CAR T-cell immunotherapy of MET-expressing malignant mesothelioma

Mesothelioma is an incurable cancer for which effective therapies are required. Aberrant MET expression is prevalent in mesothelioma, although targeting using small molecule-based therapeutics has proven disappointing. Chimeric antigen receptors (CARs) couple the HLA-independent binding of a cell surface target to the delivery of a tailored T-cell activating signal. Here, we evaluated the anti-tumor activity of MET re-targeted CAR T-cells against mesothelioma. Using immunohistochemistry, MET was detected in 67% of malignant pleural mesotheliomas, most frequently of epithelioid or biphasic subtype. The presence of MET did not influence patient survival. Candidate MET-specific CARs were engineered in which a CD28+CD3ζ endodomain was fused to one of 3 peptides derived from the N and K1 domains of hepatocyte growth factor (HGF), which represents the minimum MET binding element present in this growth factor. Using an NIH3T3-based artificial antigen-presenting cell system, we found that all 3 candidate CARs demonstrated high specificity for MET. By contrast, these CARs did not mediate T-cell activation upon engagement of other HGF binding partners, namely CD44v6 or heparan sulfate proteoglycans, including Syndecan-1. NK1-targeted CARs demonstrated broadly similar in vitro potency, indicated by destruction of MET-expressing mesothelioma cell lines, accompanied by cytokine release. In vivo anti-tumor activity was demonstrated following intraperitoneal delivery to mice with an established mesothelioma xenograft. Progressive tumor regression occurred without weight loss or other clinical indicators of toxicity. These data confirm the frequent expression of MET in malignant pleural mesothelioma and demonstrate that this can be targeted effectively and safely using a CAR T-cell immunotherapeutic strategy.

Intracavitary 'T4 immunotherapy' of malignant mesothelioma using pan-ErbB re-targeted CAR T-cells

Malignant mesothelioma remains an incurable cancer. We demonstrated that mesotheliomas expressed EGFR (79.2%), ErbB4 (49.0%) and HER2 (6.3%), but lacked ErbB3. At least one ErbB family member was expressed in 88% of tumors. To exploit ErbB dysregulation in this disease, patient T-cells were engineered by retroviral transduction to express a panErbB-targeted chimeric antigen receptor (CAR), co-expressed with a chimeric cytokine receptor that allows interleukin (IL)-4 mediated CAR T-cell proliferation. This combination is referred to as T4 immunotherapy. T-cells from mesothelioma patients were uniformly amenable to T4 genetic modification and expansion/enrichment thereafter using IL-4. Patient-derived T4⁺ T-cells were activated upon contact with a panel of four mesothelioma cell lines, leading to cytotoxicity and cytokine release in all cases. Adoptive transfer of T4 immunotherapy to SCID Beige mice with an established bioluminescent LO68 mesothelioma xenograft was followed by regression or eradication of disease in all animals. Despite the established ability of T4 immunotherapy to elicit cytokine release syndrome in SCID Beige mice, therapy was very well tolerated. These findings provide a strong rationale for the clinical evaluation of intracavitary T4 immunotherapy to treat mesothelioma.

Effect of time delay on survival in patients with non-small cell lung cancer — A Malaysian study

The prognosis of lung cancer remains poor with overall five year survival figures varying between five and 10% worldwide, However, it has been shown that surgery in patients with early stage disease in non-small cell lung cancer can achieve five year survival rates up to 80%, suggesting that early or delay diagnosis can influence prognosis. Nevertheless, studies addressing this have been inconclusive and mostly derived from Western countries.

Abstract A075: Immunotherapy of malignant pleural mesothelioma using cMET specific T-cells

Background: Malignant pleural mesothelioma (MPM) is an incurable cancer predominantly induced by asbestos exposure. This aggressive tumour commonly presents at an advanced stage of disease. Although surgery, combination chemotherapy and radiotherapy may be used in disease management, median survival from diagnosis is less than 12 months. New therapeutic approaches are required to improve outcome in this disease.

