Ado-trastuzumab emtansine (T-DM1) in patients with HER2-amplified tumors excluding breast and gastric/gastroesophageal junction (GEJ) adenocarcinomas: results from the NCI-MATCH trial (EAY131) subprotocol Q.

BACKGROUND: The National Cancer Institute-Molecular Analysis for Therapy Choice (NCI-MATCH) is a national precision medicine study incorporating centralized genomic testing to direct refractory cancer patients to molecularly targeted treatment subprotocols. This treatment subprotocol was designed to screen for potential signals of efficacy of ado-trastuzumab emtansine (T-DM1) in HER2-amplified histologies other than breast and gastroesophageal tumors. METHODS: Eligible patients had HER2 amplification at a copy number (CN) >7 based on targeted next-generation sequencing (NGS) with a custom Oncomine AmpliSeq™ (ThermoFisher Scientific) panel. Patients with prior trastuzumab, pertuzumab or T-DM1 treatment were excluded. Patients received T-DM1 at 3.6 mg/kg i.v. every 3 weeks until toxicity or disease progression. Tumor assessments occurred every three cycles. The primary end point was centrally assessed objective response rate (ORR). Exploratory end points included correlating response with HER2 CN by NGS. The impact of co-occurring genomic alterations and PTEN loss by immunohistochemistry were also assessed. RESULTS: Thirty-eight patients were enrolled and 36 included in efficacy analysis. Median prior therapies in the metastatic setting was 3 (range 0-9; unknown in one patient). Median HER2 CN was 17 (range 7-139). Partial responses were observed in two (5.6%) patients: one mucoepidermoid carcinoma of parotid gland and one parotid gland squamous cell cancer. Seventeen patients (47%) had stable disease including 8/10 (80%) with ovarian and uterine carcinomas, with median duration of 4.6 months. The 6-month progression-free survival rate was 23.6% [90% confidence interval 14.2% to 39.2%]. Common toxicities included fatigue, anemia, fever and thrombocytopenia with no new safety signals. There was a trend for tumor shrinkage with higher levels of gene CN as determined by the NGS assay. CONCLUSION: T-DM1 was well tolerated. While this subprotocol did not meet the primary end point for ORR in this heavily pre-treated diverse patient population, clinical activity was seen in salivary gland tumors warranting further study in this tumor type in dedicated trials.

Site-directed neovessel formation in vivo.

Angiogenesis is an important component of organogenesis and wound repair and occurs during the pathology of oncogenesis, atherogenesis, and other disease processes. Thus, it is important to understand the physiological mechanisms that control neovascularization, especially with methods that permit the molecular dissection of the phenomenon in vivo. Heparin-binding growth factor-1 was shown to bind to collagen type I and type IV. When complexed with gelatin, heparin-binding growth factor-1 can induce neovascularization at polypeptide concentrations that are consistent with the biological activity of the mitogen in vitro. The adsorption strategy induces rapid blood vessel formation at and between organ- and tissue-specific sites and permits recovery of the site-specific implant for examination and manipulation by molecular methods.

High-level recombinant gene expression in rabbit endothelial cells transduced by retroviral vectors.

By virtue of its immediate contact with the circulating blood, the endothelium provides an attractive target for retroviral vector transduction for the purpose of gene therapy. To see whether efficient gene transfer and expression was feasible, rabbit aortic endothelial cells were infected with three Moloney murine leukemia virus-derived retroviral vectors. Two of these vectors carry genes encoding products that are not secreted: N2, containing only the selectable marker gene neoR, and SAX, containing both neoR gene and an SV40-promoted adenosine deaminase (ADA) gene. The third vector, G2N, contains a secretory rat growth hormone (rGH) gene and an SV40-promoted neoR gene. Infection with all three vectors resulted in expression of the respective genes. A high level of human ADA expression was observed in infected endothelial cell populations both before and after selection in G418. G2N-infected rabbit aortic endothelial cells that were grown on a synthetic vascular graft continued to secrete rGH into the culture medium. These studies suggest that endothelial cells may serve as vehicles for the introduction in vivo of functioning recombinant genes.

