DNA-PKcs-dependent modulation of cellular radiosensitivity by a selective cyclooxygenase-2 inhibitor

PURPOSE

Inhibition of cyclooxygenase-2 has been shown to increase radiosensitivity. Recently, the suppression of radiation-induced DNA-dependant protein kinase (DNA-PK) activity by the selective cyclooxygenase-2 inhibitor celecoxib was reported. Given the importance of DNA-PK for repair of radiation-induced DNA double-strand breaks by nonhomologous end-joining and the clinical use of the substance, we investigated the relevance of the DNA-PK catalytic subunit (DNA-PKcs) for the modulation of cellular radiosensitivity by celecoxib.

METHODS AND MATERIALS

We used a syngeneic model of Chinese hamster ovarian cell lines: AA8, possessing a wild-type DNK-PKcs; V3, lacking a functional DNA-PKcs; and V3/WT11, V3 stably transfected with the DNA-PKcs. The cells were treated with celecoxib (50 muM) for 24 h before irradiation. The modulation of radiosensitivity was determined using the colony formation assay.

RESULTS

Treatment with celecoxib increased the cellular radiosensitivity in the DNA-PKcs-deficient cell line V3 with a dose-enhancement ratio of 1.3 for a surviving fraction of 0.5. In contrast, clonogenic survival was increased in DNA-PKcs wild-type-expressing AA8 cells and in V3 cells transfected with DNA-PKcs (V3/WT11). The decrease in radiosensitivity was comparable to the radiosensitization in V3 cells, with a dose-enhancement ratio of 0.76 (AA8) and 0.80 (V3/WT11) for a survival of 0.5.

CONCLUSIONS

We have demonstrated a DNA-PKcs-dependent differential modulation of cellular radiosensitivity by celecoxib. These effects might be attributed to alterations in signaling cascades downstream of DNA-PK toward cell survival. These findings offer an explanation for the poor outcomes in some recently published clinical trials.

SNS-032 prevents tumor cell-induced angiogenesis by inhibiting vascular endothelial growth factor

Cell proliferation, migration, and capillary network formation of endothelial cells are the fundamental steps for angiogenesis, which involves the formation of new blood vessels. The purpose of this study is to investigate the effect of a novel aminothiazole SNS-032 on these critical steps for in vitro angiogenesis using a coculture system consisting of human umbilical vein endothelial cells (HUVECs) and human glioblastoma cells (U87MG). SNS-032 is a potent selective inhibitor of cyclin-dependent kinases 2, 7, and 9, and inhibits both transcription and cell cycle. In this study, we examined the proliferation and viability of HUVECs and U87MG cells in the presence of SNS-032 and observed a dose-dependent inhibition of cellular proliferation in both cell lines. SNS-032 inhibited threedimensional capillary network formations of endothelial cells. In a coculture study, SNS-032 completely prevented U87MG cell-mediated capillary formation of HUVECs. This inhibitor also prevented the migration of HUVECs when cultured alone or cocultured with U87MG cells. In addition, SNS-032 significantly prevented the production of vascular endothelial growth factor (VEGF) in both cell lines, whereas SNS-032 was less effective in preventing capillary network formation and migration of endothelial cells when an active recombinant VEGF was added to the medium. In conclusion, SNS-032 prevents in vitro angiogenesis, and this action is attributable to blocking of VEGF.

A phase II study of cetuximab (C225) in combination with chemoradiation (CRT) in patients (pts) with stage III A/B non-small cell lung cancer (NSCLC): An interim report of the RTOG 0324 trial

7531

Background: Cetuximab (C225) is a chimerized monoclonal antibody that targets the epidermal growth factor receptor (EGFR). NSCLC commonly expresses the EGFR, which is associated with aggressive tumor behavior and poor clinical outcome. Preclinical model systems demonstrate radiosensitization following molecular inhibition of EGFR signaling. Methods: We report a phase II trial testing the combination of C225 with CRT in unresectable stage III NSCLC with a planned sample size of 84 PTS. Eligibility criteria included Zubrod performance status (PS) = 1, weight loss = 5% over past 3 months, FEV1 = 1.2 l, adequate hematologic, hepatic, and renal function. PTS received an initial dose of C225 (400 mg/m2) on day 1 of week 1, then weekly doses of C225 (250 mg/m2) until completion of therapy (weeks 2 –17). During week 2, patients started CRT (63 Gy/35 fractions) with weekly carboplatin (C) AUC 2 and paclitaxel (P) 45 mg/m2 × 6 doses followed by C (AUC 6) and P (200 mg/m2) × 2 cycles (weeks 12–17). Interim monitoring for severe (grade = 3) or excessive non-hematologic toxicities occurred after pts had been treated and followed for at least 90 days after RT. Primary endpoints include safety and compliance of concurrent C225 and CRT. Results: 93 pts were enrolled with 87 evaluable pts. Pts characteristics: 57% male, median age 64 years (range 42–85), 47% PS 0, 46% stage IIIA. Median follow-up is 14 months. Response rate is 62% (n=54) and 12 month overall survival (OS) is 68% (# at risk=56). Adverse events related to treatment include 20% (n=17) of pts with grade 4 hematologic toxicities and 7 pts who had grade 3 esophagitis. There was 1 infection related death, 1 death NOS, and 3 pts who died of pulmonary complications (adult respiratory distress syndrome, pneumonitis, and hypoxia). Conclusions: The combination of C225 with CRT is feasible. Further study will be needed to determine whether the addition C225 to CRT enhances toxicity or efficacy. Complete compliance and toxicity data along with 18 month OS will be reported.

No significant financial relationships to disclose.