Chimeric antigen receptors (CAR) are fusion molecules that couple the HLA- independent binding of a selected cell surface target antigen to the delivery of a tailored T-cell activating signal. Using CAR technology, we aim to develop a novel immunotherapy for MPM that is both safe and effective. These molecules are delivered to patient T-cells using retroviral gene-transfer, thereby stably re-directing their specificity for antigen. The receptor tyrosine kinase MET is overexpressed in >80% of MPM patients making it an attractive candidate for CAR directed immunotherapy.

Methods: Three second-generation cMet-targeted CARs (containing a fused CD28/CD3ζ endodomain) have been developed, distinguished by peptide-binding motifs. Functionality of MET-re targeted T-cells has been assessed by co-cultivation of genetically enhanced test and control T-cells with MPM cell lines that express MET at various levels.

Results: Studies to date have shown that human T-cells engineered to express cMet CARs can destroy mesothelioma tumour cell monolayers, accompanied by T-cell proliferation and cytokine production. To further potentiate the activity of the cMet targeted CARs, a dual targeting approach to both cMet and the ErbB family is currently under evaluation. The second advantage of this approach is in diminishing the potential toxicity risks associate with “on target, off tumour” toxicity. An MPM xenograft model has been established utilising bioluminescence to further evaluate functionality and toxicity in vivo.

Conclusions: These findings demonstrate proof of concept for the utility of CAR engineered T-cells to recognise and destroy cMet-expressing MPM tumour cells. We envisage that regional i.e. intrapleural delivery of human CAR positive T-cells could be used to maximise therapeutic index of this approach.

Citation Format: Thivyan Thayaparan, Sjoukje J.C. van der Stegen, Ana C. Parente Pereira Puri, Roseanna Maria Petrovic, James Spicer, John Maher. Immunotherapy of malignant pleural mesothelioma using cMET specific T-cells. [abstract]. In: Proceedings of the CRI-CIMT-EATI-AACR Inaugural International Cancer Immunotherapy Conference: Translating Science into Survival; September 16-19, 2015; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(1 Suppl):Abstract nr A075.

Abstract 2800: Immunotherapy of malignant pleural mesothelioma using MET specific t – cells

Background: Malignant pleural mesothelioma (MPM) is an incurable cancer predominantly induced by asbestos exposure. This aggressive tumor commonly presents at an advanced stage of disease. Although surgery, combination chemotherapy and radiotherapy may be used in disease management, median survival from diagnosis is less than 12 months. New therapeutic approaches are required to improve outcome in this disease.

Chimeric antigen receptors (CAR) are fusion molecules that couple the HLA-independent binding of a selected cell surface target antigen to the delivery of a tailored T-cell activating signal. Using CAR technology, we aim to develop a novel immunotherapy for MPM that is both safe and effective. These molecules are delivered to patient T-cells using retroviral gene transfer, thereby stably re-directing their specificity for antigen. The receptor tyrosine kinase MET is overexpressed in >80% of MPM patients making it an attractive candidate for CAR directed immunotherapy.

Methods: Three MET-targeted peptide-binding motifs have been incorporated into a second generation CAR framework containing a fused CD28/CD3ζ endodomain. Functional assessment of MET-targeted CARs has been assessed by co-cultivation of genetically enhanced test and control T-cells with MPM cell lines that express MET at various levels.

Results: In preliminary studies we have shown that human T-cells engineered to express MET CARs can destroy mesothelioma tumor cell monolayers, accompanied by T-cell proliferation and cytokine production. Xenograft models are currently under development using bioluminescence to further evaluate functionality and toxicity in vivo.

Conclusions: These findings demonstrate proof of concept for the utility of CAR engineered T-cells to recognise and destroy MET-expressing MPM tumor cells. We envisage that regional i.e. intrapleural delivery of human CAR positive T-cells could be used to maximise therapeutic index of this approach.

