DLTs Of Grade Research Articles

A phase 1 dose escalation/expansion study of FID-007, a novel nanoparticle paclitaxel formulation, in patients with solid tumors.

3026 Background: FID-007 (FID) consists of paclitaxel encapsulated in a polyethyloxazoline (PEOX) polymer excipient designed to enhance PK, biodistribution, and tolerability. In addition to allowing the drug to remain in solution until it can enter a cancer cell, the PEOX nanoparticle preferentially delivers paclitaxel to the tumor through the leaky hyperpermeable vasculature. In xenograft studies, FID reduced or limited tumor growth in multiple tumor types including lung, gastric, breast, pancreatic, and ovarian cancer. Preclinically, FID was more effective at lower or comparable taxane doses, including nab-paclitaxel, with fewer side effects. We present the first-in-human trial of FID. Methods: The study is evaluating the safety, PK, and efficacy of FID in pts with advanced solid tumors. The primary objective is to determine the MTD and RP2D. Pts received FID in doses between 15mg/m2 and 160mg/m2 using a standard 3+3 dose escalation design. FID was given IV on Days 1, 8, and 15 of a 28-day cycle. Eligibility included ECOG 0-2, adequate organ function, and ≤ 3 prior lines of cytotoxic therapy for advanced disease. Results: Thirty-six patients were treated across 7 dose levels. Median age was 61 (39-65). ECOG PS was 2 in 1 patient, 1 in 69% of patients. Median number of prior therapies was 2 (1-5). Median number of cycles was 2.5 (1-30). There were 2 DLTs of grade 3 rash at 100 mg/m2. Given the transient nature of the rash and response to topical therapy, DLT definition was modified to exclude grade 3 rash that lasts ≤ 7 days and 3 additional patients were treated at 100 mg/m2 which was deemed tolerable. There was 1 DLT of grade 4 WBC decrease at 125 mg/m2, and 1 DLT of G3 febrile neutropenia at 160 mg/m2. There was no MTD. All grade treatment related adverse events (TRAEs) in ≥ 25% of pts were rash (64%), alopecia (56%), leukopenia (47%), pruritus (44%), neutropenia (42%), anemia (42%), fatigue (39%), nausea (33%), anorexia (31%), dysgeusia (25%) and peripheral sensory neuropathy (25%). Grade 3/4 TRAEs occurring in >1 pt were maculopapular rash (25%), anemia, neutropenia, and leukopenia (17% each). Of 36 evaluable patients, 7 (19%) had a partial response by RECIST 1.1 (pancreatic, biliary tract, and HNSCC) and 13 (36%) had stable disease. Three out of 4 HNSCC patients with PR had previously been treated with docetaxel. PK is linear and dose proportional. There is no paclitaxel accumulation after weekly dosing, and t1/2 is between 18-26 hours. Based on overall tolerability and PK, the dose of 125mg/m2 (dose level 6) has been chosen as RP2D. Conclusions: FID has a manageable safety profile and demonstrates preliminary evidence of anti-tumor activity in heavily pre-treated pts across different tumor types. No high-grade neuropathy has been noted to date. RP2D of FID is set at 125mg/m2. PK is linear, dose proportional and comparable to that of nab-paclitaxel. Clinical trial information: NCT03537690 .

Analysis of systemic immune changes in patients with advanced cancer treated with immunotoxin LMB-100 and tofacitinib.

