Pathway level alterations rather than mutations in single genes predict response to HER2-targeted therapies in the neo-ALTTO trial

Background

We performed whole-exome sequencing of pretreatment biopsies and examined whether genome-wide metrics of overall mutational load, clonal heterogeneity or alterations at variant, gene, and pathway levels are associated with treatment response and survival.

Patients and Methods

Two hundred and three biopsies from the NeoALTTO trial were analyzed. Mutations were called with MuTect, and Strelka, using pooled normal DNA. Associations between DNA alterations and outcome were evaluated by logistic and Cox-proportional hazards regression.

Results

There were no recurrent single gene mutations significantly associated with pathologic complete response (pCR), except PIK3CA [odds ratio (OR) = 0.42, P = 0.0185]. Mutations in 33 of 714 pathways were significantly associated with response, but different genes were affected in different individuals. PIK3CA was present in 23 of these pathways defining a ‘trastuzumab resistance-network’ of 459 genes. Cases with mutations in this network had low pCR rates to trastuzumab (2/50, 4%) compared with cases with no mutations (9/16, 56%), OR = 0.035; P < 0.001. Mutations in the ‘Regulation of RhoA activity’ pathway were associated with higher pCR rate to lapatinib (OR = 14.8, adjusted P = 0.001), lapatinib + trastuzumab (OR = 3.0, adjusted P = 0.09), and all arms combined (OR = 3.77, adjusted P = 0.02). Patients (n = 124) with mutations in the trastuzumab resistance network but intact RhoA pathway had 2% (1/41) pCR rate with trastuzumab alone (OR = 0.026, P = 0.001) but adding lapatinib increased pCR rate to 45% (17/38, OR = 1.68, P = 0.3). Patients (n = 46) who had no mutations in either gene set had 6% pCR rate (1/15) with lapatinib, but had the highest pCR rate, 52% (8/15) with trastuzumab alone.

Conclusions

Mutations in the RhoA pathway are associated with pCR to lapatinib and mutations in a PIK3CA-related network are associated with resistance to trastuzumab. The combined mutation status of these two pathways could define patients with very low response rate to trastuzumab alone that can be augmented by adding lapatinib or substituting trastuzumab with lapatinib.

Abstract S5-01: Whole exome sequencing of pre-treatment biopsies from the neoALTTO trial to identify DNA aberrations associated with response to HER2-targeted therapies

Background: We examined if alterations in nucleic acid variants, genes, pathways, and overall mutational load and clonal entropy are associated with pathologic complete response (pCR) and survival after neoadjuvant anti-HER2 therapies in the NeoALTTO trial.

Methods: Whole exome sequencing was performed of 203 baseline biopsies with outcome information. The mean nucleotide coverage was 150x with &gt;90% of target bases showing &gt; 30x coverage in &gt; 99% of samples. Somatic mutations were called by MuTect and indels by Strelka, using pooled reference normal DNA. Significantly mutated genes (FDR&lt;10%) were identified by MutSigCV. Mutations in 714 canonical biological pathways were assessed and mutational load and genome clonal entropy (MATH) were calculated. Association with pCR and survival were evaluated by logistic regression adjusted for ER status and Cox-proportional hazards regression.

