Development Of Dose-limiting Toxicities Research Articles

First in Human Clinical Responses and Persistence Data on TEG001: A Next Generation of Engineered Αβ T Cells Targeting AML and MM with a High Affinity γ9δ2TCR

Introduction: γδT cells target malignant cells by sensing cancer mediated metabolic changes via their γδTCR[1]. We have developed the TEG001 cell product as an 'academic in house product', which are αβ T cells expressing the high affinity Vγ9Vδ2 TCR clone 5 [2]. TEG001 showed tumor reactivity towards a range of malignant cell lines, primary material from patients with various hematological malignancies as well as efficacy in murine models[3]. Here we present the results of dose level 1 and 2, addressing the safety and tolerability of TEG001 in patients with acute myeloid leukemia (AML) or multiple myeloma (MM) (NL6357). Methods: The TEG001 study (NL6357), is a single center, investigator-initiated study, with a standard 3+3 dose escalation design. Cohorts receive a single infusion of 1x106 TEG001 cells/kg (dose level 1), 3x106 TEG001 cells/kg (dose level 2) and 1x107 TEG001 cells/kg (dose level 3). Relapsed and/or refractory AML/high risk MDS and MM patients were eligible. AML patients with > 30% blasts or circulating blasts required bridging therapy. TEG001 cells were produced as previously described[2]. The conditioning regimen consisted of fludarabine i.v. 25 mg/m2 (day -4 to -2) and cyclophosphamide i.v. 900 mg/m2 (day -2). Pamidronate (PAM) (30 mg I.V.) was administered on day 0 and on day 28 to propagate TEG001 activity. TEG001 is detected in peripheral blood samples by flow cytometry as part of immune monitoring (details in Fig. 2). The primary endpoint was the development of dose-limiting toxicities (DLTs) in order to determine the maximum tolerated dose. Main criteria for reaching DLTs were TEG001 related adverse events (AEs) requiring ventilator support and grade 4 AEs not related to the underlying disease. AEs contributable to cytokine release syndrome (CRS) and/or immune effector cell-associated neurotoxicity syndrome (iCANS) grade 3 responding to tocilizumab and/or steroids were not defined as a DLT. Results: Fourteen patients were included. Of the six patients that were not infused, three patients did not respond to bridging chemotherapy, for two patients TEG001 product could not be manufactured for the intended target dose level and one patients went off study due to COVID-19 induced hospital restrictions. Eight patients were dosed: three patients in dose level 1 and three patients in dose level 2. Two patients received an 'out of specification' dose (77% of dose level 1; and 36% of dose level 2, respectively). Of the six patients infused in dose level 1 and 2, five patients had AML and one patient had MM (Fig. 1). No DLTs were observed. No AEs > grade 3 related to TEG001 were observed. Patient 16 (dose level 2), who received PAM according to the protocol on day 0 and 28, developed 2 seizures at day 29 and 30. The seizure responded well to levetiracetam and no other neurological signs associated with iCANS were observed. No infections or abnormalities in the spinal fluid or brain imaging were identified and connection of the seizure to TEG001 remained inconclusive. In all patients TEG001 cells were detectable in peripheral blood by flowcytometry (dose level 2 depicted in Fig. 2). In dose level 1, patient 7 had stable disease (SD, duration 3M). In dose level 2, patient 9 had a blast reduction (not meeting criteria for partial remission (PR); duration 12M) and patient 16, who had 28% bone marrow blasts prior to TEG001 infusion showed full hematological recovery (Fig. 2) and achieved a complete remission (CR, duration 6M). Conclusion: TEG001 cells are well-tolerated at the first 2 dose levels tested. TEG001 cells show persistence up to day 56. One out of three AML patients in dose level 2 achieved a CR one month after TEG001 infusion and SD was observed in both dose levels. The TEG001 study is currently recruiting patients for dose level 3 (1x107 cells/kg). This study was financially supported by Gadeta b.v. [1] Sebestyen, Z., et al., Translating gammadelta (gammadelta) T cells and their receptors into cancer cell therapies. Nat Rev Drug Discov, 2019. [2] Straetemans, T., et al., GMP-Grade Manufacturing of T Cells Engineered to Express a Defined gammadeltaTCR. Front Immunol, 2018. 9: p. 1062 [3] Johanna, I., et al., Evaluating in vivo efficacy - toxicity profile of TEG001 in humanized mice xenografts against primary human AML disease and healthy hematopoietic cells. J Immunother Cancer, 2019. 7(1): p. 69. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Abstract LB-113: Positioning a selective, bi-steric inhibitor of mTORC1 as a combination partner in RAS-driven cancers

