Liquid Biopsy Can Rapidly Detect EGFR Mutations and KRAS mutations with High Specificity

SUMMARY: It has been well established that treatment with EGFR TKIs results in superior outcomes, for patients with tumors harboring exon 19 deletions and exon 21 mutations. The application of precision medicine with targeted therapy, requires detection of molecular abnormalities in a tumor specimen, following progression or recurrence. Archived biopsy specimens may not be helpful as it is important to identify additional mutations in the tumor at the time of recurrence or progression, in order to plan appropriate therapy. Further, recurrent tumors may be inaccessible for a safe biopsy procedure or the clinical condition of the patient may not permit a repeat biopsy. Additionally, the biopsy itself may be subject to sampling error due to tumor heterogeneity. Genotyping cell free DNA in the plasma can potentially overcome the shortcomings of repeat biopsies and tissue genotyping, allowing the detection of many more targetable gene mutations, thus resulting in better evaluation of the tumor genome landscape.

The purpose of this study was to prospectively validate plasma droplet digital PCR (ddPCR) for the rapid detection of common Epidermal Growth Factor Receptor (EGFR) and KRAS mutations, as well as the EGFR T790M acquired resistance mutation. The authors prospectively evaluated the feasibility and accuracy of this assay in patients with newly diagnosed advanced non-squamous Non Small Cell Lung Cancer (NSCLC) who either were newly diagnosed and initial therapy was planned (N=120) or had developed acquired resistance to an EGFR kinase inhibitor and rebiopsy was planned (N=60). The median age was 62 years and 62% were females.

Following initial blood sampling of all patients, plasma droplet digital Polymerase Chain Reaction (ddPCR) for EGFR and KRAS mutations, including EGFR exon 19 deletion, EGFR L858R, KRAS G12X and EGFR T790M acquired resistance mutation, was performed. All patients underwent biopsy for tissue genotyping, and this was used as a reference standard for comparison with the liquid biopsy results. Important study outcomes included sensitivity and specificity of plasma ddPCR assay, as well as test turnaround time, which was defined as the number of business days between blood sampling and test reporting.

Tumor genotypes identified included 80 EGFR exon 19 or L858R mutations, 35 EGFR T790M mutations, and 25 KRAS G12X mutations. The ddPCR assay median turnaround time was 3 days compared with 12 days for tissue genotyping and 27 days for patients with acquired resistance. Plasma ddPCR exhibited a positive predictive value of 100% for EGFR 19 del, 100% for EGFR L858R mutation and 100% for KRAS. The positive predictive value for EGFR T790M was lower at 79%. The sensitivity of plasma ddPCR assay was 82% for EGFR exon19 del, 74% for EGFR L858R mutation, and 77% for EGFR T790M acquired resistance mutation, but lower for KRAS at 64%. Sensitivity for EGFR or KRAS was higher in patients with multiple metastatic sites (P=0.001), specifically in those with bone and hepatic metastases.

The authors concluded that in this first prospective study, plasma ddPCR assay can rapidly detect EGFR and KRAS mutations with high specificity, allowing treatment selection, without repeat biopsies. Additionally, this assay may also detect EGFR T790M mutation, missed by tissue genotyping, due to tumor heterogeneity in resistant disease. Prospective Validation of Rapid Plasma Genotyping for the Detection of EGFR and KRAS Mutations in Advanced Lung Cancer. Sacher AG, Paweletz C, Dahlberg SE, et al. JAMA Oncol. Published online April 07, 2016. doi:10.1001/jamaoncol.2016.0173

Impact of Treatment Delay on Clinical Outcomes in Breast Cancer Patients

SUMMARY: Breast cancer is the most common cancer among women in the US and about 1 in 8 women (12%) will develop invasive breast cancer during their lifetime. Approximately, 246,660 new cases of invasive breast cancer will be diagnosed in 2016 and 40,450 women will die of the disease. Patients with early stage breast cancer often receive adjuvant chemotherapy and this is even more so true for HER positive and triple negative (ER, PR and HER negative) breast cancer patients, who are at an increased risk to develop recurrent disease. Even though majority of the patients start their adjuvant chemotherapy within 4-6 weeks following surgery, the impact of delay in the initiation of adjuvant therapy on outcomes, has remained unclear. Preclinical models have suggested that there is phase of increased angiogenesis and accelerated growth of micrometastases, as well as development of drug resistant clones, following removal of the primary tumor. Previously published data from a large meta-analysis had suggested that a four week delay in the initiation of adjuvant chemotherapy resulted in a 6% increase in the risk of death and an 8% increase in the risk of relapse. Nonetheless, over the past 2 decades, there has been increasing delay for both surgery and adjuvant chemotherapy treatment intervention, following diagnosis of breast cancer. These delays have been attributed to the increasing use of prognostic tools prior to treatment intervention, in order to optimize breast cancer care, germ-line genetic testing to plan appropriate surgical intervention, as well as patients seeking immediate reconstructive surgical options. Two studies addressed the impact of delay in treatment intervention following diagnosis of breast cancer, by investigating outcomes, in a very large group of patients with breast cancer.

