Vivek Subbiah

Of mice and men: divergent risks of teriparatide-induced osteosarcoma

SummarySince approval by the U.S. Food and Drug Administration (FDA) in December 2002, teriparatide (recombinant 1-34 PTH; Forteo®) has been safely used by more than 430,000 patients. Prior to FDA approval, however, there was concern that teriparatide might increase the risk for patients to develop osteosarcoma, as almost 45% of the rats treated with this drug at the highest-tested dose level developed this aggressive form of bone cancer. Balancing the proven benefits of teriparatide shown by clinical trials with the theoretical risk for teriparatide-induced human osteosarcoma, the FDA mandated both a ‘black-box’ warning of this potential side-effect and a company-sponsored postmarketing surveillance program. As a participating institute of that surveillance program, we report upon the second person with potential teriparatide-induced osteosarcoma, in this case, complicated by a history of pelvic radiation.IntroductionGiven the theoretic risk of the drug teriparatide and the known risk of radiation in inducing osteosarcoma, we raise the issue of whether teriparatide magnified the risk of radiation-induced osteosarcoma in our patient and try to determine which factor played the predominant role in the development of his disease.MethodsWe analyzed preclinical rat data, human clinical experience with teriparatide, and our patient’s clinical history to assess the human risk of teriparatide and radiation exposure.ResultsAfter the first case of suspected osteosarcoma was reported in December 2005, we encountered a second possible teriparatide-induced osteosarcoma less than a year later. Review of the preclinical animal data would suggest that teriparatide is safe for human use when used as recommended by the manufacturer. Given the location of the sarcoma within the field of radiation and the limited exposure to teriparatide before diagnosis, it is unlikely that teriparatide played the predominant role in the emergence of this patient’s osteosarcoma. We cannot, however, exclude the possibility that teriparatide magnified the carcinogenic effect of radiation therapy to induce the osteosarcoma.ConclusionOf more than 430,000 persons who have received teriparatide for treatment of severe osteoporosis, we report the second patient to develop osteosarcoma. Although teriparatide reduces osteoporosis-related fractures in select patient populations, important contraindications, such as prior radiation exposure, should be considered before use.

Ewing’s Sarcoma: Standard and Experimental Treatment Options

Opinion statementEwing sarcoma family tumors (EWS), which include classic Ewing’s sarcoma in addition to primitive neuroectodermal tumor and Askin tumor, are the second most common variety of primary bone cancer to afflict adolescents and young adults. Multi-disciplinary care incorporating advances in diagnosis, surgery, chemotherapy, and radiation has substantially improved the survival rate of patients with localized Ewing sarcoma to nearly 70%. Unfortunately, those advances have not significantly changed the long-term outcome for those with metastatic or recurrent disease; 5-year survival remains less than 25%. This apparent therapeutic plateau exists despite extensive effort during the last four decades to optimize the efficacy of cytotoxic chemotherapy through combination of chemotherapies of mechanistically diverse action, dose-dense scheduling (provided as frequently as every 2 weeks), increased adjuvant treatment duration, and higher dosage per cycle (facilitated with parallel strides in supportive care incorporating growth factors). As has already occurred for malignancies such as breast or colon cancer, the “-omics-based” revolution has enhanced our understanding of the molecular changes responsible for Ewing’s tumor formation and identified a number of potential targets (such as IGF-1R or mTOR) amenable to biological therapy. It has also created both a challenge and an opportunity to develop predictive biomarkers capable of selecting patients most likely to benefit from targeted therapy. In this review, we discuss current standard-of-care for patients with Ewing’s sarcoma and highlight the most promising experimental therapies in early-phase clinical trials.

Targeted Morphoproteomic Profiling of Ewing's Sarcoma Treated with Insulin-Like Growth Factor 1 Receptor (IGF1R) Inhibitors: Response/Resistance Signatures