National Cancer Institute Formulary: A Public-Private Partnership Providing Investigators Access to Investigational Anticancer Agents.

As part of the White House Cancer Moonshot Initiative, the National Cancer Institute (NCI) has developed a drug formulary to provide investigational anticancer agents to the extramural research community. This article describes how the NCI Formulary functions, how researchers may apply for access to drugs in the formulary, and the NCI's initial goals for formulary participation. Approved investigators may apply for access to formulary agents at: https://nciformulary.cancer.gov.

Angiogenesis-directed implantation of genetically modified endothelial cells in mice.

By virtue of their location within blood vessels and their ability to express foreign genes, endothelial cells are attractive vehicles for the delivery of therapeutic molecules in vivo. We wished to determine whether i.v.-injected, genetically modified endothelial cells can become incorporated into sites of active angiogenesis in vivo. To do so, we studied the fate of i.v.-injected, lacZ-expressing human umbilical vein endothelial cells in athymic nude mice bearing lethally irradiated NIH 3T3 murine fibroblast cells transfected with a sp-hst/KS3:fibroblast growth factor-1 chimera that forces the secretion of the angiogenic protein, fibroblast growth factor-1. Following i.v. injection, lacZ-labeled human umbilical vein endothelial cells accumulated at sites of fibroblast growth factor-1-induced angiogenesis, persisting for at least 4 weeks. These results suggest that i.v.-administered, genetically modified endothelial cells can migrate into and survive within an angiogenic site. This strategy may be useful for delivery of therapeutic molecules to sites of pathological angiogenesis during tumor metastasis.

Partial purification of transforming growth factors from human milk.

Crude, delipidated milk and the acid:ethanol extracts of primary human breast tumors contain several activities that biologically resemble transforming growth factors (TGFs) in that they promote the anchorage-independent growth of normal rat kidney and Mm5mt/c1 mouse mammary tumor cells in soft agar. Three major TGF species with isoelectric points (pl) of about 4.0, 6.0-6.5, and 7.0 have been detected in both tumors and milk. The pl 4.0 species from milk has been purified about 10,000-fold by isoelectric focusing and high-performance liquid chromatography. This species, designated milk-derived growth factor II (MDGFII), coelutes from gel filtration columns with an authentic human epidermal growth factor standard when using a low ionic strength eluting buffer. However, on the same column, MDGFII is completely resolved from human epidermal growth factor with high ionic strength eluting buffers. Nevertheless, MDGFII purified by the latter technique still competes with 125I-epidermal growth factor for receptor binding to A431 cell membranes. Additionally the TGF activity of MDGFII present in the pl 4.0 fraction of milk is markedly inhibited by anti-epidermal growth factor receptor antibody preparations. Consequently MDGFII appears to be an alpha-TGF. MDGFII is a pepsin-sensitive, disulfide reducing agent-sensitive, heat-stable protein that may be physiologically important for the mammary gland or the neonate.

Presence of transforming growth factors in human breast cancer cells.