e15017 Background: LMB-100 recombinant immunotoxin delivers a modified Pseudomonas exotoxin A payload to mesothelin-expressing tumors. Almost all patients receiving LMB-100 develop anti-drug antibodies (ADAs) after 2 cycles/ 6 doses of the drug, therefore reducing peak serum drug concentrations to near the lower limit of detection. Tofacitinib is an oral JAK inhibitor that had been shown to prevent ADA formation in pre-clinical studies. Apart from assessing safety and tolerability, this trial sought to determine whether co-administration of tofacitinib with LMB-100 delays the formation of neutralizing ADAs so more patients could achieve the peak LMB-100 concentration of > 600 ng/mL during treatment cycle 2. Correlative data examining circulating immune cell subsets and cytokines pre- and on-treatment are presented here. Methods: Patients with pancreatic adenocarcinoma (n = 13) and other mesothelin-expressing solid tumors (n = 3; cholangiocarcinoma, appendix, cystadenocarcinoma) were treated for up to 3 cycles (21 days) with LMB-100 given on days 4, 6, and 8 at 2 dose levels (100 and 140 mcg/kg), accompanied by oral tofacitinib for the first 10 days of the cycle (10 mg BID). Adverse events were assessed as per CTCAE 5.0. Analysis of the cytokine data was performed using a Wilcoxon signed-rank test. Results: DLTs of grade 3 cardiac toxicity (n = 1) and grade 4 hyponatremia (n = 1) were seen at the 140mcg/kg dose of LMB-100. One patient treated at 100 mcg/kg developed a grade 4 pericardial effusion, resulting in early closure of the study for safety. The two patients who experienced cardiac toxicity had lower baseline CD4+ cells and increased CD19+ cells post-LMB-100 treatment. Four out of 8 evaluable patients achieved LMB-100 concentration above the threshold during cycle 2, and 2 out of 3 did so during cycle 3. Analysis of peripheral blood cytokine levels showed sustained increases in TNF-α, IL-8, and IL-10 following LMB-100 administration through to the start of cycle 2. Percentage of Tregs increased through cycle 1 in patients who developed drug-neutralizing ADAs and was significantly higher than in patients with LMB-100 levels above threshold at the start of cycle 2. Conclusions: Combination of LMB-100 with tofacitinib is not safe. An insufficient number of patients was treated to conclusively assess the ability of tofacitinib to stop or delay ADA formation. Increases in circulating Tregs were observed in patients with early neutralizing ADA formation. Clinical trial information: NCT04034238 .

The CDK4/6 inhibitor FCN-437c plus letrozole for the treatment of HR+/HER2– advanced breast cancer: Updated results from a phase 1b study.

e13025 Background: FCN-437c is an oral potent and highly selective CDK4/6 inhibitor without the inhibition of CDK1, CDK2, or CDK5. In the phase 1a dose-escalation part of this study (NCT04488107), the safety profile of FCN-437c was acceptable in patients with ABC, and the maximum tolerated dose was determined to be 300 mg QD when used as monotherapy (presented at AACR 2021). Phase 1b aimed to explore the RP2D and to evaluate the tolerability and antitumor activity of FCN-437c combined with letrozole in patients with previously untreated HR+/HER2– ABC. Methods: Adult, post-menopausal female patients diagnosed with treatment-naive ER+/HER2– ABC were eligible for this expansion stage. Patients received FCN-437c once daily at 200 mg or 300 mg on a 21-day-on and 7-day-off schedule in combination with letrozole 2.5 mg once daily in 28-day cycles. The primary endpoints were safety and RP2D. Results: As of November 26, 2021, 29 patients were enrolled and had a median follow-up of 10.4 months. Of these patients, 25 (86.2%) were endocrine-sensitive and 4 (13.8%) were endocrine-resistant. Visceral disease was present in 21 patients (72.4%), and 1 (3.4%) patient had bone-only disease. DLTs of grade 4 neutropenia occurred in 2 patients (40.0%) in 300 mg dose group; they were considered intolerable. One out of the first 6 patients experienced DLTs in 200 mg dose group (grade 4 neutropenia, leukopenia, and thrombocytopenia); these were also considered to be FCN-437c-related SAEs. FCN-437c-related grade ≥3 TEAEs were observed in 26 (89.7%) patients, with neutropenia (n=24, 82.8%) and leukopenia (n=14, 48.3%) being most common. Among the 28 measurable patients, 16 patients had a PR, the ORR was 57.1% (95% CI 37.2–75.5); the CBR was 82.1% (95% CI 63.1–93.9) (Table). Median PFS, DOR, and OS were not reached. At 6 and 12 months, PFS rates were 92.3% and 83.5%, and DOR rates were 100% and 90%, respectively. A RP2D of 200 mg was suggested per safety considerations and preliminary antitumor activity. Conclusions: FCN-437c plus letrozole was well tolerated and demonstrated antitumor activity in patients with previously untreated HR+/HER2– ABC. FCN-437c in combination with NSAI as the first-line treatment for HR+/HER2– ABC will be further investigated in a phase 3 trial. Clinical trial information: NCT04488107. [Table: see text]