Background Insulin-like growth factor 1 receptor (IGF1R) targeted therapies have resulted in responses in a small number of patients with advanced metastatic Ewings sarcoma. We performed morphoproteomic profiling to better understand response/resistance mechanisms of Ewings sarcoma to IGF1R inhibitor-based therapy. Methodology/Principal Findings This pilot study assessed two patients with advanced Ewings sarcoma treated with IGF1R antibody alone followed by combined IGF1R inhibitor plus mammalian target of rapamycin (mTOR) inhibitor treatment once resistance to single-agent IGF1R inhibitor developed. Immunohistochemical probes were applied to detect p-mTOR (Ser2448), p-Akt (Ser473), p-ERK1/2 (Thr202/Tyr204), nestin, and p-STAT3 (Tyr 705) in the original and recurrent tumor. The initial remarkable radiographic responses to IGF1R-antibody therapy was followed by resistance and then response to combined IGF1R plus mTOR inhibitor therapy in both patients, and then resistance to the combination regimen in one patient. In patient 1, upregulation of p-Akt and p-mTOR in the tumor that relapsed after initial response to IGF1R antibody might explain the resistance that developed, and the subsequent response to combined IGF1R plus mTOR inhibitor therapy. In patient 2, upregulation of mTOR was seen in the primary tumor, perhaps explaining the initial response to the IGF1R and mTOR inhibitor combination, while the resistant tumor that emerged showed activation of the ERK pathway as well. Conclusion/Significance Morphoproteomic analysis revealed that the mTOR pathway was activated in these two patients with advanced Ewings sarcoma who showed response to combined IGF1R and mTOR inhibition, and the ERK pathway in the patient in whom resistance to this combination emerged. Our pilot results suggests that morphoproteomic assessment of signaling pathway activation in Ewings sarcoma merits further investigation as a guide to understanding response and resistance signatures.

Cancer therapy directed by comprehensive genomic profiling: a single center study

Innovative molecular diagnostics deployed in the clinic enable new ways to stratify patients into appropriate treatment regimens. These approaches may resolve a major challenge for early-phase clinical trials, which is to recruit patients who, while having failed previous treatments, may nevertheless respond to molecularly targeted drugs. We report the findings of a prospective, single-center study conducted in patients with diverse refractory cancers who underwent comprehensive genomic profiling (CGP; next-generation sequencing, 236 genes). Of the 500 patients enrolled, 188 (37.6%) received either matched (N = 122/188, 65%) or unmatched therapy (N = 66/188, 35%). The most common reasons that patients were not evaluable for treatment included insufficient tissue, death, or hospice transfer. The median number of molecular alterations per patient was five (range, 1-14); median number of prior therapies, four. The most common diagnoses were ovarian cancer (18%), breast cancer (16%), sarcoma (13%), and renal cancer (7%). Of the 339 successfully profiled patients, 317 (93.5%) had at least one potentially actionable alteration. By calculating matching scores, based on the number of drug matches and genomic aberrations per patient, we found that high scores were independently associated with a greater frequency of stable disease ≥6 months/partial/complete remission [22% (high scores) vs. 9% (low scores), P = 0.024], longer time-to-treatment failure [hazard ratio (HR) = 0.52; 95% confidence interval (CI) = 0.36-0.74; P = 0.0003], and survival (HR = 0.65; 95% CI = 0.43-1.0; P = 0.05). Collectively, this study offers a clinical proof of concept for the utility of CGP in assigning therapy to patients with refractory malignancies, especially in those patients with multiple genomic aberrations for whom combination therapies could be implemented. Cancer Res; 76(13); 3690-701. ©2016 AACR.

Ipilimumab with Stereotactic Ablative Radiation Therapy: Phase I Results and Immunologic Correlates from Peripheral T Cells

Purpose: Little prospective data are available on clinical outcomes and immune correlates from combination radiation and immunotherapy. We conducted a phase I trial (NCT02239900) testing stereotactic ablative radiotherapy (SABR) with ipilimumab. Experimental Design: SABR was given either concurrently (1 day after the first dose) or sequentially (1 week after the second dose) with ipilimumab (3 mg/kg every 3 weeks for 4 doses) to five treatment groups: concurrent 50 Gy (in 4 fractions) to liver; sequential 50 Gy (in 4 fractions) to liver; concurrent 50 Gy (in 4 fractions) to lung; sequential 50 Gy (in 4 fractions) to lung; and sequential 60 Gy (in 10 fractions) to lung or liver. MTD was determined with a 3 + 3 dose de-escalation design. Immune marker expression was assessed by flow cytometry. Results: Among 35 patients who initiated ipilimumab, 2 experienced dose-limiting toxicity and 12 (34%) grade 3 toxicity. Response outside the radiation field was assessable in 31 patients. Three patients (10%) exhibited partial response and 7 (23%) experienced clinical benefit (defined as partial response or stable disease lasting ≥6 months). Clinical benefit was associated with increases in peripheral CD8+ T cells, CD8+/CD4+ T-cell ratio, and proportion of CD8+ T cells expressing 4-1BB and PD1. Liver (vs. lung) irradiation produced greater T-cell activation, reflected as increases in the proportions of peripheral T cells expressing ICOS, GITR, and 4-1BB. Conclusions: Combining SABR and ipilimumab was safe with signs of efficacy, peripheral T-cell markers may predict clinical benefit, and systemic immune activation was greater after liver irradiation. Clin Cancer Res; 23(6); 1388–96. ©2016 AACR.

