Neoadjuvant Gemcitabine, Oxaliplatin, and Radiation Therapy for Pancreatic Cancer

Pancreatic Cancer Clinical Trial

Official title: A Multi-Institutional Phase II Study of Neoadjuvant Gemcitabine and Oxaliplatin With Radiation Therapy in Patients With Pancreatic Cancer

Status Active, not recruiting

Clinical Trial Summary

Primary Objective

1.1 To determine the two-year disease-free survival in patients with resectable pancreatic cancer treated preoperatively with a combination of full-dose gemcitabine, oxaliplatin and concurrent radiation therapy.

Secondary Objectives

1.2 To determine the toxicity profile of this treatment regimen.

1.3 To determine the objective response rate, the surgical resectability rate, the time-to-treatment failure, patterns of treatment failure and overall survival of the proposed treatment.

1.4 To evaluate pathologic effects of neoadjuvant therapy.

1.5 To evaluate the utility of FDG-PET imaging in determining resp.

1.4 To evaluate pathologic effects of neoadjuvant therapy.

1.5 To evaluate the utility of FDG-PET imaging in determining response to preoperative therapy and predicting disease free survival.

Clinical Trial Description

Pancreatic cancer remains incurable in the great majority of patients afflicted with the disease 1. Most patients present with tumor that is localized but unresectable. Median survival in this group of patients averages 6-10 months, with some suggestion of improvement for patients treated with combinations of radiation and chemotherapy 2, 3. Surgical treatment, when possible, is provided with curative intent. In those who have undergone surgery, however, median survival is only 13-20 months. Following resection, patients may benefit from the addition of adjuvant radiation and/or chemotherapy 4-6. Even in this most favorable group of patients, the 5 year survival is less than 30% in single institution series 7, 8. The vast majority of patients treated with surgery, with or without adjuvant therapy, fail with hepatic metastases. It is clear that a local treatment modality will have a limited impact on outcome in these patients. More effective treatment for pancreatic cancer must simultaneously address both local and distant sites of failure.

In advanced pancreatic cancer, gemcitabine is the standard for systemic therapy 9. Emerging data indicate that gemcitabine combinations, with additional cytotoxics or targeted agents, increase response rates, time to progression and overall survival in patients with advanced disease 10, 11. While the impact on survival is limited in the advanced disease setting, the potential for more active combination therapy to control or eradicate micro-metastatic disease as pre- or post-operative adjuvant treatment might be expected, as has been observed in other diseases 12, 13. Since a large majority of patients with pancreatic cancer relapse with a component of distant disease, investigation and development of adjuvant systemic combination treatments are warranted.

In resectable pancreatic cancer, surgery is most often the initial treatment. The adequacy of that resection is questionable, however, in that a significant minority of patients have positive margins and some patients have incomplete resection (R2 resections) 14, 15. Median survivals in patients with R2 resections or positive margins are no different than that observed with non-operative therapy. A reasonable strategy to address the limitations of surgery is neoadjuvant therapy 16. Potential advantages of neoadjuvant therapy also include an improved tolerance of combined modality treatment preoperatively, and a greater proportion of patients receiving all components of multimodality therapy completed over a shorter time interval. Recognizing a role for multimodality therapy in resectable pancreatic cancer, as many as 30 % of initially resected patients do not receive post-operative adjuvant therapy due to inadequate recovery from surgery or refusal. Treatment delays following surgery may also impact efficacy of adjuvant treatment. In the recently reported ESPAC adjuvant trial, the median time to initiation of post operative chemotherapy was 46 days and for combined modality treatment 61 days 5. Neoadjuvant treatment provides a more timely systemic therapy. Furthermore, patients presenting with borderline resectable lesions may become operable because of neoadjuvant treatment. We have successfully and safely resected patients following gemcitabine based chemoradiotherapy 17, 18. Finally, patients that progress during neoadjuvant therapy likely have a biologically aggressive disease and are unlikely to benefit from surgery. Patients who develop metastases during pre-operative treatment avoid a major operation which provides no benefit.

There are, admittedly, barriers to neoadjuvant treatment. These include biliary obstruction and a requirement for decompression of the biliary system, as well as a need for a pathologically confirmed diagnosis prior to treatment. Practical barriers to neoadjuvant therapy in this disease also include emotion, a desire by the patient and caregivers to have the tumor removed "before it's too late." Similar circumstances and obstacles have been overcome in other malignancies in which neoadjuvant treatment has become established.

The prognosis for resected pancreatic cancer remains poor. Clinical-pathologic parameters which correlate with survival are limited to lymph node and margin status. Additional potential prognostic parameters, including pathologic response to neoadjuvant treatment and functional imaging using positron emission tomography (PET) scans and standard uptake value (SUV) estimation in pancreatic cancer, are poorly characterized.

