Phase i/ii trial of 5-Fluorouracil, leucovorin, Zidovudine and dipyridamole for patients with metastatic colorectal-cancer, renal-cell carcinoma and malignant-melanoma

We conducted a phase I/II trial of 5-fluorouracil (5-FU), calcium leucovorin (LV), zidovudine (AZT) and dipyridamole (DP), (FLAP) in patients with metastatic colorectal cancer, renal cell carcinoma and malignant melanoma. AZT and DP were given to enhance the biochemical modulation and antitumor activity of 5-FU and LV. All patients received 5-FU (370 mg/m(2) i.v. bolus day 0-4), LV (50 mg/m(2) p.o. every 4 h day 0-4) and DP (50 mg/m(2) p.o. every 6 h days 0-27). In the phase I portion of the study, AZT was dose escalated in cohorts of 5 patients each, from 50 mg p.o. every 6 h days 0-27 to the MTD of 200 mg p.o. every 6 h days 0-27. Thirty-three patients received 200 mg of AZT in the phase II portion of the trial. Eleven patients developed grade III and 5 patients developed grade IV leukopenia. Four patients developed grade III and 21 patients developed grade IV neutropenia, with six febrile neutropenic episodes. Six patients experienced grade III anemia and four grade III thrombocytopenia. Diarrhea or stomatitis of greater than or equal to grade III occurred in six and four patients, respectively. Fifty-eight percent (19 of 33) of patients required dose reductions of AZT for hematologic toxicity (13 of 19 in the first treatment cycle). At the 200 mg AZT dose level, there were two partial responses in nine colorectal cancer patients (22%), no objective responses in 14 patients with renal cell carcinoma or in 14 patients with melanoma. FLAP does not have significant activity in melanoma, renal cell carcinoma or 5-FU-treated colorectal cancer patients, although it may have activity in untreated colon cancer.

A randomized, double-blind phase II trial of docetaxel plus prednisone (DP) combined with either AT101 or placebo for the first-line therapy of metastatic castration-resistant prostate cancer (CRPC)

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Background: AT-101 (A), a small molecule oral inhibitor of the Bcl-2 protein family has broad preclinical activity including synergy with docetaxel (D). AT-101 has demonstrated activity alone and in combination with D in D-refractory patients with metastatic CRPC.

Methods: A randomized, double-blind, placebo-controlled phase II trial was conducted to compare the combination of DP with either A or placebo in chemo-naive men with progressive metastatic CRPC. A key requirement was progression (bone scan, RECIST or rising PSA ≥ 2 ng/mL) despite androgen deprivation. Stratification factors were pain and performance status. Patients received DP (75mg/m2 day 1; 5mg PO b.i.d.) Q 21 days (1 cycle) with either A (40 mg b.i.d.) or placebo PO on days 1–3. Radiological assessments were performed every 3 cycles. Primary endpoint was overall survival (OS) and 221 patients were planned for 110 events (80% power, HR 0.67, 1-sided alpha 0.1).

Results: 221 patients were randomized to ADP or placebo-DP and baseline factors were balanced. Efficacy outcomes (OS, PFS, PSA declines, disease control) were not significantly different ( Table ). In a subgroup of patients with poor-risk CRPC (n=34), efficacy endpoints appeared to favor ADP with a median OS of 19 months vs.14 months for placebo-DP. Grade 3/4 AEs that occurred with higher incidence in the ADP arm compared to placebo-DP included cardiac AEs (5% vs. 2%), lymphopenia (23% vs. 16%), neutropenia (47% vs. 40%), ileus (2% vs. 0%) and pulmonary embolism (6% vs. 2%).

Conclusions: The combination of AT-101 with DP in men with chemonaive metastatic CRPC was well tolerated but did not extend OS compared to placebo-DP. There was a potential benefit in a subset of high-risk patients.

[Table: see text]

[Table: see text]

An open-label, multicenter, phase I/II study of AT-101 in combination with docetaxel (D) and prednisone (P) in men with castrate-resistant prostate cancer (CRPC)