Citation Format: Thivyan Thayaparan, Sjoukje v.d Stegen, Ana C. Parente Pereira, Roseanna Petrovic, James Spicer, John Maher. Immunotherapy of malignant pleural mesothelioma using MET specific t – cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2800. doi:10.1158/1538-7445.AM2014-2800

Klebsiella pneumoniae respiratory isolates from 2000 to 2004 in a Malaysian hospital: characteristics and relation to hospital antibiotics consumption

INTRODUCTION

Klebsiella pneumoniae ranks high as a cause of community-acquired pneumonia in hospitalised patients in Malaysia.

METHODS

A retrospective study of 5,990 clinical respiratory specimens in patients, with a mean age of 54 (standard deviation 18.5) years, admitted to an urban-based general hospital between 2000 and 2004, was conducted.

RESULTS

The percentages of K. pneumoniae isolates during these years were 11, 19.1, 41.4, 27.8 and 16.6 percent, respectively. During this time, the percentage of isolates resistant to ampicillin were consistently in excess of 80 percent, those resistant to cephalosporins were relatively stable between eight and 23 percent, while those resistant to beta-lactam/beta-lactamase inhibitors [amoxicillin clavulanic acid/ ampicillin-sulbactam] and aminoglycosides steadily increased between six and 58 percent. Compared with hospital consumption of these corresponding antibiotic classes, only beta-lactam/beta-lactamase inhibitors and aminoglycosides showed a clear trend of eight- and four-fold increases, respectively. Co-resistance rates in isolates resistant to ampicillin and amoxicillin-clavulanic acid/ampicillin-sulbactam were generally low to second to third generation cephalosporins (less than 20 percent).

CONCLUSION

Our local findings highlighted the changing trend in respiratory K. pneumoniae over a five-year period, and its escalating resistance to beta-lactam/beta-lactamase inhibitors and aminoglycosides that is possibly attributable to the widespread use of these antibiotics in our hospital.

Ethnicity as a determinant of asthma-related quality of life in a multiracial country

In a multiracial country like Malaysia, ethnicity may influence the measurement of health-related quality of life (HRQL) in asthmatic patients. We invited 131 adult patients [44 Malays, 42 Chinese and 45 Indians; mean (95% CI) age: 43 (40.2-45.7) yrs; 28.2% male] with moderate-to-severe persistent asthma followed up in an urban-based hospital outpatient clinic to complete a disease-specific HRQL questionnaire [St Georges' Respiratory Questionnaire (SGRQ)] and to provide socio-demographic and asthma-related data. Indians reported significantly worse SGRQ total score, compared to Malays [mean (95% CI) difference: 10.15 (0.51-19.78); p = 0.037] and SGRQ activity score, compared to Malays [13.50 (1.95-25.05); p = 0.019] and Chinese [11.88 (0.19-25.05); p = 0.046]. Further analysis using multivariate linear regression showed that Indian ethnicity remained independently associated with SGRQ scores. Our finding highlights the relevance of ethnicity in assessing HRQL of asthmatic patients in a multiracial country such as Malaysia.

Influence of co-morbidity in the interpretation of tuberculin skin reactivity in multi-ethnic adult patients with tuberculosis

In the Malaysian setting of multi-ethnicity and high BCG coverage, interpretation of Tuberculin Skin Testing (TST) may be difficult. Between January 2001 and December 2003, a retrospective study on all adult patients with documented TST results treated for tuberculosis (TB) in chest clinics of two government hospitals was conducted to determine the reliability of TST and factors affecting its interpretation. One hundred and three patients [mean age (SD): 43 (17); male: 67%] were eligible for data collection: 72% and 57% of patients had positive TST results based on cut-off points of 10mm and 15mm respectively. The only significant univariate association with TST results was the severity of co-morbidity. A patient with co-morbidity score of 3 defined as those with any cancer, end-stage renal or liver disease, or HIV disease, was more likely to have a negative TST results [10mm cut-off point: Odd Ratio (95% CI) 6.6 (1.82 to 24.35), p = 0.003; 15mm cut-off point: 4.8 (1.21 to 18.95), p = 0.012]. A TST reading of 10mm had a higher sensitivity than 15mm as the cut-off point in diagnosing TB infection. Considering all possible confounding factors like ethnicity, prior BCG vaccination and TB burden in the population, severity of co-morbidity remains strongly predictive of a negative TST. Caution should be exercised in interpreting TST in these patients.