Abstract The RAS and PI3K/mTOR signaling pathways function downstream of receptor tyrosine kinases (RTK), and are hyperactivated in a wide range of human cancers. Several points of cross-talk and intersecting feedback mechanisms have also been described, in which inhibition of one pathway node leads to activation of the parallel signaling pathway, thereby decreasing the effectiveness of single-pathway targeted therapies. Concomitant inhibition of both pathways is clearly effective in RAS-driven cancers as demonstrated via genetic means and by the combination of pharmacologic inhibitors of MEK and PI3 kinase in a variety of preclinical models (Engelman 2008, Collisson 2012, Eser 2013) However, the clinical translation of this combination has been largely unsuccessful, primarily due to development of dose-limiting toxicities that prohibit the achievement of optimal therapeutic drug concentrations. Recent advances in the treatment paradigm for RAS mutant non-small cell lung cancer (NSCLC) and colorectal cancer (CRC) include several first-in-class covalent inhibitors of KRASG12C (e.g., AMG510, MRTX849) which have demonstrated a favorable safety profile along with early promising anti-tumor activity in patients with advanced cancers harboring a KRASG12C mutation. Drug-anchored CRISPR screens and combination experiments have identified mTOR signaling as a key mediator that limits therapeutic response to KRASG12C inhibition (Molina-Arcas 2019, Hallin 2019). We have developed a novel class of selective mTORC1 inhibitors, termed ‘bi-steric', that covalently links rapamycin analogs with a mTOR kinase active-site inhibitor, and interacts with both the ATP- and FKBP12/FRB-binding sites of mTORC1. These compounds exhibit potent and selective (>10-fold) inhibition of mTORC1 over mTORC2, durably suppress S6K and 4EBP1 phosphorylation, and induce growth suppression and apoptosis in multiple cancer cell lines. In preclinical tests, these mTORC-1 selective inhibitors do not induce hyperglycemia and are predicted to have reduced mTORC2-mediated toxicities. We tested the combinatorial activity of these mTOR inhibitors and covalent KRASG12C inhibitors in preclinical models of two KRASG12C mutant tumor types predicted to have limited sensitivity to KRASG12C inhibitor monotherapy: a) STK11 deficient NSCLC wherein activation of mTORC1 signaling is also an oncogenic driver (~20% co-occurrence in KRAS-mutant NSCLC, Scheffler 2018) and b) colorectal cancer wherein RTK activation is thought to co-activate PI3 kinase signaling (Ebi, 2011). In each case, we showed combinatorial activity manifest as decreased tumor cell viability in vitro and tumor regressions in vivo. In contrast, single agents exhibited cytostatic effects in vitro and modest effects on tumor growth in vivo. Our data demonstrate that the combination of KRASG12C and bi-steric mTORC1 selective inhibitors elicits marked anti-tumor activity at well tolerated doses in vivo in models of cancer patient populations with current unmet medical need. The mechanistic bases for these combinatorial effects are currently under investigation. Our preclinical results reinforce the importance of mTORC1 as a concurrent target in genetically defined RAS-mutant cancers, and showcase the therapeutic potential of a novel and selective bi-steric mTORC1 inhibitor, currently in IND-enabling studies. Citation Format: Yu Chi Yang, Christopher Schulze, Jingjing Jiang, Denise F. Reyes, Tiffany Choy, Tram Nguyen, Zhican Wang, Dong Lee, Robert J. Nichols, Zhengping Wang, Jacqueline A. Smith, Steve M. Kelsey, Mallika Singh. Positioning a selective, bi-steric inhibitor of mTORC1 as a combination partner in RAS-driven cancers [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr LB-113.

Significance of introduction of alternative dosing schedule for sunitinib during first-line treatment of patients with metastatic renal cell carcinoma.