A phase I study of neoadjuvant paclitaxel/radiation in patients with potentially resectable adenocarcinoma of the pancreas

15067

Background: To determine the maximum tolerated dose (MTD) and dose-limiting toxicities (DLT) of weekly paclitaxel when given with concurrent radiation in the neoadjuvant setting to patients with potentially resectable adenocarcinoma of the pancreas. A secondary goal was to assess the value of 18-fluoro-deoxy-glucose positron emission tomography (FDG-PET) as an early marker of therapeutic response. Methods: Patients received weekly paclitaxel, given as a 3-hour infusion, during the course of radiation. The starting dose of paclitaxel was 30 mg/m2/week. Doses were escalated in increments of 15 mg/m2 in successive cohorts of 3–6 patients. Radiation therapy consisted of 45Gy in 25 fractions over 5 weeks. CT and PET scans were obtained prior to initiating treatment and one month following completion of chemoradiation. Results: Nine patients with resectable pancreatic cancer were enrolled through two dose levels. DLT was defined as grade 3 or greater. There were no DLTs at the first dose level of 30 mg/m2/ week. DLTs consisted of nausea, neutropenia and hepatic toxicity developed at the second dose level of 45 mg/m2/ week. Pre-treatment PET scans revealed uptake in all nine of the patients whereas pre-treatment CT scans detected disease in only 5 of 9 patients. Post-treatment PET scans correlated with pathologic findings in all 9 patients. Conclusions: The MTD for concurrent paclitaxel/radiation in the neoadjuvant setting was determined to be 30 mg/m2/week. DLTs were nausea, neutropenia and hepatic toxicity. FDG-PET may be superior to CT scans as a radiographic marker of treatment response.

[Table: see text]

Toxicities in a phase II study of accelerated high dose thoracic radiation therapy (TRT) with concurrent chemotherapy for limited small cell lung cancer (LSCLC) (RTOG 0239)

7717

Background: Accelerated fractionation proved beneficial in INT0096, but the total dose was low and local recurrence was high with higher acute grade (Gr.) 3+ esophagitis. RTOG 0239 was a phase II trial to improve local control and survival with LSCLC with acceptable acute Gr. 3+ esophagitis using accelerated high dose TRT and concurrent cisplatin/etoposide. This is the first report of acute Gr.3+ esophagitis and Gr.5 toxicities. Methods: Patients (pts) with LSCLC without pleural effusion, contralateral hilar or contralateral supraclavicular nodes and PS 0–1 were enrolled. TRT was given to large fields to 28.8 Gy at 1.8 Gy per fraction, 5 days per week for 16 fractions followed by BID with large field in AM, boost in PM, then off-cord boost BID for last 5 days, all at 1.8 Gy per fx for a total dose of 61.2 Gy in 34 fx in 5 weeks. Concurrent chemotherapy was started with TRT with cisplatin, 60 mg/m2 i.v. day 1; etoposide, 120 mg/m2 i.v. day 1; etoposide, 240 mg/m2 p.o. per day or 120 mg/m2 i.v. per day on days 2 or 3. Cycles were repeated q.3 wks during and for 2 cycles after TRT. Pts who have achieved complete response one month after completion of 4 cycles of chemotherapy were asked to participate in a prophylactic cranial irradiation (PCI) study. Common toxicity criteria (CTC) 2.0 was used for acute toxicity. Results: From 10/2003 to 5/2006, 72 pts were accrued. Median age was 63 yrs with 52% females. Survival data is still maturing. Acute toxicity information is available for 68 pts. Eleven pts (16%) experienced acute Gr. 3 and 1 pt (1%) had acute Gr. 4 esophagitis. 47 pts (69%) had grade 4 blood/bone marrow toxicities. There were 2 (3%) Gr. 5 toxicities reported [1 infection with neutropenia; 1 pulmonary (pneumonia)]. Conclusions: This accelerated high dose TRT with concurrent chemotherapy for LSCLC resulted in 17% acute Gr.3+ esophagitis compared to 27% with BID TRT with 45Gy in 3 weeks by INT0096. There were 3% grade 5 toxicities. This preliminary report suggests that RTOG-0239 has tolerable toxicity. The acute Gr3+ esophageal toxicity correlated with V20 and V40 will be presented. Pts continue to be followed for the primary endpoint of 2-year survival.

No significant financial relationships to disclose.

Patterns of practice in radiation therapy for non-small cell lung cancer among members of American Society of Therapeutic Radiology and Oncology

7693

Purpose: To investigate the dominant pattern of current practice in radiation therapy (RT) for lung cancer among members of American Society of Therapeutic Radiology and Oncology (ASTRO). Methods: A 35-item survey was designed by a panel of 8 board certified radiation oncologists regarding RT for lung cancer. Surveys were sent through email to 3,800 radiation oncologist members on September 10, 2006, with the results collected online on December 10, 2006. Here we report results on radiation decisions for non-small cell lung cancer (NSCLC). Results: The response rate was 19% (n = 727). The respondents saw an average of 8 consults (ranged 1–25) monthly during the survey time (summing up to a total of >60,000 new cases yearly). For stage I peripherally located NSCLC, 33%, 10% and 20% of respondents reported conventional fractionated, hypofractioned and stereotactic RT, respectively. Another 25% of respondents would have offered stereotactic RT if this technique were available at their center. For stage I centrally located tumors, 78% of respondents did not agree with, but 10% selected, stereotactic RT. For stage II and III, 76% of respondents selected 60–70 Gy in 1.8–2 Gy with chemotherapy. With regard to the combined modality approach for stage II and III disease, 76–77% of respondents selected concurrent chemoRT followed by adjuvant chemotherapy, and 11–16% sequential followed by concurrent chemoRT for patients with good performance status. For stage IV NSCLC with remarkable local disease, the consideration of RT ranged from 0 Gy, 3 Gyx10, 3 Gyx15, 2.5 Gyx20, to 2 Gyx30 in 27%, 17%, 8%, 13%, and 21% of respondents, respectively. Conclusions: The dominant pattern of practice for stage II/III disease is concurrent chemoRT, consistent with results of phase III trials. The treatment decisions for stage I and IV disease are diverse, partially due to technology advancement and the lack of large phase III trials.

No significant financial relationships to disclose.