In the study by Bleicher, et al., the relationship between the time from diagnosis to breast cancer surgery and survival was investigated, by collecting data from the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database and the National Cancer Database (NCDB). The SEER-Medicare cohort had 94,544 patients 66 years or older, diagnosed between 1992 and 2009 and the NCDB cohort included 115,790 patients 18 years or older, diagnosed between 2003 and 2005. Patients included in this analysis underwent surgery as initial treatment and had a diagnosis of non-inflammatory, non-metastatic, invasive breast cancer. The primary outcome was Overall and Disease-Specific Survival, as a function of time between diagnosis and surgery, measured in 30 day increments. They noted that with each interval of treatment delay increase, Overall Survival was lower (HR=1.09; P<0.001 in the SEER-Medicare cohort and HR=1.10; P<0.001 in the NCDB cohort). This relationship was statistically significant only in stages I and II breast cancer. The authors in this study concluded that longer time to surgery is associated with lower Overall and Disease-Specific Survival.

Chavez-MacGregor et al. analyzed the outcomes of 24, 843 patients in the California Cancer Registry with stage I-III invasive breast cancer, diagnosed between January 2005 and December 2010, and treated with adjuvant chemotherapy. Time to chemotherapy was defined as the number of days between surgery and the first dose of chemotherapy, and delayed treatment was defined as 91 or more days from surgery to the first dose of adjuvant chemotherapy. Median age at the time of diagnosis was 53 years, and median time to adjuvant chemotherapy was 46 days. Patients were evaluated for Overall Survival and Breast Cancer-Specific Survival. They noted that patients receiving adjuvant chemotherapy 91 or more days following surgery experienced worse Overall Survival (HR=1.34) and worse Breast Cancer-Specific Survival (HR=1.27) compared with patients receiving adjuvant chemotherapy within 31 days from surgery and these adverse outcomes were even more so, among patients with triple negative breast cancer (HR=1.53). Factors associated with adjuvant therapy delays included, low socioeconomic status, breast reconstruction, non-private insurance, and Hispanic or African American ethnicity. The authors in this study concluded that delaying initiation of adjuvant chemotherapy 91 days or more, results in adverse outcomes and this may be even more detrimental, in patients with triple negative breast cancer.

These two studies strongly suggest that treatment delays should be avoided in patients with early stage breast cancer and if surgery is to be delayed, neoadjuvant treatment approach may be reasonable, to avoid adverse outcomes.

Time to Surgery and Breast Cancer Survival in the United States. Bleicher RJ, Ruth K, Sigurdson ER, et al. JAMA Oncol. 2016;2:330-339.

Delayed Initiation of Adjuvant Chemotherapy Among Patients With Breast Cancer. Chavez-MacGregor M, Clarke CA, Lichtensztajn DY, et al. JAMA Oncol. 2016;2:322-329.

Clinical Guidelines for the Evaluation of Hematuria as a Marker of Occult Urinary Tract Cancer

SUMMARY: Hematuria is a common finding in clinical practice and millions of patients have routine urine evaluation. However, the magnitude of the risk for an underlying malignancy can vary significantly. Screening healthy, asymptomatic patients with urinalysis for malignancy is not currently recommended by any major health organization. This article describes the indications for the evaluation of hematuria, as a marker of occult urinary tract cancer, and is meant to help Health Care Providers make appropriate referral of patients, for urologic evaluation. The information in this article was gathered following a review of published clinical guidelines that addressed the evaluation of hematuria as a marker of occult urinary tract cancer, as well as other relevant studies, from the peer-reviewed literature. The American College of Physicians' High Value Care Task Force put this information together, with the intent to increase awareness and provide practical advice, based on the best available evidence.

High-Value Care Advice 1: Clinicians should include gross hematuria in their routine review of systems and specifically ask all patients with microscopic hematuria about any history of gross hematuria.

High-Value Care Advice 2: Clinicians should not use screening urinalysis for cancer detection in asymptomatic adults.

High-Value Care Advice 3: Clinicians should confirm heme-positive results of dipstick testing with microscopic urinalysis that demonstrates 3 or more erythrocytes per high-powered field before initiating further evaluation in all asymptomatic adults.

High-Value Care Advice 4: Clinicians should refer all adults with gross hematuria, even if self-limited, for further urologic evaluation.

High-Value Care Advice 5: Clinicians should consider urology referral for cystoscopy and imaging in adults with microscopically confirmed hematuria, in the absence of some demonstrable benign cause.

High-Value Care Advice 6: Clinicians should pursue evaluation of hematuria even if the patient is receiving antiplatelet or anticoagulant therapy.

High-Value Care Advice 7: Clinicians should not obtain urinary cytology or other urine-based molecular markers for bladder cancer detection in the initial evaluation of hematuria.

Hematuria as a Marker of Occult Urinary Tract Cancer: Advice for High-Value Care from the American College of Physicians. Nielsen M, Qaseem A, for the High Value Care Task Force of the American College of Physicians. Ann Intern Med. 2016;164:488-497.

