Michael S. Rabin

Exon 19 Deletion Mutations of Epidermal Growth Factor Receptor Are Associated with Prolonged Survival in Non–Small Cell Lung Cancer Patients Treated with Gefitinib or Erlotinib

Purpose: Somatic mutations in the epidermal growth factor receptor (EGFR) have been detected in patients with non–small cell lung cancer (NSCLC) and are associated with sensitivity to treatment with gefitinib or erlotinib. Our study explored the relationship between the two most common types of somatic EGFR mutations, exon 19 deletions and the L858R point mutation, and outcomes of patients following treatment with gefitinib or erlotinib. Experimental Design: Tumor specimens obtained before treatment with gefitinib or erlotinib were analyzed for EGFR mutations. Patients with exon 19 deletion or L858R mutations were identified. The response rate, time to progression, and overall survival were determined for the two groups. Results: We identified 36 patients with NSCLC and an EGFR mutation who were treated with gefitinib or erlotinib. Patients with an exon 19 deletion had a significantly longer overall survival compared with patients with an L858R mutation (38 versus 17 months; P = 0.04). There were also trends toward higher response rate (73% versus 50%) and improved time to progression (24 versus 10 months) for the patients with an exon 19 deletion, although these were not independently significant in a multivariate analysis. A difference in response rate for patients treated with gefitinib compared with erlotinib was also noted [18 of 23 (78%) versus 3 of 9 (33%); P = 0.04]. No obvious difference in time to progression or overall survival was noted between gefitinib- and erlotinib-treated patients. Conclusions: Patients with NSCLC and EGFR exon 19 deletions have a longer survival following treatment with gefitinib or erlotinib compared with those with the L858R mutation. Pooling of greater numbers of patients and completion of prospective trials are needed to further define the predictive and prognostic roles of different EGFR mutations with respect to treatment with gefitinib, erlotinib, and other EGFR inhibitors.

Phase II Clinical Trial of Chemotherapy-Naïve Patients ≥ 70 Years of Age Treated With Erlotinib for Advanced Non–Small-Cell Lung Cancer

PURPOSE This is a phase II, multicenter, open-label study of chemotherapy-naïve patients with non-small-cell lung cancer (NSCLC) and age > or = 70 years who were treated with erlotinib and evaluated to determine the median, 1-year, and 2-year survival. The secondary end points include radiographic response rate, time to progression (TTP), toxicity, and symptom improvement. PATIENTS AND METHODS Eligible patients with NSCLC were treated with erlotinib 150 mg/d until disease progression or significant toxicity. Tumor response was assessed every 8 weeks by computed tomography scan using Response Evaluation Criteria in Solid Tumors. Tumor samples were analyzed for the presence of somatic mutations in EGFR and KRAS. RESULTS Eighty eligible patients initiated erlotinib therapy between March 2003 and May 2005. There were eight partial responses (10%), and an additional 33 patients (41%) had stable disease for 2 months or longer. The median TTP was 3.5 months (95% CI, 2.0 to 5.5 months). The median survival time was 10.9 months (95% CI, 7.8 to 14.6 months). The 1- and 2- year survival rates were 46% and 19%, respectively. The most common toxicities were acneiform rash (79%) and diarrhea (69%). Four patients developed interstitial lung disease of grade 3 or higher, with one treatment-related death. EGFR mutations were detected in nine of 43 patients studied. The presence of an EGFR mutation was strongly correlated with disease control, prolonged TTP, and survival. CONCLUSION Erlotinib monotherapy is active and relatively well tolerated in chemotherapy-naïve elderly patients with advanced NSCLC. Erlotinib merits consideration for further investigation as a first-line therapeutic option in elderly patients.

Genomic Characterization of Brain Metastases Reveals Branched Evolution and Potential Therapeutic Targets

UNLABELLED Brain metastases are associated with a dismal prognosis. Whether brain metastases harbor distinct genetic alterations beyond those observed in primary tumors is unknown. We performed whole-exome sequencing of 86 matched brain metastases, primary tumors, and normal tissue. In all clonally related cancer samples, we observed branched evolution, where all metastatic and primary sites shared a common ancestor yet continued to evolve independently. In 53% of cases, we found potentially clinically informative alterations in the brain metastases not detected in the matched primary-tumor sample. In contrast, spatially and temporally separated brain metastasis sites were genetically homogenous. Distal extracranial and regional lymph node metastases were highly divergent from brain metastases. We detected alterations associated with sensitivity to PI3K/AKT/mTOR, CDK, and HER2/EGFR inhibitors in the brain metastases. Genomic analysis of brain metastases provides an opportunity to identify potentially clinically informative alterations not detected in clinically sampled primary tumors, regional lymph nodes, or extracranial metastases. SIGNIFICANCE Decisions for individualized therapies in patients with brain metastasis are often made from primary-tumor biopsies. We demonstrate that clinically actionable alterations present in brain metastases are frequently not detected in primary biopsies, suggesting that sequencing of primary biopsies alone may miss a substantial number of opportunities for targeted therapy.

