Androgen receptors (ARs) play a critical role in the development of prostate cancer. Targeting ARs results in important salutary effects in this malignancy. Despite mounting evidence that ARs also participate in the pathogenesis and/or progression of diverse tumors, exploring the impact of hormonal manipulation of these receptors has not been widely pursued beyond prostate cancer. This review describes patterns of AR expression in a spectrum of cancers, and the potential to exploit this knowledge in the clinical therapeutic setting.

Background

The presence of multiple molecular aberrations in patients with breast cancer may correlate with worse outcomes.

Case presentations

We performed in-depth molecular analysis of patients with estrogen receptor-positive, HER2-negative, hormone therapy-refractory breast cancer, who achieved partial or complete responses when treated with anastrozole and everolimus. Tumors were analyzed using a targeted next generation sequencing (NGS) assay in a Clinical Laboratory Improvement Amendments laboratory. Genomic libraries were captured for 3,230 exons in 182 cancer-related genes plus 37 introns from 14 genes often rearranged in cancer and sequenced to high coverage. Patients received anastrozole (1 g PO daily) and everolimus (5 or 10 mg PO daily). Thirty-two patients with breast cancer were treated on study and 5 (16 %) achieved a partial or complete response. Primary breast tissue was available for NGS testing in three of the responders (partial response with progression free survival of 11 and 14 months, respectively; complete response with progression free survival of 9+ months). The following molecular aberrations were observed: PTEN loss by immunohistochemistry, CCDN1 and FGFR1 amplifications, and PRKDC re-arrangement (NGS) (patient #1); PIK3CA and PIK3R1 mutations, and CCDN1, FGFR1, MYC amplifications (patient #2); TP53 mutation, CCNE1, IRS2 and MCL1 amplifications (patient #3). Some (but not all) of these aberrations converge on the PI3K/AKT/mTOR pathway, perhaps accounting for response.

Conclusions

Patients with estrogen receptor-positive breast cancer can achieve significant responses on a combination of anastrozole and everolimus, even in the presence of multiple molecular aberrations. Further study of next generation sequencing-profiled tumors for convergence and resistance pathways is warranted.

Despite significant investments in the development of new agents only 5% of cancer drugs entering Phase I clinical trials are ultimately approved for routine clinical cancer care. Drug repurposing strategies using novel combinations of previously tested anticancer agents could reduce the cost and improve treatment outcomes. At MD Anderson Cancer Center, early phase clinical trials with drug repurposing strategies demonstrated promising outcomes in patients with both rare and common treatment refractory advanced cancers. Despite clinical efficacy advancing drug repurposing strategies in the clinical trial trajectory beyond early phase studies has been challenging mainly due to lack of funding and interest from the pharmaceutical industry. In this review, we delineate our experience and challenges with drug repurposing strategies.

We hypothesized that aberrations activating epidermal growth factor receptor (EGFR) via dimerization would be more sensitive to anti-dimerization agents (e.g., cetuximab). EGFR exon 19 abnormalities (L747_A750del; deletes amino acids LREA) respond to reversible EGFR kinase inhibitors (TKIs). Exon 20 in-frame insertions and/or duplications (codons 767 to 774) and T790M mutations are clinically resistant to reversible/some irreversible TKIs. Their impact on protein function/therapeutic actionability are not fully elucidated.In our study, the index patient with non-small cell lung cancer (NSCLC) harbored EGFR D770_P772del_insKG (exon 20). A twenty patient trial (NSCLC cohort) (cetuximab-based regimen) included two participants with EGFR TKI-resistant mutations ((i) exon 20 D770>GY; and (ii) exon 19 LREA plus exon 20 T790M mutations). Structural modeling predicted that EGFR exon 20 anomalies (D770_P772del_insKG and D770>GY), but not T790M mutations, stabilize the active dimer configuration by increasing the interaction between the kinase domains, hence sensitizing to an agent preventing dimerization. Consistent with predictions, the two patients harboring D770_P772del_insKG and D770>GY, respectively, responded to an EGFR antibody (cetuximab)-based regimen; the T790M-bearing patient showed no response to cetuximab combined with erlotinib. In silico modeling merits investigation of its ability to optimize therapeutic selection based on structural/functional implications of different aberrations within the same gene.