FDA Approves VENCLEXTA®, a BCL2 Inhibitor for the Treatment of Chronic Lymphocytic Leukemia

SUMMARY: The FDA on April 11, 2016, granted an accelerated approval to Venetoclax (VENCLEXTA®) for the treatment of patients with Chronic Lymphocytic Leukemia (CLL) with 17p deletion, as detected by an FDA-approved test, who have received at least one prior therapy. The FDA also approved Vysis CLL FISH probe kit, as a companion diagnostic to VENCLEXTA®, for detection of the del(17p). There are two main types of lymphocytes, B and T lymphocytes. B-cell CLL is the most common type of leukemia in adults. Normal B-cell activation and proliferation is dependent on B-cell receptor (BCR) signaling. This signaling is also important for initiation and progression of B-cell lymphoproliferative disorders. Bruton's Tyrosine Kinase (BTK) is a member of the Tec family of kinases, downstream of the B-cell receptor and is predominantly expressed in B-cells. It is a mediator of B-cell receptor signaling in normal and transformed B-cells. Following binding of antigen to the B-Cell Receptor, kinases such as Syk (Spleen Tyrosine Kinase), Lyn (member of the Src family of protein tyrosine kinases) and BTK (Bruton's Tyrosine Kinase) are activated, with subsequent propagation through PI3K/Akt, MAPK, and NF-κB pathways. This results in B-cell activation and proliferation. PI3K (PhosphoInositide 3-Kinase) delta signaling, is hyperactive in B-cell malignancies and is important for the activation, proliferation, homing of malignant B cells in the lymphoid tissues and their survival. The delta isoform of PI3K enzyme is predominantly expressed in leukocytes. Targeting proteins in key pathways of B-cell biology has fundamentally changed the management and outcomes of CLL, over the past 5 years. IMBRUVICA® (Ibrutinib) is an oral, irreversible inhibitor of BTK and inhibits cell proliferation and promotes programmed cell death (Apoptosis) by blocking B-cell activation and signaling. ZYDELIG® (Idelalisib) is a highly selective oral inhibitor of the enzyme PI3K and specifically blocks the delta isoform of PI3K enzyme and its signaling pathway. The pro-survival (anti-apoptotic) protein BCL2, is over expressed by CLL cells and regulates clonal selection and cell survival. A new class of anticancer agents known as BH3-mimetic drugs are in development that mimic the activity of the physiologic antagonists of BCL2 and related proteins and promote apoptosis (programmed cell death).

VENCLEXTA® is a second generation, oral, selective, small molecule inhibitor of BCL2 and restores the apoptotic processes in tumor cells. VENCLEXTA® causes markedly less thrombocytopenia but more neutropenia compared to its first generation predecessor, Navitoclax. In the phase I study by Roberts, et al. (N Engl J Med 2016;374:311-322), high response rates of 71 to 79% were observed in CLL patients with poor prognostic features, when treated with VENCLEXTA®, with a 15-month Progression Free Survival (PFS) of 69%.

Based on this phase I data, a pivotal phase II, single-arm, multicenter study was conducted, to evaluate the efficacy of VENCLEXTA® monotherapy in patients with Relapsed/Refractory del(17p) CLL. This study included 106 patients with a median age of 67 years and patients had received a median of 2 prior chemotherapy regimens. More than a third of the patients were refractory to prior therapy with Fludarabine and Bendamustine. Treatment consisted of VENCLEXTA® tablets given once daily with a weekly dose ramp-up schedule (20 mg for 1 week, followed by 1 week at each dose level of 50 mg, 100 mg, and 200 mg and then the recommended daily dose of 400 mg), over a period of 5 weeks, given along with Tumor Lysis Syndrome (TLS) prophylaxis. Patients were treated with the daily 400 mg dosing until disease progression or unacceptable toxicity. The primary endpoint was Overall Response Rate (ORR). Secondary endpoints included Complete Response (CR), Partial Response (PR) rates, Time to first response, Duration of Response (DoR), Progression Free Survival (PFS), Overall Survival (OS), the proportion of patients proceeding to allogeneic Stem Cell Transplant (allo-SCT) and Safety.

The ORR was 79.4% with 8% Complete Response (including 2% Complete Response with incomplete marrow recovery-CRi). Minimal Residual Disease (MRD) was evaluated in peripheral blood and bone marrow for patients who achieved CR or CRi, following treatment with VENCLEXTA®. Forty five (N=45) patients were evaluated for MRD and 18 attained MRD-negative status in their peripheral blood. The median time to first response was 0.8 months (range: 0.1 to 8.1 months) and median time to CR/CRi was 8.2 months. With a median follow up of 12 months, the median Duration of Response (DoR) has not been reached (2.9-19.0 months).

The most common adverse reactions of any grade were neutropenia, diarrhea, nausea, anemia, upper respiratory tract infection, thrombocytopenia, and fatigue. Patients should be closely monitored and should receive prophylaxis for Tumor Lysis Syndrome, which can occur as a result of rapid reduction in tumor volume.

The authors concluded that monotherapy with VENCLEXTA® resulted in a high ORR and sustained remissions, in high risk patients with CLL. Undetectable Minimal Residual Disease was noted in more than 20% of responders, with more than 10% of all patients achieving a deep response. Venetoclax (ABT-199/GDC-0199) monotherapy induces deep remissions, including complete remission and undetectable MRD, in ultra-high risk relapsed/refractory chronic lymphocytic leukemia with 17p deletion: results of the pivotal international phase II study. Stilgenbauer S, Eichhorst BF, Schetelig JS, et al. Presented at: 57th American Society of Hematology Annual Meeting; Orlando, Florida; December 5-8, 2015. Abstract LBA6.

