Encorafenib plus binimetinib versus vemurafenib or encorafenib in patients with BRAF-mutant melanoma (COLUMBUS): a multicentre, open-label, randomised phase 3 trial.

BACKGROUND: Combined BRAF-MEK inhibitor therapy is the standard of care for BRAFV600-mutant advanced melanoma. We investigated encorafenib, a BRAF inhibitor with unique target-binding properties, alone or in combination with the MEK inhibitor binimetinib, versus vemurafenib in patients with advanced BRAFV600-mutant melanoma. METHODS: COLUMBUS was conducted as a two-part, randomised, open-label phase 3 study at 162 hospitals in 28 countries. Eligible patients were aged 18 years or older and had histologically confirmed locally advanced (American Joint Committee on Cancer [AJCC] stage IIIB, IIIC, or IV), unresectable or metastatic cutaneous melanoma, or unknown primary melanoma; a BRAFV600E or BRAFV600K mutation; an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1; and were treatment naive or had progressed on or after previous first-line immunotherapy. In part 1 of the study, patients were randomly assigned (1:1:1) via interactive response technology to receive either oral encorafenib 450 mg once daily plus oral binimetinib 45 mg twice daily (encorafenib plus binimetinib group), oral encorafenib 300 mg once daily (encorafenib group), or oral vemurafenib 960 mg twice daily (vemurafenib group). The primary endpoint was progression-free survival by blinded independent central review for encorafenib plus binimetinib versus vemurafenib. Efficacy analyses were by intention-to-treat. Safety was analysed in patients who received at least one dose of study drug and one postbaseline safety assessment. The results of part 2 will be published separately. This study is registered with ClinicalTrials.gov, number NCT01909453, and EudraCT, number 2013-001176-38. FINDINGS: Between Dec 30, 2013, and April 10, 2015, 577 of 1345 screened patients were randomly assigned to either the encorafenib plus binimetinib group (n=192), the encorafenib group (n=194), or the vemurafenib group (n=191). With a median follow-up of 16·6 months (95% CI 14·8-16·9), median progression-free survival was 14·9 months (95% CI 11·0-18·5) in the encorafenib plus binimetinib group and 7·3 months (5·6-8·2) in the vemurafenib group (hazard ratio [HR] 0·54, 95% CI 0·41-0·71; two-sided p<0·0001). The most common grade 3-4 adverse events seen in more than 5% of patients in the encorafenib plus binimetinib group were increased γ-glutamyltransferase (18 [9%] of 192 patients), increased creatine phosphokinase (13 [7%]), and hypertension (11 [6%]); in the encorafenib group they were palmoplantar erythrodysaesthesia syndrome (26 [14%] of 192 patients), myalgia (19 [10%]), and arthralgia (18 [9%]); and in the vemurafenib group it was arthralgia (11 [6%] of 186 patients). There were no treatment-related deaths except for one death in the combination group, which was considered possibly related to treatment by the investigator. INTERPRETATION: Encorafenib plus binimetinib and encorafenib monotherapy showed favourable efficacy compared with vemurafenib. Overall, encorafenib plus binimetinib appears to have an improved tolerability profile compared with encorafenib or vemurafenib. Encorafenib plus binimetinib could represent a new treatment option for patients with BRAF-mutant melanoma. FUNDING: Array BioPharma, Novartis.

Overall survival in patients with BRAF-mutant melanoma receiving encorafenib plus binimetinib versus vemurafenib or encorafenib (COLUMBUS): a multicentre, open-label, randomised, phase 3 trial.

