Combined therapy with a chemotherapeutic agent and an...

Details Combined therapy with a chemotherapeutic agent and an... Combined therapy with a chemotherapeutic agent and an...

1999-11-08

2002-08-06

Park, Hankyel T. (Department: 1641)

Chemistry: molecular biology and microbiology

Measuring or testing process involving enzymes or...

Involving antigen-antibody binding, specific binding protein...

C435S005000

Reexamination Certificate

active

06428968

ABSTRACT:

FIELD OF THE INVENTION
The field of the invention is killing tumor cells in a subject.
BACKGROUND OF THE INVENTION
Cancer remains one of the leading causes of morbidity and mortality of humans worldwide. Known cancer therapies include chemotherapy, radiation, surgery, and gene therapy. The combined use of chemotherapy, radiation, and surgery has augmented the benefits of these therapies in some types of cancer, but in only a few types of cancer has it resulted in eradication of the tumor. Despite the promise afforded by gene therapy anti-cancer strategies, various shortcomings in virus vectors and other gene vectors have limited the efficacy of gene therapy methods for eradicating tumor cells from subjects such as humans afflicted with cancer.
Recent advances in virology and molecular biology have made possible the engineering of recombinant virus with specific properties, creating new interest in virus-based therapy of solid tumors. One promising approach is the use of genetically modified herpes simplex virus-1 (HSV-1) to treat central nervous system (CNS) malignancies (Mineta et al., 1995, Nature Med. 1:938-943; Martuzza et al., 1991, Science 252:854-856; Market et al., 1992, J. Neurosurg. 77:590-594; Randazzo et al., 1995, Virology 211:94-101; Kesari et al., 1995, Lab. Invest. 73:636-648). Mutant HSV-1 viruses, such as HSV-1716, HSV-3616, HSV-4009, HSV-3410 and HSV-G207 have a deletion or impaired function in the gene encoding ICP34.5 which is a major determinant of pathogenicity (MacLean et al., 1991, J. Gen. Virol. 72:630-639; Chambers et al., 1995, Proc. Natl. Acad. Sci. USA 92:1411-1415; Meignier et al., 1988, J. Infect. Dis. 158:602-614; Mineta et al., 1995, Nature Med. 1:938-943).
Mutation of ICP34.5 affects host protein shut-off. These mutants have markedly attenuated neurovirulence and can replicate much more efficiently in dividing cells and malignant cells than in non-dividing cells (MacLean et al., 1991, J. Gen. Virol. 72:630-639; Robertson et al., 1992, J. Gen. Virol. 73:967-970; Brown et al., 1994, J. Gen. Virol. 75:3767-3686; Chou et al., 1990, Science 250:1262-1265).
Although most studies of oncolytic HSV-1 viruses have involved treatment of CNS malignancies, it has been shown that such viruses are also effective for treatment of localized non-CNS malignancies (e.g. malignant mesothelioma and non-small cell lung cancer) in vitro and in vivo. Lung tissue, for example, is a tissue which expresses high level of HSV receptors (Montgomery et al., 1996, Cell 87:427-436). The ability to use HSV-1 mutant virus to treat patients with non-small cell lung cancer has significant clinical importance. However, prior art methods of using oncolytic viruses are limited by, among other things, the efficacy of the viruses for killing tumor cells.
HIV-1716 is a replication-competent herpes simplex virus type 1 which has a 759-bp deletion in both copies of the RL1 portion of its genome at a gene which encodes the protein ICP34.5. Viruses with this mutation exhibit drastically reduced neurovirulence. These viruses do not cause encephalitis when inoculated either intracerebrally or peripherally into a host. Moreover, these mutants replicate as well as their wild-type parental strain (e.g. 17+) in a variety of dividing cells lines, but replicate poorly in cells not undergoing mitosis. These characteristics make HSV-1716 and other RL1 mutants attractive as vectors for cancer gene therapy.