Caplacizumab, a Novel Anti-vWF targeted Nanobody, for Acquired TTP

SUMMARY: Thrombotic Thrombocytopenic Purpura (TTP), Hemolytic Uremic Syndrome (HUS) and Atypical Hemolytic Uremic Syndrome (aHUS) are life-threatening Thrombotic MicroAngiopathies (TMAs) associated with systemic microvascular thrombosis, MicroAngiopathic Hemolytic Anemia (MAHA), thrombocytopenia and organ failure. Even though their clinical presentation has some similarities, they are distinct entities with different pathophysiology and hence managed differently. Patients with TTP have either severe deficiency of ADAMTS13 (A Disintegrin And Metalloproteinase with a ThromboSpondin type 1 motif, member 13) secondary to anti-ADAMTS13 autoantibodies or rarely due to ADAMTS13 gene mutations. The physiological role of ADAMTS13 is to prevent intravascular platelet thrombosis. ADAMTS13 accomplishes this by cleaving ultralarge von Willebrand Factor multimers (which bind to platelets and induce aggregation), thereby mitigating the tendency of von Willebrand Factor (vWF) and platelets to form aggregates in normal microcirculation. Deficiency of ADAMTS13 causes vWF-platelet aggregation in the arterioles and capillaries, characteristic of TTP, resulting in tissue ischemia from microthrombi and end organ damage. Thus the microthrombi in TTP are platelets bound to vWF and not to fibrinogen. Rapid initiation of Plasma Exchange, the frontline therapy in patients with TTP, removes the anti-ADAMTS13 autoantibodies and ultra large vWF multimers and replenishes ADAMTS13. Immunosuppressive therapy with glucocorticoids and RITUXAN® (Rituximab) inhibits anti-ADAMTS13 autoantibody formation, by targeting the B lymphocytes. These interventions have significantly improved the survival rate among patients with TTP. Despite these advances with the use of Plasma Exchange, approximately 10-20% of the patients with TTP will succumb to their disease.

Caplacizumab is an anti-von Willebrand Factor, humanized, single-variable-domain immunoglobulin (Nanobody), directed against the A1 domain of von Willebrand Factor and prevents the interaction of vWF with the platelet glycoprotein Ib-IX receptor. TITAN is an international, multicenter, phase II, randomized, placebo-controlled study, designed to assess the efficacy and safety of Caplacizumab given as an adjunct to Plasma Exchange, in patients with acquired TTP. Seventy five patients (N=75) were randomized in a 1:1 ratio to receive Plasma Exchange plus either Caplacizumab 10 mg subcutaneous or placebo, daily. The mean age was 42 years and the mean platelet count was 24,600 per cubic millimeter. Majority of the patients in both groups received concomitant glucocorticoids and 23% of the patients in the placebo group received RITUXAN® during daily Plasma Exchange compared 6% in the Caplacizumab group. The primary end point was the time to response, defined as normalization of the platelet count (150,000 per cubic millimeter or higher) and a Lactate DeHydrogenase (LDH) level that was no more than twice the upper limit of the normal range. Secondary end points included TTP exacerbations and relapses.

It was noted that the median time to a response was significantly reduced with Caplacizumab as compared with placebo (39% reduction in median time, P=0.005). The mean number of Plasma Exchange days was lower with Caplacizumab (5.9 versus 7.9 days), the mean volume of Plasma administered was lower with Caplacizumab (19.9L versus 28.3L), normalization of LDH and creatinine occurred more rapidly with Caplacizumab and Complete Remissions after initial course of Plasma Exchange was more common in the Caplacizumab group (81% versus 46%), when compared to the placebo group. Mild to moderate bleeding was more common with Caplacizumab than with placebo (54% versus 38%).

The authors concluded that the addition of Caplacizumab to Plasma Exchange induces a faster resolution of acute TTP compared with placebo and Caplacizumab maintained a platelet-protective effect during the treatment period. Caplacizumab for Acquired Thrombotic Thrombocytopenic Purpura. Peyvandi F, Scully M, Hovinga JK, et al. for the TITAN Investigators. N Engl J Med 2016; 374:511-522

Aromatase Inhibitors-Induced Carpal Tunnel Syndrome

SUMMARY: Breast cancer is the most common cancer among women in the US and about 1 in 8 women (12%) will develop invasive breast cancer during their life time. Approximately, 246,660 new cases of invasive breast cancer will be diagnosed in 2016 and 40,450 women will die of the disease. Approximately 75% of patients with breast cancer are hormone receptor positive (Estrogen Receptor/Progesterone Receptor positive) and this is a predictor of response to endocrine therapy. These patients are often treated with anti-estrogen therapy as first line treatment. In premenopausal woman, the ovary is the main source of estrogen production, whereas in postmenopausal women, the primary source of estrogen is the Aromatase enzyme mediated conversion of androstenedione and testosterone to estrone and estradiol, in extragonadal/peripheral tissues. NOLVADEX® (Tamoxifen) is a nonsteroidal Selective Estrogen Receptor Modulator (SERM) and works mainly by binding to the Estrogen Receptor and thus blocks the proliferative actions of estrogen on the mammary tissue. ARIMIDEX® (Anastrozole), FEMARA® (Letrozole) and AROMASIN® (Exemestane) are Aromatase Inhibitors (AIs) that binds to the Aromatase enzyme and inhibit the conversion of androgens to estrogens in the extra-gonadal tissues. The use of Aromatase Inhibitors (AIs) has been long associated with musculoskeletal symptoms, as well as accelerated bone loss, leading to a decrease in Bone Mineral Density (BMD). Approximately 25% of the patients on AIs are non-compliant during the first year of therapy and this has been attributed to musculoskeletal symptoms. Increased risk of Carpal Tunnel Syndrome (CTS) has also been reported with AIs.