BACKGROUND: Encorafenib plus binimetinib and encorafenib alone improved progression-free survival compared with vemurafenib in patients with BRAFV600-mutant melanoma in the COLUMBUS trial. Here, we report the results of the secondary endpoint of overall survival. METHODS: COLUMBUS was a two-part, randomised, open-label, phase 3 study done at 162 hospitals in 28 countries. Eligible patients were aged at least 18 years with histologically confirmed, locally advanced, unresectable, or metastatic cutaneous melanoma, or unknown primary melanoma, BRAFV600E or BRAFV600K mutation, an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1, and were treatment naive or had progressed on or after first-line immunotherapy. In part 1 of the study, patients were randomly assigned (1:1:1) by use of interactive response technology to receive oral encorafenib 450 mg once daily plus oral binimetinib 45 mg twice daily (encorafenib plus binimetinib group), oral encorafenib 300 mg once daily (encorafenib group), or oral vemurafenib 960 mg twice daily (vemurafenib group). Randomisation was stratified by the American Joint Committee on Cancer stage, ECOG performance status, and BRAF mutation status. The primary outcome of the trial, progression-free survival with encorafenib plus binimetinib versus vemurafenib, was reported previously. Here we present the prespecified interim overall survival analysis. Efficacy analyses were by intent to treat. Safety was analysed in patients who received at least one dose of study drug. Part 2 of the study was initiated at the request of the US Food and Drug Administration to better understand the contribution of binimetinib to the combination therapy by comparing encorafenib 300 mg once daily plus binimetinib 45 mg twice daily with encorafenib 300 mg once daily alone. Results of part 2 will be published separately. This trial is ongoing and is registered with ClinicalTrials.gov, number NCT01909453, and EudraCT, number 2013-001176-38. FINDINGS: Between Dec 30, 2013, and April 10, 2015, 577 of 1345 screened patients were randomly assigned to receive encorafenib plus binimetinib (n=192), encorafenib (n=194), or vemurafenib (n=191). Median follow-up for overall survival was 36·8 months (95% CI 35·9-37·5). Median overall survival was 33·6 months (95% CI 24·4-39·2) with encorafenib plus binimetinib and 16·9 months (14·0-24·5) with vemurafenib (hazard ratio 0·61 [95% CI 0·47-0·79]; two-sided p<0·0001). The most common grade 3 or 4 adverse events did not change substantially from the first report; those seen in more than 5% of patients treated with encorafenib plus binimetinib were increased γ-glutamyltransferase (18 [9%] of 192 patients), increased blood creatine phosphokinase (14 [7%]), and hypertension (12 [6%]); those seen with encorafenib alone were palmar-plantar erythrodysaesthesia syndrome (26 [14%] of 192 patients), myalgia (19 [10%]), and arthralgia (18 [9%]); and with vemurafenib the most common grade 3 or 4 adverse event was arthralgia (11 [6%] of 186 patients). One death in the combination treatment group was considered by the investigator to be possibly related to treatment. INTERPRETATION: The combination of encorafenib plus binimetinib provided clinically meaningful efficacy with good tolerability as shown by improvements in both progression-free survival and overall survival compared with vemurafenib. These data suggest that the combination of encorafenib plus binimetinib is likely to become an important therapeutic option in patients with BRAFV600-mutant melanoma. FUNDING: Array BioPharma, Novartis.

Pomalidomide augments fetal hemoglobin production without the myelosuppressive effects of hydroxyurea in transgenic sickle cell mice.

Pharmacologic induction of fetal hemoglobin (HbF) expression is an effective treatment strategy for sickle cell disease (SCD) and ß-thalassemia. Pomalidomide is a potent structural analog of thalidomide and member of a new class of immunomodulatory drugs. Recent reports demonstrated that pomalidomide reduced or eliminated transfusion requirements in certain hematologic malignancies and induced HbF ex vivo in CD34(+) progenitor cells from healthy and SCD donors. We investigated the effects of pomalidomide on erythropoiesis and hemoglobin synthesis in a transgenic mouse model of SCD. We found that 8 weeks of treatment with pomalidomide induced modest increases of HbF with similar efficacy as hydroxyurea. However, in stark contrast to hydroxyurea's myelosuppressive effects, pomalidomide augmented erythropoiesis and preserved bone marrow function. Surprisingly, combinatory therapy with both drugs failed to mitigate hydroxyurea's myelotoxic effects and caused loss of HbF induction. These findings support further evaluation of pomalidomide as a novel therapy for SCD.

