unresectable patients.

Conclusion

Full-dose gemcitabine with concurrent radiotherapy was well tolerated and active. Evaluation of this regimen in a larger, randomized trial for patients with resectable or borderline-resectable disease may be warranted.

Recurrent total hip arthroplasty dislocation in combination with massive osteolysis: an outline of management using a proximal femoral replacement

Recurrent dislocation of a total hip arthroplasty is a most distressing complication for both patient and surgeon. The situation is worsened when massive osteolysis occurs in combination with recurrent dislocation. Management options become more limited in this situation. We present such a case along with a discussion of the management options utilised.

IKKalpha in the regulation of inflammation and adaptive immunity

Inflammation is a beneficial response to insult or injury which plays an important role in orchestrating the adaptive immune response. The resolution of acute inflammation is an active process that involves the release of anti-inflammatory mediators and the termination of pro-inflammatory signalling pathways coincident with leucocyte apoptosis and phagocytic clearance and the migration of antigen-presenting cells from the site of inflammation to the local lymphatic tissue. The latter process is required for the development of adaptive immunity and immunological memory. The NF-kappaB (nuclear factor kappaB) pathway is an important regulator of inflammation and immunity; NF-kappaB activation is controlled by IKK [IkappaB (inhibitor of NF-kappaB) kinase] complex, which regulates NF-kappaB activation in response to pro-inflammatory stimuli. The IKK complex has two catalytic subunits, IKKalpha and IKKbeta; recent research shows that these highly homologous kinases have distinct roles in inflammation and adaptive immunity. Here, we discuss the emerging roles for IKKalpha in the tight regulation of inflammation and the development of adaptive immune responses.