Carpal tunnel syndrome (CTS), also called median nerve compression, is the most common entrapment neuropathy and results from compression of the median nerve, as it runs from the forearm into the palm of the hand, through the carpal tunnel. The carpal tunnel is a narrow and rigid passage at the base of the hand and houses the median nerve and tendons. In most cases, CTS is due to a congenital predisposition, with the carpal tunnel being simply smaller in some individuals than others. Secondary CTS is caused by any condition that further narrows this osteofibrous passage such as arthritis, acromegaly and mechanical problems in the wrist joint or effects the contents of this passage such as tenosynovitis, synovial hypertrophy, hypothyroidism, fluid retention during pregnancy or menopause, or the development of a cyst or tumor in the passage. Bilateral oophorectomy and use of the combined oral contraceptive have also been identified as risk factors for CTS. Patients often experience nocturnal paraesthesias in median nerve distribution (thumb, index and middle fingers), such as burning sensation, tingling, or heaviness, with the pain radiating to the forearm or elbow. It has been postulated that estrogen has antinociceptive properties and estrogen deprivation with AIs decreases the threshold for pain stimuli. Estrogen deprivation may also impact the metabolism of transverse carpal ligament on which estrogen and progesterone receptors are expressed and lack of estrogen may additionally result in morphological changes in the contents of carpal tunnel including, thickening of the tendon sheaths and fluid accumulation. This may directly induce CTS.

To address the risk factors and incidence of CTS in women taking AIs, the authors conducted an exploratory analysis of the International Breast Cancer Intervention Study II, a double-blind randomized clinical trial, in which women at increased risk of breast cancer were randomly assigned to receive ARIMIDEX® or placebo for 5 years. In this study, a total of 3,864 women were randomly assigned to receive either ARIMIDEX® (N=1920) or placebo (N=1944). The median age was 60 years and majority of the women (69%) had a BMI of greater than 25 kg/m2.

After a median follow up of 6.4 years, 96 patients had symptoms of Carpal Tunnel Syndrome (CTS). Patients receiving ARIMIDEX® were more likely to have CTS related symptoms than those receiving placebo (3.4% versus 1.6%; P<0.001). Eight of the 10 participants reported as having severe CTS were taking ARIMIDEX® (P =0.08). Eighteen women (0.9%) in the ARIMIDEX® group required surgical intervention for CTS compared to six women (0.3%) in the placebo group and this was significantly different (P=0.018). Participants experiencing CTS symptoms did so early in the course of treatment and only 6 women discontinued the allocated treatment. In addition to taking AIs, high Body Mass Index and prior complaints of musculoskeletal symptoms, were the only other risk factors for developing CTS.

The authors concluded that the use of ARIMIDEX® was associated with a higher incidence of Carpal Tunnel Syndrome (CTS), although few participants required surgery. Given the association between CTS and other musculoskeletal symptoms induced by AIs (Aromatase Inhibitors), the authors suggested that these findings induced by AIs, may share the same pathobiology. Anastrozole-Induced Carpal Tunnel Syndrome: Results from the International Breast Cancer Intervention Study II Prevention Trial. Spagnolo F, Sestak I, Howell A, et al. J Clin Oncol 2016;34:139-143

IMBRUVICA® in Combination with BR Regimen Shows Significant Benefit in Relapsed CLL patients

SUMMARY: The American Cancer Society estimates that approximately 18,960 new cases of Chronic Lymphocytic Leukemia (CLL) will be diagnosed in 2016 and approximately 4660 patients will die from the disease. CLL is a disease of the elderly and the average age at the time of diagnosis is 72 years. There are two main types of lymphocytes, B and T lymphocytes/cells. B-cell CLL is the most common type of leukemia in adults. Normal B-cell activation and proliferation is dependent on B-cell receptor (BCR) signaling. This signaling is also important for initiation and progression of B-cell lymphoproliferative disorders. Bruton's Tyrosine Kinase (BTK) is a member of the Tec family of kinases, downstream of the B-cell receptor and is predominantly expressed in B-cells. It is a mediator of B-cell receptor signaling in normal and transformed B-cells. Following binding of antigen to the B-Cell Receptor, kinases such as Syk (Spleen Tyrosine Kinase), Lyn (member of the Src family of protein tyrosine kinases) and BTK (Bruton's Tyrosine Kinase) are activated, with subsequent propagation through PI3K/Akt, MAPK, and NF-κB pathways. This results in B-cell activation and proliferation. IMBRUVICA® (Ibrutinib) is an oral, irreversible inhibitor of BTK and inhibits cell proliferation and promotes programmed cell death (Apoptosis) by blocking B-cell activation and signaling. The FDA initially granted accelerated approval to IMBRUVICA® in February 2014 for previously treated patients with CLL and this was followed by full FDA approval and a new treatment indication for high-risk CLL patients with 17p deletions, in July 2014. Previously published studies had shown significant Response Rates and and Event-Free Survival with BR (Bendamustine-TREANDA® and Rituximab-RITUXAN®) in FLUDARA® (Fludarabine) refractory patients, with Chronic Lymphocytic Leukemia.