A phase III study of Æ-941 with induction chemotherapy (IC) and concomitant chemoradiotherapy (CRT) for stage III non- small cell lung cancer (NSCLC) (NCI T99–0046, RTOG 02–70, MDA 99–303)

7527

Background: Æ-941 is a shark cartilage extract with antiangiogenic properties. We conducted a placebo-controlled trial testing Æ-941, with IC and CRT, in unresectable stage III NSCLC. Methods: Eligibility criteria included performance status (PS) < 2, weight loss < 10%. Subjects received one of two treatment regimens depending on site of enrollment: carboplatin (C) (AUC 6) and paclitaxel (P) (200 mg/m2) × 2 cycles followed by CRT (60 Gy/30 fractions) with weekly C (AUC 2) and P (45 mg/m2) × 6 doses or cisplatin (CDDP) (75 mg/m2, d1) and vinorelbine (V) (30 mg/m2, d1 and 8) × 2 cycles followed by CRT (60 Gy/30 fractions) with CDDP (75 mg/m2, day 1) and V (15 mg/m2, d1 and 8) × 2 cycles. Subjects were randomized to receive Æ-941 (Arm A) or placebo (Arm B), 120 mL orally twice daily, at the start of IC and continuing after CRT as maintenance therapy. Randomization was stratified for stage, gender, and type of chemotherapy. The primary endpoint was overall survival (OS), with a planned sample size of 756 subjects providing 80% power to detect a 25% difference in OS, assuming a control arm median survival time (MST) of 13 months, type I error 0.05. Results: Between 6/00 and 2/06, 384 subjects were enrolled onto the trial and randomized. In 2/06 the trial was closed to new patient entry due to insufficient accrual. This final analysis is based on 379 randomized and eligible subjects (188 arm A, 191 arm B). Subject characteristics: 60% male, median age 63 years (range 37–84), 56% stage IIIB, 58% C-based chemotherapy, median follow-up 3.7 years. There was no significant difference in OS between arms A and B, with MSTs of 14.4 (95% CI 12.6–17.9) and 15.6 (95% CI 13.8–18.1) months, respectively (log-rank p=0.73). OS by pre-specified stratification factors: stage IIIB vs IIIA (MST 13.9 vs. 17.4 months, p=0.25), C vs. CDDP chemotherapy (MST 14.4 vs. 16.7 months, p=0.13), and male vs. female (MST 15.7 vs. 15.1 months, p=0.74). The study drug was well tolerated. Fewer subjects in arm A experienced grade 3 or higher adverse events (66% vs. 77%, p=0.018). Conclusions: The addition of Æ−941 to IC and CRT does not improve OS in patients with unresectable stage III NSCLC.

No significant financial relationships to disclose.

4-Dimensional conformal radiation therapy: image-guided radiation therapy and its application in lung cancer treatment

The goal of all cancer therapies is to increase the therapeutic ratio, that is, to increase the probability of cure while minimizing the toxicity. Theoretically, all cancers can be cured if a sufficient dose of radiation can be delivered to all clonogens without causing undue toxicity to the patient. Obviously, this is not the case in most instances. Precise target localization, in theory, can improve the therapeutic ratio by allowing more conformal radiation delivery, enabling one to escalate the tumor dose while sparing surrounding normal tissue. In the past few decades, conventional 2-dimensional radiation therapy (RT), based on surface anatomy and bony landmarks, has given way to the computed tomography-based 3-dimensional RT, allowing the use of internal soft tissue anatomy. Great interests are now emerging in the field of radiation oncology in assessing the motion of the tumor and surrounding normal tissue, from day to day or during each treatment session, and delivering treatments that adapt to the detected motion. Commercially available 4-dimensional imaging capabilities and various strategies to deliver the radiation dose to the moving target made this new paradigm possible. In this review article, we will discuss the concept of 4-dimensional RT, particularly as it applies to lung cancer, and elaborate on the technical advances that made it possible.

Satraplatin: an orally available platinum analog for the treatment of cancer

Satraplatin is a novel, orally bioavailable, platinum anticancer drug. Platinum analogs form the mainstay of treatment for a number of cancers, including lung, ovarian, colorectal and head and neck cancer. A disadvantage of the currently marketed platinum analogs is that they must all be administered via intravenous infusion. In addition, their utility is often limited by toxicity, particularly neurotoxicity, ototoxicity and renal toxicity. Satraplatin has preclinical antitumor activity comparable with that of cisplatin and, clinically, has a more manageable side-effect profile. Satraplatin is active in lung, ovarian and prostate cancer, and appears to have good efficacy in combination with radiation for lung and head and neck cancer. Preclinical data suggest it may also be effective for the treatment of certain cisplatin-refractory tumors. A large, randomized Phase III trial is currently evaluating satraplatin in combination with prednisone for the treatment of patients with hormone-refractory prostate cancer whose disease has progressed following prior systemic therapy. Positive results from this trial would support regulatory approval for satraplatin for this indication. The availability of an active oral platinum agent, such as satraplatin, with few of the serious toxicities associated with traditional intravenous platinum compounds makes satraplatin an alternative to other platinum agents and a new treatment option in the oncologist's armamentarium.

Phase I study of irinotecan (Ir) and cisplatin (DDP) in combination with thoracic radiotherapy (RT), either twice daily (45 Gy) or once daily (70 Gy), in patients with limited (Ltd) small cell lung carcinoma (SCLC): Early analysis of RTOG 0241

7058

Background: Ir in combination with DDP has proven superior to DDP & VP-16 in extensive stage SCLC (Noda et al NEJM 1/02), with marked increase in 2 yr survival (19.5%, vs 5.2%). Hence, it is critical to determine if Ir can be safely & effectively integrated with concurrent RT and DDP in earlier stage, Ltd SCLC. Methods: 1° endpoint: Determine maximum tolerated dose (MTD) of Ir d 1 & 8 plus DDP 60 mg/m2 q 3 wks & either BID RT (45 Gy) or QD RT (70 Gy). Eligibility stipulated Tx-naïve patients (pts) with Ltd SCLC, PS 0–1, adequate heme (ANC ≤ 1500/mL; plts ≥ 120,000/mL) hepatic (bili ≤ 1.5/dL) & renal (creat ≤ 1.5gr/dL) function, & baseline FEV1 of ≥ 1 liter. Ir was escalated in sequential (seq) cohorts from 40 mg/m2 (level 1) to 50 mg/m2 (level 2) & then to 60 mg/m2 (level 3) d 1 & 8 q 3 wks during each cycle of treatment. Ir & DDP were given concurrently with RT for cycle 1 in seq A (45 Gy) & during cycles 1 & 2 in seq B (70 Gy). 36 pts were targeted for accrual. DLT was defined as gr 4 esophagitis, pneumonitis, or diarrhea; gr 4 neutropenic fever, or any attributable gr 5 toxicity Results: As of 12/05, 36 pts were accrued, (21 - seq A; 15 - seq B). Median age was 64 (range 49–79) Of 33 eval pts, 18 (55%) were female; 24 (73%) PS 0; 67% had ≤ 5% wt loss. Attributable DLT was not seen in seq A, but was observed in seq B (70 Gy) at 50 mg/m2 with 1 episode each of gr 4 diarrhea & esophagitis, necessitating hospitalization. In addition, 1 pt in seq B had non-attributable gr 4 cardiovascular AEs. There has been no acute gr 5 toxicity. 1 pt experienced late gr 3 pulm toxicity, another gr 3 constitutional toxicity, including wt loss. The overall incidence of gr 3 esophagitis was 34%. Conclusions: In Ltd SCLC, I at 60 mg/m2 d 1 & 8 is safe & feasible in combination with DDP 60 mg/m2 q 3 wks & BID RT (45 Gy). The MTD for I in combination with RT (70 Gy) & DDP 60 mg/m2 is 40 mg/m2 d 1 and 8. Response, progression, survival data remain immature.

