[Immunotherapy of advanced pancreatic carcinoma with the monoclonal antibody BW 494]

Pancreatic cancer: a review of emerging therapies

The incidence of adenocarcinoma of the pancreas has risen steadily over the past 4 decades. Since pancreatic cancer is diagnosed at an advanced stage, and because of the lack of effective therapies, the prognosis of such patients is extremely poor. Despite advances in our understanding of the molecular biology of pancreatic cancer, the systemic treatment of this disease remains unsatisfactory. Conventional chemotherapy has not produced dramatic improvements in response rates or patient survival. New treatment strategies are clearly needed. This paper reviews emerging therapies for pancreatic carcinoma. A more profound understanding of the molecular biology of cell growth and proliferation, as well as of neoplastic cell transformation, has led to advances in several areas, including the use of somatostatin analogues and antiandrogens as adjuvant therapy; inhibition of tumour growth and metastasis by inhibitors of matrix metalloproteinases and angiogenesis, and by small molecules such as retinoids, which interfere with progression through the cell cycle; immunotherapy with monoclonal antibodies; disruption of intracellular signal transduction with farnesyltransferase inhibitors; and finally gene therapy with specifically designed vaccines.

Adjuvant therapy of pancreatic cancer using monoclonal antibodies and immune response modifiers

Pancreatic cancer is a devastating disease with poor survival. At present, no effective adjuvant or palliative therapies are available. Unresponsiveness to chemotherapy, radiotherapy, and antihormonal treatment is one of the reasons that pancreatic cancer patients have an overall median survival time of 4-6 mo. This article summarizes clinical trials on immunotherapy of pancreatic cancer using the murine monoclonal antibodies (MAbs) 17-1A and BW 494. In addition, the use of MAb treatment in combination with immune response modifiers is discussed. In four clinical trials, MAb 17-1A was given by iv infusion to 100 patients with pancreatic cancer. In 30 of the these patents, antibody treatment was accompanied by gamma-interferon, also given intravenously. Complete response, partial response, and stable disease were reported in 1,5, and 23 patients, respectively. Passive immunotherapy using the MAb BW 494 was carried out in 148 pancreatic cancer patients in two phase I and two phase II trials. In 1 out of 75 patients a partial response and in 25 out of 74 patients stable disease were reported. However, in a controlled randomized trial enrolling 61 patients following Whipple resection, comparable survival times in patients with and without MAb BW 494 treatment led to the termination of further clinical trials with this antibody. New clinical studies using humanized MAbs in combination with immune response modifiers should be initiated to further evaluate immunotherapy as a treatment option in pancreatic cancer.

A randomized controlled trial of adjuvant immunotherapy (murine monoclonal antibody 494/32) in resectable pancreatic cancer

In a prospective randomized multicentric trial, 61 patients from six hospitals with resectable pancreatic cancer were recruited between 1987 and 1989. All patients underwent a Whipple resection. Two weeks after surgery, the patients were randomized to be given either intravenous (IV) treatment with 370 mg (100 mg loading dose, 9 x 30 mg continuing within 10 days) of monoclonal antibody (MoAb) 494/32 (Behringwerke AG, Marsburg, Germany) or no additional anti-cancer treatment. This murine immunoglobulin (Ig) G1 antibody has been shown to strongly bind to human pancreatic cancer cells and to induce an antibody-dependent cellular cytotoxicity (ADCC). Both study groups were well matched with respect to age, sex, tumor staging, and grading. Six patients suffered from minor toxicity (vomiting and abdominal pain) after immunotherapy. Ten months after the end of the recruitment period, 65% and 53% of the patients in the treatment and control groups, respectively, had died. Of the living patients, 60% and 53% are alive with recurrent or progressive cancer disease. Median survival time was 428 days (range, 248 to 510 days) and 386 days (range, 296 to 509 days) in the treatment and control groups, respectively. The authors concluded that repeated IV treatment with the antibody 494/32 is not helpful in resectable pancreatic cancer. This study provides the first controlled data on passive immunotherapy in solid cancer.

Composition and production of pancreatic tumor related antigens

Large numbers of specific and highly purified antibodies that react with tumor-associated antigens (TAAs) have been produced over the last decade as a result of the hybridoma technology that was developed during the previous decade. The availability of monoclonal antibodies (MAbs) rapidly led to studies of their clinical applicability. It has recently become apparent that further characterization of TAAs at the molecular level is needed before the MAbs, which react with TAAs, can have extensive use in the diagnosis and treatment of pancreatic cancer. The information that is currently available concerning the molecular composition and production of pancreatic TAAs is summarized in this presentation.

Studies of pancreatic cancer utilizing monoclonal antibodies

Since 1985, 150 patients with pancreatic ductal adenocarcinoma have been treated with the monoclonal antibody BW 494 in four different multicentric trials in Germany. The antibody recognizes a human pancreatic cancer associated antigen and mediates an antibody dependent cellular cytotoxicity (ADCC) in vitro, when human mononuclear cells are coincubated as effector cells. In patients with at advanced unresectable pancreatic cancer there where two phase-I-studies finished in 1987 and 1989, respectively, and one uncontrolled phase-II-study finished in 1988. In 1987, we started a controlled randomized trial in patients with resectable (Whipple) pancreatic cancer, which will be finished in 1990. There were no major side effects if the intravenous antibody application was restricted to a 10-d treatment protocol (up to 370 mg given in 10 different dosages). Human anti-mouse-antibodies could be demonstrated in all patients investigated for within 4 wk after immunotherapy. In patients with advanced pancreatic cancer (n = 87), monoclonal antibody treatment did not induce significant response rates. There was stable disease in 1/3 to 1/2 of the patients lasting three months or longer. Therapeutic success may be expected in patients with minor tumor burden.