5062

Background: Antiapoptotic Bcl-2 family proteins are overexpressed in CRPC and contribute to resistance to therapy. The oral pan-Bcl-2 inhibitor AT-101 (Bcl-2, Bcl-XL, Bcl-W, Mcl-1) is active as a single agent and in combination in in vitro and in vivo tumor models and as a single agent in CRPC. The Phase 1 portion of the study determined the recommended dose for phase II to be D (75mg/m2 q3weeks) in combination with P (5mg b.i.d. on days 1–21), and AT-101 at 40mg b.i.d. on days 1–3 of each 21-day cycle, and was previously reported. Methods: Men ≥18 years of age with chemotherapy-naïve CRPC (N = 36). Safety (NCI CTCAE v3.0) and efficacy (Bubley Criteria for PSA) were assessed at 3-wk intervals. Radiological assessments were performed at 6-wk intervals for pts with soft tissue disease and bone scans were performed after cycle 6 and at the completion of therapy. Results: 36 patients (pts) have been enrolled in the study. Twenty-four (67%) pts achieved a partial response (PR) (>50% PSA decline), and 26 (72%) pts treated had at least a 30% decrease in PSA level. Nine of 19 pts (47%) with measurable disease had a PR. One PR was unconfirmed per RECIST. Thirteen pts (36%) completed >10 cycles of therapy (range 2–24) thus far. Four pts remains active. Safety data is available for 31 pts. The most common (>20%) Adverse Events (AEs) include: fatigue (68%), nausea (52%), diarrhea (45%), alopecia (32%), constipation and dysgeusia (26%), and neutropenia and vomiting (26%). Neutropenia was the only gr. 4 event occurring in more than one pt (3pts). Serious Adverse Events (SAEs) considered related were reported in 5 pts (16%). The only SAEs reported in 2 or more pts were urinary tract infection (3 pts) and deep vein thrombosis (2 pts) and none were considered related. No ileus has been reported. Conclusions: AT-101 when given in combination with D/P is well tolerated and shows preliminary evidence of efficacy in pts with CRPC. A randomized trial is ongoing.

[Table: see text]

Preliminary report of an open-label, multicenter, phase I/II study of AT-101 in combination with docetaxel (D) and prednisone (P) in men with docetaxel refractory prostate cancer

5145

Background: Antiapoptotic Bcl-2 family proteins are overexpressed in castrate resistant prostate cancer (CRPC) and contribute to resistance to therapy. AT-101 is a pan-Bcl-2 inhibitor (Bcl-2, Bcl-XL, Bcl-W, and Mcl-1) and potent inducer of proapoptotic proteins. AT-101 is active as a single agent and in combinations with standard therapies in in vitro and in vivo tumor models, as a single agent in a phase II trial in CRPC, and in combination with D/P as first-line therapy in CRPC, as demonstrated by declines in PSA and RECIST responses. Methods: Men ≥18 years of age with docetaxel-refractory CRPC were eligible. Patients (pts) must have PSA progression per the Bubley criteria or documented disease progression while receiving prior D/P therapy. Pts (n = 40) were treated with D (75 mg/m2 day 1), P (5mg b.i.d. on days 1–21) and AT-101 40mg b.i.d. on days 1–3 of each 21-day cycle. Safety (NCI CTCAE v3.0) and efficacy (Bubley Criteria for PSA) were assessed at 3-wk intervals. Radiological assessments were performed at 6-wk intervals for pts with soft tissue disease and bone scans were performed after cycle 6 and at the completion of therapy. Results: Efficacy data was available on 34 pts. Thirty-five percent (12/34) of pts treated had at least a 30% decrease in PSA level and 18% (6/34) of pts achieved a >50% PSA decline. Twenty one of 34 pts included in this analysis had measurable disease. Five pts (24%) with measurable disease had a PR or CR by RECIST criteria and one additional patient had tumor shrinkage of 29%. Two (2) RECIST PRs are unconfirmed. Thus far, 3 pts have been on therapy for 6 months or more and 15 pts remain on study. Safety data was available on 22 pts. The most common (>20%) adverse events (AEs) included fatigue (55%), anorexia, including weight decreased (45%), diarrhea and nausea (27%), vomiting and neutropenia (23%). The grade 3/4 AEs occurring in more than 1 pt were: neutropenia (5), anemia, anorexia, dyspnea and leukopenia (2 pts each). One partial small bowel obstruction was the only related, serious adverse event (SAE) reported to date. Conclusions: This data supports that AT-101 can be administered safely with D/P in pts with CRPC who are docetaxel-refractory. Durable PSA and RECIST responses were observed.