Abstract CT111: Results of a phase 1 dose escalation study of ERY974, an anti-glypican 3 (GPC3)/CD3 bispecific antibody, in patients with advanced solid tumors

Abstract Background: ERY974, a bispecific T cell-redirecting antibody, redirects T cells to tumor cells by engaging the CD3 antigen on T cells and the glypican 3 (GPC3) antigen selectively expressed on tumors. ERY974 demonstrates T cell-dependent cellular cytotoxicity in vitro and transient cytokine elevations in preclinical toxicology studies (Ishiguro et al. 2017). The primary objective of this dose escalation (DE) study was to determine ERY974's maximum tolerated dose in patients with locally advanced or metastatic solid tumors expressing GPC3. Methods: The study included adult patients with advanced or metastatic solid tumors not amenable to standard therapy, histologically confirmed, with measurable disease and a life expectancy ≥ 3 months, including patients with ≤ 1cm and ≤ 1 brain metastasis. Patients with interstitial lung disease, or acute/active chronic infection were excluded. ERY974 was administered IV and dosed weekly. DE was initiated with an accelerated titration design of single patient cohorts followed by three patient cohorts. To mitigate for the toxicity of cytokine release syndrome (CRS), steroid prophylaxis and a flexible study design was implemented which included a two-step intra-patient escalation (regimen A), and a three-step intra-patient escalation (regimen B). Results: 29 patients were enrolled in dose levels ranging from 0.003 μg/kg to 0.81 μg/kg. Treatment-related adverse events that occurred in greater than 20% of patients included CRS and pyrexia. Dose level 0.81 μg/kg (regimen A) was confirmed not tolerable due to DLTs of Grade 3 CRS and Grade 2 CRS in two out of three patients (assessed according to Lee, et al. 2014). The Grade 3 CRS was associated with Grade 3 transaminitis and a Grade 3 elevation of bilirubin. Both CRS events led to dose delay and dose reduction. Increases in IL-6, IL-8 and IL-10 were observed in patients with the CRS. The severity and frequency of CRS in regimen B were similar to those observed in regimen A at the same dose level. One partial response (per modified RECIST criteria) was observed in a patient with esophageal cancer treated with 0.54 μg/kg (regimen B) and having 40% of the tumor tissue staining positive for GPC3 via immunohistochemistry. Stable disease lasting 3 months or longer was observed in four patients. Conclusions: The observed responses and CRS side effects are markers of ERY974 biologic activity. At doses below 0.81 μg/kg (regimen A), ERY974 was generally well tolerated with a manageable toxicity profile, including ERY-induced CRS which was manageable with steroid administration and anti-IL6R therapy. Further research is required to determine if combined prophylactic anti-IL6R and steroid therapy is a more effective strategy for managing CRS.

A phase 1 trial of FID-007, a novel nanoparticle paclitaxel formulation, in patients with solid tumors.