A Novel Autologous CAR-T Therapy, YTB323, with Preserved T-cell Stemness Shows Enhanced CAR T-cell Efficacy in Preclinical and Early Clinical Development.

CAR T-cell product quality and stemness (Tstem) are major determinants of in vivo expansion, efficacy, and clinical response. Prolonged ex vivo culturing is known to deplete Tstem, affecting clinical outcome. YTB323, a novel autologous CD19-directed CAR T-cell therapy expressing the same validated CAR as tisagenlecleucel, is manufactured using a next-generation platform in <2 days. Here, we report the preclinical development and preliminary clinical data of YTB323 in adults with relapsed/refractory diffuse large B-cell lymphoma (r/r DLBCL; NCT03960840). In preclinical mouse models, YTB323 exhibited enhanced in vivo expansion and antitumor activity at lower doses than traditionally manufactured CAR T cells. Clinically, at doses 25-fold lower than tisagenlecleucel, YTB323 showed (i) promising overall safety [cytokine release syndrome (any grade, 35%; grade ≥3, 6%), neurotoxicity (any grade, 25%; grade ≥3, 6%)]; (ii) overall response rates of 75% and 80% for DL1 and DL2, respectively; (iii) comparable CAR T-cell expansion; and (iv) preservation of T-cell phenotype. Current data support the continued development of YTB323 for r/r DLBCL. SIGNIFICANCE: Traditional CAR T-cell manufacturing requires extended ex vivo cell culture, reducing naive and stem cell memory T-cell populations and diminishing antitumor activity. YTB323, which expresses the same validated CAR as tisagenlecleucel, can be manufactured in <2 days while retaining T-cell stemness and enhancing clinical activity at a 25-fold lower dose. See related commentary by Wang, p. 1961. This article is featured in Selected Articles from This Issue, p. 1949.

Pomalidomide and lenalidomide regulate erythropoiesis and fetal hemoglobin production in human CD34+ cells.

Sickle-cell disease (SCD) and beta thalassemia constitute worldwide public health problems. New therapies, including hydroxyurea, have attempted to augment the synthesis of fetal hemoglobin (HbF) and improve current treatment. Lenalidomide and pomalidomide are members of a class of immunomodulators used as anticancer agents. Because clinical trials have demonstrated that lenalidomide reduces or eliminates the need for transfusions in some patients with disrupted blood cell production, we investigated the effects of lenalidomide and pomalidomide on erythropoiesis and hemoglobin synthesis. We used an in vitro erythropoiesis model derived from human CD34+ progenitor cells from normal and SCD donors. We found that both compounds slowed erythroid maturation, increased proliferation of immature erythroid cells, and regulated hemoglobin transcription, resulting in potent induction of HbF without the cytotoxicity associated with other HbF inducers. When combined with hydroxyurea, pomalidomide and, to a lesser extent, lenalidomide were found to have synergistic effects on HbF upregulation. Our results elucidate what we believe to be a new mechanism of action of pomalidomide and lenalidomide and support the hypothesis that pomalidomide, used alone or in combination with hydroxyurea, may improve erythropoiesis and increase the ratio of fetal to adult hemoglobin. These findings support the evaluation of pomalidomide as an innovative new therapy for beta-hemoglobinopathies.

Targeting the p27 E3 ligase SCF(Skp2) results in p27- and Skp2-mediated cell-cycle arrest and activation of autophagy.