Purpose

Body weight and composition play a role in cancer etiology, prognosis, and treatment response. Therefore, we analyzed the weight, body composition changes, and outcome in patients treated with temsirolimus, an mTor inhibitor that has weight loss as one of its side effects.

Patients and methods

Sixteen patients with advanced solid tumors treated with temsirolimus were studied; body composition was evaluated utilizing computerized tomography images. Sarcopenia was defined as skeletal muscle index lower than 38.5 cm(2)/m(2) for women and 52.4 cm(2)/m(2) for men.

Results

Five of 16 patients (31 %) were men; median age, 60 years. Forty-four percent (7/16) of patients were sarcopenic. Fatigue, anemia, hyperglycemia, and hyperlipidemia were common. Baseline sarcopenia and body composition did not correlate with worse toxicity or treatment outcome. However, there was a trend for greater loss of adipose area (p = 0.07), fat mass (p = 0.09), and adipose index (p = 0.07) for patients with grade 3 or 4 toxicities versus those with grade 1 and 2 side effects.

Conclusion

Patients with higher grade toxicities tended to lose more body fat, suggesting a possible end-organ metabolic effect of temsirolimus. These observations merit exploration in a larger cohort of patients.

Background

Patients with BRAF mutation-positive advanced melanoma respond well to matched therapy with BRAF or MEK inhibitors, but often quickly develop resistance.

Methods

Tumor tissue from ten patients with advanced BRAF mutation-positive melanoma who achieved partial response (PR) or complete response (CR) on BRAF and/or MEK inhibitors was analyzed using next generation sequencing (NGS) assay. Genomic libraries were captured for 3230 exons in 182 cancer-related genes plus 37 introns from 14 genes often rearranged in cancer and sequenced to average median depth of 734X with 99% of bases covered >100X.

Results

Three of the ten patients (median number of prior therapies = 2) attained prolonged CR (duration = 23.6+ to 28.7+ months); seven patients achieved either a PR or a short-lived CR. One patient who achieved CR ongoing at 28.7+ months and had tissue available close to the time of initiating BRAF inhibitor therapy had only a BRAF mutation. Abnormalities in addition to BRAF mutation found in other patients included: mutations in NRAS, APC and NF1; amplifications in BRAF, aurora kinase A, MYC, MITF and MET; deletions in CDKN2A/B and PAX5; and, alterations in RB1 and ATM. Heterogeneity between patients and molecular evolution within patients was noted.

Conclusion

NGS identified potentially actionable DNA alterations that could account for resistance in patients with BRAF mutation-positive advanced melanoma who achieved a PR or CR but whose tumors later progressed. A subset of patients with advanced melanoma may harbor only a BRAF mutation and achieve a durable CR on BRAF pathway inhibitors.

Purpose

Sodium stibogluconate (SSG), a small molecule inhibitor of protein tyrosine phosphatases, combined with IFN-alpha-2b (IFN-α) inhibited solid tumor cell line growth in vitro. We conducted a phase I clinical trial with SSG plus IFN-α in advanced cancer patients to assess tolerance, maximum tolerated dose (MTD) and immune system effects.

Experimental design

SSG was administered intravenously alone for five days of week 1, cycle 1 (21 days per cycle) and together with IFN-α 2b s (3 million units sc TIW) in week 2, and after a rest during week 3, on a 2-week on/1-week off cycle. SSG dose levels were 400, 600, 900, 1125, and 1350 mg/m(2).

Results

Twenty-four patients were studied. Common toxicities included asymptomatic elevated serum lipase, thrombocytopenia, fatigue, fever, chills and anemia. The dose-limiting toxicities (DLT) were hypokalemia, thrombocytopenia, fatigue, pancreatitis and skin rash. The MTD was 900 mg/m(2 )SSG and IFN-α, 3 million units TIW. At this dose, patients had a significantly lower number of regulatory T cells (T(R )Cells) (p = 0.012), myeloid dendritic cells (mDC) (p = 0.028); higher percentage of natural killer (NK) cells that synthesized perforin (p = 0.046) and of plasmacytoid dendritic cells (pDC) that secreted IFN-α (p = 0.018) in response to activation through toll-like receptor (TLR) 7 and TLR 8 by CL097, the highly water-soluble derivative of the imidazoquinoline compound R848.

Conclusions

SSG in combination with IFN-α 2b was well tolerated and augmented cellular immune parameters.

