Testing Cancer Immunotherapy in a Human Immune System Mouse Model: Correlating Treatment Responses to Human Chimerism, Therapeutic Variables and Immune Cell Phenotypes

Over the past decade, immunotherapies have revolutionized the treatment of cancer. Although the success of immunotherapy is remarkable, it is still limited to a subset of patients. More than 1500 clinical trials are currently ongoing with a goal of improving the efficacy of immunotherapy through co-administration of other agents. Preclinical, small-animal models are strongly desired to increase the pace of scientific discovery, while reducing the cost of combination drug testing in humans. Human immune system (HIS) mice are highly immune-deficient mouse recipients rtpeconstituted with human hematopoietic stem cells. These HIS-mice are capable of growing human tumor cell lines and patient-derived tumor xenografts. This model allows rapid testing of multiple, immune-related therapeutics for tumors originating from unique clinical samples. Using a cord blood-derived HIS-BALB/c-Rag2nullIl2rγnullSIRPαNOD (BRGS) mouse model, we summarize our experiments testing immune checkpoint blockade combinations in these mice bearing a variety of human tumors, including breast, colorectal, pancreatic, lung, adrenocortical, melanoma and hematological malignancies. We present in-depth characterization of the kinetics and subsets of the HIS in lymph and non-lymph organs and relate these to protocol development and immune-related treatment responses. Furthermore, we compare the phenotype of the HIS in lymph tissues and tumors. We show that the immunotype and amount of tumor infiltrating leukocytes are widely-variable and that this phenotype is tumor-dependent in the HIS-BRGS model. We further present flow cytometric analyses of immune cell subsets, activation state, cytokine production and inhibitory receptor expression in peripheral lymph organs and tumors. We show that responding tumors bear human infiltrating T cells with a more inflammatory signature compared to non-responding tumors, similar to reports of "responding" patients in human immunotherapy clinical trials. Collectively these data support the use of HIS mice as a preclinical model to test combination immunotherapies for human cancers, if careful attention is taken to both protocol details and data analysis.

Treatment of metastatic breast cancer with somatostatin analogues--a meta-analysis

BACKGROUND

Somatostatin analogues appear to have antiproliferative effects in breast cancer by inhibiting various hormones. Several small phase 1 and 2 clinical trails have evaluated the efficacy of somatostatin analogues, but the results are varied. The purpose of this study was to use the technique of meta-analysis to determine the effect of somatostatin analogues on tumor response, toxicity, and serum hormone levels in women with metastatic breast cancer.

METHODS

All published and unpublished trials were reviewed. Meta-analysis was preformed by best linear unbiased estimate regression with observations weighted inversely to their variance. Significance was considered at P < .05.

RESULTS

Fourteen studies (N = 210) were included. Positive tumor response was reported in 87 patients (41.4%). Mean duration of response was 3.9 months. Response was best when somatostatin analogues were given as first-line therapy (69.5% versus 28.5%, P < .006) and in patients with < or =2 metastases (45.0% versus 5.6%, P = .3). Mild side effects occurred in 47 of 185 patients (25.4%). Therapy was associated with a decrease in serum insulin-like growth factor (IGF-1) and an increase in growth hormone.

CONCLUSIONS

In patients with metastatic breast cancer, treatment with somatostatin analogues was associated with a tumor response of over 40% with few side effects. Best results were achieved when somatostatin analogues were given as first-line therapy.

Low use of breast conservation surgery in medically indigent populations

BACKGROUND

Breast conservation surgery (BCS) with radiation is an acceptable treatment for early-stage breast cancer.

METHODS

Data were obtained from hospital cancer registries on women surgically treated for Stage 0 to II breast cancer from 1993 to 1997. Data on 1,747 patients were analyzed for surgical treatment, hospital type (private versus public), disease stage, and ethnic origin.

RESULTS

In this study, 34% of women received BCS. Women treated in private hospitals received BCS more often than women treated in public hospitals. Women with stage II disease received BCS less often than women with earlier stage disease. Hospital type (public versus private) and disease stage were strong, independent predictors for use of BCS. When hospital type and disease stage were statistically controlled, no treatment differences across ethnic groups were identified.

CONCLUSIONS

Use of BCS in this study was low compared with National Cancer Database statistics. Women treated in publicly funded hospitals and those with stage II disease were significantly less likely to receive BCS.

Low rate of breast conservation surgery in large urban hospital serving the medically indigent

BACKGROUND

Breast conservation surgery (BCS) with radiation therapy is an acceptable treatment for stage I and II breast carcinoma. The purpose of this study was to measure the use of BCS in a large, urban, university-affiliated hospital serving primarily medically indigent patients.

METHODS

A chart review of patients receiving operative treatment for breast carcinoma during 1995 and 1996 was done. Patients with stage I or II disease were selected. Data were analyzed for clinical stage, surgical treatment, age, and ethnic origin.

RESULTS

Of patients eligible, only 16% received BCS. There were slight trends for younger women to receive BCS and for decreased use of BCS with stage II disease. No differences in surgical treatment were seen across ethnic groups.

CONCLUSIONS

We suggest that poverty, poor education, and cultural differences may play a role in selection of surgical treatment for breast carcinoma. Further investigation is needed to facilitate best treatment.