Decreased p27(Kip1) levels are a poor prognostic factor in many malignancies, and can occur through up-regulation of SCF(Skp2) E3 ligase function, resulting in enhanced p27 ubiquitination and proteasome-mediated degradation. While proteasome inhibitors stabilize p27(Kip1), agents inhibiting SCF(Skp2) may represent more directly targeted drugs with the promise of enhanced efficacy and reduced toxicity. Using high-throughput screening, we identified Compound A (CpdA), which interfered with SCF(Skp2) ligase function in vitro, and induced specific accumulation of p21 and other SCF(Skp2) substrates in cells without activating a heat-shock protein response. CpdA prevented incorporation of Skp2 into the SCF(Skp2) ligase, and induced G(1)/S cell-cycle arrest as well as SCF(Skp2)- and p27-dependent cell killing. This programmed cell death was caspase-independent, and instead occurred through activation of autophagy. In models of multiple myeloma, CpdA overcame resistance to dexamethasone, doxorubicin, and melphalan, as well as to bortezomib, and also acted synergistically with this proteasome inhibitor. Importantly, CpdA was active against patient-derived plasma cells and both myeloid and lymphoblastoid leukemia blasts, and showed preferential activity against neoplastic cells while relatively sparing other marrow components. These findings provide a rational framework for further development of SCF(Skp2) inhibitors as a novel class of antitumor agents.

Lenalidomide and CC-4047 inhibit the proliferation of malignant B cells while expanding normal CD34+ progenitor cells.

Clinical studies involving patients with myelodysplastic syndromes or multiple myeloma have shown the efficacy of lenalidomide by reducing and often eliminating malignant cells while restoring the bone marrow function. To better understand these clinical observations, we investigated and compared the effects of lenalidomide and a structurally related analogue, CC-4047, on the proliferation of two different human hematopoietic cell models: the Namalwa cancer cell line and normal CD34+ progenitor cells. Both compounds had antiproliferative effects on Namalwa cells and pro-proliferative effects on CD34+ cells, whereas p21WAF-1 expression was up-regulated in both cell types. In Namalwa cells, the up-regulation of p21WAF-1 correlated well with the inhibition of cyclin-dependent kinase (CDK) 2, CDK4, and CDK6 activity leading to pRb hypophosphorylation and cell cycle arrest, whereas in CD34+ progenitor cells the increase of p21WAF-1 did not inhibit proliferation. Similarly, antiproliferation results were observed in two B lymphoma cell lines (LP-1 and U266) but interestingly not in normal B cells where a protection of apoptosis was found. Finally, CC-4047 and lenalidomide had synergistic effects with valproic acid [a histone deacetylase (HDAC) inhibitor] by increasing the apoptosis of Namalwa cells and enhancing CD34+ cell expansion. Our results indicate that lenalidomide and CC-4047 have opposite effects in tumor cells versus normal cells and could explain, at least in part, the reduction of malignant cells and the restoration of bone marrow observed in patients undergoing lenalidomide treatment. Moreover, this study provides new insights on the cellular pathways affected by lenalidomide and CC-4047, proposes new potential clinical uses, such as bone marrow regeneration, and suggests that the combination of lenalidomide or CC-4047 with certain HDAC inhibitors may elevate the therapeutic index in the treatment of hematologic malignancies.

Phase I Dose-Escalation and -Expansion Study of the BRAF Inhibitor Encorafenib (LGX818) in Metastatic BRAF-Mutant Melanoma.