Conditioned medium (CM) from a human mammary carcinoma cell line, MCF-7, and ten individual clones derived from these cells was examined for the presence of transforming growth factors (TGFs). Concentrated CM from all of the MCF-7 cell lines was found to stimulate the anchorage-independent growth of normal rat kidney cells in soft agar and to inhibit the binding of epidermal growth factor (EGF) to mouse NIH/3T3 fibroblasts and to A431 human epidermoid carcinoma cell membranes. The soft agar stimulating activity was heat stable but sensitive to treatment with dithiothreitol. EGF receptors were measured on the MCF-7 cell lines to determine whether the amount of TGFs associated with the CM from the various cell lines was correlated with the level of EGF receptors being expressed on these cells. Moreover, the intrinsic cloning efficiency of these lines in soft agar was measured to ascertain if any correlation might exist between the level of TGFs associated with these cells and the ability of these cell lines to form colonies in soft agar. Although all the MCF-7 cell lines had approximately the same number of EGF receptors per cell, ranging from 3 to 6 X 10(3) sites/cell, CM from these lines varied in potency with respect to inducing the growth of normal rat kidney cells as colonies in soft agar and in inhibiting the binding of EGF to NIH/3T3 cells. Likewise, the level of TGFs associated with the CM from the various clones showed no correlation with the ability of these individual lines to grow as colonies in soft agar. TGF activity was also detected in acid-ethanol extracts prepared from MCF-7 cells propagated in nude mice as tumors and in the extracts from two transplantable human mammary adenocarcinomas, Clouser I and II. In addition, approximately 50% of the normal rat kidney colonies formed in response to the Clouser II tumor extracts exhibited a branching morphology in contrast to spherical colonies produced by Clouser I or MCF-7 extracts. These results demonstrate that human mammary carcinoma cells from both established cell lines and cells maintained in nude mice as tumors contain TGF-like activities. Furthermore, the variation in TGFs associated with the CM from the MCF-7 clones suggests that the parent MCF-7 cell line contains a heterogeneous population of cells.

Anchorage-independent growth-conferring factor production by rat mammary tumor cells.

Conditioned medium from cultures of 7,12-dimethylbenz(a)anthracene-induced rat mammary tumor cells contain factors that resemble sarcoma growth factor and other transforming growth factors in biological activity but differ in their physical properties. The mammary tumor factors (MTF) are acid stable and heat and protease sensitive. They inhibit the binding of epidermal growth factor, but not insulin, to mouse embryonal carcinoma cells. MTF confers upon normal rat kidney and BALB/c-3T3 cells the ability to grow in soft agar. This effect is enhanced synergistically by high concentrations of fetal calf serum but not by epidermal growth factor. Anchorage-independent growth promotion, however, is not seen with normal mammary epithelial cells, although MTF is mitogenic for these cells as well as normal rat kidney cells, BALB/c-3T3 cells, and chick embryo fibroblasts in monolayer culture, MTF is not mitogenic for primary cultures of the tumor cells from which the factors are derived. Two major molecular weight species of MTF, eluting at Mr 6,000 and 65,000 to 70,000 on Bio-Gel P-100 columns, are present in acid-ethanol extracts of 7,12-dimethylbenz(a)anthracene- and nitrosomethylurea-induced rat mammary tumors. Transplantable tumors derived from primary 7,12-dimethylbenz(a)anthracene- or nitrosomethylurea-induced tumors have little or no MTF activity. These results demonstrate that different chemically induced rat mammary tumors contain transforming growth factor-like activities. Furthermore, it is possible that MTF is unnecessary for the maintenance of tumorigenicity, since some tumors contain no detectable MTF.

New agents for acute myelogenous leukemia.

New agents for the treatment of acute myelogenous leukemia are discussed that reflect different treatment mechanisms. These include histone acetylation, angiogenesis inhibition, protein kinase inhibitors, and a novel retinoid. Efficacy and safety in phase I and phase II trials reviewed, as well as the problems involved in crossing over from treatment of solid tumors to blood disorders.

Insulin-like growth factor-II overexpression in MCF-7 cells induces phenotypic changes associated with malignant progression.

It has been proposed that the insulin-like growth factors (IGFs) can act as autocrine and/or paracrine growth promoters in breast cancer. To investigate this hypothesis, we infected early passage MCF-7 cells with a retroviral vector containing the coding sequence for the IGF-II preprohormone along with a constitutive cytomegalovirus promoter sequence. These cells do not normally express IGF-I or IGF-II. After infection with the retroviral vector, several single cell clones were analyzed. Seven of nine isolated clones expressed very high levels of IGF-II mRNA. Biologically active IGF-II protein was easily detectable in the medium conditioned by the IGF-II-expressing clones, and IGF receptors were down-regulated in these. All IGF-II-expressing clones showed marked morphological changes in anchorage-dependent culture, growing in large clumps and as free-floating colonies. The cells also cloned in soft agar in the absence of estrogen, while the wild-type MCF-7 cells and control cells infected with an irrelevant DNA sequence showed none of these properties. alpha IR-3, an antibody that blocks the type I IGF receptor, inhibited the growth of IGF-II-expressing clones in serum-free medium. This model demonstrates that IGF-II can serve as an autocrine growth stimulant in breast cancer epithelial cells and that IGF-II overexpression may be capable of mediating malignant progression in human breast cancer.