3021 Background: FID-007 (FID) consists of paclitaxel encapsulated in a polyethyloxazoline (PEOX) polymer excipient designed to enhance PK, biodistribution, and tolerability. In addition to allowing the drug to remain in solution until it can enter a cancer cell, the PEOX nanoparticle preferentially delivers paclitaxel to the tumor through the leaky hyperpermeable vasculature. In xenograft studies, FID reduced or limited tumor growth in multiple tumor types including lung, gastric, breast, pancreatic, and ovarian cancer. FID was more effective at lower or comparable taxane doses with fewer side effects. We present the first-in-human trial of FID. Methods: The study is evaluating the safety, PK, and efficacy of FID in pts with advanced solid tumors. The primary objective is to determine the MTD and RP2D. Pts received FID in doses between 15mg/m2 and 125mg/m2 using a standard 3+3 dose escalation design. FID was given IV on Days 1, 8, and 15 of a 28-day cycle. Eligibility included ECOG 0-2, adequate organ function, and no more than 3 prior lines of cytotoxic therapy for advanced disease. Results: Twenty-five pts were treated across 6 dose levels. Median age was 62 (44-76). ECOG PS was 2 in 1 pt and 1 in 64%. Median number of cycles was 2 (1-16). There were 2 DLTs of grade 3 rash at 100 mg/m2. Given the transient nature of the rash and response to topical therapy, DLT definition was modified to exclude grade 3 rash that lasts ≤ 7 days and additional patients were treated at 100 mg/m2 which was deemed tolerable. There was 1 DLT of grade 3 neutropenia at 125 mg/m2. All grade treatment related adverse events (TRAEs) in ≥ 25% of pts were rash (64%), alopecia (52%), pruritus (44%), anemia (44%) leukopenia, fatigue (40% each), dysgeusia, anorexia, nausea (32% each), and neutropenia (28%). Grade 3/4 TRAEs occurring in > 1 pt were anemia (20%), neutropenia, leukopenia, and maculopapular rash (16%). There were no treatment discontinuations due to toxicity. Twenty-two pts were evaluable for response by RECIST 1.1 with a PR rate of 14% (PR in pancreatic, biliary tract and NSCLC) and disease control rate of 59%. PK is linear and dose proportional. There is no paclitaxel accumulation after weekly dosing, and the t1/2 is between 18-26 hours. Conclusions: FID has a manageable safety profile with MTD not reached. Accrual is continuing at 125 mg/m2. PK is linear, dose proportional and comparable to that of nab-paclitaxel. There is preliminary evidence of anti-tumor activity in heavily pre-treated pts across different tumor types. Enrollment in dose escalation continues. Combination studies with immunotherapeutic agents are planned. Clinical trial information: NCT03537690.

A phase I trial of MK-2206 and hydroxychloroquine in patients with advanced solid tumors

Given the evidence that coordinate inhibition of AKT induces autophagy, we studied the combination of the AKT inhibitor, MK-2206 with hydroxychloroquine (HCQ) in patients with advanced solid tumors. Patients were treated with weekly MK-2206 (135mg or 200mg) plus HCQ (200mg, 400mg or 600mg BID). Thirty-five patients were enrolled across 5 dose levels. Two DLTs of grade 3 maculo-papular rash were observed at dose level 2 (MK-2206 200mg weekly plus HCQ at 400mg BID) and 1 DLT of grade 3 fatigue at dose level 2B (MK-2206 135mg weekly plus HCQ 600mg BID). The maximum tolerated dose (MTD) was declared as dose level 2B. The most common adverse events attributed to MK-2206 were hyperglycemia (N = 18; 51%), fatigue (N = 17; 49%), maculo-papular rash (N = 16; 46%), diarrhea (N = 12; 34%), anorexia (N = 11; 31%), and nausea (N = 11; 31%). Patients experiencing adverse events attributed to HCQ were small in number (N = 13) and primarily included fatigue (N = 5; 14%) and maculo-papular rashes (N = 3; 9%). Statistically significant effects on the pharmacokinetic properties of MK-2206 were observed in combination with HCQ. In addition, the plasma concentrations of HCQ in the combination with MK-2206 were significantly higher than the plasma levels of HCQ as monotherapy in prior studies. The best overall response of stable disease was observed in 5/34 (15%) patients. The combination of MK-2206 and hydroxychloroquine was tolerable, but with substantial number of drug-related AEs and minimal evidence of antitumor activity.

Phase I study of TH-302, an investigational hypoxia-targeted drug, and dexamethasone in patients with relapsed/refractory multiple myeloma.