Purpose: Encorafenib, a selective BRAF inhibitor (BRAFi), has a pharmacologic profile that is distinct from that of other clinically active BRAFis. We evaluated encorafenib in a phase I study in patients with BRAFi treatment-naïve and pretreated BRAF-mutant melanoma.Experimental Design: The pharmacologic activity of encorafenib was first characterized preclinically. Encorafenib monotherapy was then tested across a range of once-daily (50-700 mg) or twice-daily (75-150 mg) regimens in a phase I, open-label, dose-escalation and -expansion study in adult patients with histologically confirmed advanced/metastatic BRAF-mutant melanoma. Study objectives were to determine the maximum tolerated dose (MTD) and/or recommended phase II dose (RP2D), characterize the safety and tolerability and pharmacokinetic profile, and assess the preliminary antitumor activity of encorafenib.Results: Preclinical data demonstrated that encorafenib inhibited BRAF V600E kinase activity with a prolonged off-rate and suppressed proliferation and tumor growth of BRAF V600E-mutant melanoma models. In the dose-escalation phase, 54 patients (29 BRAFi-pretreated and 25 BRAFi-naïve) were enrolled. Seven patients in the dose-determining set experienced dose-limiting toxicities. Encorafenib at a dose of 300 mg once daily was declared the RP2D. In the expansion phase, the most common all-cause adverse events were nausea (66%), myalgia (63%), and palmar-plantar erythrodysesthesia (54%). In BRAFi-naïve patients, the overall response rate (ORR) and median progression-free survival (mPFS) were 60% and 12.4 months [95% confidence interval (CI), 7.4-not reached (NR)]. In BRAFi-pretreated patients, the ORR and mPFS were 22% and 1.9 months (95% CI, 0.9-3.7).Conclusions: Once-daily dosing of single-agent encorafenib had a distinct tolerability profile and showed varying antitumor activity across BRAFi-pretreated and BRAFi-naïve patients with advanced/metastatic melanoma. Clin Cancer Res; 23(18); 5339-48. ©2017 AACR.

Modulation of cellular differentiation and cell fate for cancer therapy.

Dysregulation of fundamental processes in developmental biology such as stem cell differentiation and proliferation may be the basis of many neoplastic diseases. Cancer stem cells have recently been identified in a number of malignancies, including leukemia and breast tumors. Drugs that affect differentiation, such as retinoic acid, have found therapeutic niches for the treatment of various forms of leukemia. As new understanding of stem cell biology and its role in cancer emerges, the development and application of drugs that target stem cell differentiation and cell fate will provide new therapeutic modalities for the management and treatment of malignant diseases.

Final results of a multicenter phase 1 study of lenalidomide in patients with relapsed or refractory chronic lymphocytic leukemia.

Based on clinical activity in phase 2 studies, lenalidomide was evaluated in a phase 2/3 study in patients with relapsed/refractory chronic lymphocytic leukemia (CLL). Following tumor lysis syndrome (TLS) complications, the protocol was amended to a phase 1 study to identify the maximum tolerated dose-escalation level (MTDEL). Fifty-two heavily pretreated patients, 69% with bulky disease and 48% with high-risk genomic abnormalities, initiated lenalidomide at 2.5 mg/day, with dose escalation until the MTDEL or the maximum assigned dose was attained. Lenalidomide was safely titrated to 20 mg/day; the MTDEL was not reached. Most common grade 3-4 adverse events were neutropenia and thrombocytopenia; TLS was mild and rare. The low starting dose and conservative dose escalation strategy resulted in six partial responders and 30 patients obtaining stable disease. In summary, lenalidomide 2.5 mg/day is a safe starting dose that can be titrated up to 20 mg/day in patients with CLL.

Effects of antiretroviral drugs on human immunodeficiency virus type 1-induced CD4(+) T-cell death.

Apoptosis of peripheral blood T cells plays an important role in the pathogenesis of human immunodeficiency virus (HIV) infection. In this study, we found that HIV type 1 (HIV-1) primes CD4(+) T cells from healthy donors for apoptosis, which occurs after CD95 ligation or CD3-T-cell receptor (TCR) stimulation. CD95-mediated death did not depend on CD4 T-cell infection, since it occurred in the presence of the reverse transcriptase inhibitor didanosine (ddI). In contrast, apoptosis induced by productive infection (CD3-TCR stimulation) is prevented by both CD95 decoy receptor and ddI. Our data suggest that HIV-1 triggers at least two distinct death pathways: a CD95-dependent pathway that does not require viral replication and a viral replication-mediated cell death independent of the CD95 pathway. Further experiments indicated that saquinavir, a protease inhibitor, at a 0.2 microM concentration, decreased HIV-mediated CD95 expression and thus cell death, which is independent of its role in inhibiting viral replication. However, treatment of peripheral blood mononuclear cells from healthy donors with a higher concentration (10 microM) of an HIV protease inhibitor, saquinavir or indinavir, induced both a loss in mitochondrial membrane potential (DeltaPsim) and cell death. Thus, protease inhibitors have the potential for both beneficial and detrimental effects on CD4(+) T cells independent of their antiretroviral effects.