The HELIOS study is a double-blind, randomized, phase III trial which evaluated the benefit of combining IMBRUVICA® with BR compared to placebo plus BR, in patients with previously treated, relapsed/refractory Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma. In this study, of the 578 randomized patients, 289 patients received a maximum of six cycles of BR with IMBRUVICA® 420 mg PO daily and 289 patients received BR with placebo. The median patient age was 64 years, patients had received a median of two prior therapies and 38% of the patients had Rai Stage III/IV disease. Patients with 17p deletions in more than >20% of cells, were excluded. The planned six cycles of BR were completed by 83% in the IMBRUVICA® group and 78% in the placebo group. The primary endpoint was Progression Free Survival (PFS). Secondary endpoints included Overall Survival (OS) and Overall Response Rate (ORR).

Following an interim analysis, this study was unblinded as there was a significant PFS benefit with IMBRUVICA® and patients receiving placebo, were allowed to cross over to the IMBRUVICA® group, per study protocol,. Thirty one percent (31%) of the patients in the BR plus placebo group with confirmed progressive disease crossed over to receive BR plus IMBRUVICA®. At a median follow up of 17.2 months, the PFS in the IMBRUVICA® plus BR group was not yet reached whereas the PFS was 13.3 months for patients receiving placebo plus BR (HR=0.203; P<0.0001). This PFS benefit was seen across subgroups of high-risk patients as well. The ORR was 82.7% in the IMBRUVICA® plus BR group compared to 67.8% in the placebo plus BR group (P <0.0001). Complete Response (CR) rates which included CR with incomplete blood count recovery were 10.4% versus 2.8% with IMBRUVICA® and placebo, respectively. The median OS was not reached. The incidence of most adverse events were comparable between the two treatment groups and the most frequent side effects were neutropenia affecting about 55% of the patients and nausea experienced by about 35% of the patients.

The authors concluded that IMBRUVICA® plus BR resulted in an 80% reduction in the risk of disease progression, as well as improved Overall Response Rates, compared to placebo plus BR. This triplet combination of IMBRUVICA®, TREANDA® and RITUXAN® should therefore be considered an important treatment option for patients with previously treated Chronic Lymphocytic Leukemia and Small Lymphocytic Lymphoma. Ibrutinib combined with bendamustine and rituximab compared with placebo, bendamustine, and rituximab for previously treated chronic lymphocytic leukaemia or small lymphocytic lymphoma (HELIOS): a randomised, double-blind, phase 3 study. Chanan-Khan A, Cramer P, Demirkan F, et al. The Lancet Oncology 2016;17:200-211

EGFR Inhibition may not be Effective Immediately after VEGF blockade in Metastatic ColoRectal Cancer

SUMMARY: ColoRectal Cancer (CRC) is the third most common cancer diagnosed in both men and women in the United States. The American Cancer Society estimates that approximately 135,000 new cases of ColoRectal Cancer will be diagnosed in the United States in 2016 and over 49,000 patients are expected to die of the disease. Even though colon cancer localized to the bowel is potentially curable with surgery and adjuvant chemotherapy, advanced colon cancer is often incurable. Standard chemotherapy when combined with anti EGFR (Epidermal Growth Factor Receptor) targeted monoclonal antibodies such as VECTIBIX® (Panitumumab) and ERBITUX® (Cetuximab) as well as anti VEGF agent AVASTIN® (Bevacizumab), have demonstrated improvement in Progression Free Survival (PFS) and Overall Survival (OS). The benefit with anti EGFR agents however is only demonstrable in patients with metastatic CRC, whose tumors do not harbor KRAS mutations in codons 12 and 13 of exon 2 (KRAS Wild Type). It is now becoming clear that even among the KRAS Wild Type patients, about 15% to 20% have other rare mutations such as NRAS and BRAF mutations, which confer resistance to anti EGFR agents. Therefore, pan RAS (expanded RAS) testing is now recommended.

The CALGB/SWOG 80405 study reported that either ERBITUX® or AVASTIN® in combination with chemotherapy have equivalent Overall Survival benefit, when given as first line therapy, for patients with metastatic ColoRectal Cancer (mCRC), whose tumors are KRAS Wild Type. Consequently, the optimal first-line therapy for patients with KRAS Wild Type metastatic CRC still remains unclear. ERBITUX® has a similar activity across all treatment lines whereas AVASTIN® appears to lose its efficacy along the course of treatment lines. Although FOLFOX and FOLFIRI are equally effective as first line treatment for patients with metastatic CRC, FOLFOX might be more effective as second line treatment. Preclinical studies have suggested that a prior anti VEGF therapy, may lower sensitivity to a subsequent anti EGFR treatment.

The authors in a phase III randomized multicenter trial addressed these issues by comparing two different sequences of ERBITUX® and FOLFOX chemotherapy in KRAS Wild Type metastatic CRC patients, refractory to first line FOLFIRI chemotherapy and AVASTIN®. Patients with mCRC (N=110) were randomly assigned in a 1:1 ratio to receive CAMPTOSAR® (Irinotecan)/ERBITUX® as second line followed by FOLFOX-4 chemotherapy as third line (Arm A) or the reverse sequence (FOLFOX-4 chemotherapy second line followed by CAMPTOSAR®/ERBITUX® as third line – Arm B). The primary endpoint was Progression Free Survival (PFS) and secondary endpoints included Overall Survival (OS) and toxicity. It was noted that the median PFS in Arm A was 9.9 months compared to 11.3 months in Arm B (HR=0.85; P=0.42) and the median OS was 12.3 months in Arm A and 18.6 months in Arm B (HR=0.79; P=0.28). The Objective Response Rate in Arm A was 37% and in Arm B was 57% (P=0.05). Treatment was well tolerated with a low incidence of serious adverse events.