Development of Central Nervous System Metastases in Patients with Advanced Non-Small Cell Lung Cancer and Somatic EGFR Mutations Treated with Gefitinib or Erlotinib

Purpose: Gefitinib and erlotinib can penetrate into the central nervous system (CNS) and elicit responses in patients with brain metastases (BM) from non–small cell lung cancer (NSCLC). However, there are incomplete data about their impact on the development and control of CNS metastases. Experimental Design: Patients with stage IIIB/IV NSCLC with somatic EGFR mutations initially treated with gefitinib or erlotinib were identified. The cumulative risk of CNS progression was calculated using death as a competing risk. Results: Of the 100 patients, 19 had BM at the time of diagnosis of advanced NSCLC; 17 of them received CNS therapy before initiating gefitinib or erlotinib. Eighty-four patients progressed after a median potential follow-up of 42.2 months. The median time to progression was 13.1 months. Twenty-eight patients developed CNS progression, 8 of whom had previously treated BM. The 1- and 2-year actuarial risk of CNS progression was 7% and 19%, respectively. Patient age and EGFR mutation genotype were significant predictors of the development of CNS progression. The median overall survival for the entire cohort was 33.1 months. Conclusions: Our data suggest a lower risk of CNS progression in patients with advanced NSCLC and somatic EGFR mutations initially treated with gefitinib or erlotinib than published rates of 40% in historical series of advanced NSCLC patients. Further research is needed to distinguish between the underlying rates of developing CNS metastases between NSCLC with and without EGFR mutations and the impact of gefitinib and erlotinib versus chemotherapy on CNS failure patterns in these patients. Clin Cancer Res; 16(23); 5873–82. ©2010 AACR.

The Impact of Initial Gefitinib or Erlotinib versus Chemotherapy on Central Nervous System Progression in Advanced Non–Small Cell Lung Cancer with EGFR Mutations

Purpose: This retrospective study was undertaken to investigate the impact of initial gefitinib or erlotinib (EGFR tyrosine kinase inhibitor, EGFR-TKI) versus chemotherapy on the risk of central nervous system (CNS) progression in advanced non–small cell lung cancer (NSCLC) with EGFR mutations. Experimental Design: Patients with stage IV or relapsed NSCLC with a sensitizing EGFR mutation initially treated with gefitinib, erlotinib, or chemotherapy were identified. The cumulative risk of CNS progression was calculated using death as a competing risk. Results: One hundred and fifty-five patients were eligible (EGFR-TKI: 101, chemotherapy: 54). Twenty-four patients (24%) in the EGFR-TKI group and 12 patients (22%) in the chemotherapy group had brain metastases at the time of diagnosis of advanced NSCLC (P = 1.000); 32 of the 36 received CNS therapy before initiating systemic treatment. Thirty-three patients (33%) in the EGFR-TKI group and 26 patients (48%) in the chemotherapy group developed CNS progression after a median follow-up of 25 months. The 6-, 12-, and 24-month cumulative risk of CNS progression was 1%, 6%, and 21% in the EGFR-TKI group compared with corresponding rates of 7%, 19%, and 32% in the chemotherapy group (P = 0.026). The HR of CNS progression for upfront EGFR-TKI versus chemotherapy was 0.56 [95% confidence interval (CI), 0.34–0.94]. Conclusions: Our data show lower rates of CNS progression in EGFR-mutant advanced NSCLC patients initially treated with an EGFR-TKI compared with upfront chemotherapy. If validated, our results suggest that gefitinib and erlotinib may have a role in the chemoprevention of CNS metastases from NSCLC. Clin Cancer Res; 18(16); 4406–14. ©2012 AACR.

Quality of care for older patients with cancer in the Veterans Health Administration versus the private sector: a cohort study.

