SUMMARY: Chronic Myeloid Leukemia (CML) constitutes approximately 10% of all new cases of leukemia. The American Cancer Society estimates that 6,660 new CML cases will be diagnosed in the United States in 2015 and about 1,140 people will die of the disease. The hallmark of CML, the Philadelphia Chromosome (Chromosome 22), is a result of a reciprocal translocation 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.
Gleevec® (Imatinib) inhibits the BCR-ABL tyrosine kinase and is the standard first line treatment, of Ph chromosome positive (Ph+) leukemias. Lack of response due to resistance to GLEEVEC® and in some instances drug intolerance, has led to the development of newer agents including Second and Third generation Tyrosine Kinase Inhibitors (TKIs). Resistance to Gleevec® and other TKIs sharing the same therapeutic target (BCR-ABL kinase), has been attributed to point mutations in the ABL kinase domain, amplification of the BCR-ABL gene as well as other BCR- ABL independent mechanisms such as upregulation of SRC kinases. Mutation analysis at the time of TKI failure, utilizing high sensitivity sequencing techniques such as Next Generation Sequencing, can give clinically relevant information related to low level mutations and compound mutations and this information in turn, can dictate choice of second line therapy. 
The Second generation TKIs, TASIGNA® (Nilotinib) and SPRYCEL® (Dasatinib) although initially approved for second line treatment of CML after GLEEVEC® resistance or intolerance, are now FDA approved for the treatment of newly diagnosed Chronic Phase CML. This approval was based on the rapid and superior Major Molecular Responses (MMR) noted, when compared to GLEEVEC®. Now, that the Second generation TKIs are being used as first line therapy, the choice of second line therapy after failure with Second generation TKIs has become more nebulous. It is clear however that, patients with primary cytogenetic resistance to ï¬rst and second line therapy do not beneï¬t from sequential therapy with Second generation TKIs and BCR-ABL mutation analysis should be performed in all patients who develop TKI resistant disease. Before switching from a Second to a Third generation TKI such as Ponatinib, the following considerations should be taken into account
BCR-ABL Mutations and Sensitivity to Second Generation TKIs
1) Patients with F317L/V/I/C mutations are more sensitive to TASIGNA® (Nilotinib) or BOSULIF® (Bosutinib) than to SPRYEL® (Dasatinib)
2) Patients with V299L mutation are more sensitive to TASIGNA® than to BOSULIF® or SPRYCEL®
3) Patients with Y253F/H, E255K/V, and F359V/I/C mutations are more sensitive to SPRYCEL® or BOSULIF® than to TASIGNA®
Tolerability of Second Generation TKIs
1) Patients who experience pleural effusion during SPRYCEL® treatment might better tolerate TASIGNA® or BOSULIF®
2) Patients who experience rash during treatment with TASIGNA® or BOSULIF® could be switched to SPRYCEL®
3) Some toxicities common with other TKIs such as pleural effusion and cardiac toxicity are less common with BOSULIF® and this agent also has activity against many BCR-ABL kinase domain mutations resistant to GLEEVEC®, SPRYCEL® and TASIGNA®, with the exception of T315I mutation.
It should be noted that Second generation TKI as third line therapy has limited value in majority of the patients with CML. ICLUSIG® (Ponatinib) is a Third generation kinase inhibitor approved for the treatment of patients with T315I positive CML or T315I-positive Philadelphia Chromosome positive Acute Lymphoblastic Leukemia (Ph+ ALL) and for whom no other TKI is indicated. Other treatment options include SYNRIBO® (Omacetaxine Mepesuccinate), a first-in-class Cephalotaxine and a semi synthetic purified Homoharringtonine (HHT) compound. Unlike Tyrosine Kinase Inhibitors , SYNRIBO® is a protein synthesis inhibitor and reduces the levels of multiple Oncoproteins including BCR-ABL, BCL-2, MCL-1 and promotes apoptosis of leukemic stem cells. This agent is presently approved for the treatment of Chronic or Accelerated phase Chronic Myeloid Leukemia (CML) with resistance and/or intolerance to two or more Tyrosine Kinase Inhibitors, with cytopenias being the most common toxicity. Allogeneic Hematopoietic Stem Cell transplantation should be considered for eligible patients with T315I mutation not responding to ICLUSIG®, those with mutations resistance to second and third generation TKIs and patients with Accelerated or Blast phase CML, following remission with TKIs. Use of Second- and Third-Generation Tyrosine Kinase Inhibitors in the Treatment of Chronic Myeloid Leukemia: An Evolving Treatment Paradigm. Jabbour E, Kantarjian H and Cortes J. Clinical Lymphoma, Myeloma & Leukemia 2015;15:323-334