A comparison of valsartan and perindopril in the treatment of essential hypertension in the malaysian population

This study was conducted to determine the tolerability and efficacy of valsartan (DIOVAN) compared to perindopril (COVERSYL) in Malaysian patients with mild to moderate hypertension. Two hundred and fifty adult Malaysian patients with a mean sitting diastolic blood pressure of more than 95 mmHg and less than 115 mmHg after a 14 day washout period were randomized to receive either valsartan 80 mg once daily (n=125) or perindopril 4 mg daily (n=125) for eight weeks. The primary end point for efficacy was the change in mean sitting systolic and diastolic blood pressure (SiSBP and SiDBP). The primary criteria for evaluation of tolerability was the incidence of adverse events. There were no significant differences between the two groups with respect to sex, age, weight, baseline sitting and standing systolic and diastolic blood pressure. At 0, 4 and 8 weeks the mean SiDBP in the valsartan group were 101.4, 92.8 and 91.0 mmHg respectively. The corresponding BP for the perindopril treated group was 102.6, 93.8 and 93.2 mmHg. (95% CI -1.39 to +3.27). There were no significant differences in the mean BP measurements between the valsartan and perindopril group at 0, 4 and 8 weeks. In each group there were significant differences between the BP at 4 and 8 weeks compared to baseline. A similar pattern was seen with SiSBP. At 4 weeks 28.7% of the valsartan and 25% of the perindopril group had their BP normalized (SiDBP <90 mmHg) The percentages of patients who responded (SiDBP reduction >10 mmHg but SiDBP >90 mmHg) were 21.3 in the valsartan group and 20.8 in the perindopril group. At 8 weeks, 31.1% of the valsartan group and 30.8% of the perindopril group had their BP normalized. The response rate was 27% and 22.5% for valsartan and perindopril respectively. The major adverse event was cough which occurred in 18 patients (14.4%) in the perindopril and 1 (0.8%) in the valsartan group at 4 weeks. At 8 weeks the figures were 24 (19.2%) and 2 (1.6%) respectively. The results indicate that Valsartan is safe and efficacious in the treatment of mild to moderate hypertension. It is equally efficacious to Perindopril and not associated with any major adverse event. It has a better tolerability profile with respect to dry cough.

Metered-dose inhaler technique in asthmatic patients--a revisit of the Malaysian scene

Inefficient metered-dose inhaler (MDI) technique results in poor drug delivery, suboptimal disease control a possibility of inhaled medication overuse. The MDI technique of 134 government hospital and clinic followed-up adult asthmatic patients followed-up in a government hospital and a heath clinic was pragmatically assessed based on the 3 obligatory steps of adequate lip seal, appropriate hand-breath coordination and sufficient breath holding after inhalation. The relationship between technique efficiency and frequency of daily short-acting beta2-agonist (SABA) use via the MDI and asthma exacerbations over a 12-month period was also assessed. Fifty-six patients (42%) had inefficient MDI technique. All demographic and asthma-related variables between the 'efficient' and 'inefficient' technique groups of patients were comparable except for significantly longer mean years of MDI use in the 'efficient' technique group [mean (SD): 10 (7) vs. 7 (5); p=0.003]. There were no significant differences between the two groups in relation to frequency of daily SABA use or asthma exacerbations over the past 12 months. Despite having been available in Malaysia for a considerable period of time, the MDI device is still poorly handled by a large proportion of adult asthmatic patients. Changing to other more user-friendly devices or use of spacer devices to facilitate delivery should be considered for these patients.