[Table: see text]

[Table: see text]

Efficacy of High Dose Per Fraction Radiation for Implanted Human Prostate Cancer in a Nude Mouse Model

PURPOSE

SBRT is a new therapeutic paradigm using large dose per fraction treatments (aggressive hypofractionation). While SBRT has shown efficacy for treating patients with lung, liver and spine tumors, to our knowledge there have been no preclinical studies evaluating the efficacy of this treatment for prostate cancer. We investigated the dose-response characteristics of SBRT for treating human prostate cancer in a nude mouse model.

MATERIALS AND METHODS

Nude mice were injected subcutaneously into the right flank with C4-2 prostate cancer cells grown in culture. A dose escalation trial was performed to assess toxicity and response. Tumor bearing animals were radiated with 3 fractions (1 per week) for a total dose of 15 Gy in 11, 22.5 Gy in 9 and 45 Gy in 10, while 8 untreated animals served as controls. The mice were weighed, and tumor volume and PSA measurements were performed at baseline and weekly until 4 weeks after treatment.

RESULTS

There was no treatment related toxicity. There was a significant difference in the tumor response to higher radiation doses. In the 15 and 22.5 Gy groups mean tumor volume decreased to 58% and 90% of the original volume, respectively, but the rats experienced progressive tumor regrowth within 1 week after the completion of therapy. The 45 Gy group had a mean tumor volume and PSA decrease of greater than 90%, which was sustained 1 month after treatment in all except 2 mice.

CONCLUSIONS

SBRT dose level treatments were able to significantly decrease tumor volume and PSA. However, using 15 and 22.5 Gy durable responses were not achieved except in a few mice. The 45 Gy group demonstrated sustained PSA and tumor volume decreases in most mice. These results clearly show an increasing dose-response relationship for a range of hypofractionated dose levels, as used in SBRT.

Efficacy of ablative high-dose-per-fraction radiation for implanted human renal cell cancer in a nude mouse model

OBJECTIVES

Stereotactic body radiation therapy (SBRT) is a new therapeutic paradigm that uses a very large dose per fraction treatments (ablative hypofractionation). We investigated the use of ablative hypofractionation in treating human renal cell carcinoma using a nude mouse model.

METHODS

Nude mice were injected subcutaneously with A498 human renal carcinoma cells. Tumour-bearing animals were radiated with three fractions (one per week) for a total dose of 48 Gy (n = 12), while untreated animals served as controls (n = 7). The mice were weighed, and tumour volumes were measured at baseline and weekly until 7 weeks post-treatment.

RESULTS

Control animals demonstrated progressive tumour growth and were sacrificed because of either tumour size or ulceration. Tumours in the treatment group grew to three times their initial size over the 3 weeks of treatment but subsequently decreased progressively to less than 30% of their initial volume. All treated tumours exhibited marked cytologic changes. Tumours from mice sacrificed before post-treatment week 4 had a mitotic count of 1-4/10 hpf. Tumours from mice sacrificed more than 4 weeks post-treatment (n = 4) demonstrated no mitoses.

CONCLUSIONS

Treatment with high-dose-per-fraction radiation to 48 Gy resulted in a sustained decrease in tumour volume and marked cytologic changes. These results are preliminary--but promising--and encourage further research into this application of ablative hypofractionated radiation for kidney cancer.

The cyclin-dependent kinase 2 inhibitor down-regulates interleukin-1beta-mediated induction of cyclooxygenase-2 expression in human lung carcinoma cells

Overexpression of cyclooxygenase-2 (COX-2) is frequently observed in several human cancers, including lung, colon, and head and neck. Malignancies are also associated with the dysregulation of cell cycle events and concomitant elevated activity of cyclin-dependent kinases (CDK). CDK2 is a key cell cycle regulatory protein that controls the transition of cells from G(1) to S phase. In this study, we furnish several lines of evidence that show a functional role for the CDK2 in interleukin-1beta (IL-1beta)-induced COX-2 expression in H358 human non-small cell lung carcinoma cell line by blocking CDK2 activity. First, we show that BMS-387032, a potent CDK2 inhibitor, blocks IL-1beta-induced expression as well as steady-state mRNA levels of COX-2. Second, we show that small interfering RNA that abrogates CDK2 expression also blocks IL-1beta-induced COX-2 expression. Third, results from in vitro kinase assays clearly show that IL-1beta induces CDK2 activity in H358 cells and this activity is significantly inhibited by BMS-387032. Moreover, CDK2 inhibition blocks IL-1beta-induced binding to the NF-IL6 element of the COX-2 promoter and inhibits transcription of the COX-2 gene. We also observed that BMS-387032 does not inhibit endogenous expression of COX-2 or prostaglandin synthesis in lung carcinoma cells. Finally, we provide evidence showing that IL-1beta-induced signaling events, such as p38 mitogen-activated protein kinase, phosphorylated stress-activated protein kinase/c-Jun NH(2)-terminal kinase, phosphorylated AKT, and phosphorylated extracellular signal-regulated kinase 1/2, are not inhibited by CDK2 inhibitor. Taken together, the data suggest that CDK2 activity may play an important event in the IL-1beta-induced COX-2 expression and prostaglandin E(2) synthesis and might represent a novel target for BMS-387032.