Constitutive expression of the steroid sulfatase gene supports the growth of MCF-7 human breast cancer cells in vitro and in vivo.

Many human breast tumors are driven by high intratumor concentrations of 17beta-estradiol that appear to be locally synthesized. The role of aromatase is well established, but the possible contribution of the steroid sulfatase (STS), which liberates estrogens from their biologically inactive sulfates, has been inadequately assessed and remains unclear. To evaluate the role of STS further, we transduced estrogen-dependent MCF-7 human breast cancer cells with a retroviral vector directing the constitutive expression of the human STS gene. Gene integration was confirmed by Southern hybridization, production of the appropriately sized messenger RNA by Northern hybridization, and expression of functional protein by metabolism of [(3)H]estrone sulfate to [(3)H]estrone. Maximum velocity estimates of estrone formation are 64.2 pmol estrone/mg protein.h in STS-transduced cells (STS Clone 20), levels comparable to those seen in some human breast tumors. Lower levels of endogenous activity are seen in MCF-7 cells (13.0 pmol estrone/mg protein.h) and in cells transduced with vector lacking the STS gene (Vector 3 cells; 12.0 pmol estrone/mg protein.h). 17beta-Estradiol sulfate induces expression of the progesterone receptor messenger RNA only in STS Clone 20 cells, whereas estrone sulfate produces the greatest stimulation of anchorage-independent growth in these cells. STS Clone 20 cells retain responsiveness to antiestrogens, which block the ability of estrogen sulfate to increase the proportion of cells in both the S and G(2)/M phases of the cell cycle. Consistent with these in vitro observations, only STS Clone 20 cells exhibit a significant increase in the proportion of proliferating tumors in nude ovariectomized mice supplemented with 17beta-estradiol sulfate. The primary activity in vivo appears to be from intratumor STS, rather than hepatic STS. Surprisingly, 17beta-estradiol sulfate appears more effective than 17beta-estradiol when both are administered at comparable concentrations. This effect, which is seen only in STS Clone 20 cells, may reflect differences in the cellular pharmacology of exogenous estrogens compared with those released by the activity of intracellular STS. These studies directly demonstrate that intratumor STS activity can support estrogen-dependent tumorigenicity in an experimental model and may contribute to the promotion of human breast tumors.

The gene therapy of cancer: transgenic immunotherapy.

Gene therapy can be defined as the insertion of functional genes into cells to treat a disease. Cellular augmentation, whereby gene transfer confers a novel function to the cell, has proved to be useful in designing strategies for the treatment of cancer. In particular, a variety of cell types may be transduced with immune response genes that are intended to elicit a more effective immune attack against tumor cells. This process has been termed transgenic immunotherapy. Preclinical studies involving the transduction of tumor cells, stromal cells, and lymphocytes with a number of immune response genes have demonstrated potent cytotoxic lymphocyte responses against tumor cells, and in some cases the induction of long-lasting immunity against tumor rechallenge. It is hoped that this form of cancer immunotherapy will permit the development of vaccines effective in eradicating minimal residual disease and immunizing individuals at risk for cancer.

Endothelial cell-based systemic gene therapy of metastatic melanoma.