[Table: see text]

Extended phase I trial of the oral pan-Bcl-2 inhibitor AT-101 by multiple dosing schedules in patients with advanced cancers

3583

Background: Over-expression of Bcl-2 family proteins is common in human cancers. Initial trials of the oral pan-Bcl-2 inhibitor AT-101 showed acute dose limiting toxicity of Gr 3–4 AST/ALT (MTD 40 mg/d), and ileus with prolonged dosing daily (QD) for 21/28 days per cycle (Saleh, NCI_EORTC, 2005; James, ASCO, 2006). Our ongoing Phase 1 study tests different dosing schedules of AT-101 in adults with advanced cancers. Methods: Serial patient (pt) cohorts received AT-101 at escalating doses twice a day for three days every other week (BIDx3dEOW) or once weekly (QW). Adverse events (AEs) were graded by the NCI CTCAE v. 3.0. Results: 24 pts have received pulse dosing; safety data are available for 20 pts (30–70 mg BIDx3dEOW, N=13; 80–160 mg QW, N=7). For comparison, 38 pts received 5–60 mg QD. Median number of cycles (range): BIDx3dEOW_2(1–9); QW_3(1–3), QD_2(1–12). AST/ALT is not yet dose limiting, nor the MTD reached, at 70 mg BIDx3dEOW or 160 mg QW. Ileus occurred in 4/38 pts dosed daily but in no pts on either pulse schedule. Other potentially related Gr 3–4 AEs were: BIDx3dEOW (6 pts)–AST (1 pt), abdominal pain (2 pts), elevated CK/right ventricular dysfunction (1 pt w/history of COPD/doxil therapy), hypokalemia (1 pt);QW: none; QD: AST/ALT (5 pts), nausea/vomiting/diarrhea (3 pts each) fatigue (2 pts), hypocalcemia (2 pts), hypokalaemia/anorexia/dehydration/hypophosphatemia (1 pt), elevated GGT (1 pt). The most common Gr 1–2 AEs_nausea/vomiting/fatigue_occurred in over 50% of QD and BIDx3dEOW pts but only 1/7 QW pts. Plasma Cmax (mean ± SD, μM): 70 mg BIDx3d EOW, 2.4 ± 0.9; 160 mg QW, 3.5 ± 1.3; 40 mg/d (MTD, 21/28 d), 2.6 ± 2.0. T ½ was approx. 3 hours on all schedules. Conclusions: Pulse dosing of AT-101 appears associated with reduced toxicity than more continuous daily dosing, and may be preferable in combination regimens.

No significant financial relationships to disclose.

Phase I Trial of ISIS 5132, an antisense oligonucleotide inhibitor of c-raf-1, administered by 24-hour weekly infusion to patients with advanced cancer

Raf-1 is a serine/threonine kinase that functions as a critical effector of Ras-mediated signal transduction via the mitogen-activated protein kinase pathway. Constitutive activation of this pathway directly contributes to malignant transformation in many human tumors. A 20-base phosphorothioate oligonucleotide complementary to c-raf-1 mRNA (ISIS 5132; CGP 69846A) has been shown to specifically suppress Raf-1 expression both in vitro and in vivo. This Phase I trial, involving 22 patients with advanced cancer, was designed to evaluate the safety, feasibility, and maximum tolerated dose of ISIS 5132 administration as a weekly 24-h i.v. infusion. Pharmacokinetic analysis was performed, and c-raf-1 mRNA levels in peripheral blood mononuclear cells were assessed using quantitative reverse transcription-PCR. This trial defined a maximum tolerated dose of 24 mg/kg/week on this schedule. Two of four patients treated at 30 mg/kg/week had serious adverse events after the first dose of ISIS 5132, including acute hemolytic anemia and acute renal failure and anasarca. There were no major responses documented. Dose-dependent complement activation was demonstrated on this schedule, but not on previously evaluated schedules, of ISIS 5132 administration. In contrast to other trials of ISIS 5132, there appeared to be no consistent suppression of peripheral blood mononuclear cell c-raf-1 mRNA level on this schedule at any of the dose levels analyzed. These data suggest that the efficacy and toxicity profiles of antisense oligonucleotides may be highly dependent on the schedule of administration and support the analysis of the putative molecular target in the evaluation of novel therapeutics.

c-raf-1 depletion and tumor responses in patients treated with the c-raf-1 antisense oligodeoxynucleotide ISIS 5132 (CGP 69846A)

Abnormally regulated signaling through proliferative signal transduction pathways characterizes many of the common solid tumors. The best described of these involves potentially oncogenic proteins of the Ras family, which activate Raf proteins in the early steps of the mitogen-activated protein kinase cascade. ISIS 5132, a phosphorothioate antisense oligodexoynucleotide directed to the 3' untranslated region of the c-raf-1 mRNA, inhibits the growth of human tumor cell lines in vitro and in vivo in association with specific down-regulation of target message expression. Using a semiquantitative reverse transcription-PCR assay, we analyzed changes in c-raf-1 mRNA expression in peripheral blood mononuclear cells collected from patients with advanced cancers treated with ISIS 5132 as part of a clinical trial. Specimens were collected for analysis pretreatment and on days 3, 5, 8, and 15 of the first cycle and on day 1 of each subsequent cycle. We observed significant reductions of c-raf-1 expression from baseline by day 3 in 13 of 14 patients (P = 0.002). The time course and depletion of c-raf-1 message in peripheral blood mononuclear cells paralleled the clinical benefit in two patients. These findings demonstrate that ISIS 5132 specifically reduces target gene expression in treated patients and that peripheral blood mononuclear cells are suitable tissues for biomarker studies in future trials.