Productive HIV-1 infection of primary CD4+ T cells induces mitochondrial membrane permeabilization leading to a caspase-independent cell death.

We have explored in vitro the mechanism by which human immunodeficiency virus, type 1 (HIV-1) induces cell death of primary CD4+ T cells in conditions of productive infection. Although HIV-1 infection primed phytohemagglutinin-activated CD4+ T cells for death induced by anti-CD95 antibody, T cell death was not prevented by a CD95-Fc decoy receptor, nor by decoy receptors of other members of the TNFR family (TNFR1/R2, TRAILR1/R2/OPG, TRAMP) or by various blocking antibodies, suggesting that triggering of death receptors by their cognate ligands is not involved in HIV-induced CD4 T cell death. HIV-1 induced CD4 T cell shrinkage, cell surface exposure of phosphatidylserine, loss of mitochondrial membrane potential (Deltapsim), and mitochondrial release of cytochrome c and apoptosis-inducing factor. A typical apoptotic phenotype (nuclear chromatin condensation and fragmentation) only occurred in around half of the dying cells. Treatment with benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone, a broad spectrum caspase inhibitor, prevented nuclear chromatin condensation and fragmentation in HIV-infected CD4+ T cells and in a cell-free system (in which nuclei were incubated with cytoplasmic extracts from the HIV-infected CD4+ T cells). Nevertheless, benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone did not prevent mitochondrial membrane potential loss and cell death, suggesting that caspases are dispensable for HIV-mediated cell death. Our findings suggest a major role of the mitochondria in the process of CD4 T cell death induced by HIV, in which targeting of Bax to the mitochondria may be involved.

Polyclonal proliferation and apoptosis of CCR5+ T lymphocytes during primary human immunodeficiency virus type 1 infection: regulation by interleukin (IL)-2, IL-15, and Bcl-2.

We measured apoptosis of subsets of T lymphocytes by single-cell analysis of caspase activation, to confirm high turnover of chemokine receptor CCR5(+) T cells in subjects with acute, primary human immunodeficiency virus type 1 (HIV-1) infection (PHI). High levels of spontaneous apoptosis, consisting mainly of CD8(+) T lymphocytes, were closely associated with increases in the activation markers Ki-67, CD38, and the HIV coreceptor CCR5 and with decreases in Bcl-2 and the interleukin (IL)-7 receptor at the single-cell level. Increased expression of Ki-67 and CCR5 ex vivo, as well as increased apoptosis, was seen in all T cell receptor beta-chain variable region (TCRBV) subfamilies studied. The addition of IL-2 or IL-15, but not IL-7, significantly inhibited caspase activation, increased Bcl-2 expression, and rapidly initiated proliferation in vitro of CD8(+) T cells expressing CCR5 and multiple TCRBV subfamilies. Furthermore, IL-15 receptor alpha-chain messenger RNA levels were increased in peripheral blood mononuclear cells during PHI. These results suggest that CCR5(+)Ki-67(+)Bcl-2(dim) activated T cells generated during PHI traffic via blood to tissue sites, where the cells may survive and/or further proliferate under the local influence of IL-2 or IL-15. Understanding cytokine effects on CCR5(+) T cells will be important in understanding chronic HIV-1 replication and pathogenesis.