8602 Background: TH-302 is an investigational 2-nitroimidazole prodrug of the DNA alkylator Br-IPM designed to be selectively activated in hypoxia. In multiple myeloma (MM) mouse models, diseased animals demonstrate a marked expansion of areas of hypoxia in the bone marrow. TH-302 exhibited anti-tumor activity against MM in vitro and in vivo and synergism was seen when combined with bortezomib (Hu et al, Blood 2010; Chesi et al, Blood 2012). Based on these findings, a phase I/II study of TH-302 plus dexamethasone (dex) was initiated for patients (pts) with relapsed/refractory MM. Methods: Eligible pts in the study (NCT01522872) had ECOG PS ≤ 2, receipt of at least two prior therapies, and acceptable hepatorenal function and hematologic status. A standard 3+3 dose escalation design was used with a fixed oral 40 mg dose of dex and 40% dose increments of TH-302. TH-302 was administered IV with dex on days 1, 4, 8, and 11 of a 21-day cycle. The objectives were to determine DLTs and the MTD; assess the safety, tolerability and preliminary clinical activity of TH-302 plus dex; and study the relationship between hypoxia within the bone marrow and response to TH-302. Results: Eleven pts have been treated: 7M/4F with a median age 61 years (range: 53 – 86) and 6 prior therapies (range: 3 – 10). All received both bortezomib and lenalidomide/thalidomide containing regimens. TH-302 was dosed at 240 (n=5), 340 (n=4), and 480 (n=2) mg/m² for a median of 5 cycles. No DLTs were reported at 240 or 340 mg/m². Two pts treated at 480 mg/m² had DLTs of grade 3 mucositis, exceeding the definition of MTD. A dose expansion is thus ongoing at 340 mg/m2. Two patients had SAEs related to TH-302 (pneumonia). Five pts continue on study after a median of 7 cycles (range: 2–11). Nine pts have had efficacy evaluations: 2 pts with partial responses, 2 pts with minimal responses, and 5 pts with stable disease, for an overall response rate (of MR or better) of 44%. Conclusions: TH-302 can be administered at 340 mg/m2 biweekly + dex, with dose limiting mucositis seen at higher doses. Initial clinical activity has been noted with an ORR of 44% in heavily pretreated MM pts who are relapsed/refractory to both bortezomib and lenalidomide. Clinical trial information: NCT01522872.

Abstract LB-167: Phase I dose escalation study of abexinostat and doxorubicin in patients with metastatic sarcomas.