Background

Activated PI3K/AKT/mTOR pathway frequently occurs in metastatic or recurrent cervical carcinomas. However, the clinical benefits of matched therapy, a therapeutic approach targeting a specific mutational abnormality, have not yet been established.

Methods

We analyzed the outcomes of patients with metastatic or recurrent cervical carcinomas who had a test for PIK3CA mutation and/or PTEN loss/mutation, and received ≥1 phase I therapeutic regimen between January 2006 and June 2013.

Results

Patients with adenocarcinoma had fewer PIK3CA mutations (14%), and survived longer (median, 14.2 months) than those with squamous cell carcinoma (48% and 7.2 months; p = 0.016, and 0.001, respectively). Matched therapy targeting the activated PI3K/AKT/mTOR pathway led to a favorable rate of SD ≥ 6 months/CR/PR (53%) and significantly longer progression-free survival (median, 6.0 months) than non-matched therapy (11% and 1.5 months; p = 0.08 and 0.026; respectively). In patients with squamous cell carcinoma of the cervix, the presence of PIK3CA mutations was associated with a significantly longer overall survival (median, 9.4 months) than the absence of PIK3CA mutations (median, 4.2 months; p = 0.019).

Conclusions

Matched therapy targeting the activated PI3K/AKT/mTOR pathway provided meaningful clinical benefits. Thus, further evaluation of PI3K/AKT/mTOR pathway targeted therapy is warranted, especially in metastatic or recurrent squamous cell carcinoma.

Background

Bevacizumab and temsirolimus are active agents in gynecologic tumors. Temsirolimus attenuates upregulation of HIF-1α levels, a resistance mechanism for antiangiogenics, and targets the PI3-kinase/AKT/mTOR axis, commonly aberrant in these tumors.

Patients and methods

We analyzed safety and responses in 41 patients with gynecologic cancers treated as part of a Phase I study of bevacizumab and temsirolimus.

Results

Median age of the 41 women was 60 years (range, 33-80 years); median number of prior systemic therapies was 4 (1-11). Grade 3 or 4 treatment-related toxicities included: thrombocytopenia (10%), mucositis (2%), hypertension (2%), hypercholesterolemia (2%), fatigue (7%), elevated aspartate aminotransferase (2%), and neutropenia (2%). Twenty-nine patients (71%) experienced no treatment-related toxicity greater than grade 2. Full FDA-approved doses of both drugs (bevacizumab 15mg/kg IV Q3weeks and temsirolimus 25mg IV weekly) were administered without dose-limiting toxicity. Eight patients (20%) achieved stable disease (SD) > 6 months and 7 patients (17%), a partial response (PR) [total = 15/41 patients (37%)]. Eight of 13 patients (62%) with high-grade serous histology (ovarian or primary peritoneal) achieved SD > 6 months/PR.

Conclusion

Bevacizumab and temsirolimus was well tolerated. Thirty-seven percent of heavily-pretreated patients achieved SD > 6 months/PR, suggesting that this combination warrants further study.

There is limited data on co-expression of FGFR/FGR amplifications and PI3K/ AKT/mTOR alterations in breast cancer. Tumors from patients with metastatic breast cancer referred to our Phase I Program were analyzed by next generation sequencing (NGS). Genomic libraries were selected for all exons of 236 (or 182) cancer-related genes sequenced to average depth of >500× in a CLIA laboratory (Foundation Medicine, Cambridge, MA, USA) and analyzed for all classes of genomic alterations. We report genomic profiles of 112 patients with metastatic breast cancer, median age 55 years (range, 27-78). Twenty-four patients (21%) had at least one amplified FGFR or FGF. Fifteen of the 24 patients (63%) also had an alteration in the PI3K/ AKT/mTOR pathway. There was no association between alterations in FGFR/FGF and PI3K/AKT/mTOR (P=0.49). Patients with simultaneous amplification in FGFR/FGF signaling and the PI3K/AKT/mTOR pathway had a higher rate of SD≥6 months/PR/ CR when treated with therapies targeting the PI3K/AKT/mTOR pathway than patients with only alterations in the PI3K/AKT/mTOR pathway (73% vs. 34%; P=0.0376) and remained on treatment longer (6.8 vs. 3.7 months; P=0.053). Higher response rates were seen in patients with simultaneous amplification in FGFR/FGF signaling and alterations in the PI3K/AKT/mTOR pathway who were treated with inhibitors of that pathway.