Results: Only 12 genes had mutation rates significantly above background and among these only PI3KCA was associated with lower pCR rate (OR=0.42, p=0.019). Genes with somatic mutations in more than 10 patients were also assessed, but none were associated with pCR or survival. Clonal entropy or adjusted mutation load also did not correlate with response. Mutations in 33 pathways showed significant association with response in the entire cohort. In the trastuzumab arm, 23 of the 33 pathways showed an association with response but none was independent of PIK3CA mutation. We constructed "PIK3CA-gene network" that included all unique genes (n=439) from theese 23 pathways. Of the 66 patients in the trastuzumab arm, 50 carried at least one mutation in one of the 439 genes and among these only 2 achieved pCR (4%) compared to 9 of 16 pCR (56%) among the wild type (OR=0.035; p &lt; 0.001). The same genes/mutations had little impact on pCR in the lapatinib arm (pCR 20%). In the lapatinib arm, mutations in 3 pathways conferred higher probability of pCR. The "Regulation of RhoA activity" pathway, had the most significant association with pCR in the entire cohort (OR=3.77, p=0.0009) and in the lapatininb (pCR 67% vs 17%, OR=14.8, p=0.008) and lapatinib + trastuzumab (OR=3.0, p=0.06) arms, but not in the trastuzumab arm (OR=1.4, p=0.7). Event free and overall survival were also significantly higher in patients who had mutations in this pathway. Twenty seven of the 48 genes in this pathway had mutations affecting 33 patients but different genes were affected in different individuals.

Conclusions: There are no high frequency recurrent single mutations associated with response to HER2-targeted therapies, other than PIK3CA. We identified several biological pathways, including RhoA activity, and a network of PIK3CA associated genes that are significantly associated with response when affected by mutations, however, different genes are mutated in different individuals.

Citation Format: Pusztai L, Shi W, Jiang T, Nuciforo P, Holmes E, Harbeck N, Sotiriou C, Rimm D, Hatzis C, de la Peña L, Armour A, Piccart-Gebhart M, Baselga J. Whole exome sequencing of pre-treatment biopsies from the neoALTTO trial to identify DNA aberrations associated with response to HER2-targeted therapies. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr S5-01.

Biomarker analyses from a phase III, randomized, open-label, first-line study of gefitinib (G) versus carboplatin/paclitaxel (C/P) in clinically selected patients (pts) with advanced non-small cell lung cancer (NSCLC) in Asia (IPASS)

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Background: IPASS demonstrated overall superiority of first-line G vs C/P for progression-free survival (PFS) in never/light ex-smokers with stage IIIB/IV adenocarcinoma NSCLC in Asia. PFS favored CP initially and then G. Outcome was correlated with biomarkers (preplanned exploratory objective). Methods: 683 patients provided tissue samples. Analyses included primary endpoint PFS (Cox proportional hazards) and secondary endpoint objective response rate (ORR; logistic regression) by biomarker status. Results: EGFR mutation (M) status was evaluable in 437 pts by Amplification Refractory Mutation System (ARMS; 60% M+). M+ pts had significantly longer PFS and higher ORR and M- pts significantly shorter PFS and lower ORR with G than C/P. In M unknown pts PFS and ORR were similar to overall population. Post hoc analysis of overall survival favored G in M+ pts (31% maturity; HR 0.78; 95% CI 0.50–1.20) and C/P in M- pts (53% maturity; HR 1.38; 95% CI 0.92–2.90); differences were not statistically significant and follow-up is ongoing. EGFR gene-copy number was evaluable in 406 pts by fluorescence in situ hybridization (FISH; 61% FISH +). Similar PFS and ORR results to analyses by M status were observed, driven by the overlap in EGFR FISH and M status. EGFR protein expression (PE) was evaluable in 365 pts by immunohistochemistry (73% PE+). PFS outcomes did not differ statistically between PE+ and PE-. ORR favored G in both PE+ and - pts. Conclusions: EGFR M status was a strong predictive biomarker for the efficacy of G vs C/P in this clinically selected first-line setting.

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No significant financial relationships to disclose.

ASCO Conflict of Interest Policy and Exceptions

In compliance with the guidelines established by the ASCO Conflict of Interest Policy (J Clin Oncol. 2006 Jan 20;24[3]:519–521) and the Accreditation Council for Continuing Medical Education (ACCME), ASCO strives to promote balance, independence, objectivity, and scientific rigor through disclosure of financial and other interests, and identification and management of potential conflicts. According to the ASCO Conflict of Interest Policy, the following financial and other relationships must be disclosed: employment or leadership position, consultant or advisory role, stock ownership, honoraria, research funding, expert testimony, and other remuneration (J Clin Oncol. 2006 Jan 20;24[3]:520). The ASCO Conflict of Interest Policy disclosure requirements apply to all authors who submit abstracts to the Annual Meeting.