Abstract Intro/Objective: Several inhibitors of histone deacetylase have been shown to enhance chemotherapy induced apoptosis and reduce sarcoma tumor burden in preclinical models. We sought to determine the MTD, PK/PD, safety and toxicity of the histone deacetylase inhibitor (HDACi) abexinostat when administered with doxorubicin in patients with metastatic sarcomas. Methods: Participants were enrolled in a standard 3x3 dose escalation phase I study design. Abexinostat was administered on days 1-5 with 75 mg/m2 of doxorubicin administered on day 4 of every 21 day cycle until disease progression, drug intolerance, or a cumulative lifetime dose of 450 mg/m2 of doxorubicin was reached. GCSF support was provided at physician discretion on Arm A or provided to all participants in Arm B. 3-6 subjects were administered abexinostat at doses of 15, 30, 45, and 60 mg/m2 BID. All patients without progressive disease after receiving a cumulative lifetime dose of 450 mg/m2 of doxorubicin continued with abexinostat as a single agent until disease progression. Results: 22 participants (10 with prior doxorubicin therapy) were enrolled (6 in Arm A, 14 in Arm B), 20 were evaluable for DLT, and 17 were evaluable for radiologic response. In Arm A, participants were administered abexinostat at 30 or 15 mg/m2 BID. DLTs of grade 3 and 4 ANC were observed in two out of three participants dosed at 30 mg/m2 BID. Neither of these patients received GCSF prophylaxis. In Arm B, participants were administered abexinostat at 30, 45, or 60 mg/m2 BID, all with mandated GCSF support. Two DLTs were observed on the 60 mg/m2 BID dose (grade 3 infection and grade 4 thrombocytopenia). The pharmacokinetics of abexinostat was not affected by doxorubicin. HDAC activity, as measured by histone acetylation in PBMC, was maximally inhibited at 30mg/m2 BID. In the 17 participants evaluable for radiologic response there was 1 PR, 11 SD, and 5 PD as best response, with 7 participants completing 5 cycles or more. 3 of those participants remain in SD as their last disease status when this abstract was submitted. 4 participants who continued on monotherapy remained in SD for a median of 9.8 weeks after completing doxorubicin. The most common toxicities were fatigue, thrombocytopenia, and anemia (see Table 1). No study related deaths were observed. Conclusion: The MTD for abexinostat is 45 mg/m2 BID when administered on days 1-5 when doxorubicin is given at 75 mg/m2 on day 4 of a 3-week cycle and GCSF support is provided. Toxicities were manageable and tumor responses were seen. Additional studies are needed to further define the specific contributions of HDAC inhibition for patients receiving doxorubicin to treat metastatic sarcoma. Grade Type 1 2 3 4 Totals Fatigue 13 6 0 0 19 Platelets 10 3 1 2 16 Hemoglobin 11 4 1 0 16 Nausea 13 1 0 0 14 Neutrophils 4 1 4 3 12 Leukocytes 6 3 3 0 12 Diarrhea w/o prior colostomy 7 3 1 0 11 Hyperglycemia 7 1 1 0 9 QTc interval 7 2 0 0 9 Alopecia 1 5 1 0 7 Hypophosphatemia 3 4 0 0 7 Constipation 5 2 0 0 7 Extremity/limb pain 6 1 0 0 7 Anorexia 7 0 0 0 7 Lymphopenia 0 2 4 0 6 Pain: other 5 1 0 0 6 Hypomagnesemia 4 1 0 0 5 Hyponatremia 5 0 0 0 5 Taste disturbance 5 0 0 0 5 Citation Format: Edwin Choy, Sriram Balasubramanian, James Butrynski, Jeffrey Morgan, Mint Sirisawad, Chitra Mani, Suzanne George, Andrew Wagner, David Harmon, Yael Rubinstein, Zhenfeng Duan, Francis Hornicek, George Demetri. Phase I dose escalation study of abexinostat and doxorubicin in patients with metastatic sarcomas. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-167. doi:10.1158/1538-7445.AM2013-LB-167

A phase I/II study of AZD6244 in combination with sorafenib in advanced hepatocellular carcinoma.

4100^ Background: Preclinical studies have shown that pharmacological inhibition of the MEK/ERK pathway by AZD6244 enhanced the anti-tumor effect of sorafenib in both orthotopic and ectopic models of HCC. We conducted this study to determine tolerability, pharmacokinetics, and pharmacodynamics of AZD6244 when combined with sorafenib in advanced HCC. Methods: Patients with biopsy-proven unresectable BCLC B/C hepatocellular carcinoma were recruited. Only those with Childs-Pugh A or B (7) liver cirrhosis and without prior systemic therapy were included. Sorafenib at 400mg bd was given 1 week before initiation of AZD6244 which was escalated in subsequent cohorts from 75mg om based on 3+3 design. PK and PD studies and QOL assessments were performed. DCE-MRI imaging was performed to assess tumor vascularity in response to treatment. Results: Fourteen patients were recruited (including 2 replaced). 11 had evaluable disease. Characteristics: all male, all Chinese, 12 were BCLC C stage. Two DLTs were seen out of 6 patients at dose level 1 (AZD6244 at 50mg bd) which were grade 3 fatigue and grade 3 abdominal pain with elevated transaminases. When an additional dose level 1A was added (ADZ6244 at 100mg om), 2 out of 3 patients had DLTs of grade 3 raised aspartate transaminase and grade 3 diarrhea. Thus, the MTD was determined to be AZD6244 at 75mg om when combined with sorafenib 400mg bd. Common toxicities were diarrhea (83%), rash (58%), fatigue (50%), hypertension (42%), anorexia/vomiting/thrombocytopenia (25%). Two patients had reversible LVEF dysfunction and there were no eye toxicities. PK of AZD6244 showed oral clearance of 11.2 + 6.8 L/h and terminal half-life of 6.0 +2.0 h.Objective responses were 3 PR, 6 SD and 2 PD.DCE-MRI measurements demonstrated significant reductions in permeability surface area product (PS, ml/100ml/min) and fractional intravascular blood volume (v1, ml/100ml) seven days after starting sorafenib. No additional antivascular activity was observed when AZD6244 was added to sorafenib. Conclusions: The recommended phase II dose for AZD6244 is 75mg om when combined with sorafenib 400mg bd for advanced HCC patients. This combination is feasible, shows activity and warrants further investigation.

