The feasibility of using an autologous GM-CSF-secreting breast cancer vaccine to induce immunity in patients with stage II-III and metastatic breast cancers

PURPOSE

The antigenic targets of immunity and the role of vaccination in breast cancer are unknown. We performed a phase I study of an autologous GM-CSF-secreting breast cancer vaccine in patients with metastatic and stage II-III breast cancer.

METHODS

Tumor cells from patients with metastatic (n = 15) and stage II-III (n = 7) disease were transduced with a replication-defective adenoviral vector encoding GM-CSF, and then irradiated. Twelve and seven patients with metastatic and stage II-III disease, respectively, received weekly vaccination for three weeks, followed by every other week until disease progression or vaccine supply was exhausted (metastatic) or until six total vaccine doses were administered (stage II-III).

RESULTS

Among those patients with metastatic disease who received vaccinations, eight had progressive disease at two months, three had stable disease for 4-13 months, and one has had no evidence of disease for 13 years. Of the patients with stage II-III disease, five died of metastatic disease between 1.16 and 8.49 years after the start of vaccinations (median 6.24 years) and two are alive as of September 2021. Toxicities included injection site reactions, fatigue, fever, upper respiratory symptoms, joint pain, nausea, and edema. Four of five evaluable patients with metastatic disease developed a skin reaction with immune cell infiltration after the fifth injection of unmodified, irradiated tumor cells.

CONCLUSION

We conclude that tumor cells can be harvested from patients with metastatic or stage II-III breast cancer to prepare autologous GM-CSF-secreting vaccines that induce coordinated immune responses with limited toxicity. TRIAL REGISTRATION AND DATE OF REGISTRATION: clinicaltrials.gov, NCT00317603 (April 25, 2006) and NCT00880464 (April 13, 2009).

New approaches to the treatment of pancreatic cancer: from tumor-directed therapy to immunotherapy

The development of novel therapeutic strategies for pancreatic adenocarcinoma (PAC) has traditionally been considered particularly challenging for clinical and laboratory investigators due to its aggressive underlying biology and inherent resistance to currently available therapies. More recently, however, advances have been made in the identification of promising therapeutic targets for intervention, along with several key insights into the complex sequence of genetic alterations involved in the evolution of PAC from premalignant precursor lesion to malignant cells with metastatic potential. FOLFIRINOX (5-fluorouracil/leucovorin/irinotecan/oxaliplatin) has recently been identified as a combination cytotoxic therapy associated with a significant survival benefit over single-agent gemcitabine in good performance status patients with advanced disease; it is hoped that a similar benefit will be seen in planned trials of FOLFIRINOX as perioperative therapy. The success of immune therapy with the anti-cytotoxic T-lymphocyte antigen-4 antibody ipilimumab in advanced melanoma has spurred interest in the development of vaccines and immune therapies for other solid tumors. Certainly, the concept of harnessing the power of the immune system for cancer treatment is an attractive concept to patients and clinicians alike. Herein we discuss recent advances in the development of novel therapeutic approaches to PAC, focusing in particular on recent developments in immune and vaccine therapy.

Targeting mutated K-ras in pancreatic adenocarcinoma using an adjuvant vaccine

PURPOSE

Codon 12 mutations of K-ras are frequent in pancreatic adenocarcinoma, and represent potential tumor-specific neoantigens. The objective of this study was to assess the safety and efficacy of immunizing patients with resected pancreatic cancer with a vaccine targeted against their tumor-specific K-ras mutation.

METHODS

Patients with resected pancreatic cancer, with K-ras mutations at codon 12, were vaccinated once monthly for 3 months with a 21-mer peptide vaccine containing the corresponding K-ras mutation of the patient's tumor. About 200 μg of peptide vaccine was injected intradermally on day 7 of a 10-day course of intradermal granulocyte macrophage colony-stimulating factor. Toxicity was assessed by National Cancer Institute Common Toxicity Criteria v2.0. Immune responses were evaluated by delayed-type hypersensitivity (DTH) tests and the enzyme-linked immunosorbent spot assays.

RESULTS

Of 62 screened patients, 24 were vaccinated. There were no grade 3-5 vaccine-specific toxicities. The only National Cancer Institute grade 1 and 2 toxicity was erythema at the injection site (94%). Nine patients (25%) were evaluable for immunologic responses. One patient (11%) had a detectable immune response specific to the patient's K-ras mutation, as assessed by DTH. Three patients (13%) displayed a DTH response that was not specific. Median recurrence free survival time was 8.6 months (95% confidence interval, 2.96-19.2) and median overall survival time was 20.3 months (95% confidence interval, 11.6-45.3).

CONCLUSIONS

K-ras vaccination for patients with resectable pancreatic adenocarcinoma proved to be safe and tolerable with however no elicitable immunogenicity and unproven efficacy. Future development of adjuvant vaccine therapies should use more immunogenic vaccines.