The objective of this study was to investigate the significance of an alternative dosing schedule for sunitinib in metastatic renal cell carcinoma (mRCC) patients. This study included 154 patients treated with sunitinib as first-line systemic therapy for mRCC, consisting of 62, 47, and 45 receiving sunitinib based on a traditional schedule (TS, 4weeks on and 2weeks off) alone (TS group), alternative schedule (AS, 2weeks on and 1week off) alone (AS group), and TS followed by AS after the development of dose-limiting toxicities (TS-to-AS group), respectively. There were no significant differences in the major clinicopathological characteristics among these three groups. The progression-free survival in the TS group was significantly shorter than in the other two groups, while no significant differences in the overall survival were noted among the three groups. Adverse events (AEs) ≥ grade 3 in the TS and TS-to-AS groups occurred more frequently than in the AS group. Furthermore, there were significant differences in the incidences of AEs, including diarrhea, fatigue, and hypertension, among the three groups, favoring the AS compared with the other two groups. Despite the lack of a significant difference in the incidence of dose reduction among the three groups, the incidences of the interruption and discontinuation of sunitinib in the AS group were significantly lower than in the other two groups. These findings suggest that the introduction of AS for sunitinib during first-line treatment for mRCC patients may promote favorable clinical outcomes regarding the prognosis as well as tolerability compared with treatment on TS alone.

Evaluation of relative dose intensity during the early phase of first-line sunitinib treatment using a 2-week-on/1-week-off regimen for metastatic renal cell carcinoma

Sunitinib treatment with a 2-week-on/1-week-off schedule (Schedule 2/1) is a common alternative regimen with high relative dose intensity (RDI) and superior tolerability for patients with metastatic renal cell carcinoma (mRCC). The prognostic impact of RDI is reported only in 4-week-on/2-week-off or mixed regimens. Herein, we evaluated the prognostic impact of RDI during early-phase sunitinib treatment using Schedule 2/1. Seventy-four patients who received first-line sunitinib treatment using Schedule 2/1 were evaluated. Endpoints were progression-free survival (PFS) and overall survival (OS). We assessed RDI within the initial two cycles (2c-RDI), and its prognostic impact. Predictive factors for 2c-RDI deterioration were also evaluated. The cut-off value of 2c-RDI was set at 65%. Based on this cut-off, 31 patients (42.0%) were classified into the low 2c-RDI group (< 65%). PFS and OS were significantly shorter in the low-2c-RDI patients, compared with the high 2c-RDI patients (median PFS: 6.15 vs. 18.4 months, p = 0.0005; OS 11.0 vs. 39.3 months, p = 0.0002). Furthermore, multivariate analyses showed that the development of dose-limiting toxicities (DLTs) within the initial two cycles, as well as low initial dose, were independent factors for low 2c-RDI (DLTs: OR 18.6, 95% CI 3.27-105.30, p = 0.0010; initial dose: OR 9.26, 95% CI 1.42-60.40, p = 0.020). The most common adverse event was thrombocytopenia (any grade: 24.3%; grade ≥ 3: 8.1%). More than 65% of 2c-RDI should be maintained for optimal therapeutic effect of sunitinib treatment using Schedule 2/1. To achieve the appropriate 2c-RDI, careful follow-up for patient tolerability is needed to avoid early DLT development.

A Phase Ib/II Study of Combined Obinutuzumab (Gazyva) and High-Dose Methylprednisolone (HDMP) As Treatment for Patients with Chronic Lymphocytic Leukemia (CLL)