Phase I clinical/pharmacokinetic and pharmacodynamic trial of the c-raf-1 antisense oligonucleotide ISIS 5132 (CGP 69846A)

PURPOSE

Raf-1 is a protein kinase that plays a broad role in oncogenic signaling and acts as a downstream effector of Ras in the mitogen-activated protein kinase pathway. The present study was designed to determine the maximum-tolerated dose (MTD), toxicity profile, pharmacokinetics, and antitumor activity of the c-raf-1 antisense oligodeoxynucleotide ISIS 5132 (CGP 69846A; ISIS Pharmaceuticals Inc, Carlsbad, CA). The effect of ISIS 5132 on c-raf-1 gene expression in peripheral-blood mononuclear cells (PBMCs) of treated patients was studied using a reverse transcriptase polymerase chain reaction assay.

PATIENTS AND METHODS

Patients with refractory malignancies received ISIS 5132 as a 2-hour intravenous infusion three times weekly for 3 consecutive weeks. Pharmacokinetic sampling was performed during the first cycle in all patients; PBMCs for c-raf-1 mRNA analysis were collected at baseline and on days 3, 5, 8, and 15 of cycle 1 and on day 1 of each cycle thereafter.

RESULTS

Thirty-one patients received ISIS 5132 at one of nine dose levels ranging from 0.5 mg/kg to 6.0 mg/kg. Clinical toxicities included fever and fatigue, but these were not dose limiting. A clinically defined MTD was not reached. The harmonic mean half-life of ISIS 5132 was 59.8 minutes (range, 35.5 to 107.3 minutes). The area under the concentration-time curve increased linearly with dose, and mean plasma clearance was 1.86 mL/kg/min (range, 1.21 to 2.41 mL/kg/min). Two patients experienced prolonged stable disease lasting more than 7 months, which was associated with persistent reduction in c-raf-1 expression in PBMCs. Significant decreases in c-raf-1 expression were identified at time points after the baseline value (P <.05) at doses >/= 2.5 mg/kg.

CONCLUSION

ISIS 5132 is well tolerated at doses up to 6.0 mg/kg when administered as a thrice weekly 2-hour infusion for 3 consecutive weeks. The pharmacokinetic behavior of the drug is reproducible, and suppression of target gene expression is observed in circulating PBMCs.

Antigen-specific agents in development

Differences in antigen expression between tumor cells and normal cells can be exploited to develop a variety of therapeutic anticancer agents. For example, vaccines containing tumor antigens can be administered to patients to elicit an immune-mediated attack against the tumor. Tumor antigens can also be targeted by passive transfer of monoclonal antibodies (MoAbs), or MoAbs that have been modified to carry toxin molecules. A large number of these antigen-specific agents are currently in clinical or late preclinical development. For the anticancer vaccines, much of the current development is focused on determining optimum immunization approaches. In the case of antibody-based reagents, second- and third-generation constructs are being developed to improve potency, decrease immunogenicity, and increase distribution to tumor.

A phase I randomized study of subcutaneous adjuvant IL-2 in combination with an autologous tumor vaccine in patients with advanced renal cell carcinoma

We performed a prospective, randomized study to determine whether subcutaneous administration of interleukin-2 (IL-2) in combination with an autologous renal cell vaccine is feasible and can potentiate antitumor immunity. Seventeen patients with metastatic renal cell carcinoma underwent surgical resection with preparation of an autologous tumor cell vaccine. Patients were vaccinated intradermally twice at weakly intervals with 10(7) irradiated tumor cells plus bacillus Calmette-Guérin, and once with 10(7) tumor cells alone. Patients were randomized to one of three groups: no adjuvant IL-2, low-dose IL-2 (1.2 x 10(6) IU/m2), or high-dose IL-2 (1.2 x 10(7) IU/m2). IL-2 was administered subcutaneously on the day of vaccination and the subsequent 4 days. Immune response was monitored by delayed-type hypersensitivity (DTH) response to tumor cells as compared with normal autologous renal cells. Sixteen of 17 patients received vaccine therapy. Four patients developed cellular immunity specific for autologous tumor cells as measured by DTH responses; two had received no IL-2 and two had received high-dose IL-2. There were two partial responses (PR) noted, both in patients who received high-dose IL-2. One responding patient was DTH(+) and one was negative. A third patient who was DTH(+) after vaccination with no IL-2 had a dramatic PR after receiving IL-2 subcutaneously in a subsequent protocol. Prospective testing of response to recall antigens indicated that only 5 of 12 tested patients were positive, including both clinical responders. These data suggest that subcutaneously administered adjuvant IL-2 does not dramatically augment the immunologic response to autologous renal cell vaccines as determined by the development of tumor-specific DTH response.