The integration of chemoradiation in the care of patient with localized pancreatic cancer

The use of chemoradiation for patients with localized pancreatic cancer is controversial. Although some randomized trials have indicated that chemoradiation improves the median survival of patients with locally advanced as well as resected pancreatic cancer, other more recent trials have called into question the role of chemoradiation and have supported the use of chemotherapy. In the adjuvant setting, the high local tumor recurrence/persistence rate in all trials probably reflects the inclusion of patients with incompletely resected tumors, whose prognosis is similar to the prognosis of patients with locally advanced who do not undergo resection, making these trials difficult to interpret. More precise clinical staging and selection of patients appropriate for surgical resection is an important goal. The keys to the successful integration of radiotherapy in the care of patients with localized pancreatic cancer are selection, sequencing and smaller treatment volumes. A strategy of initial chemotherapy followed by consolidation with a well-tolerated chemoradiation regimen both in the adjuvant and locally advanced settings maximizes benefits of both treatment options, which are in fact complementary. Herein, we discuss the rationale for this approach as well as the ongoing investigation of novel radiation approaches designed to enhance outcome through the molecular and physical targeting of disease as well as the investigation of neoadjuvant chemoradiation in radiographically resectable and borderline resectable pancreatic cancer.

Biological approaches to therapy of pancreatic cancer

Pancreatic cancer is a lethal disease and notoriously difficult to treat. Only a small proportion is curative by surgical resection, whilst standard chemotherapy for patients with advanced disease has only modest effect with substantial toxicity. Clearly there is a need for the continual development of novel therapeutic agents to improve the current situation. Improvement of our understanding of the disease has generated a large number of studies on biological approaches targeting the molecular abnormalities of pancreatic cancer, including gene therapy and signal transduction inhibition, antiangiogenic and matrix metalloproteinase inhibition, oncolytic viral therapy and immunotherapy. This article provides a review of these approaches, both investigated in the laboratories and in subsequent clinical trials.

Adjuvant therapy for adenocarcinoma of the pancreas: analysis of reported trials and recommendations for future progress

The delivery of postoperative combined modality adjuvant therapy for completely resected pancreatic cancer was initially shown to be beneficial on the basis of a prospective, randomized trial published in 1985. Since then, oncologists have debated whether chemotherapy, chemoradiation, or both is optimal adjuvant therapy after pancreatectomy for ductal adenocarcinoma of the pancreas; no global consensus has emerged. Unfortunately, despite the completion of a number of subsequent randomized trials of adjuvant therapy since 1985, no further improvements in overall survival have materialized. This lack of progress is not simply the result of ineffective systemic therapies, but in part the result of poor trial design and calls for a more disciplined approach to the selection of patients for surgery, pathologic assessment of surgical resection margins, and postoperative (pretreatment) imaging. This is the only way to ensure that patients who receive adjuvant therapy are actually receiving therapy for radiographically occult possible microscopic disease, rather than therapy for incompletely resected locally advanced disease or early postoperative metastases. A critical analysis of completed adjuvant trials will be provided and a framework for the conduct of future trials of adjuvant therapy proposed.

Current immunotherapeutic strategies in pancreatic cancer

The immune systems of patients with newly diagnosed pancreatic cancers are functional, with T-cell responses capable of responding to tumor antigen presentation. Pancreatic tumors have been demonstrated to express tumor antigens as mutated, altered, underglycosylated and/or inappropriately overexpressed proteins. Considering these two facts, it should be possible for patients' bodies to recognize their tumors as foreign and to reject them. A number of clinical trials have been initiated to exploit this immune activation to eradicate or stabilize tumor growth. Immunotherapeutic trials include the specific testing of a variety of tumor vaccines, of cytokines as adjuvants or directed cytotoxicity, and of monoclonal antibodies to target specific molecules. This article reviews evidence for immune-cell activation and function in patients with pancreatic cancer, and evidence that pancreatic tumor cells express tumor antigens, or mutated (or altered) proteins. Nevertheless, tumors survive immune attacks by producing products that help them to circumvent effector T cells. The article thus examines complications of immune evasion by cancer cells, as well as the challenges of trying to exploit the immune system in solid tumors where tumor cell products can turn off invading immune T cells set to kill them. Finally, the article discusses the choices of a variety of clinical trials using immune modulation for patients with pancreatic cancer.

Cell based cancer vaccines: regulatory and commercial development

There is both clinical and regulatory drive to expedite development of safe, efficacious cancer therapies. Stimulation of the patients immune system through vaccination with tumour cells has long been at the vanguard of cancer therapeutic vaccines, and several have been demonstrated to be safe and to have efficacy in early clinical trials for a range of cancers including melanoma, renal cell carcinoma, prostate and colorectal cancers. A number of development-stage vaccines and strategies are currently being tested, utilising either autologous or allogeneic tumour cells, which may also have been ex vivo manipulated (e.g. cytokine transfected cells). It seems likely that clinical trial success, and hence patient benefit, could be improved through better patient identification, possibly by the discovery and use of novel immune response biomarkers. In this review, we aim to summarise the state of tumour cell vaccines in commercial development and to explore not only the difficulties of determining efficacy, but also the production challenges faced when developing a vaccine from proof of principle to pivotal phase III trials.

Immunotherapeutic approaches in pancreatic cancer

With growing understanding of the regulation of immune responses, multiple new immunotherapeutic targets have evolved. This article gives a survey over the current approaches in pancreatic cancer therapy including peptide vaccinations, unspecific immunotherapy, allogene modified tumor cell vaccines, and vector-based vaccines. Although several trials have shown detectable immune responses, such as delayed-type hypersensitivity reactions and cytokine release in enzyme-linked immunosorbent spot (ELISPOTS) assays, and some have reported prolonged survival for immune responders, immunotherapy remains experimental. However, some approaches have made it into a phase III setting. In addition, the emerging concept of tumor stem cells may lead to a new focus on immunotherapy, since these often highly chemotherapy-resistant cells are thought to be the source of recurrences.