High-dose methylprednisolone (HDMP) and rituximab (R) is an effective non-myelosuppressive treatment regimen for patients (pts) with chronic lymphocytic leukemia (CLL). Also, this combination has shown activity even in pts who have adverse leukemia-cytogenetics, such as del17p. Phase III studies have demonstrated that CLL pts treated with chlorambucil and obinutuzumab-Gazyva (G), another anti-CD20 mAb, had a superior outcome than comparable pts treated with R-chlorambucil. We hypothesized that G-HDMP is well-tolerated and effective in the treatment of pts with CLL. Accordingly, we initiated an open-label phase Ib/II clinical study.A total of 40 pts were enrolled in two cohorts of 20 pts each (previously untreated (PU) and relapsed/refractory (RR) CLL) and treated with HDMP 1 g/m2on Day 1-3 of cycles 1-4 (28 days/cycle) and G administered based on FDA dosing recommendations for 6 cycles.The pts had a median age of 67 years + 9.1 in the RR cohort and 63 years + 8.3 in the PU cohort. The median baseline absolute lymphocyte count was 30.7 + 7.3 x1,000/mm3 for pts in the RR cohort and 47.6 + 19.7 x1,000/mm3for pts in the PU cohort. Pts showed the following cytogenetic abnormalities: del(17p) in 30% RR vs. 0% PU, del(13q) in 60% RR vs. 70% PU, del(11q) in 20% RR vs. 35% PU, and trisomy 12 in 15% RR vs. 20% PU. Most AEs were grade 1-2 (RR=87%; PU=93%) without development of dose-limiting toxicities. Only two pts needed therapy discontinuation. One pt due to pulmonary embolism and the second pt due to asymptomatic gastrointestinal bleeding that required blood transfusion and resolved spontaneously. Grade 1-2 G-infusion-related reactions (IRR) were observed in 40% and 80% of pts in the RR and PU cohorts, respectively. Grade 3-4 IRR were observed in 10% of pts in the PU cohort only.We observed cytopenias (neutropenia grade 3-4: RR=55%, PU=40%; thrombocytopenia grade 3-4: RR=35%, PU=20%; and anemia grade 3-4: RR=0%, PU=0%). There were no cases of febrile neutropenia. Two pts (10%) in the RR cohort and one pt (5%) in the PU cohort developed infection grade 1-2 that was treated with oral antibiotics but did not require study treatment discontinuation. The most frequent non-hematological adverse events (AEs) were transaminitis, hyperglycemia, and electrolyte alterations (grade 1-2). There were no treatment related deaths in either cohort.The response assessment was performed in all 40 pts by iwCLL criteria. The ORR was 100% in the PU cohort and 95% in the RR cohort. 70% of the pts in the PU cohort and 85% of the pts in the RR cohort achieved a PR. CR was observed in 30% and 10% of the pts in the PU and RR cohorts, respectively. One pt (5%) in the RR cohort and four pts (20%) in the PU cohort achieved MRDneg status (<0.01% CLL in the bone marrow by multiparameter flow cytometry). Only one pt in the RR cohort achieved SD.At a median follow-up of 12.2 months, the RR cohort had a median Progression Free Survival (PFS) of 13.6 months and median Treatment Free Survival (TFS) of 14.7 months; the median Overall Survival (OS) has not been reached. In the PU cohort, the median PFS, TFS and OS have not been reached. One pt from the RR cohort and one pt from the PU cohort died during the follow-up period due to disease progression.G-HDMP was well tolerated and all 40 pts showed hematological and clinical responses during the study treatment without development of unexpected AEs. In both cohorts, most of IRR were grade 1-2 and severe IRR (grade 3-4) were much less compared with previously published data (G-chlorambucil / CLL-11 study). Compared to pts in the CLL-11 study, cytopenias appeared to be more frequent, however, the rate of infection and need for IV antibiotics or hospitalizations was lower. Of note, the eligibility criteria allowed pts with severe cytopenias and transfusion requirement to participate in our study. Response in PU pts were higher in terms of ORR, CR and CR-MRDnegativecompared with the data from the CLL-11 study and suggests a possible synergistic activity between G and HDMP.Overall, G-HDMP was well tolerated in the PU and RR CLL pts with a lower rate of IRR making this regimen more manageable in the outpatient setting. Responses were higher than previously reported in PU pts. Responses in RR pts appear to be comparable to our previous studies using R-HDMP. Our data supports G-HDMP as an alternative combination regimen for the treatment of CLL pts. DisclosuresKipps:Celgene: Consultancy, Honoraria, Research Funding; Pharmacyclics, LLC, an AbbVie Company: Consultancy, Honoraria; Gilead: Consultancy, Honoraria, Speakers Bureau; AbbVie: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria.

A Phase Ib/II Study of Ibrutinib in Combination with Obinutuzumab-Gazyva As First-Line Treatment for Patients with Chronic Lymphocytic Leukemia > 65 Years Old or with Coexisting Conditions