Phase I study of TH-302, a hypoxia-activated cytotoxic prodrug, in subjects with advanced leukemias.

6585 Background: TH-302 is a 2-nitroimidazole prodrug of the DNA alkylator, bromo-isophosphoramide mustard designed to be selectively activated in hypoxic conditions. Preclinical data in mice with ALL have demonstrated marked expansion of hypoxia in areas of marrow leukemia infiltrates (Benito et al., PlosOne, in press). TH-302 also exhibited specific hypoxia-dependent cytotoxicity when tested against primary ALL and AML samples in vitro. Based on these findings, a phase 1 study of TH-302 was designed for advanced leukemias. Methods: Eligibility: ECOG ≤ 3, relapsed/refractory leukemias for which no standard therapy options were available, and acceptable hepatorenal function. A standard 3+3 dose escalation design was used with 40% dose increments. TH-302 was administered IV over 30-60 minutes daily on Days 1-5 of a 21-day cycle. The objectives were to determine the MTD and PK profile of TH-302 with this schedule and to assess preliminary clinical activity of TH-302. Results: 34 subjects with previously treated AML (n=26), ALL (n=6) or CML in blast phase (n=1) received TH-302 at doses of 120 (n=4), 170 (n=4), 240 (n=3), 330 (n=3), 460 (n=16) or 550 (n=4) mg/m². No skin or mucosal toxicity was noted in participants treated with TH-302 doses ≤240 mg/m2. At 330 mg/m2, grade 2 dermatological toxicities included skin ulcer (n=1) and hand/foot syndrome (n=1). Grade 2 mucositis (n=3) and grade 2 skin toxicity (e.g. skin rash, skin ulcers; n=3) were reported at 460 mg/m2; none were dose-limiting. Two of 3 evaluable subjects treated at the 550 mg/m2 cohort experienced DLTs of grade 3 esophagitis. Eight subjects had stable disease or better after 1 cycle. One ALL subject (at 120 mg/m2) cleared marrow blasts with persistent neutropenia. One AML subject (at 550 mg/m2) achieved CRp after 1 cycle with resolution of leukemia cutis. Conclusions: TH-302 administered daily for 5 consecutive days every 3 weeks is well-tolerated with increased incidence of skin and mucosal toxicity at higher dose levels. Clinical activity has been noted with a few objective responses, but majority of cytoreductions in the AML subset were transient. Clinical trials combining TH-302 with various chemotherapeutics with established efficacy in AML and ALL are planned.

Phase I trial of patupilone (P) and RAD001 in patients (pts) with advanced solid tumors