Fish oil has relevant levels of fatty acid 16:4(n-3) and preclinical models have shown that the fish oil neutralized the antitumor activity of chemotherapy, thus conferring drug resistance. With this preclinical information and given that cancer patients frequently use fish oil supplements, the authors evaluated the effect of fish oil intake in healthy volunteers, on the plasma levels of fatty acid 16:4(n-3), which has been shown to induce resistance to chemotherapeutic agents. The researchers first conducted a survey to determine what percentage of cancer patients undergoing treatment at a University Medical Center in the Netherlands were taking fish oil supplements. They also analyzed fatty acid 16:4(n-3) content, in 3 brands of fish oil supplements and 4 often consumed species of fish. The authors then randomly selected 30 healthy volunteers for the fish oil study and 20 healthy volunteers for the fish consumption study and the plasma levels of fatty acid 16:4(n-3) was measured after they consumed fish oil or fish, for a period of 2 weeks. They noted that 11% of the cancer patients in their study reported using omega-3 supplements. All fish oils tested contained amounts of fatty acid 16:4(n-3) ranging from 0.2 to 5.7 μM and this was adequate to induce chemoresistance to a variety of chemotherapeutic agents. They noted that there was a significant rise in the plasma 16:4(n-3) fatty acid levels in the healthy volunteers after they consumed fish oil supplements and fish, with high levels of fatty acid 16:4(n-3). Herring and Mackerel fish contained high levels of fatty acid 16:4(n-3), in contrast to Salmon and Tuna. The authors concluded that based on this preclinical data it is best to avoid fish oils and fish such as Herring and Mackerel in the 48 hours surrounding chemotherapy, as the high plasma 16:4(n-3) fatty acid levels may negate the effects of chemotherapy. These recommendations have been adopted by the Dutch Cancer Society and by the Dutch National Working Group for Oncologic Dieticians. Increased Plasma Levels of Chemoresistance-Inducing Fatty Acid 16:4(n-3) After Consumption of Fish and Fish Oil. Daenen LGM, Cirkel GA, Houthuijzen JM, et al. JAMA Oncol. 2015;1:350-358
This is accomplished by either surgical castration (bilateral orchiectomy) or medical castration using LHRH (GnRH- Gonadotropin-Releasing Hormone) agonists given along with 2 weeks of first generation anti-androgen agents such as EULEXIN® (Flutamide), CASODEX® (Bicalutamide) or NILANDRON® (Nilutamide), with the anti-androgen agents given to prevent testosterone flare. This large intergroup trial which was developed by the NCIC Clinical Trials Group in collaboration with the Medical Research Council and the National Cancer Institute US Cancer Therapy Evaluation Program, evaluated the benefits of adding Radiation Therapy (RT) to ADT, when compared to ADT alone, in patients with locally advanced prostate cancer. In this study, 1205 patients were randomly assigned to receive either ADT alone (N=602) or ADT plus RT (N=603). Eligible patients included those with T1-2 disease with either Prostate Specific Antigen (PSA) of more than 40 μg/L or PSA of 20-40 μg/L plus Gleason score of 8-10 or patients with T3-4, N0/NX, M0 prostate cancer. ADT consisted of either bilateral orchiectomy or LHRH agonists (plus 2 weeks of oral anti-androgen therapy to prevent testosterone flare), based on patient and physician preference, and ADT was continued for life. RT consisted of a dose of 64-69 Gy given in 35-39 fractions to the prostate gland and pelvis or prostate gland alone. The median age was 70 years and the median follow up was 8 years. Eighty seven percent of patients had T3-4 disease, 63% of patients had a PSA more than 20 μg/L and 18% had a Gleason score of more than 8. The Primary Endpoint was Overall Survival (OS), defined as the time from randomization to death from any cause. Secondary Endpoints included Time To Progression (TTP), improvement in Disease Specific Survival, quality of life and toxicity. The authors had previously reported the interim analysis findings of this intergroup trial and they noted that the addition of RT to ADT significantly improved overall survival, at a median follow up of 6 years (HR= 0.77; P=0.033). In this final analysis, at a median follow up of 8 years, the interim analysis findings were confirmed and the patients assigned to ADT plus RT had significantly improved Overall Survival compared to those who received ADT alone (HR=0.70; P<0.001), with a 30% reduction in the risk of death. Disease Specific Survival was also superior with ADT plus RT compared to ADT alone, with a 54% reduction in deaths from prostate cancer (HR=0.46; P <0 .001). There was a higher incidence of grade 1 and 2 bowel toxicities in patients who received ADT plus RT, but grade 3 bowel toxicities were rare and short term. The authors concluded that this long term follow up data suggests that the addition of Radiation Therapy to Androgen Deprivation Therapy significantly prolongs Overall and Disease Specific Survival, in patients with locally advanced prostate cancer. Final Report of the Intergroup Randomized Study of Combined Androgen-Deprivation Therapy Plus Radiotherapy Versus Androgen-Deprivation Therapy Alone in Locally Advanced Prostate Cancer. Mason MD, Parulekar WR, Sydes MR, et al. J Clin Oncol 2015; 33:2143-2150