BACKGROUND The Veterans Health Administration (VHA) is the largest integrated health care system in the United States. Studies suggest that the VHA provides better preventive care and care for some chronic illnesses than does the private sector. OBJECTIVE To assess the quality of cancer care for older patients provided by the VHA versus fee-for-service Medicare. DESIGN Observational study of patients with cancer that was diagnosed between 2001 and 2004 who were followed through 2005. SETTING VHA and non-VHA hospitals and office-based practices. PATIENTS Men older than 65 years with incident colorectal, lung, or prostate cancer; lymphoma; or multiple myeloma. MEASUREMENTS Rates of processes of care for colorectal, lung, or prostate cancer; lymphoma; or multiple myeloma. Rates were adjusted by using propensity score weighting. RESULTS Compared with the fee-for-service Medicare population, the VHA population received diagnoses of colon (P < 0.001) and rectal (P = 0.007) cancer at earlier stages and had higher adjusted rates of curative surgery for colon cancer (92.7% vs. 90.5%; P < 0.010), standard chemotherapy for diffuse large B-cell non-Hodgkin lymphoma (71.1% vs. 59.3%; P < 0.001), and bisphosphonate therapy for multiple myeloma (62.1% vs. 50.4%; P < 0.001). The VHA population had lower adjusted rates of 3-dimensional conformal or intensity-modulated radiation therapy for prostate cancer treated with external-beam radiation therapy (61.6% vs. 86.0%; P < 0.001). Adjusted rates were similar for 9 other measures. Sensitivity analyses suggest that if patients with cancer in the VHA system have more severe comorbid illness than other patients, rates for most indicators would be higher in the VHA population than in the fee-for-service Medicare population. LIMITATION This study included only older men and did not include information about performance status, severity of comorbid illness, or patient preferences. CONCLUSION Care for older men with cancer in the VHA system was generally similar to or better than care for fee-for-service Medicare beneficiaries, although adoption of some expensive new technologies may be delayed in the VHA system. PRIMARY FUNDING SOURCE Department of Veterans Affairs.

Protection from pathogenic SIV challenge using multigenic DNA vaccines

To assess DNA immunization as a strategy for protecting against HIV infection in humans, we utilized SIVmne infection of Macaca fascicularis as a vaccine challenge model with moderate pathogenic potential. We compared the efficacy of DNA immunization alone and in combination with subunit protein boosts. All of the structural and regulatory genes of SIVmne clone 8 were cloned into mammalian expression vectors under the control of the CMV IE-1 promoter. Eight M. fascicularis were immunized twice with 3 mg of plasmid DNA divided between two sites; intramuscular and intradermal. Four primed macaques received a further two DNA immunizations at weeks 16-36, while the second group of four were boosted with 250 microg recombinant gp160 plus 250 microg recombinant Gag-Pol particles formulated in MF-59 adjuvant. Half of the controls received four immunizations of vector DNA; half received two vector DNA and two adjuvant immunizations. As expected, humoral immune responses were stronger in the macaques receiving subunit boosts, but responses were sustained in both groups. Significant neutralizing antibody titers to SIVmne were detected in one of the subunit-boosted animals and in none of the DNA-only animals prior to challenge. T-cell proliferative responses to gp160 and to Gag were detected in all immunized animals after three immunizations, and these responses increased after four immunizations. Cytokine profiles in PHA-stimulated PBMC taken on the day of challenge showed trends toward Thl responses in 2/4 macaques in the DNA vaccinated group and in 1/4 of the DNA plus subunit vaccinated macaques; Th2 responses in 3/4 DNA plus subunit-immunized macaques; and Th0 responses in 4/4 controls. In bulk CTL culture, SIV specific lysis was low or undetectable, even after four immunizations. However, stable SIV Gag-Pol- and env-specific T-cell clones (CD3+ CD8+) were isolated after only two DNA immunizations, and Gag-Pol- and Nef-specific CTL lines were isolated on the day of challenge. All animals were challenged at week 38 with SIVmne uncloned stock by the intrarectal route. Based on antibody anamnestic responses (western, ELISA, and neutralizing antibodies) and virus detection methods (co-culture of PBMC and LNMC, nested set PCR- of DNA from PBMC and LNMC, and plasma QC-PCR), there were major differences between the groups in the challenge outcome. Surprisingly, sustained low virus loads were observed only in the DNA group, suggesting that four immunizations with DNA only elicited more effective immune responses than two DNA primes combined with two protein boosts. Multigenic DNA vaccines such as these, bearing all structural and regulatory genes, show significant promise and may be a safe alternative to live-attenuated vaccines.