Phase I study of subcutaneously administered interleukin-2 in combination with interferon alfa-2a in patients with advanced cancer

PURPOSE

Although high-dose interleukin-2 (IL-2) can produce durable remissions in a subset of responding patients with renal cell carcinoma (RCC), this occurs in the setting of significant toxicity. The purpose of this study is to define the maximum-tolerated dosage (MTD) of IL-2 and interferon alfa-2a (IFN alpha-2a) that can be administered chronically on an outpatient basis.

PATIENTS AND METHODS

Fifty-three patients with advanced cancer of variable histology with good prognostic features were treated in six cohorts. Patients in cohorts one through five received IL-2 (1.5 or 3.0 x 10(6) million units (mU)/m2) Monday through Friday and IFN alpha-2a (1.5 or 3 x 10(6) mU/m2) daily for a 4-week cycle. In cohort six, IFN alpha-2a was given three times a week. Immunologic monitoring, including serum levels of soluble IL-2 receptor (sIL-2R) and neopterin, flow cytometry, and natural killer cell (NK) activity, were measured. Patients were evaluated for toxicity, response, and survival.

RESULTS

Almost all patients developed grade I/II toxicities commonly associated with cytokine therapy. Symptoms were most severe with the first treatment of each week. Dose-limiting toxicities included grade III fatigue, hypotension, and creatinine elevations. The MTD was 1.5 mU/m2 daily x 5 given subcutaneously repeated weekly for IL-2 and 1.5 mU/m2 daily subcutaneously (dose level 3) for IFN. Six of 25 assessable patients with RCC (24%) achieved a partial response (PR), including four of eight patients who were previously untreated. There were no objective responses in patients with other tumors, including 12 melanoma patients.

CONCLUSION

IL-2 and IFN alpha-2a can be given with tolerable toxicities on an outpatient basis and shows significant activity in patients with metastatic RCC.

Treatment of cancer patients with ex vivo anti-CD3-activated killer cells and interleukin-2

PURPOSE

This study describes the physiologic and biologic effects resulting from the adoptive transfer of ex vivo anti-CD3-stimulated T-killer cells (T-AK) to patients with advanced cancer in combination with interleukin-2 (IL-2).

METHODS

Autologous peripheral-blood mononuclear cells were obtained by leukapheresis and stimulated ex vivo with anti-CD3. The stimulated cells were reinfused at one of three dose levels on the next day (5 x 10(9), 7.5 x 10(9), and 1 x 10(10)). Cell administration was followed by IL-2 given by bolus and continuous infusion (1.5 x 10(6) U/m2 and 3.0 x 10(6) U/m2, respectively) for 7 days, or continuous infusion alone (3.0 x 10(6) U/m2) for 14 days.

RESULTS

Pronounced leukocytosis and atypical lymphocytosis were observed with individual values as high as 80,000 and 50,000 cells/microL, respectively. The other major clinical sequelae included a marked lactic acidosis with bicarbonate levels as low as 4.0 mmol/L in some patients, and prolongation of the prothrombin time (PT) and partial thromboplastin time (PTT) due to decreases in clotting factors VII, IX, and X. Antithrombin III levels were also reduced. Hypotension associated with increased serum nitrate and neopterin levels was observed. These toxicities were accompanied by increases in hepatocellular enzymes and creatinine previously described with IL-2. These events occurred at a time when the number of circulating T-AK cells reached their peak. The amount of bolus IL-2 correlated with increases in WBC count (P = .0311), atypical lymphocytes (P = .0241), PT (P = .0006), and PTT (P = .0122).

CONCLUSION

Substantial in vivo expansion of activated T lymphocytes was induced by a protocol combining ex vivo activation of peripheral-blood cells with anti-CD3 antibody followed by adoptive transfer and IL-2 administration. The synchronous expansion of these T cells superimposed on diminished liver and kidney function from IL-2 can cause profound but reversible metabolic changes.