A phase I study of concurrent 9-nitro-20(s)-camptothecin (9NC/Orathecin) and radiation therapy in the treatment of locally advanced adenocarcinoma of the pancreas

BACKGROUND AND PURPOSE

In vitro studies have suggested that 9-nitro-20(s)-Camptothecin (9NC/Orathecin/Rubitecan) can enhance the effects of radiation. We conducted a phase I study to assess the toxicity and determine the maximum tolerated dose of 9NC when combined with radiation in patients with locally advanced adenocarcinoma of the pancreas.

PATIENTS AND METHODS

Eleven patients with locally advanced adenocarcinoma of the pancreas received 9NC, orally during radiation. Radiation therapy consisted of 45 Gy in 25 fractions given over 5 weeks. The starting dose of 9NC was 1 mg/m2/day.

RESULTS

Eight patients received 9NC at a dose of 1 mg/m2/day and three patients received a dose of 1.25 mg/m2/day. Dose-limiting toxicity (DLT) was defined as >or=grade 3 non-hematologic toxicity and >or=grade 4 hematologic toxicity. Dose-limiting toxicity of grade 3 nausea/vomiting developed in one patient at the first dose level. At dose level 2, two of three patients developed DLT. Both developed grade 3 nausea, fatigue, and anorexia. Additionally, one of these patients had grade 3 dehydration and the other had grade 4 leukopenia, grade 3 vomiting, and grade 3 weakness.

CONCLUSIONS

9NC, 1 mg/m2/day, can be given concurrently with radiation with acceptable toxicity.

Correlation of HER1/EGFR expression and degree of radiosensitizing effect of the HER1/EGFR-tyrosine kinase inhibitor erlotinib

Epidermal growth factor receptor (HER1/EGFR)-mediated signal transduction pathways are important in cellular response to ionizing radiation. High HER1/EGFR expression on cancer cells may contribute to radioresistance. In this pre-clinical study, we evaluated the radiosensitizing effect of erlotinib, a small molecule HER1/EGFR inhibitor in three human cancer cell lines with different HER1/EGFR expression--A431 (very high expression), H157 (moderate expression) and H460 (low expression). Our results demonstrated that A431 was the most radioresistant, while H460 was the most radiosensitive. However, A431 cells were the most sensitive to erlotinib (IC50 = 300 nM) and H460 cells the most resistant (IC50 = 8 microM). H157 had intermediate sensitivity to radiation and erlotinib (IC50 = 3 microM). With 300 nM erlotinib, the radiation dose enhancement ratios (DER) were 1.40, 1.17 and 1.04 in A431, H157 and H460, respectively. Treatment with erlotinib for 24 hr at 300 nM increased G1 arrest by 18.6, 2.0 and 4.8% in A431, H157 and H460, respectively. Erlotinib-induced apoptosis was augmented by radiation in A431 cells only. In conclusion, high HER1/EGFR expression may result in a high degree of radiosensitization with erlotinib combined with radiation. The extent of erlotinib-induced radiosensitization was proportional to HER1/EGFR expression, as well as autophosphorylation of the human epidermal growth factor receptor (HER1/EGFR).

Improving outcomes in the treatment of locally-advanced NSCLC with gemcitabine

Multiple approaches of combined modality therapy have emerged as potential treatments for improving unresectable, locoregionally advanced non-small-cell lung cancer (NSCLC). Several agents have been used either sequentially or concurrently in clinical trials of combined chemoradiotherapy. However, no specific regimen has been clearly defined, particularly with regard to the timing of chemotherapy (sequential and/or concurrent), the specific chemotherapeutic drugs, and the dose and intensity of the radiation therapy. Concurrent chemoradiotherapy demonstrates a survival advantage compared to sequential chemoradiotherapy. Initial data suggest that induction chemotherapy prior to concurrent chemoradiotherapy does not further improve survival. The potent radiosensitizer gemcitabine has been evaluated in combination chemotherapy with radiation therapy and appears to be a promising agent, although further trials are needed to define its optimal dose, toxicity and efficacy.

Long term follow up and analysis of long term survivors in patients treated with paclitaxel-based concurrent chemo/radiation therapy for locally advanced non-small cell lung cancer

PURPOSE

For patients with locally advanced non-small cell lung cancer (LANSCLC), concurrent chemotherapy/radiation therapy (RT) has become the standard of care. Three multi-institutional phase II studies with paclitaxel-based chemotherapeutic regimen given concurrently with RT for patients with LANSCLC were performed from March of 1994 to May of 1997. We sought to determine mature data from this database of patients, as well as to perform analysis of a cohort of patients who have achieved long term survival (LTS) when treated with this regimen.

PATIENTS AND METHODS

Database of these patients was analyzed retrospectively upon longer follow up, with median follow up for the three studies being 498 days (range 11-2905 days, average 780 days). Weight loss limitation for the three studies was liberal: weight loss <10% and <15% 3 months preceding diagnosis (LUN-27 and LUN-63, respectively), and no weight loss limitation for LUN-56.

RESULTS

The 4-year overall survival (OS) for the three trials was 16.3%, and 2-year progression free survival (PFS) was 25.7%. Statistical analysis of the long term survivors (OS > 4 years) was performed, and performance status (PS) was found to be a significant factor predictive of LTS. PS of 0 compared to 1 yielded a 2.5-fold increased likelihood of LTS (p = .04). There was also a trend (p = .067) for responders (complete or partial response) to yield a five-fold likelihood of LTS compared to non-responders (stable or progressive disease).

CONCLUSION

Our results support the efficacy of combined modality therapy (CMT) for patients with LANSCLC even despite our more liberal weight loss eligibility criteria. Furthermore, our analysis indicates that LTS is more likely to be achievable in patients with PS = 0 compared to 1 when treated with CMT for LANSCLC.

Response to combined modality therapy correlates with survival in locally advanced non–small-cell lung cancer

PURPOSE

Although concurrent chemoradiotherapy can now achieve demonstrated long-term survival in patients with locally advanced non-small-cell lung cancer (LANSCLC), it is difficult to predict which patients will benefit most from this therapeutic approach. Studies have suggested that local control, and the response to therapy, may be linked to improved survival; however, detailed analysis of the impact of tumor response to chemoradiotherapy on survival has not been thoroughly reported. Therefore, we sought to determine the impact of the response rate on survival for patients who were treated with combined modality therapy for LANSCLC.