Cancer metastasis accounts for a significant proportion of morbidity and mortality in patients. Effective means of treating disseminated disease remains elusive. The purpose of this study was to determine whether genetically modified endothelial cells (GMEC) can selectively target and deliver recombinant therapeutic molecules to sites of tumor metastases. Following the establishment of lung metastases of 4T1 mammary tumor in mice, intravenously (i.v.) administered, lacZ transgene-expressing endothelial cells (lacZ-GMEC) accumulated at the tumor sites. An average of 32% and 90% of the pulmonary metastases were X-gal stained following one and three tail vein injections of 10(5) lacZ-GMEC, respectively. The linear pattern of X-gal staining seen within the tumor sites and the histological appearance of the tumor vasculature were consistent with the incorporation of lacZ-GMEC into blood vessels. In C57Bl/6 mice harboring lung metastases of melanoma, the administration of three sequential i.v. injections of 10(5) endothelial cells expressing a human interleukin 2 transgene abrogated the tumor metastases and prolonged survival of the animals. These results demonstrate that i.v.-administered GMEC can selectively accumulate, survive, and stably express exogenous genes at multiple tumor sites. These findings support a role for i.v.-administered GMEC as a potential therapeutic strategy for the systemic treatment of cancer metastases.

Human breast cancer cell metastasis to long bone and soft organs of nude mice: a quantitative assay.

Bone is a common metastatic site in human breast cancer (HBC). Since bone metastasis occurs very rarely from current spontaneous or experimental metastasis models of HBC cells in nude mice, an arterial seeding model involving the direct injection of the cells into the left ventricle has been developed to better understand the mechanisms involved in this process. We present here a sensitive polymerase chain reaction (PCR) method to detect and quantitate bone and soft organ metastasis in nude mice which have been intracardially inoculated with Lac Z transduced HBC cells. Amplification of genomically incorporated Lac Z sequences in MDA-MB-231-BAG HBC cells enables us to specifically detect these cells in mouse organs and bones. We have also created a competitive template to use as an internal standard in the PCR reactions, allowing us to better quantitate levels of HBC metastasis. The results of this PCR detection method correlate well with cell culture detection from alternate long bones from the same mice, and are more sensitive than gross Lac Z staining with X-gal or routine histology. Comparable qualitative results were obtained with PCR and culture in a titration experiment in which mice were inoculated with increasing numbers of cells, but PCR is more quantifiable, less time consuming, and less expensive. This assay can be employed to study the molecular and cellular aspects of bone metastasis, and could easily be used in conjunction with RT-PCR-based analyses of gene products which may be involved with HBC metastasis.

lacZ transduced human breast cancer xenografts as an in vivo model for the study of invasion and metastasis.

A number of human cancer cell lines have been described as being invasive and metastatic in immune incompetent animals. However, it is difficult to assess metastatic spread of a subcutaneously injected or inoculated cell line, since an exact detection of all microfoci of human tumour cells in the animals by usual histological procedures would require extensive sectioning of the whole animal. To overcome this problem, we transduced human breast cancer cells with a replication-defective Moloney murine leukaemia retroviral vector (M-MuLV) containing both neoR (neomycin resistance) and lacZ genes. The resulting cell lines were selected for antibiotic (G418) resistance, and cell-sorted for lacZ expression. lacZ continued to be expressed in cultured cells for at least 20 passages without further G418 selection. The lacZ gene codes for beta-D-galactosidase, and cells expressing this gene stain blue with the chromogenic substrate X-gal. The lacZ-expressing cells retained the pre-transduction ability to traverse Matrigel in vitro, to form subcutaneous tumours in nude mice, and to grow invasively with the formation of metastases. X-gal staining showed high specificity, staining the tumour cells but not the surrounding mouse tissue on either whole tissue blocks or histological sections. The staining procedure was highly sensitive, allowing detection of microfoci of human cancer cells, and quantitative estimation of the metastatic capacity of the cells. These results indicate that lacZ transduction of human tumour cells is a powerful means of studying human cancer cell invasion and metastases in vivo.

Cancer gene and oncolytic virus therapy.