It was concluded that EGFR inhibition is not active immediately after VEGF blockade and therefore ERBITUX® is less effective immediately after AVASTIN®. The sequence of biological agents appears to be more important than the first-line chemotherapy choice. In RAS Wild Type metastatic CRC patients progressing after a first line AVASTIN® based therapy, ERBITUX® should be given in the third line setting or should be considered in first line treatment regimen. Efficacy of cetuximab immediately after bevacizumab: A phase III multicenter trial comparing two different sequences of cetuximab and FOLFOX in K-Ras WT metastatic colorectal cancer patients refractory FOLFIRI/bevacizumab. Cascinu S, Zaniboni A, Lonardi S, et al. J Clin Oncol 34, 2016 (suppl 4S; abstr 632)

BCR-ABL Transcript Type May Predict Outcomes in Patients with Chronic Phase CML Treated with Tyrosine Kinase Inhibitors

SUMMARY: Chronic Myeloid Leukemia (CML) constitutes a little over 10% of all new cases of leukemia. The American Cancer Society estimates that about 8,220 new CML cases will be diagnosed in the United States in 2016 and about 1,070 patients will die of the disease. The hallmark of CML, the Philadelphia Chromosome (Chromosome 22), is a result of a reciprocal translocation-t(9;22), between chromosomes 9 and 22, wherein the ABL gene from chromosome 9, fuses with the BCR gene on chromosome 22. As a result, the auto inhibitory function of the ABL gene is lost and the BCR-ABL fusion gene is activated resulting in cell proliferation and leukemic transformation of hematopoietic stem cells. Even though the reciprocal translocation resulting in the formation of Philadelphia chromosome involves a fairly constant breakpoint in the ABL gene on chromosome 9, the breakpoint in the BCR gene on chromosome 22 can vary, resulting in different BCR-ABL transcript types. There has been ongoing debate whether the type of transcript, has prognostic significance, for patients with newly diagnosed chronic phase CML. Over 95% of patients with CML have expression of e13a2 (b2a2), e14a2 (b3a2), or both transcripts, coding for p210 BCR-ABL tyrosine kinase, whereas a small minority of patients express rare variants such as e1a2 transcripts, which code for p190 BCR-ABL, which is associated with aggressive disease. Previously published studies have shown that expression of certain type of transcripts may predict response to therapy, as well as outcomes.

The purpose of this study was to evaluate the prognostic relevance of the commonly expressed BCR-ABL transcripts in patients with chronic phase CML and the influence of the transcript type, on molecular and cytogenetic responses, across chronic phase CML patients, treated with different Tyrosine Kinase Inhibitors (TKI). This analysis included 481 treatment naïve patients with chronic phase CML treated with different TKI modalities, expressing e13a2 (42%), e14a2 (41%), or coexpression of both e13a2 with e14a2 (18%) transcripts. These patients were treated with 4 different frontline TKIs which included, GLEEVEC® (Imatinib) 400 mg daily (N=69), GLEEVEC® 800 mg daily (N=199), SPRYCEL® (Dasatinib) 50 mg twice daily or 100 mg daily (N=105) and TASIGNA® (Nilotinib) 400 mg twice daily (N=108).

It was noted that patients with e13a2 transcripts who received GLEEVEC® 400 mg had an inferior Complete Cytogenetic Response (77%) compared with other TKI modalities (90-95%). Unlike these patients, patients with e14a2 transcripts or those expressing both e13a2 and e14a2 transcripts treated with GLEEVEC® 400 mg, had a Complete Cytogenetic Response rate of 93%, which was similar to treatment with other TKI modalities (93-96%). Even though the time to Complete Cytogenetic Response was 3 months and similar in all treatment groups, the trend for lower rates of Complete Cytogenetic Response and Major Cytogenetic Response for the e13a2 transcript cohort compared with the e14a2 cohort, persisted even at 60 months. Patients with e13a2 treated with GLEEVEC® 400 mg similarly had an inferior Major Molecular Response (MMR) at all time points than individuals with e14a2 and inferior MR4.5, compared with those treated with other TKI modalities. In patients with e14a2 transcripts, the MMR and MR4.5 rates were generally similar with all TKI modalities. In a multivariate analysis, patients with e14a2 alone or those with coexpressed e13a2, achieved an earlier and deeper response, compared to those with e13a2 transcripts, and predicted for longer event-free and transformation-free survival.