METHODS AND MATERIALS

We reviewed the data from 116 patients enrolled between 1994 and 1997 in three trials investigating paclitaxel-based concurrent chemoradiotherapy for LANSCLC. Tumor size measurements were assessed immediately before and 2 months after completion of combined modality therapy to determine the response and to calculate the percentage of decrease in tumor size.

RESULTS

Patients with a response (complete or partial) had an improved 4-year overall survival rate compared with patients with no response (stable or progressive disease; 21.1% vs. 3.3%, p <0.0001) in the 109 assessable patients. Progression-free survival also improved significantly with response. An analysis of the percentage of decrease in tumor size vs. survival was performed (n = 74) using Cox proportion model analysis. After combined modality therapy, a 20%, 40%, 60%, 80%, and 100% decrease in tumor size conferred a 39%, 63%, 78%, 86%, and 92% reduction in risk of death compared with a 0% decrease in tumor size (p <0.0001).

CONCLUSION

The response by conventional response criteria correlated strongly with improved overall survival and progression-free survival and an increasing percentage of decrease in tumor size resulted in a reduction in the risk of death. Additional investigation of the degree of response as a factor predictive of improved therapeutic efficacy, translating into improved survival, is warranted.

Phase II multicenter study of induction chemotherapy followed by concurrent efaproxiral (RSR13) and thoracic radiotherapy for patients with locally advanced non-small-cell lung cancer

PURPOSE

Efaproxiral (RSR13) reduces hemoglobin oxygen-binding affinity, facilitates oxygen release, and increases tissue pO2. We conducted a phase II multicenter study that assessed the efficacy and safety of efaproxiral when administered with thoracic radiation therapy (TRT), following induction chemotherapy, for treatment of locally advanced non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

Fifty-one patients with locally advanced NSCLC were enrolled at 13 sites. Treatment comprised two cycles of paclitaxel (225 mg/m2) and carboplatin (area under the curve, 6), 3 weeks apart, followed by TRT (64 Gy/32 fractions) with concurrent efaproxiral (50 to 100 mg/kg). Survival results were compared with results of study Radiation Therapy Oncology Group (RTOG) 94-10.

RESULTS

Overall response rate was 75% (37 of 49 patients). Complete and partial response rates were 6% (three of 49 patients) and 69% (34 of 49 patients), respectively. Median survival time (MST) was 20.6 months (95% CI, 14.0 to 24.2); overall survival rates at 1- and 2-years were 67% and 37%, respectively. Survival results were compared with the sequential (S-CRT) and concurrent (C-CRT) chemoradiotherapy arms of RTOG 94-10. MSTs for cases matched by stage, Karnofsky performance status, and age were: RT-010, 20.6 months; S-CRT, 15.1 months; and C-CRT, 17.9 months. Grade 3 to 4 toxicities related to efaproxiral that occurred in more than one patient included transient hypoxemia (19%), radiation pneumonitis (11%), and fatigue (4%).

CONCLUSION

Addition of efaproxiral to S-CRT represents a promising approach in NSCLC treatment, and a randomized study should be pursued. The low incidence of grade 3 to 4 toxicities suggests that the use of efaproxiral instead of a cytotoxic agent, as a radiation sensitizer, may be advantageous.

Rationale for investigation of epidermal growth factor receptor inhibitors in definitive treatment of locally advanced non-small cell lung cancer and head and neck cancer

Designing targeted therapies has become an important field in cancer therapeutics. The epidermal growth factor receptor (EGFR) is a molecular target that has gained immense attention as preclinical and clinical studies have supported its potential role for therapy of a variety of cancers, including non-small cell lung cancer (NSCLC) and head and neck (HN) cancer. Several compounds that specifically inhibit EGFR have been developed, including ZD1839, C225, and OSI-774. Interestingly, studies suggesting a potential role for EGFR inhibitors as an adjunct to the current combined-modality approach for therapy of NSCLC and HN cancer have been performed in the preclinical and clinical setting. Therefore, determining the potential of EGFR inhibitors to improve the efficacy of standard combined-modality regimens (chemotherapy/radiation therapy +/- surgery) for NSCLC and HN cancer patients is of the utmost importance. An overview of the rationale and the ongoing/proposed studies aimed at determining the role for EGFR inhibitors in combination with radiation therapy for NSCLC and HN cancer patients will be presented.

Combined chemoradiotherapy regimens of paclitaxel and carboplatin for locally advanced non-small-cell lung cancer: a randomized phase II locally advanced multi-modality protocol

PURPOSE

This phase II noncomparative randomized trial was conducted to determine the optimal sequencing and integration of paclitaxel/carboplatin with standard daily thoracic radiation therapy (TRT), in patients with locally advanced unresected stage III non-small-cell lung cancer (NSCLC). Survival data were compared with historical standard sequential chemoradiotherapy data from the Radiation Therapy Oncology Group.

PATIENTS AND METHODS

Patients with unresected stages IIIA and IIIB NSCLC, with Karnofsky performance status > or = 70% and weight loss < or = 10%, received two cycles of induction paclitaxel (200 mg/m2)/carboplatin (area under the plasma concentration time curve [AUC] = 6) followed by TRT 63.0 Gy (arm 1, sequential) or two cycles of induction paclitaxel (200 mg/m2)/carboplatin (AUC = 6) followed by weekly paclitaxel (45 mg/m2)/carboplatin (AUC = 2) with concurrent TRT 63.0 Gy (arm 2, induction/concurrent), or weekly paclitaxel (45 mg/m2)/carboplatin (AUC = 2)/TRT (63.0 Gy) followed by two cycles of paclitaxel (200 mg/m2)/carboplatin (AUC = 6; arm 3, concurrent/consolidation).

RESULTS

With a median follow-up time of 39.6 months, median overall survival was 13.0, 12.7, and 16.3 months for arms 1, 2, and 3, respectively. During induction chemotherapy, grade 3/4 granulocytopenia occurred in 32% and 38% of patients on study arms 1 and 2, respectively. The most common locoregional grade 3/4 toxicity during and after TRT was esophagitis, which was more pronounced with the administration of concurrent chemoradiotherapy on study arms 2 and 3 (19% and 28%, respectively).