By far, cancer accounts for the majority of gene therapy trials that are being carried out worldwide. Seventy percent of the gene therapy protocols that have been reviewed by the National Institutes of Health Recombinant DNA Advisory Committee (NIH RAC) are for the treatment of cancer. Of these, two thirds involve immunotherapy, with transfer of genes for cytokines, immune accessory molecules, or tumor antigens into a variety of cellular targets. Other clinical protocols include chemoprotection, prodrug activation, or tumor-suppressor gene replacement. Either local or distal bystander effects may mediate antitumor effects. These bystander mechanisms may help to overcome poor transduction efficiencies by currently available vectors. Replicating oncolytic viruses entering the clinic include herpes virus, Newcastle disease virus, reovirus, and others. These viruses have been shown to replicate selectively in cancer cells, albeit by different mechanisms. Reovirus, for example, requires the presence of an activated Ras signaling pathway in order to replicate and destroy cells. Tumor selectivity can be achieved by placing an essential viral gene under the control of a tumor-specific promoter. The tumoricidal effects of replicating viruses may be enhanced by genetic modification-for example, by the insertion of a cytokine gene to elicit antitumor immunity. Clearly, much work needs to be done both in the laboratory and in the clinic in order to exploit the full potential of these novel gene and viral therapies.

Chronic lymphocytic leukemia: staging and prognostic factors.

While both the Rai and Binet staging systems continue to provide the most useful tools for assessing prognosis in chronic lymphocytic leukemia (CLL), both fail to identify subsets of patients that may, or may not, benefit from therapy. While numerous factors have been identified that correlate with stage, few have proven to be independent predictors of disease progression, survival, or resistance to chemotherapy. Several factors, including beta2-microglobulin, soluble CD23, and lymphocyte doubling time show particular promise as independent prognostic factors. Their usefulness, however, will remain uncertain until they have been adequately evaluated in prospective, randomized studies. Future studies should focus on the characterization of relevant biologic and immunologic markers in order to direct appropriate treatment for different subsets of patients and to lead to improved outcome in CLL.

Novel therapeutic agents for the treatment of myelodysplastic syndromes.

Few chemotherapy agents have demonstrated activity in patients with myelodysplastic syndromes (MDS) and supportive management remains the standard of care. An increasing number of new drugs in development are being directed at specific molecular or biological targets of these diseases. Topotecan, a topoisomerase I inhibitor, has shown single-agent activity and is now being combined with other agents, including cytarabine. The aminothiol amifostine induces responses in about 30% of patients; however, its role is still being clarified. Agents that inhibit histone deacetylase and target DNA hypermethylation, thus permitting derepression of normal genes, include 5-azacytidine, decitabine, phenylbutyrate, and depsipeptide. Arsenic trioxide has demonstrated impressive activity in acute promyelocytic leukemia and preclinical data suggest the potential for activity in MDS. UCN-01 is a novel agent that inhibits protein kinase C and other protein kinases important for progression through the G1 and G2 phases of the cell cycle. Dolastatin-10 has extremely potent in vitro activity against a variety of tumor cell lines. Since its dose-limiting toxicities include myelosuppression, it is being studied in acute myelogenous leukemia (AML) and MDS. Ras may play a role in MDS, and activation of this gene and its signaling pathways may require farnesylation. Several farnesyl transferase inhibitors are now available for study in patients with MDS. An increasing body of data suggests a possible role for angiogenesis in MDS, and several antiangiogenesis agents are in clinical trials, including thalidomide, SU5416, and anti-vascular endothelial growth factor (VEGF) antibodies. Development of new drugs and regimens will be facilitated by recently developed standardized response criteria. Future clinical trials should focus on rational combinations of these agents and others with the goal of curing patients with MDS.

Temporal association of marrow eosinophilia with inversion of chromosome 16 in recurrent blast crises of chronic myelogenous leukemia.

We report a patient with Ph+ chronic myelogenous leukemia (CML) whose recurrent blast crises were associated with marrow eosinophilia and inv(16). After intensive chemotherapy, for each blast crisis, the patient reentered chronic phase with disappearance of both the inv(16) and the eosinophilia.