For clinical trials that began accrual on or after April 29, 2004, ASCO's Policy places some restrictions on the financial relationships of principal investigators (J Clin Oncol. 2006 Jan 20;24[3]:521). If a principal investigator holds any restricted relationships, his or her abstract will be ineligible for placement in the 2009 Annual Meeting unless the ASCO Ethics Committee grants an exception. Among the circumstances that might justify an exception are that the principal investigator (1) is a widely acknowledged expert in a particular therapeutic area; (2) is the inventor of a unique technology or treatment being evaluated in the clinical trial; or (3) is involved in international clinical oncology research and has acted consistently with recognized international standards of ethics in the conduct of clinical research. NIH-sponsored trials are exempt from the Policy restrictions. Abstracts for which authors requested and have been granted an exception in accordance with ASCO's Policy are designated with a caret symbol (^) in the Annual Meeting Proceedings.

For more information about the ASCO Conflict of Interest Policy and the exceptions process, please visit www.asco.org/conflictofinterest .

Late radiation side-effects in three patients undergoing parotid irradiation for benign disease

We report three patients in whom standard radiation therapy was given and serious late radiation damage was seen. The first patient suffered recurrent parotiditis and a parotid fistula. He was treated initially with 20 Gy in ten fractions via a 300 kV field. Further irradiation was required 1 year later and 40 Gy was given in 2 Gy fractions by an oblique anterior and posterior wedged photon pair. Ten years later he developed localized temporal bone necrosis. The second patient, with pleomorphic salivary adenoma, developed localized temporal bone necrosis 6 years after 60 Gy had been given using standard fractionation and technique. The third patient received 55 Gy in 25 fractions for a pleomorphic salivary adenoma and after 3 years developed temporal bone necrosis. Sixteen years later the same patient developed cerebellar and brainstem necrosis. All patients developed chronic persistent infection during or shortly after the radiation therapy, which increased local tissue sensitivity to late radiation damage. As a result, severe bone, cerebellar and brainstem necrosis was observed at doses that are normally considered safe. We therefore strongly recommend that any infection in a proposed irradiated area should be treated aggressively, with surgical debridement if necessary, before radiotherapy is administered, or that infection developing during or after irradiation is treated promptly.

Apoptosis in cervical squamous carcinoma: predictive value for survival following radiotherapy

BACKGROUND

Apoptosis, or programmed cell death, can be induced by radiotherapy. The extent of apoptosis in a tumour before treatment may have important implications for response to radiotherapy and long term survival.

AIM

To examine the extent of apoptosis in tumour tissue from patients with squamous carcinoma of the cervix before radiotherapy, and to correlate this with response to treatment and prognosis.

METHODS

The percentage of apoptotic cells was assessed in 146 carcinomas of the cervix from patients scheduled to receive radiotherapy. The CAS 200 static image analysis system was used to count the number of tumour nuclei per high power field, while the numbers of apoptotic cells in the same field were visualised simultaneously on the image analyser and recorded manually.

RESULTS

The median apoptotic level was 0.73%. Patients were divided into two groups around the median. There was no statistically significant difference in outcome between the two groups as determined by long term survival following radiotherapy.

CONCLUSIONS

The CAS 200 static image analyser system can be used to assist in the rapid semiautomated assessment of apoptosis in conventionally prepared tissue. The results suggest that the apoptotic state of a tumour before treatment is of no value in predicting response to radiotherapy and subsequent prognosis. Tumour stage, size, and BrdU labelling index, as a measure of proliferation rate, remain the most important prognostic factors in terms of predicting local tumour control.