Conventional morphologic imaging modalities after neoadjuvant treatment of pancreatic cancer such a CT and MRI often have difficulty distinguishing viable tumor from inflammatory changes, necrotic debris or scar tissue. Functional imaging modalities such as 2-fluoro-2-deoxy-D-glucose (FDG) PET which rely on the metabolic activity in tumor may be able to discern these differences 19. FDG-PET imaging has been studied as a predictive tool in evaluating response to preoperative therapy in solid tumors 19-22. Decreases in the SUVs have allowed a semi-quantified evaluation that correlates with tumor histopathologic response and survival 21, 22. Additionally, preoperative FDG-PET imaging after neoadjuvant therapy has been useful in detecting unsuspected metastases avoiding radical surgical intervention in the patient with metastatic disease 22. These data in pancreatic cancer have been limited thus far 23. We propose to incorporate pre- and post-therapy FDG-PET imaging to further evaluate its utility in determining resectability, pathologic response to therapy and its relationship to survival.

In 1997, a phase 1 gemcitabine based chemotherapy and radiation therapy protocol was initiated at the University of Michigan that differed from other gemcitabine based combined modality regimens in two important ways. First, a standard dose or full dose of gemcitabine was used (as opposed to a "radiosensitizing" dose), considering the clinical benefit associated with standard dose gemcitabine as a systemic agent 9. The use of a standard dose was also consistent with laboratory data that demonstrate maximum radiosensitization when cytotoxic concentrations of drug are used 24. However, considering prior clinical experience indicating that substantial normal tissue radiosensitization could occur, use of full dose gemcitabine required reduction and investigation of the radiation dose. This approach differed from the more traditional approach of chemotherapy dose escalation with a fixed dose of radiation. Secondly, a decision was made to irradiate the primary tumor alone, without the inclusion of normal appearing regional lymph nodes. This was based on the assumption that the majority of the benefit from radiation would result from control of the primary tumor, rather than control of subclinical disease in these nodes. Regional nodes could potentially be controlled by standard doses of systemic therapy, as would distant sites of microscopic disease. Concerns for excess normal tissue toxicity that might occur with the use of more conventional treatment volumes contributed to this decision. This strategy required more accurate identification of the primary tumor and 3D radiation treatment planning.

In the ensuing phase I trial, thirty-seven patients with unresectable (34) or incompletely resected pancreatic cancer (3) were treated 25. Suspected or confirmed metastatic disease was identified at the time of enrollment in fourteen. Gemcitabine was administered as a 30 minute intravenous infusion at a dose of 1000 mg/m2 on day 1, 8 and 15 of a 28 day cycle. Radiation therapy was initiated on day 1 and directed at the primary tumor alone as indicated above. The starting radiation dose was 24 Gy in 1.6 Gy fractions. Escalation was achieved by increasing the fraction size in 0.2 Gy increments, keeping the duration of radiation constant at 3 weeks. A second cycle of gemcitabine alone was given following a one week rest. Two patients experienced dose limiting toxicity (DLT) at the final dose level (42 Gy), consisting of grade 4 vomiting and gastric/duodenal ulceration. Two additional patients at this dose level experienced late gastrointestinal toxicity which required surgical repair. Hematological toxicity was not substantively different than with gemcitabine alone. Median survival for the study population was 11.6 months. Isolated local or regional progression, a possible consequence of lower dose and limited field radiation, was observed in one patient only.

Based on these results, we conducted a multi-institutional phase II trial using full dose gemcitabine with 36 Gy in 2.4 Gy fractions for patients with resectable (20) and unresectable (21) pancreatic cancer17, 26. Protocol therapy included 3 cycles of gemcitabine with radiation therapy during the second cycle. Patients who remained or became resectable based on CT scanning were surgically explored 4-6 weeks following the last gemcitabine infusion. A total of 41 patients were enrolled at 6 institutions. Grade > 3 non-hematologic toxicity was seen in 19.5% of patients including five with grade 3 gastrointestinal toxicity, 2 with grade 3 fatigue and one unexplained death. A total of 20 patients underwent surgical exploration, with 17 patients resected. Those resected included 16 patients with clear margins, 1 pathologic complete response and 3 with only microscopic foci of tumor remaining. The complication rate was 24% with average length of stay 13.5 days and there was no 30 day mortality. After a median follow-up of 12 months, ten of 17 patients were alive without recurrence17. The development of liver metastasis in some of these patients following successful resection describes the need for a more active systemic treatment than gemcitabine alone.

In an effort to increase local and systemic treatment effects of combined modality therapy in pancreatic cancer, we have investigated combination chemotherapy with radiation therapy 27, 28. Our initial trial incorporated cisplatin with gemcitabine, based on activity of this combination in advanced disease as well as therapeutic interactions with radiation therapy

27. While activity was observed and we were able to give full doses of gemcitabine and cisplatin (40 mg/m2 every other week), the overall burden of treatment was felt to be too great for further development of this combination. Oxaliplatin, as compared to cisplatin, has less gastrointestinal and constitutional toxicities, and may be better suited for combined modality therapy in pancreatic cancer.