CONCLUSION

Concurrent weekly paclitaxel, carboplatin, and TRT followed by consolidation seems to be associated with the best outcome, although this schedule was associated with greater toxicity.

Prophylactic cranial irradiation with combined modality therapy for patients with locally advanced non-small cell lung cancer

Central nervous system (CNS) metastasis is a significant problem for many patients with non-small cell lung cancer (NSCLC). The earlier data reported a high incidence of CNS metastasis in patients with locally advanced NSCLC who were treated with radiotherapy alone. However, poor control of both thoracic and extracranial systemic disease dominated the results of the early trials. The risk for CNS metastasis as the first site of failure remains a significant concern for patients who have completed modern combined modality therapy. With improvements in the treatment of thoracic and systemic disease, there is renewed interest in prophylactic cranial irradiation (PCI). The results from the Radiation Therapy Oncology Group (RTOG) trial of PCI to prevent CNS relapse in patients with locally advanced NSCLC are anticipated.

Induction Paclitaxel/Carboplatin Followed by Concurrent Chemoradiation Therapy for Unresectable Stage III Non–Small-Cell Lung Cancer: A Limited-Access Study (CALGB 9534)

BACKGROUND

This phase II cooperative group study of patients with unresectable stage III non-small-cell lung cancer was designed to treat patients with induction chemotherapy with paclitaxel and carboplatin (PC) followed by concurrent chemotherapy with the same chemotherapy plus thoracic irradiation to 66 Gy.

PATIENTS AND METHODS

All enrolled patients were scheduled to receive 2 cycles of induction PC at conventional doses. All nonprogressing patients were subsequently treated with concurrent chemoradiation, including 7 weekly doses of PC and once-daily thoracic irradiation. The eligibility criteria allowed treatment of an expanded population of patients, unrestricted by previous weight loss.

RESULTS

Despite the fact that 22% of patients had experienced > 5% weight loss in the preceding 6 months, 23 of the 40 eligible patients (58%) responded to the overall regimen. A 3-year failure-free survival rate of 15% and a 3-year overall survival rate of 27% were achieved. The 3-year overall survival rate is consistent with landmark cooperative group results for the combined modality treatment of a more highly selected patient population.

CONCLUSION

The feasibility of this therapeutic approach in a cooperative group setting and inclusive of patients who were representative of the general population of stage III lung cancer patients was established.

Phase I trial of Orzel (UFT plus leucovorin), cisplatin, and radiotherapy in the treatment of potentially resectable esophageal cancer

PURPOSE

Fluorinated pyrimidines have been established as radiosensitizers in the combined modality therapy of esophageal cancer. UFT, an oral combination of a 5-fluorouracil pro-drug (uracil) and a dihydropyrimidine dehydrogenase inhibitor (ftorafur), may provide improvement in the ease of administration with equal efficacy. This Phase I study was designed to determine the maximal tolerated dose and dose-limiting toxicity of UFT, leucovorin, and cisplatin when given with radiotherapy in the neoadjuvant treatment of resectable esophageal cancer.

METHODS

Chemotherapy consisted of i.v. cisplatin 80 mg/m(2) (Days 1 and 22) and UFT with leucovorin orally on Days 1-35. UFT was escalated in 50-mg/m(2) increments, starting at 200 mg/m(2)/d. Radiotherapy consisted of 4500 cGy in 25 fractions. Patients underwent resection 4-6 weeks after chemoradiotherapy.

RESULTS

Ten patients with resectable esophageal cancer were enrolled. Of the 7 patients entered at dose level 1, 1 developed a dose-limiting toxicity of nausea. All 3 patients entered at dose level 2 developed dose-limiting toxicity. The maximal tolerated dose for UFT was the starting level, 200 mg/m(2)/d. Of the 10 patients enrolled, 8 underwent esophagectomy and 2 developed progressive disease and did not undergo surgery. The disease of 6 of the 8 patients was downstaged at surgery.

CONCLUSION

The recommended UFT dose for Phase II studies is 200 mg/m(2)/d given orally in two divided doses when given with leucovorin, cisplatin, and radiotherapy.

Dosimetric uncertainties of three-dimensional dose reconstruction from two-dimensional data in a multi-institutional study

Inconsistencies in the treatment planning process leading to dosimetric uncertainties may affect conclusions drawn from interinstitutional radiation oncology clinical trials. The purpose of this study was to assess the dosimetric uncertainties resulting from the process of reconstructing three-dimensional dose distributions from two-dimensional treatment plan information provided by participating institutions in a randomized clinical trial. This study was based on American College of Radiology Protocol #427, Locally Advanced Multi-Modality Protocol; a multi-institutional phase II randomized study involving radiation therapy for patients with inoperable non-small cell lung cancer. Several sources of dosimetric uncertainty were identified and analyzed, including image quality of hard-copy computed tomography (CT) images, slice spacing of CT scans, treatment position, interpretations of target volumes by radiation oncologists, the contouring of normal anatomic structures, and the use of common beam models for all dose calculations. Each source of uncertainty was investigated using a set of plans, with the ideal characteristics of digital images with 3-mm axial slice spacing and a flat couch, consisting of eight cases from Vanderbilt University Medical Center with electronically transferred CT data. The target volume DVH values were dependent on the additional uncertainty introduced by differences in delineation of the target volumes by the participating radiation oncologists. The DVH values for the lungs and heart were dependent on image quality and treatment position. Esophagus DVH values were not dependent on any of the sources of uncertainty. None of the structure DVH values were dependent on slice thickness or variations in the contouring of normal anatomic structures. Reconstruction of three-dimensional dose distributions from two-dimensional treatment plan information may be useful in cases for which digital CT data is not available or for historical data review. However, dosimetric accuracy will depend on image quality of the treatment planning CT data and consistency in the delineation of tumor volumes.

Trastuzumab, Paclitaxel, Cisplatin, and Radiation for Adenocarcinoma of the Esophagus: A Phase I Study #

PURPOSE

To conduct a phase I study incorporating trastuzumab with paclitaxel, cisplatin, and radiation for adenocarcinoma of the esophagus.