Dilutional hyponatraemia: a cause of massive fatal intraoperative cerebral oedema in a child undergoing renal transplantation

A four year old boy with polyuric renal failure resulting from recurrent urinary tract infections and vesicoureteric reflux from birth underwent renal transplantation. In the past he had had five ureteric reimplant operations and a gastrostomy, as he ate nothing by mouth. He required peritoneal dialysis 13 hours a night, six nights a week. His fluid requirements were 2100 ml per day. This included a night feed of 1.5 litres Nutrizon. Before operation he received 900 ml of Dioralyte instead of the Nutrizon feed, and peritoneal dialysis was performed as usual. The operation itself was technically difficult and there was more blood loss than anticipated, requiring intravenous fluids and blood. The operation ended about four hours later but he did not wake up. Urgent computed tomography revealed gross cerebral oedema. He died the next day. At necropsy the brain was massively oedematous and weighed 1680 g.

Nosological Inaccuracies in death certification in Northern Ireland. A comparative study between hospital doctors and general practitioners

We aimed to audit nosological inaccuracies in death certification in Northern Ireland and to compare performance of hospital doctors and general practitioners. Nosology is the branch of medicine which treats of the classification of disease. 1138 deaths were registered in Northern Ireland in a 4-week period commencing 3/10/94. 195 of these were either registered by HM Coroners (HMC) or required further investigation by their staff; these cases were excluded from the study. The remaining 943 were analysed for wording and formulation inaccuracies according to the revised notes (1974), Northern Ireland Medical Certificate of Cause of Death. These are issued in book form by the Registrar of Births and Deaths. The commonest inaccuracies in death certification occur in the areas of poor terminology, sequence errors and unqualified mode. One or more inaccuracies were found in 317 (33.6%) of cases. In 13 of these (4%) cases, the inaccuracies were serious enough to warrant referral by the Registrar of Deaths to HM Coroner. The numbers of general practitioners and hospital doctors were recorded, with general practitioners being responsible for 122 (38%) and hospital doctors being responsible for 195 (62%) of inaccuracies.

The effect of cisplatin pretreatment on the accumulation of MIBG by neuroblastoma cells in vitro

[131I]meta-iodobenzylguanidine ([131I]MIBG) provides a means of selectively delivering radiation to neuroblastoma cells and is a promising addition to the range of agents used to treat neuroblastoma. As MIBG is now being incorporated into multimodal approaches to therapy, important questions arise about the appropriate scheduling and sequencing of the various agents employed. As the ability of neuroblastoma cells to actively accumulate MIBG is crucial to the success of this therapy, the effect of chemotherapeutic agents on this uptake capacity needs to be investigated. We report here our initial findings on the effect of cisplatin pretreatment on the neuroblastoma cell line SK-N-BE (2c). After treating these cells with therapeutically relevant concentrations of cisplatin (2 microM and 20 microM), a stimulation in uptake of [131I]MIBG was observed. Reverse transcription-polymerase chain reaction (RT-PCR) analysis demonstrated that this effect was due to increased expression of the noradrenaline transporter. These results suggest that appropriate scheduling of cisplatin and [131I]MIBG may lead to an increase in tumour uptake of this radiopharmaceutical with consequent increases in radiation dose to the tumour.

A study of gunshot suicides in Northern Ireland from 1989 to 1993

A study of 104 gunshot suicides, including six women, in Northern Ireland over a 5-year period. Forty-five suicides in the security forces are compared with 59 which took place in the civilian population. The former were commonly associated with marital problems and overwhelmingly occurred in young males under the age of 40, whereas the civilian deaths were predominantly associated with mental ill health, with a wider age range distribution. The security forces used rifled weapons in 44 cases, whereas civilians used shotguns in 46 cases. Twelve out of the 45 were witnessed, compared to one in the civilian population. The security forces favoured the head as site of entry in 40 cases compared to 35 in the civilian population. Alcohol consumption was involved in 23 of the security forces suicides and 18 civilian. Of the 6 women, one was in the security forces and 4 had a history of mental illness.