Previous studies have demonstrated that RL1 mutant herpesviruses like HSV-1716 replicate well in established dividing human glioma cell lines, as well as in primary cell cultures derived from human biopsy material. Infection of these cultures result in cell death in the majority of cases. It is also believed that, in some cell lines, premature shut-off of host protein synthesis occurs in response to a lack of expression of ICP34.5. This has been designated “the double hit phenomenon.” In vivo studies involving these viruses have also been encouraging. Several groups have demonstrated oncolytic efficacy in both immunocompromised and immunocompetent mouse models of intracranial malignancies. Furthermore, it has been shown that HSV antigen staining is restricted to the tumor weight, with no spread to adjacent normal tissue.
Similar studies have been performed in animal models of malignant mesothelioma, a uniformly fatal neoplasia of the lining of the pleural cavity which does not respond well to surgery, chemotherapy or radiation. Kucharczuk et al. (1997, Cancer Res. 57:466-471) demonstrated that several non-neuronally derived human cell lines support HSV-1716 growth in vitro. Furthermore, their in vivo study was based on a well-characterized intraperitoneal model of human malignant mesothelioma involving REN cells injected into SCID mice. Those results demonstrated reduced tumor burden and significantly prolonged survival after intraperitoneal injection of HSV-1716 into tumor-bearing animals. Still, however, tumor cells were not completely eradicated from the test subjects. Thus, the subjects were not cured of cancer, even though their tumor burden was significantly reduced. It follows that although such therapies are useful for treating cancer, these therapies remain amenable to improvement, and that supplemental treatments may remain necessary to prevent re-establishment of nearly ablated tumors, to kill residual tumor cells following surgical tumor excision, and to inhibit growth of immature metastases by killing tumor cells distributed throughout the body of a subject.
Although malignant mesothelioma lends itself to study because of its location in the lining of the pleural cavity, there is interest in other, more prevalent, thoracic malignancies which have poor prognoses unless identified early. Other malignancies in which morbidity is associated with localized disease include, for example, bronchoalveolar cell, bladder, endometrial, cervical, and ovarian cancers.
Currently, lung cancer is the leading cause of cancer death in the United States, with an estimated incidence and mortality of 178,100 cases and 160,400 deaths, respectively (data from 1997; Parker et al., 1997, CA Cancer J. Clin. 47:5-27). The prognoses for lung cancer patients are still very poor, and most patients die within one year of diagnosis. At the time of diagnosis, only 15% of all lung cancer patients have local disease, 25% have disease spread to the regional lymph nodes, and 55% have distant metastatic cancer. Even in patients having localized disease, the 5-year survival rate is only 48%, survival is 18% for patients having regional disease and 14% overall (Fauci et al., 1998, In:
Principals of Internal Medicine,
14th ed., McGraw-Hill Co., Inc., pp. 552-562). Although chemotherapy, radiotherapy, or both, are often given to patients having inoperable disease, traditional therapy does not offer much clinical value to the majority of patients (Midthun et al., 1997, Postgrad. Med. 101:187-194; Nesbitt et al., 1995, Ann. Thorac. Surg. 60:466-72; Johnson, 1994, Chest 106(6 Supp.):313S-317S; Green, 1993, Chest 103(4 Supp.):370S-372S; Jett, 1993, Mayo Clin. Proc. 68:603-611; Elias, 1993, Chest 103(4 Supp.):362S-366S; Shaw et al., 1993, Mayo Clin. Proc. 68:593-602).
Taken together, these studies demonstrate that use of various oncolytic viruses to kill tumor cells is well accepted, even if prior art uses of such oncolytic vectors have been plagued with shortcomings such as low efficacy, low tissue specificity, rapid clearing of oncolytic viruses, and inability to deliver a sufficiently high or prolonged doses of virus to the desired tumor tissue. The present invention overcomes the shortcomings of prior art anti-cancer therapies involving oncolytic viruses by improving the efficacy of oncolytic virus therapy.
BRIEF SUMMARY OF THE INVENTION
The invention relates to a method of killing tumor cells in a subject having tumor cells. The method comprises administering a chemotherapeutic agent and an oncolytic virus to the subject. Tumor cells in the subject are thereby killed. The oncolytic virus is not an adenovirus.
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