A comparison of sputum induction methods: ultrasonic vs compressed-air nebulizer and hypertonic vs isotonic saline inhalation

Airway inflammation can be demonstrated by the modem method of sputum induction using ultrasonic nebulizer and hypertonic saline. We studied whether compressed-air nebulizer and isotonic saline which are commonly available and cost less, are as effective in inducing sputum in normal adult subjects as the above mentioned tools. Sixteen subjects underwent weekly sputum induction in the following manner: ultrasonic nebulizer (Medix Sonix 2000, Clement Clarke, UK) using hypertonic saline, ultrasonic nebulizer using isotonic saline, compressed-air nebulizer (BestNeb, Taiwan) using hypertonic saline, and compressed-air nebulizer using isotonic saline. Overall, the use of an ultrasonic nebulizer and hypertonic saline yielded significantly higher total sputum cell counts and a higher percentage of cell viability than compressed-air nebulizers and isotonic saline. With the latter, there was a trend towards squamous cell contaminations. The proportion of various sputum cell types was not significantly different between the groups, and the reproducibility in sputum macrophages and neutrophils was high (Intraclass correlation coefficient, r [95%CI]: 0.65 [0.30-0.91] and 0.58 [0.22-0.89], p < 0.001). Overall changes in median FEV, were small and comparable between all groups. Induction using ultrasonic nebulizers together with hypertonic saline was generally less well tolerated than compressed-air nebulizers and isotonic saline. We conclude that in normal subjects, although both nebulizers and saline types can induce sputum with reproducible cellular profile, ultrasonic nebulizers and hypertonic saline are more effective but less well tolerated.

Disease impact and patient insight--a study on a local population of asthmatics

The cornerstone of asthma management is achieving adequate symptom control and patient education. We studied in our local population of asthmatic patients how well their symptoms were controlled with currently prescribed treatment and their insight into the disease and its management. Over a 6-month period, 93 asthmatics recruited from two local government health clinics and a state hospital were interviewed using a standard questionnaire. Patients were classified into 4 groups based on the treatment they were on according to Global Initiative for Asthma (GINA) treatment guidelines. The number of patients in Step 1 (rescue medication alone), Step 2 (1 controller medication), Step 3 (2 controller medications) and Step 4 (at least 3 controller medications) were 8, 39, 34 and 12, respectively. Except for day symptoms in Step 1 group, fewer than 50% achieved minimum day or night symptoms and no restriction of daily activities. Questions on patient insight were only available for 50 patients. Weather change (74%), air pollution (66%) and physical stress (46%) were the three highest ranked common asthma triggers. More than half correctly recognized the important symptoms of a serious asthma attack but fewer than 15% were familiar with the peak flow meter and its use or with the asthma self-management plan. Most patients perceived that their treatment had helped reduce disease severity and exacerbations. We conclude that symptom control and some aspect of patient education are still lacking in our local asthmatics.

A study of admission criteria and early management of adult patients with acute asthma

We studied the admission criteria and first 24-hour management of 62 asthmatic patients admitted from Accident and Emergency (A&E) department of a state hospital. Data was collected prospectively over a 6-month period from the doctors' medical records with reference to recommendations of the Malaysian Thoracic Society (MTS) on management of acute asthma. Peak Expiratory Flow Rate (PEFR) records were present in only 14.5% of the A&E notes and 54.8% of the ward notes. Most of these readings were below 75% of predicted normal values. Over half of the patients had records on ability to speak full sentences, and respiratory and pulse rates. Based on other records on criteria for life-threatening features (including arterial blood gases), 42% of patients studied had life threatening asthma exacerbations. Most received appropriate treatment as recommended by the MTS. We conclude that while most patients were admitted and treated appropriately, medical documentation regarding acute asthma assessment were inadequate in some.

Treatment of acute Nipah encephalitis with ribavirin

Nipah virus, a newly identified paramyxovirus caused a severe outbreak of encephalitis in Malaysia with high fatalities. We report an open-label trial of ribavirin in 140 patients, with 54 patients who were managed prior to the availability of ribavirin or refused treatment as control. There were 45 deaths (32%) in the ribavirin arm; 29 deaths (54%) occurred in the control arm. This represents a 36% reduction in mortality (p = 0.011). There was no associated serious side effect. This study suggests that ribavirin is able to reduce the mortality of acute Nipah encephalitis.