Phase IB study of vemurafenib in combination with irinotecan and cetuximab in patients with metastatic colorectal cancer with BRAFV600E mutation

In vitro, EGFR inhibition, combined with the BRAF inhibitor vemurafenib, causes synergistic cytotoxicity for BRAFV600E metastatic colorectal cancer, further augmented by irinotecan. The safety and efficacy of vemurafenib, irinotecan, and cetuximab in BRAF-mutated malignancies are not defined. In this 3+3 phase I study, patients with BRAFV600E-advanced solid cancers received cetuximab and irinotecan with escalating doses of vemurafenib. Nineteen patients (18 with metastatic colorectal cancer and 1 with appendiceal cancer) were enrolled. Three patients experienced dose-limiting toxicities. The MTD of vemurafenib was 960 mg twice daily. Six of 17 evaluable patients (35%) achieved a radiographic response by Response Evaluation Criteria in Solid Tumors 1.1 criteria, consistent with in vivo models demonstrating tumor regressions with the triplet regimen. Median progression-free survival was 7.7 months. BRAFV600E circulating cell-free DNA (cfDNA) trends correlated with radiographic changes, and acquired mutations from cfDNA in genes reactivating MAPK signaling were observed at progression. SIGNIFICANCE Vemurafenib, in combination with irinotecan and cetuximab, was well tolerated in patients with refractory, BRAF-mutated metastatic colorectal cancer, and both survival outcomes and response rates exceeded prior reports for vemurafenib and for irinotecan plus cetuximab in BRAFV600E metastatic colorectal cancer. In vivo models demonstrated regressions with the triplet, in contrast with vemurafenib and cetuximab alone. cfDNA predicted radiographic response and identified mutations reactivating the MAPK pathway upon progression. Cancer Discov; 6(12); 1352-65. ©2016 AACR.This article is highlighted in the In This Issue feature, p. 1293.

Targeted therapy by combined inhibition of the RAF and mTOR kinases in malignant spindle cell neoplasm harboring the KIAA1549-BRAF fusion protein

BackgroundOncologic patients who are extreme responders to molecularly targeted therapy provide an important opportunity to better understand the biologic basis of response and, in turn, inform clinical decision making. Malignant neoplasms with an uncertain histologic and immunohistochemical characterization present challenges both on initial diagnostic workups and then later in management, as current treatment algorithms are based on a morphologic diagnosis. Herein, we report a case of a difficult to characterize sarcoma-like lesion for which genomic profiling with clinical next generation sequencing (NGS) identified the molecular underpinnings of arrested progression(stable disease) under combination targeted therapy within a phase I clinical trial.MethodsGenomic profiling with clinical next generation sequencing was performed on the FoundationOne™ platform (Foundation Medicine, Cambridge MA). Histopathology and immunohistochemical studies were performed in the Department of Pathology, MD Anderson Cancer Center (Houston, TX). Treatment was administered in the context of a phase I clinical trial ClinicalTrials.gov Identifier: (NCT01187199).ResultsThe histology of the tumor was that of a spindle cell neoplasm, grade 2 by FNCLCC standards. Immunohistochemical staining was positive for S100 and CD34. Genomic profiling identified the following alterations: a KIAA1549-BRAF gene fusion resulting from a tandem duplication event, a homozygous deletion of PTEN, and frameshift insertion/deletions in CDKN2A A68fs*51, SUFU E283fs*3, and MAP3K1 N325fs*3. The patient had a 25% reduction in tumor (RECIST v1.1) following combination therapy consisting of sorafenib, temsirolimus, and bevazicumab within a phase I clinical trial.ConclusionsThe patient responded to combination targeted therapy that fortuitously targeted KIAA1549-BRAF and PTEN loss within a spindle cell neoplasm, as revealed by genomic profiling based on NGS. This is the first report of a tumor driven by a KIAA1549-BRAF fusion responding to sorafenib-based combination therapy.