Survival of Older Patients With Cancer in the Veterans Health Administration Versus Fee-for-Service Medicare

PURPOSE The Veterans Health Administration (VHA) provides high-quality preventive chronic care and cancer care, but few studies have documented improved patient outcomes that result from this high-quality care. We compared the survival rates of older patients with cancer in the VHA and fee-for-service (FFS) Medicare and examined whether differences in the stage at diagnosis, receipt of guideline-recommended therapies, and unmeasured characteristics explain survival differences. PATIENTS AND METHODS We used propensity-score methods to compare all-cause and cancer-specific survival rates for men older than age 65 years who were diagnosed or received their first course of treatment for colorectal, lung, lymphoma, or multiple myeloma in VHA hospitals from 2001 to 2004 to similar FFS-Medicare enrollees diagnosed in Surveillance, Epidemiology, and End Results (SEER) areas in the same time frame. We examined the role of unmeasured factors by using sensitivity analyses. RESULTS VHA patients versus similar FFS SEER-Medicare patients had higher survival rates of colon cancer (adjusted hazard ratio [HR], 0.87; 95% CI, 0.82 to 0.93) and non-small-cell lung cancer (NSCLC; HR, 0.91; 95% CI, 0.88 to 0.95) and similar survival rates of rectal cancer (HR, 1.05; 95% CI, 0.95 to 1.16), small-cell lung cancer (HR, 0.99; 95% CI, 0.93 to 1.05), diffuse large-B-cell lymphoma (HR, 1.02; 95% CI, 0.89 to 1.18), and multiple myeloma (HR, 0.92; 95% CI, 0.83 to 1.03). The diagnosis of VHA patients at earlier stages explained much of the survival advantages for colon cancer and NSCLC. Sensitivity analyses suggested that additional adjustment for the severity of comorbid disease or performance status could have substantial effects on estimated differences. CONCLUSION The survival rate for older men with cancer in the VHA was better than or equivalent to the survival rate for similar FFS-Medicare beneficiaries. The VHA provision of high-quality care, particularly preventive care, can result in improved patient outcomes.

Radiographic assessment and therapeutic decisions at RECIST progression in EGFR-mutant NSCLC treated with EGFR tyrosine kinase inhibitors

PURPOSE Advanced NSCLC harboring epidermal growth factor receptor (EGFR) mutations treated with EGFR tyrosine kinase inhibitors (TKIs) typically progresses after initial response due to acquired resistance. TKIs are often continued beyond progressive disease by RECIST. We investigated the practice of continuing EGFR-TKIs after RECIST-PD via CT findings. METHODS Among 101 advanced NSCLC patients with sensitizing EGFR mutations treated with first-line EGFR-TKIs, 70 patients had baseline and at least one follow-up CT for retrospective radiographic assessments using RECIST1.1; 56 patients had experienced PD by the data closure date of June 2011. RESULTS Among 56 patients experiencing PD, 82% were female, median age was 63 years, 50% were never-smokers, 57% had distant metastasis, 57% had exon 19 deletion, and 89% were treated with erlotinib. 49 patients (88%) continued TKI therapy beyond retrospectively assessed PD. 31/32 (97%) patients who progressed by an increase in their target lesions continued TKI. 13/16 (81%) patients who progressed by appearance of a new lesion remained on TKI. 5/6 (83%) patients with both increase of target lesions and new lesion at PD continued TKI. Two patients with PD in non-target lesions discontinued therapy at PD. In 49 continuing patients, the median time from retrospectively assessed RECIST-PD to termination of TKI was 10.1 months. CONCLUSIONS 88% of EFGR-mutant NSCLC patients who progressed on first-line TKI continued therapy beyond RECIST-PD, which is not the single determining factor for terminating TKI in EGFR-mutant NSCLC patients. Additional radiographically defined progression criteria are needed for this population.

Percutaneous CT–guided Radiofrequency Ablation of Symptomatic Bilateral Adrenal Metastases in a Single Session

Percutaneous computed tomography (CT)-guided radiofrequency (RF) ablation has been used in the palliative treatment of symptomatic bilateral adrenal tumors, often with each tumor addressed separately over the course of multiple treatment sessions. In the present case, a 71-year-old man with a diagnosis of lung cancer and painful bilateral metastases to the adrenal glands underwent percutaneous CT-guided RF thermal ablation of both adrenal masses in a single session (left adrenal mass, 4.7 cm; right adrenal mass, 4.3 cm), without occurrence of blood pressure instability or other acute complications. Measurement of plasma levels of cortisol, adrenocorticotropic hormone (ACTH), and glucose before and after RF ablation revealed transient changes that suggested preservation of endocrine feedback mechanisms. The patient experienced marked relief in pain bilaterally. By 5 days after the procedure, cortisol, ACTH, and glucose levels returned to preprocedural levels. On further follow-up at 6 months, the patient noted a lack of endocrine sequelae and continued pain relief.