No-carrier-added iodine-131-MIBG: evaluation of a therapeutic preparation

Iodine-131-metaiodobenzylguanidine ([131I]MIBG) is a radiopharmaceutical for imaging as well as targeted radiotherapy of neuroblastoma. It is predicted that the use of no-carrier-added [131I]MIBG, rather than the conventional low specific activity preparation, will result in an enhanced therapeutic ratio because of different transport processes in neuroblastoma compared with most normal tissues.

METHODS

The main aims of the study were: (1) to determine whether [131I]MIBG of substantially greater specific activity is transported into tumor cells by the same process as the existing compound; (2) to evaluate the effect of nonradiolabeled MIBG on the cytotoxicity of no-carrier-added [131I]MIBG; and (3) to compare the biodistribution of both preparations of the radiochemical in neuroblastoma xenografts.

RESULTS

Active uptake of no-carrier-added [131I]MIBG was temperature-, sodium- and oxygen-dependent; ouabain- and desmethylimipramine-inhibitable; and could be blocked competitively by monoamine inhibitors of the noradrenaline transport mechanism. The rank order of specific uptake capacity in a panel of neuroblastoma cell lines was the same for both low and high specific activity drug. Neuroblastoma spheroid regrowth was 85% inhibited by no-carrier-added [131I]MIBG at 2 MBq.ml-1. Inhibitory potency was reduced in a dose-dependent manner by nonradiolabeled MIBG. The accumulation of no-carrier-added [131I]MIBG was significantly greater in tumor, adrenal, heart and skin of tumor-bearing mice than that of the conventional therapy preparation of [131I]MIBG.

CONCLUSION

These data indicate that there may be clinical advantages in the use of no-carrier-added [131I]MIBG rather than conventional [131I]MIBG.

Modification of meta-iodobenzylguanidine uptake in neuroblastoma cells by elevated temperature

Successful imaging or treatment of neuroblastoma with 131I-meta-iodobenzylguanidine (131I-mIBG) depends on the selectivity of active (type 1) uptake of mIBG in neuroblastoma cells relative to passive (type 2) uptake present in most normal tissues. This study investigates the effects of moderately elevated temperature (39-41 degrees C) on the cellular uptake of 131I-mIBG in two neuroblastoma cell lines [SK-N-BE(2c) and IMR-32] and in a non-neuronal (ovarian carcinoma) cell line (A2780). In SK-N-BE(2c), a cell line with high active uptake capacity, the specific (type 1) uptake was reduced by 75% (P < 0.001) at 39 degrees C. Both IMR-32 and A2780 have a low capacity for accumulation of mIBG by active uptake. These cell lines demonstrated a statistically significant increase in accumulation at 39 degrees C, mainly as a result of increased non-specific transport. At 41 degrees C uptake of 131I-mIBG was reduced in all cell lines. Thus, the active component of mIBG uptake is more vulnerable to increased temperature than the passive component. It seems probable that moderately increased temperature will have an unfavourable effect on the therapeutic differential for targeted radiotherapy of neuroblastoma using radiolabelled mIBG.

Ectopic cervical hamartomatous thymoma showing extensive myoid differentiation

Ectopic 'hamartomatous' thymoma is a rare benign neoplasm. These tumours are found in the neck and are thought to be part of a spectrum of ectopic cervical thymic neoplasia. The clinical and histological features are discussed and the literature is reviewed. An attempt is made to explain in embryological terms why such lesions appear to occur more commonly on the left side.

Paracetamol cardiotoxicity

A 29 year old man with a significant paracetamol overdose was found to have an abnormal electrocardiograph which, in the absence of hepatic encephalopathy, was considered due to a direct cardiotoxic effect of the drug. A functional coronary insufficiency resulting from inhibition of endothelium-derived relaxing factor secondary to depletion of sulphydryl groups is postulated, and it is suggested that in paracetamol poisoning evidence of cardiotoxicity alone may be sufficient justification for treatment with acetylcysteine.