Approximately 80% of breast tumors express Estrogen Receptors and/or Progesterone Receptors and these patients are often treated with anti-estrogen therapy as first line treatment. Cyclin Dependent Kinases (CDK) play a very important role to facilitate orderly and controlled progression of the cell cycle. Genetic alterations in these kinases and their regulatory proteins have been implicated in various malignancies. Cyclin Dependent Kinases 4 and 6 (CDK4 and CDK6) phosphorylate RetinoBlastoma protein (RB) and initiate transition from the G1 phase to the S phase of the cell cycle. CDK4 and CDK6 are activated in hormone receptor positive breast cancer, promoting breast cancer cell proliferation. Further, there is evidence to suggest that endocrine resistant breast cancer cell lines depend on CDK4 for cell proliferation. IBRANCE® (Palbociclib) is a reversible, oral, selective, small molecule inhibitor of Cyclin Dependent Kinases, CDK4 and CDK6, and prevent RB1 phosphorylation. IBRANCE® is the first CDK inhibitor approved by the FDA. It exhibits synergy when combined with endocrine therapies. In an open-label, randomized, phase II study, which included treatment naïve postmenopausal women with ER-positive, HER2-negative, advanced breast cancer, IBRANCE® given along with Aromatase Inhibitor FEMARA® (Letrozole) significantly prolonged Progression Free Survival, Overall Response rate and median duration of response, compared to FEMARA® alone. Based on this data, the U. S. Food and Drug Administration on February 3, 2015 granted accelerated approval to IBRANCE® (Palbociclib), for use in combination with FEMARA® (Letrozole) in this patient population. FASLODEX® (Fulvestrant) is a selective estrogen receptor down-regulator presently indicated for the treatment of hormone receptor positive metastatic breast cancer patients, with disease progression following antiestrogen therapy.
Immune checkpoints are cell surface inhibitory proteins/receptors that are expressed on activated T cells. They harness the immune system and prevent uncontrolled immune reactions. Survival of cancer cells in the human body may be to a significant extent, related to their ability to escape immune surveillance, by inhibiting T lymphocyte activation. The T cells of the immune system therefore play a very important role in modulating the immune system. Under normal circumstances, inhibition of an intense immune response and switching off the T cells of the immune system, is an evolutionary mechanism and is accomplished by Immune checkpoints or gate keepers. With the recognition of Immune checkpoint proteins and their role in suppressing antitumor immunity, antibodies are being developed that target the membrane bound inhibitory Immune checkpoint proteins/receptors such as CTLA-4 (Cytotoxic T-Lymphocyte Antigen 4), also known as CD152, PD-1(Programmed cell Death-1), etc. By doing so, one would expect to unleash the T cells, resulting in T cell proliferation, activation and a therapeutic response. The first Immune checkpoint protein to be clinically targeted was CTLA-4. YERVOY® (Ipilimumab), an antibody that blocks Immune checkpoint protein/receptor CTLA- 4, has been shown to prolong overall survival in patients with previously treated, unresectable or metastatic melanoma. KEYTRUDA® (Pembrolizumab) is a fully humanized, Immunoglobulin G4, monoclonal antibody, that binds to the PD-1 receptor and blocks its interaction with ligands PD-L1 and PD-L2, thereby undoing PD-1 pathway-mediated inhibition of the immune response and unleashing the tumor-specific effector T cells. The FDA granted accelerated approval to KEYTRUDA® in September 2014, for the treatment of patients with unresectable or metastatic melanoma and disease progression following YERVOY® and, if BRAF V600 mutation positive, a BRAF inhibitor. The activity of KEYTRUDA® as a single agent in advanced SCCHN patients, was previously published and was noted in PD-L1 positive tumors, regardless of the Human PapillomaVirus (HPV) status. The Overall Response Rate in this patient group was 20% and 29% of patients had stable disease. The authors in this study reported the efficacy of once every three week dose of KEYTRUDA®, in a larger expansion cohort of KEYNOTE 012 study. In this study, 132 patients with recurrent/metastatic SCCHN were enrolled, regardless of their PD-L1 expression or HPV