2529 Background: P is an epothilone with activity in solid tumors including docetaxel (D) resistant prostate cancer. R is an oral mTOR inhibitor that demonstrates synergy with P in pre-clinical models, possibly by decreasing resistance to apoptosis. This on-going phase I study is assessing the tolerability of P in combination with R in pts with advanced solid tumors. Methods: Eligible patients with ECOG PS 0–2, adequate organ function and no more than 3 prior chemotherapy treatment received P every 21 days and weekly R using a standard 3+3 dose escalation schema in a 21 day(d) cycle starting at 50% of the phase II dose of P and 60% of the standard weekly dosing of R. Dosing levels are (1) P 5mg/m2 D1, R 30mg D1; (2) P 7.5mg/m2 D1, R 30mg D1 (3) P 7.5mg/m2 D1 R 30mg D1, D8 (3A) P 7.5mg/m2 D1 R 30mg D1, D8, D15 (3B) P 8mg/m2 D1 R 50mg D1, D8 (4) P 10 mg/m2 D1, D8 R 30mg D1, D8 (5) P 10 mg/m2 D1, D8 R 50mg D1, D8. Pharmacokinetic (PK) levels of R were obtained D1, D2 and PBMC were obtained to assess phospho-S6 and to assess markers of apoptosis and autophagy. Results: A total of 24 pts have been enrolled and 23 pts are evaluable for toxicity (tumor types: colon-7, prostate-6, lung-3, ampulla-3, leiomyosarcoma-2, cervical cancer-1). DLTs of grade(g) 3 diarrhea, g3 colitis and g3 fatigue were observed in dose levels 5, 4 and 1 pt in cohort 3A with a colostomy. Cohorts 1–3 were well tolerated with the common AEs of g1 diarrhea, g2 neuropathy after cycle 7, g1/g2 anemia, g1 triglycerides. In pts with prostate cancer (all previously pretreated with D) PSA declines of >50% occurred in 3/5 pts treated with >2 cycles; 1/7 pts with colon cancer had a PR and 3/7 pts with colon cancer had stable disease (SD) > 8 cycles; 1/3 pts with ampullary ca had a PR and a pt with cervical ca had SD x10 cycles. Conclusions: P 7.5mg/m2 and R 30mg D1, D8 is safe and well tolerated. Encouraging evidence of clinical activity is observed in prostate, colon and other tumor types. Enrollment to cohort 3A is ongoing. [Table: see text]

A phase I study of oral belinostat (PXD101) in patients with advanced solid tumors

14092 Background: Belinostat (PXD101) is a hydroxamate HDAC inhibitor which demonstrates broad anti-neoplastic activity in vitro and in vivo. In Phase I studies in patients (pts) with advanced cancer, IV belinostat is well-tolerated up to 1000 mg/m2 daily x5. Preliminary results of an oral formulation of belinostat showed that the oral bioavailability was 20 - 50%. This Phase I trial of oral belinostat will determine the maximal tolerated dose (MTD) of once and twice daily dosing, tolerability and pharmacokinetics (PK) in pts with advanced solid tumors. Methods: Sequential cohorts of 3–6 pts with advanced solid tumors refractory to standard therapy or for which no standard therapy exists were administered belinostat 250–500mg once or twice daily in 4 week cycles. Fasting (day 1) and non-fasting (day 7) pharmacokinetic studies were performed on all patients along with serial ECGs to evaluate any potential effects on QTc prolongation. Patients were evaluated with routine blood work weekly and tumor imaging at the end of cycle 1 then every other cycle. Results: Sixteen pts have been treated in 3 dose levels at 250mg QD (6 pts), 500mg QD (6 pts) and 250mg BID (4 pts). The median number of cycles of therapy is 1 (range 1–5), nine pts continue to be treated. The most common reasons for discontinuation were adverse event (3 pts) and PD (3 pts). No DLTs were identified at 250mg QD or 250mg BID. DLTs of grade 3 dehydration and grade 3 fatigue were reported at 500mg QD. In pts from the first 3 dose cohorts, there were no grade 4/5 events reported. Other Grade 3 toxicities were fatigue (2 pts), abdominal pain (1 pt), ataxia (1 pt), prolonged INR (1 pt), prolonged PTT (1 pt) and confusion (1 pt). Symptoms were transient and usually resolved after drug was held. In > 500 ECG’s collected, there were no QTcF > 500 ms, and no QTcF increase > 60 ms above baseline. To date, the best clinical response observed has been SD in 7 patients. Conclusions: Oral belinostat at doses of 250mg QD and 250mg BID given on a continuous schedule appears to be well tolerated. Alternative dosing schedules are being explored to further dose escalate the belinostat. Updated safety, activity and pharmacokinetic data will be presented on these and alternate dose schedules. [Table: see text]