Standard treatment for patients (pts) with chronic lymphocytic leukemia (CLL) is rapidly evolving and gradually has incorporated the use of monoclonal antibodies (mAbs) and targeted therapy with small molecules. Single agent Ibrutinib (a first-in-class BTK inhibitor) has shown to be effective in previously untreated (PU) pts including those that are older than 65 or considered unfit to receive chemotherapy-based combinations. The response rate could be higher in pts receiving ibrutinib (overall response of 71% and complete response of 13%) but the mobilization of lymphocytes, which is typically asymptomatic, decreases the response rate due to lack of complete fulfillment of iwCLL criteria. Ibrutinib-induced lymphocytosis could be ameliorated by using mAbs like rituximab or obinutuzumab-Gazyva (G), a third-generation anti-CD20 mAb, and consequently increased the overall response rate. However, there are no data available assessing the combination of ibrutinib and G in the elderly population (> 65 years old) or in those pts < 65 years old where chemotherapy based agents are not indicated. Accordingly, we initiated an open-label phase Ib/II clinical study of Ibrutinib in combination with G for therapy of PU pts with CLL.The study will enroll 32 PU pts with CLL. Pts receive G administered based on FDA dosing recommendations for 6 cycles (28 days/cycle) and Ibrutinib 420mg po. qd for up to 3 years. All pts receive prophylactic medications (acyclovir, allopurinol and low dose glucocorticoids). Pts will undergo response assessment two months after completion of the study treatment by iwCLL criteria, and will be followed for survival during 3 years until initiation of new treatment for CLL, disease progression, consent withdrawal or death, whichever occurs first. Here we present a preliminary analysis of safety / tolerability with the first 9 pts treated with this regimen.The median age of the pts was 63 years ± 8.6. 78% of the pts had a CIRS > 6, 44% had a Rai stage III-IV and 33% had an ECOG performance >2. The median baseline absolute lymphocyte count (ALC) was 96.6 ± 20.2 x103/mm3. Pts showed the following cytogenetic abnormalities: del(13q) in 67%, trisomy 12 in 22% and del(11q) in 11%. None of these pts showed del(17p).Most adverse events (AEs) were grade 1-2 (94%) without development of dose-limiting toxicities. Only one pt (11%) had a grade 1 G-infusion-related reaction (IRR). We did not observe grade 3-4 IRR. We observed neutropenia (all grades: 33%, grade 3-4: 22%), thrombocytopenia (all grades: 78%, grade 3-4: 11%) and anemia (all grades: 44%). 78% of the pts had a decrease in ALC during the first cycle of treatment and two pts had persistent lymphocytosis up to cycle three. There were no cases of febrile neutropenia. Two pts (22%) had grade 1-2 bleeding (one pt with asymptomatic lower gastrointestinal bleeding and the second pt with epistaxis) that resolved spontaneously without requirement of blood transfusion or study treatment discontinuation. One pt (11%) developed community-acquired pneumonia requiring inpatient treatment with IV antibiotics; the study treatment was held until resolution of symptoms and re-initiated at full dose. The most frequent non-hematological AEs were diarrhea, transaminitis, hyperbilirubinemia, hyperglycemia, and electrolyte alterations (grade 1-2).Two pts were evaluable for response assessment by iwCLL criteria. One pt achieved a complete remission with MRDpositivein the bone marrow by multiparameter flow cytometry and the other pt had a partial response due to small residual lymph nodes > 1.5 cm.Overall, Ibrutinib-G combination has been well tolerated. All 9 pts have had favorable clinical and hematological responses. We observed a resolution of the lymphocytosis in 78% of the pts during the first cycle of treatment. We did not observe unexpected AEs with this regimen allowing all 9 pts to continue in the study. The most important finding thus far has been the very low rate of IRR, only one pt (11% - grade 1), and the absence of grade 3-4 IRR, suggesting that ibrutinib can strongly mitigate the incidence and severity of IRR with G. Pt enrollment continues and updated information will be presented at the meeting. DisclosuresHilger-Rolfe:Pharmacyclics: Employment; AbbVie: Employment. Kipps:AbbVie: Consultancy, Honoraria, Research Funding; Gilead: Consultancy, Honoraria, Speakers Bureau; Pharmacyclics, LLC, an AbbVie Company: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria.

Lipegfilgrastim in patients with chemotherapy-induced neutropenia

The development of dose-limiting toxicities, including myelotoxicity, can significantly limit cytostatic therapy of malignant tumors. Neutropenia associated with high risk of febrile neutropenia (FN) and infectious complications that may interfere with therapy intensity and significantly increases the cost of diagnosis and treatment. With the development of recombinant forms of human granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor, therapy of iatrogenic neutropenia has undergone significant changes. The use of G-CSF (filgrastim, lenograstim, pegfilgrastim) reduces FN incidence in patients receiving myelosuppressive chemotherapy. Until recently, the only original preparation of G-CSF with prolonged action was pegfilgrastim. Lipegfilgrastim (Lonquex, Teva) is a new highly effective long-acting pegylated G-CSF, which has been approved by European Medicines Agency experts for FN prevention in patients receiving chemotherapy. This review summarizes the characteristics of chemical structure, pharmacokinetics, safety and efficacy of lipegfilgrastim.