The authors concluded that the type of BCR-ABL transcript may determine outcomes in patients with chronic phase CML. Patients with e13a2 transcripts have lower platelet count and inferior outcomes with GLEEVEC® 400 mg, whereas patients with e14a2 have favorable outcomes regardless of TKI treatment modality. Further, expression of e14a2 or both e14a2 and e13a2 predicts optimal responses and longer Event Free Survival and Transformation Free Survival. Thus BCR-ABL transcript type may help in selecting the appropriate treatment and may predict outcomes in patients with chronic phase CML. Impact of BCR-ABL transcript type on outcome in patients with chronic-phase CML treated with tyrosine kinase inhibitors. Jain P, Kantarjian H, Patel KP, et al. Blood 2016;127:1269-1275

BRAF Inhibitors versus Immunotherapy in Patients with BRAF V600-Mutant Metastatic Melanoma

SUMMARY: It is estimated that in the US, approximately 76,380 new cases of melanoma will be diagnosed in 2016 and approximately 10,130 patients will die of the disease. The incidence of melanoma has been on the rise for the past three decades. The approval of the combination of MEKINIST® (Trametinib) and TAFINLAR® (Dabrafenib), to treat patients with advanced melanoma, was based on the understanding of the biological pathways of this malignancy. The Mitogen-Activated Protein Kinase pathway (MAPK pathway) is an important signaling pathway which enables the cell to respond to external stimuli. This pathway plays a dual role, regulating cytokine production and participating in cytokine dependent signaling cascade. The MAPK pathway of interest is the RAS-RAF-MEK-ERK pathway. The RAF family of kinases includes ARAF, BRAF and CRAF signaling molecules. BRAF is a very important intermediary of the RAS-RAF-MEK-ERK pathway. BRAF mutations have been demonstrated in 6%-8% of all malignancies. The most common BRAF mutation in melanoma is at the V600E/K site and is detected in approximately 50% of melanomas. In the BREAK-3 randomized phase III trial, TAFINLAR® (Dabrafenib), a selective oral BRAF inhibitor demonstrated a statistically significant improvement in Progression Free Survival (PFS) and Response Rate (RR) compared to Dacarbazine (DTIC), in patients with advanced BRAF V600E/K mutated melanoma. However, Squamous Cell carcinomas were seen in about 6% of the patients treated with BRAF inhibitors. Paradoxical activation of the MAPK pathway in cells without a BRAF mutation (BRAF wild-type cells) has been implicated in the emergence of drug resistance and increased incidence of BRAF-inhibitor induced skin tumors. The addition of a MEK inhibitor such as MEKINIST® (Trametinib) to a BRAF inhibitor such as TAFINLAR®, has addressed some of these limitations, in previously published studies, with improvement in PFS. MEKINIST® is a potent and selective inhibitor of MEK gene, which is downstream from RAF in the MAPK pathway and has been shown to significantly improve PFS, RR and Overall Survival (OS), when compared to chemotherapy, in advanced melanoma patients with BRAF V600E/K mutations. A combination of BRAF inhibitor TAFINLAR® and MEK inhibitor MEKINIST®, significantly improved OS, as compared with monotherapy with BRAF inhibitor, with a 31% relative reduction in the risk of death, in previously untreated patients with metastatic melanoma, with BRAF V600E or V600K mutations. This benefit was accomplished without increased overall toxicity. However, approximately 50% of patients progress after 12 months, although a significant number of patients experience long-term benefit without progression.

The purpose of this study was to identify the clinical predictors and analyze the clinical correlates of those who had prolonged survival. The authors in this manuscript report the updated OS results of a previously published study, in which BRAF inhibitor-naive patients were treated with a combination of TAFINLAR® and MEKINIST®. Additionally, the authors in this study also report the clinical factors associated with long term survival. The original open-label phase I and II study of combination therapy with TAFINLAR® and MEKINIST® (N Engl J Med. 2012;367:1694-1703) had four parts (parts A, B, C, and D). The present analysis evaluated the outcomes of a total of 78 BRAF inhibitor-naive patients, enrolled in part B (N= 24) and part C (N= 54), who received the phase III dose (optimal dose) of oral TAFINLAR® 150 mg twice daily combined with oral MEKINIST® 2 mg once daily. The remaining cohorts in parts B and C and all cohorts in parts A and D did not receive the phase III dose of the combination therapy and therefore are not described here.

It was noted that among patients in part B of the study, the 1 year Progression Free Survival (PFS) was 44%, 2 year PFS was 22% and 3 year PFS was 18%. Among patients in part C, the 1 year PFS was 41%, 2 year PFS was 25% and 3 year PFS was 21%. The median Overall Survival (OS) was 27.4 months in part B and 25 months in part C with an OS at 1, 2, and 3 years of 72%, 60%, and 47%, respectively, for part B and 80%, 51%, and 38%, respectively, for part C. Prolonged survival was associated with good prognostic factors such as metastases in fewer than three organ sites and lower baseline LDH (Lactate Dehydrogenase) levels. The 3 year OS was 62% in patients with normal baseline LDH levels and 63% in those who had a complete response.

The authors concluded that a combination of TAFINLAR® and MEKINIST® results in a median OS of more than 2 years in BRAF V600 mutation-positive metastatic melanoma, with approximately 20% of the patients remaining progression free at 3 years. Good prognostic features at baseline, were predictive of durable responses. With dilemma facing clinicians, whether to choose MAP Kinase inhibitors versus Immunotherapy, as first line therapy for this patient group, the longest follow up data presented, demonstrating durable benefit with a combination TAFINLAR® and MEKINIST®, should be very reassuring. Overall Survival and Durable Responses in Patients With BRAF V600-Mutant Metastatic Melanoma Receiving Dabrafenib Combined With Trametinib. Long GV, Weber JS, Infante JR, et al. JCO JCO629345; published online on January 25, 2016