Targeting the apoptotic pathway in chondrosarcoma using recombinant human Apo2L/TRAIL (dulanermin), a dual proapoptotic receptor (DR4/DR5) agonist.

Recombinant human Apo2L/TRAIL (dulanermin) is based on the ligand for death receptors (DR4 and DR5), which promotes apoptosis. We report a patient with refractory chondrosarcoma who showed a prolonged response to dulanermin and explore mechanisms of response and resistance. This heavily pretreated patient had progressive metastatic chondrosarcoma to the lung. On dulanermin (8 mg/kg i.v. on days 1–5 in a 21-day cycle), the patient achieved a sustained partial response with only subcentimeter nodules remaining. After 62 months of dulanermin treatment, progressive disease in the lungs was noted, and the patient underwent a resection that confirmed chondrosarcoma. DR4 was detected (immunohistochemistry) in the patients tumor, which may have enabled the response. However, upregulation of prosurvival proteins, namely, phosphorylated (p)-NF-κBp65 (Ser 536), p-STAT3 (Tyr 705), p-ERK 1/2 (Thr 202/Tyr 204), p-mTOR (Ser 2448), FASN, and Bcl-2, were also detected, which may have provided the underlying mechanisms for acquired dulanermin resistance. The patient was restarted on dulanermin and has continued on this treatment for an additional 16 months since surgery (78 months since initiation of treatment), with his most recent computed tomography (CT) scans showing no evidence of disease. Mol Cancer Ther; 11(11); 2541–6. ©2012 AACR.

Resistance to Mammalian Target of Rapamycin Inhibitor Therapy in Perivascular Epithelioid Cell Tumors

that described three patients who responded totherapy inhibiting the mammalian target of rapamycin (mTOR).We present a case of a 58-year-old woman with metastatic perivascu-lar epithelioid cell tumor (PEComa) who did not respond to anmTOR inhibitor. She presented to her primary physician with a 17 13.5 9.5cmmassinherlateralrightupperquadrant.Sheunderwentsurgicalresectionofthemass,whichappearedtoariseintheretroperi-toneum above the right kidney. The pathology was reviewed by pa-thologists at The University of Nebraska Medical Center and atBrigham and Women’s Hospital, Harvard Medical School (by one ofthe coauthors of the study

Hotspot Mutation Panel Testing Reveals Clonal Evolution in a Study of 265 Paired Primary and Metastatic Tumors

Purpose: We used a clinical next-generation sequencing (NGS) hotspot mutation panel to investigate clonal evolution in paired primary and metastatic tumors. Experimental Design: A total of 265 primary and metastatic tumor pairs were sequenced using a 46-gene cancer mutation panel capable of detecting one or more single-nucleotide variants as well as small insertions/deletions. Mutations were tabulated together with tumor type and percentage, mutational variant frequency, time interval between onset of primary tumor and metastasis, and neoadjuvant therapy status. Results: Of note, 227 of 265 (85.7%) tumor metastasis pairs showed identical mutation calls. Of the tumor pairs with identical mutation calls, 160 (60.4%) possessed defining somatic mutation signatures and 67 (25.3%) did not exhibit any somatic mutations. There were 38 (14.3%) cases that showed at least one novel mutation call between the primary and metastasis. Metastases were almost two times more likely to show novel mutations (n = 20, 7.5%) than primary tumors (n = 12, 4.5%). TP53 was the most common additionally mutated gene in metastatic lesions, followed by PIK3CA and SMAD4. PIK3CA mutations were more often associated with metastasis in colon carcinoma samples. Conclusions: Clinical NGS hotspot panels can be useful in analyzing clonal evolution within tumors as well as in determining subclonal mutations that can expand in future metastases. PIK3CA, SMAD4, and TP53 are most often involved in clonal divergence, providing potential targets that may help guide the clinical management of tumor progression or metastases. Clin Cancer Res; 21(11); 2644–51. ©2015 AACR.