status. These patients received a fixed dose of KEYTRUDA® 200 mg IV, every 3 weeks and patients were evaluated every 8 weeks with radiographic imaging. The mean age was 59 years and 57% of the patients had 2 or more lines of therapy for recurrent disease. Treatment was continued until disease progression. The primary end point was Overall Response Rate (ORR) and secondary endpoints included Progression Free Survival (PFS) and Overall Survival (OS). The Overall Response Rate was 25% and stable disease was noted in an additional 25% of the patients. This amounted to a disease control rate of 50%. Patients with HPV-positive disease had a response rate of 20.6% and patients with HPV-negative disease had a response rate of 27.2%, suggesting that KEYTRUDA® was active in both subgroups of patients. Serious toxicities were reported in fewer than 10% of patients and the most common adverse event was fatigue (15.2%). The authors concluded that KEYTRUDA® given every 3 weeks was well tolerated and demonstrated a meaningful response rate in a heavily pretreated population of patients, with recurrent/metastatic SCCHN. Evaluation of PD-L1 status for this patient group is ongoing. Antitumor activity and safety of pembrolizumab in patients (pts) with advanced squamous cell carcinoma of the head and neck (SCCHN): Preliminary results from KEYNOTE-012 expansion cohort. Seiwert TY, Haddad RI, Gupta S, et al. J Clin Oncol 33, 2015 (suppl; abstr LBA6008)</s
SIRFLOX is an International, multi-center, open-label, randomized phase III study, which evaluated the efficacy and safety of combining modified FOLFOX6 (Oxaliplatin, 5-FU and Leucovorin) chemotherapy regimen with or without AVASTIN® (Bevacizumab) with SIRT, using Y-90 resin microspheres, as first line treatment in patients with unresectable liver only or liver dominant metastatic ColoRectal Cancer (mCRC). The randomization included 530 patients of whom 263 patients received mFOLFOX6 with or without AVASTIN® (Group A) and 267 patients received mFOLFOX6 + SIRT administered once with cycle 1, with or without AVASTIN® (Group B), with the treatment given until disease progression. Patients were stratified based on the extent of liver involvement (25% or less versus more than 25%), presence of extra hepatic disease (liver only versus liver dominant disease) and treatment with AVASTIN®, which was at the discretion of the attending physician. Forty percent of the patients had extra hepatic disease. The primary endpoint was Progression Free Survival (PFS). With a median follow up of 36.1 months, the median PFS in the liver was 12.6 months versus 20.5 months in Group A versus Group B respectively (HR=0.69; P=0.002). The hepatic Response Rate was 68.8% versus 78.7% (P=0.042), with a Complete Response Rate of 1.9% versus 6.0% (P=0.02) in Groups A and B respectively. Even though hematologic and gastrointestinal adverse events were higher in the SIRT group, the toxicity levels were acceptable. The authors concluded that the addition of SIRT to chemotherapy resulted in a 7.9 month improvement in Progression Free Survival in the liver, for patients with unresectable metastatic ColoRectal cancer (mCRC), with a 31% reduction in the risk of tumor progression in the liver. With the liver being the most common site of spread in patients with metastatic CRC, this study provides Level One evidence to support the use of SIRT in combination with chemotherapy in this patient group. SIRFLOX: Randomized phase III trial comparing first-line mFOLFOX6 ± bevacizumab (bev) versus mFOLFOX6 + selective internal radiation therapy (SIRT) ± bev in patients (pts) with metastatic colorectal cancer (mCRC). Gibbs P, Heinemann V, Sharma NK, et al. J Clin Oncol 33, 2015 (suppl; abstr 3502)</s
The American Urological Association suggested that a PSA of 0.2 ng/mL or higher after Radical Prostatectomy, defines PSA failure or relapse. A PSA rise of 2 ng/ml or more above post Radiation Therapy nadir is considered PSA failure or relapse. Approximately 35% of the patients with prostate cancer will experience PSA only relapse within 10 years of their primary treatment and a third of these patients will develop documented metastatic disease within 8 years following PSA only relapse. The development and progression of prostate cancer is driven by androgens. Androgen Deprivation Therapy (ADT) has therefore been the cornerstone of treatment of advanced prostate cancer and is the first treatment intervention for hormone sensitive prostate cancer. The appropriate time (immediate versus delayed) to start Androgen Deprivation Therapy (ADT) in patients with prostate cancer with rising Prostate-Specific Antigen (PSA), as the only sign of relapse, has remained unclear. This has been partly due to lack of patient accruals and patient reluctance to be randomized, in these clinical trials.