Oxaliplatin is a platinum salt with a 1,2-diaminocyclohexane ring in its structure. Oxaliplatin has efficacy in many cell lines in vitro and has been shown to be active in gastrointestinal malignancies. In a randomized phase III study, the combination of gemcitabine and oxaliplatin (GEMOX) was superior to gemcitabine alone in patients with advanced pancreatic cancer with regard to response rate (26.8% vs. 17.3%, P=.04), progression-free survival (5.8 vs. 3.7, P=.04) and clinical benefit (38.2% vs. 26.9%, P=.03) although the median overall survival difference was not statistically significant (9.0 vs. 7.1, P=.13) 10. Oxaliplatin appears to be synergistic with radiation therapy in vivo 29. In clinical trials, oxaliplatin concurrent with radiation therapy has been reported to be tolerable and efficacious in rectal and esophageal cancer 30, 31.

With these considerations, we began a phase I dose escalation trial in 2003 incorporating oxaliplatin into our full dose gemcitabine and radiation therapy approach 28. In dose levels 1 to 4, oxaliplatin was given days 1 and 15 of a 28 day cycle, beginning at a 40 mg/m2 and escalating to a targeted dose of 85 mg/m2. Gemcitabine was given as 1000mg/m2 IV over 30 minutes on days 1, 8, and 15 of a 28 day cycle. In dose levels 5 and 6, oxaliplatin was continued at target dose 85 mg/m2, but gemcitabine 1000mg/m2 was given with infusion times increased to 65 and 100 minutes, respectively, based on reports that fixed dose rate infusion of gemcitabine may increase efficacy and toxicity 32. Radiation was delivered to 27 Gy in fifteen, 1.8 Gy fractions. Eligible patients were those with untreated resectable or unresectable pancreatic cancer including low volume metastatic disease. The objective of this study is to determine the dose level that was associated with DLT in the first two cycles in less than 20% of patients. The planned accrual is 40 patients evaluable for DLT.

The trial has been completed and 40 patients are evaluable for DLT 33. Nine patients have experienced 10 DLTs (dose levels 2, 3 (3), 4(2) and 5(3)) including four developing grade 4 thrombocytopenia, four gastrointestinal toxicity (GI bleed (2), nausea/anorexia, weight loss), and two developing a decline in performance status. The estimated probability of DLT is 21% for dose level 3 and 23% for dose level 4 with 12 patients treated at each dose level. Twelve patients were enrolled as resectable, all 12 were explored, and 7 underwent resections with clear margins. There was one pathologic complete response and two additional patients with marked treatment effect. In preparation for this neoadjuvant trial, our phase I study was amended to provide 30 Gy of radiation in the first 3 weeks and the last 7 patients received this modified radiation dose. Two patients with unresectable disease experienced grade 3 gastrointestinal toxicity. Subsequently, 3 additional patients have been treated off trial and have tolerated this neoadjuvant therapy well without experiencing DLT.

Based on tolerability seen with the addition of oxaliplatin, the anticipated benefit of combination chemotherapy in augmenting local and systemic disease control and the pathologic responses in resected specimens in our current trial, we are interested in implementing a phase II study in patients with resectable or borderline resectable pancreatic cancer using data from the current study to select dosing. We have chosen dose level 4 for the neoadjuvant trial despite a DLT estimate of 23% based on the following observations. We expect that a resectable patient population will have better tolerance of combined modality therapy than those with unresectable disease (the majority in our current trial). In our phase II gemcitabine and radiation trial, only one of 20 patients (5%) with resectable disease experienced grade 3 non-hematologic toxicity in contrast to 33% of those with unresectable disease17, 26. In our current trial, all DLT have been observed in patients with unresectable or metastatic disease. We believe that this poorer tolerance is related to a lower baseline PS and the larger radiation volume needed to encompass unresectable disease. Furthermore, in the current trial, four of the DLTs were grade 4 platelets which resolved without consequence. In the proposed trial, oxaliplatin will be dose reduced for a platelet count < 75K, in contrast to the current trial where no dose reduction was performed.

We are hopeful that the application of this novel, multimodality neoadjuvant approach will increase margin negative resections in this patient population and ultimately survival. In addition to further development and characterization of the combined modality therapy, we are interested in defining the value of FDG-PET scans in determining resectability, prognosis and response to neoadjuvant therapy in pancreatic cancer. Furthermore, the relationship between histopathologic response to neoadjuvant treatment and prognosis will be studied. It is anticipated that the data from this trial will be used in the design of a larger phase III cooperative group trial. ;

Study Design

Allocation: Non-Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Treatment

Related Conditions & MeSH terms

• Pancreatic Cancer
• Pancreatic Neoplasms

• NCT number: NCT00426738
• Study type: Interventional
• Source: Sidney Kimmel Comprehensive Cancer Center
• Status: Active, not recruiting
• Phase: Phase 2
• Start date: December 2006