METHODS AND MATERIALS

Patients with adenocarcinoma of the esophagus without distant organ metastases were eligible. All patients received cisplatin 25 mg/m2 and paclitaxel 50 mg/m2 weekly for 6 weeks with radiation 50.4 Gy. HER-2/neu-positive patients (2+/3+ by immunohistochemistry) received weekly trastuzumab at dose levels of 1, 1.5, or 2 mg/kg weekly for 5 weeks after an initial bolus of 2, 3, or 4 mg/kg, respectively. HER-2/neu-negative patients received the same chemoradiation without trastuzumab as a control for toxicity. Dose-limiting toxicities were defined as grade 3 esophageal, cardiac, or pulmonary toxicity.

RESULTS

Twelve of 36 screened patients (33%) overexpressed HER-2/neu by immunohistochemistry (seven 3+ and five 2+). Eight of 12 patients with HER-2/neu overexpression by IHC had an increase in the number of HER-2/neu genes, six from amplification of the HER-2/ neu gene and two were hypderdiploid for chromosome 17. Thirty patients were enrolled (12 HER-2/neu-positive and 18 HER-2/neu-negative controls). No increase in toxicity was seen with the addition of trastuzumab. One of 12 patients in the trastuzumab arm and 8 of 17 in the control arm had grade 3 esophagitis (p < or = .026). Mean left ventricular ejection fraction for the trastuzumab group was 57% before treatment and 56% after treatment.

CONCLUSION

HER-2/neu is overexpressed in approximately one-third of esophageal adenocarcinomas. Trastuzumab can be added at full dose to cisplatin, paclitaxel, and radiation. Future studies of trastuzumab in esophageal adenocarcinoma are indicated.

Non-small cell lung cancer and central nervous system metastases: Should we be using prophylactic cranial irradiation?

Central nervous system (CNS) failure in patients with locally advanced non-small cell; lung cancer (LA-NSCLC) is a common and debilitating problem. Standard follow-up after local regional therapy does not include routine radiologic evaluation of the brain. Imaging is performed at the onset of symptoms followed by palliative therapy for CNS failure. Some investigators support regular screening with therapy for failures before the onset of symptoms. This alternative may decrease the impact of CNS failures and lengthen survival. Other investigators have shown that prophylactic cranial irradiation (PCI) for LA-NSCLC decreases the incidence of CNS failures. The potential survival, quality of life, and neuropsychological advantage or disadvantage of these two approaches has not been systematically studied. This article will review the problem of CNS failures in patients with LA-NSCLC and the potential risks and benefits of close observation and PCI. The necessity of conducting an ambitious study evaluating the potential survival advantage of PCI will be discussed.

Locally advanced NSCLC: current state of the art, treatment and future directions

Combined chemoradiotherapy is the current treatment standard for patients with locally advanced non-small cell lung cancer. Recent trials have shown increased benefit with concurrent versus sequential administration. Specifically, recently reported results of a large, randomized phase II trial support this conclusion and provide evidence that the addition of consolidation chemotherapy after concurrent chemoradiotherapy may further improve outcome. Concurrent chemoradiotherapy offers substantially improved 2-year survival among patients with locally advanced disease over the previous standards of radiotherapy alone and sequential administration of chemotherapy and radiotherapy. To further improve survival, investigators are evaluating the addition of molecularly targeted therapy to chemoradiotherapy in this treatment setting. The current focus of research is the addition of epidermal growth factor receptor inhibitors (tyrosine kinase inhibitors or monoclonal antibodies), which appear to act synergistically with radiotherapy. Current trials are combining these inhibitors with chemoradiotherapy in a variety of treatment strategies, including induction, primary, consolidation, and maintenance therapy. This article reviews the development of the current treatment standard and current research into new treatments with epidermal growth factor receptor inhibitors.

Chemoradiation in NSCLC: focus on the role of gemcitabine

Research to identify the optimal drugs for use in chemoradiotherapy has led to the development of the potent radiosensitizing agent gemcitabine (Gemzar), which has exhibited excellent activity in non-small-cell cancer. When used in sequential chemoradiotherapy regimens, gemcitabine has been associated with response rates of 57% to 68%. A full dose of gemcitabine (1,000 mg/m2) can be safely used as induction therapy, and there is no definitive indication of enhancement of radiotoxicity. In addition, results from phase I/II trials support the efficacy of concurrent gemcitabine/radiation therapy in improving overall response rates and overall survival. Rates of 68%, 37%, and 28%, respectively, for 1-, 2-, and 3-year survival have been reported for gemcitabine/cisplatin chemotherapy administered concurrently with radiotherapy. Although the optimal dose has yet to be determined, a weekly dose of 300 mg/m2 appears to be effective with an acceptable toxicity level. Additional clinical trials are warranted to assess the long-term efficacy and safety of gemcitabine in combination with other chemotherapeutic agents and radiation therapy for treatment of non-small-cell lung cancer.

Potential role for epidermal growth factor receptor inhibitors in combined-modality therapy for non-small-cell lung cancer

There has been a surge of interest in the translation of discoveries in molecular biology into clinically relevant therapies in the field of hematology/oncology. The epidermal growth factor receptor (EGFR) has been a molecular target of significant interest and investigation, and preclinical and clinical studies support a role for targeted therapy in a variety of cancers, including non-small-cell lung cancer (NSCLC) via compounds that specifically inhibit EGFR. ZD1839, IMC-C225, and OSI-774 are the most clinically developed of these compounds. Interestingly, preclinical studies have demonstrated that EGFR inhibitors may have radiation-sensitizing properties, as well as increased cytotoxic activity in combination with chemotherapeutic agents, suggesting a potential role for EGFR inhibitors as an adjunct to the current combined-modality approach for therapy of Stage III NSCLC. Therefore, clinical trials have been proposed and initiated to address the issue of determining the impact of the addition of EGFR inhibitors to the standard combined-modality regimen (chemotherapy/radiation therapy +/- surgery) for Stage III NSCLC. This article reviews preclinical and clinical data supporting the role for EGFR inhibitors alone or in combination with chemotherapy/radiation therapy for locally advanced NSCLC. Also, it will provide an overview of ongoing and proposed clinical studies investigating the potential role for EGFR inhibitors in Stage III NSCLC.