A Phase Ib/II Study of Combined Obinutuzumab and High-Dose Methylprednisolone (HDMP) As Treatment for Patients with Chronic Lymphocytic Leukemia (CLL)

Abstract Chronic lymphocytic leukemia (CLL) is not curable and ultimately patients (pts) relapse and require additional treatment. In addition, most of CLL pts are older than 65 years old or are unfit to receive chemotherapy. Because of these reasons there is a need for the development of novel therapeutic strategies. Obinutuzumab, a third-generation anti-CD20 mAb, in combination with chlorambucil is currently approved by the FDA for previously untreated pts. Studies have demonstrated that most of the clinical benefit of this regimen is derived from obinutuzumab rather than chlorambucil, and also that obinutuzumab has superior clinical activity than rituximab. Because of these and our previous clinical studies that have shown synergism between HDMP and anti-CD20 antibodies, we initiated an open label phase Ib/II clinical study of obinutuzumab with HDMP for therapy of pts with CLL. The study is divided in two cohorts of 20 pts each, front-line (FL) and relapsed / refractory (RR) CLL. Pts receive HDMP 1g/m2 on Day 1-3 of cycles 1-4 (28 days / cycle) and obinutuzumab administered based on FDA dosing recommendations for 6 cycles. All pts received prophylactic medications (trimethoprim/sulfamethoxazole, acyclovir, fluconazole and allopurinol). 85% of target accrual has been completed (RR cohort=19 pts; FL cohort=15 pts). Here we present a preliminary analysis of safety /tolerability of this regimen. The median age in the RR cohort was 68 years +/- 7.8 and 62 years +/- 7.3 in the FL cohort. 84% and 87% of the pts in the RR and FL cohorts had a CIRS &gt; 6, respectively. The median baseline absolute lymphocyte count was 32.9 +/- 32.6 x103/mm3 for pts in the RR cohort and 49.3 +/- 98.1 x103/mm3 for pts in the FL cohort. Pts showed the following cytogenetic abnormalities: del(17p) in 32% RR vs. 0% FL, del(13q) in 63% RR vs.67% FL, del(11q) in 21% RR vs. 33% FL, and trisomy 12 in 16% RR vs. 20% FL. All 34 pts were assessed for adverse events (AEs). Most AEs were grade 1-2 (RR=88%; FL=92%) without development of dose-limiting toxicities (DLTs). One pt in the RR cohort developed asymptomatic metformin-associated lactic acidosis that required overnight inpatient observation without therapy discontinuation. Grade 1-2 obinutuzumab-infusion-related reactions (IRR) were observed in 42% and 87% of pts in the RR and FL cohort, respectively. We did not observe grade 3-4 IRR. Only one patient has required therapy discontinuation due to asymptomatic GI bleeding that required blood transfusion and resolved spontaneously. We observed neutropenia (RR: all grades: 63%, grade 3-4: 26%; FL: all grades: 53%, grade 3-4: 33%), thrombocytopenia (RR: all grades: 68%, grade 3-4: 37%; FL: all grades: 80%, grade 3-4: 40%) and anemia (RR: all grades: 58%; FL: all grades: 53%). There were no cases of febrile neutropenia. Three pts (16%) in the RR cohort developed community-acquired pneumonia, requiring outpatient treatment with oral antibiotics but not study treatment discontinuation. The most frequent non-hematological AEs were transaminitis, hyperglycemia, and electrolyte alterations (grade 1-2). All 34 pts have had favorable clinical and hematological responses. Six pts (4 pts in the RR cohort and 2 pts in the FL cohort) were evaluable for response assessment by iwCLL criteria. The four pts in the RR cohort achieved a PR. In the FL cohort, 1 pt achieved a CR MRDneg (&lt;0.01% CLL in the marrow), and the other pt achieved a PR. Overall, obinutuzumab with HDMP has been well tolerated with no evidence of DLTs. The profile of AEs appears favorable compared to those noted with obinutuzumab in combination with chlorambucil, particularly in terms of grade 3-4 IRR (0% vs 20%) or rate of therapy discontinuation (3% vs 7%). Enrollment continues and updated information will be presented during the meeting. Disclosures Choi: AbbVie: Consultancy, Other: Advisory Board, Research Funding; Gilead: Consultancy, Other: Advisory Board, Speakers Bureau. Kipps:Pharmacyclics Abbvie Celgene Genentech Astra Zeneca Gilead Sciences: Other: Advisor.

A phase I and pharmacokinetic study of XK469R (NSC 698215), a quinoxaline phenoxypropionic acid derivative, in patients with refractory acute leukemia

A phase I study was performed to determine the safety and pharmacokinetics of XK469R in patients with refractory acute leukemia. The study aimed to determine the maximum tolerated dose (MTD) and dose limiting toxicity (DLT) of XK469R given intravenously over 30 to 60 min on days 1, 3, and 5 of a 21 day cycle. Patients were treated in successive cohorts of six until DLT was observed. Once the MTD was determined, an additional cohort of six patients was enrolled at the previous dose level and that dose was considered the recommended phase 2 dose (RPTD). Forty-six patients were treated at dose levels of 1,400, 1,750, 2,200, and 2,750 mg. The DLTs were: mucositis, colitis and hyperbilirubinemia. Reversible myelosuppression was noted at all dose levels. One (2%) of 42 patients achieved a complete remission and five patients (11%) had hematologic improvement. The half-life of the drug was long with a mean value of 48 h. The mean clearance was 206 mL/h with a coefficient of variation of 32%. No correlation was observed between the development of DLT and pharmacokinetics. The RTPD is 1,750 mg. XK469R induced hematological responses in patients with refractory leukemia at tolerable doses.

A phase I study of q3W R1507, a human monoclonal antibody IGF-1R antagonist in patients with advanced cancer

3590 Background: Insulin-like growth factor receptor (IGF-1R) is a tyrosine kinase cell surface receptor overexpressed in cancer cells which mediates the mitogenic and anti-apoptotic actions of IGF, playing a key role in malignant transformation. The safety and pharmacokinetics of 3-weekly administration of R1507, a human monoclonal antibody selective for IGF-1R, were explored in this phase I dose escalation study in patients with advanced solid tumors or lymphomas. Materials and Methods: Multiple ascending doses of R1507 were administered as a 1 hour infusion every 3 weeks until the development of dose-limiting toxicity (DLT) or progressive disease. Inclusion criteria: ECOG PS 0–1, adequate hematologic, hepatic, and renal function, CD4 count &gt;200/μl. Exclusion criteria: infection, immunosuppressive agents, diabetes mellitus, uncontrolled systemic disease, NYHA III/IV CHF. DLT defined as ≥ grade 2 hypersensitivity reaction; ≥ grade 3 non-hematologic toxicity; ≥ grade 2 cardiac toxicity; ≥ grade 3 hematologic toxicity = 7 days, or dose delay &gt; 1 week due to toxicity. Blood samples were collected following 1st dose for non compartmental PK analysis and for future analysis of IGF-1R levels. Results: 21 patients (pts) (M:F 14:7) were enrolled in 1 of 4 dose levels (dose range 1–16 mg/kg). Mean pt age 57 yrs (range: 30–81), mean prior treatments 4.6 (range: 1–9). Mean treatment cycles 2.6 (range: 1- 6). Six pts remain on study. Adverse events (AE) included infection (6 pts), fatigue (4); rash, fever, arthralgia, cough, diarrhoea, abdominal and back pain (3 each). No DLT or serious AEs attributed to study drug were reported. Activity: 10 pts showed stable disease (median 33 days). PK: Clearance (CL) decreased from 812 mL/Day (Coefficient of Variation [CV] =19.9%) in the 1 mg/kg group to 418 mL/Day (CV=46.7%) in the 16 mg/kg group; Volume of distribution was in the range of 4.4 - 5.4 L (CV=10.9–34.8%). T1/2 increased from 4 to 9 days. Conclusions: Treatment with R1507 is tolerable at the dose of 16mg/kg q3W. Treatment-related toxicities are mild and clinically manageable. Decrease in CL across doses levels suggests a saturable elimination pathway. T1/2 value of ∼8 days supports a weekly dosing for future trials. [Table: see text]