Oncology phase I trial design and conduct: time for a change - MDICT Guidelines 2022

In 2021, the Food and Drug Administration Oncology Center of Excellence announced Project Optimus focusing on dose optimization for oncology drugs. The Methodology for the Development of Innovative Cancer Therapies (MDICT) Taskforce met to review and discuss the optimization of dosage for oncology trials and to develop a practical guide for oncology phase I trials. Defining a single recommended phase II dose based on toxicity may define doses that are neither the most effective nor the best tolerated. MDICT recommendations address the need for robust non-clinical data which are needed to inform trial design, as well as an expert team including statisticians and pharmacologists. The protocol must be flexible and adaptive, with clear definition of all endpoints. Health authorities should be consulted early and regularly. Strategies such as randomization, intrapatient dose escalation, and real-world eligibility criteria are encouraged whereas serial tumor sampling is discouraged in the absence of a strong rationale and appropriately validated assay. Endpoints should include consideration of all longitudinal toxicity. The phase I dose escalation trial should define the recommended dose range for later testing in randomized phase II trials, rather than a single recommended phase II dose, and consider scenarios where different populations may require different dosages. The adoption of these recommendations will improve dosage selection in early clinical trials of new anticancer treatments and ultimately, outcomes for patients.

Dyamic contrast enhanced MRI (DCE-MRI) pharmacodynamic (PD) study of sorafenib in metastatic renal cell carcinoma (RCC): Results of a randomized, phase II trial

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Background: SOR is an antiangiogenic drug for metastatic RCC. We conducted a randomized, dose ranging trial to investigate if DCE-MRI is a PD marker for SOR. Methods: Patients (pts) were randomized to placebo, 200 or 400 mg bid SOR. DCE-MRI was performed at baseline and after 4 weeks (wks) of therapy at which time placebo pts were rerandomized to 200 or 400 mg bid of SOR. RECIST based response was determined by CT every 12 wks. DCE-MRI parameters, area under the contrast concentration vs. time curve for 90 seconds after contrast injection (IAUC90) and Ktrans, were calculated for a tumor region-of-interest selected in a blinded manner. Ktrans was calculated with the Tofts model using a tumor local arterial input function from a multiple reference tissue method. Blood pressure (BP) was obtained from clinic charts. Primary endpoint: change in Ktrans or IAUC90 over 4 wks with a planned 66 pts to detect 20% and 40% decrease in 200, 400 mg groups. Results: Due to SOR approval 57 pts were enrolled, 48 with two MRIs (5 early progression, 3 withdrew, 1 toxicity); 44 are evaluable for study endpoints. Analyses were conducted with log ratio of IAUC90 and Ktrans at 4 wks relative to baseline. Mean IAUC90 log ratio (± SD) in the placebo, 200 and 400 mg cohorts were 0.041 (± 0.197), -0.040 (± 0.132), -0.356 (± 0.411) respectively (p = 0.0003 for linear trend), corresponding to changes of +4%, -4% and -30%. Ktrans log ratios were 0.131 (± 0.315), -0.148 (± 0.382), -0.271 (± 0.499) respectively (p = 0.0077 for trend) corresponding to changes of +14%, -14% and -24%. In 27 pts with plasma SOR levels, change in IAUC90 and Ktrans did not correlate with steady state levels on day 28. Using a Cox proportional hazards model, IAUC90 and Ktrans change are not predictors of progression-free survival (median f/u 24 wks). The mean BP increased with SOR dose (0.8 ± 8.0, 8.3 ± 10.4, and 10.5 ± 11.1 for the placebo, 200, and 400 mg doses) but no correlation with IAUC90 or Ktrans change was seen. Conclusions: DCE-MRI parameters IAUC90 and Ktrans have high variability and are PD markers for SOR, but the magnitude of effect in this prospective blinded study is less than previously reported. With this small study, no correlations with PK or clinical outcome are detectable.

No significant financial relationships to disclose.

Phase I and pharmacokinetic (PK) study of PTK787/ZK222584 (PTK/ZK) plus capecitabine (cape) in patients (Pts) with advanced cancer

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Background: PTK/ZK is a small molecule inhibitor of the vascular endothelial growth factor receptor family. Cape is a standard treatment for pts with breast and colon cancer, tumors for which angiogenesis inhibition is beneficial. Therefore, we conducted a phase I study of the combination to determine the maximally tolerated doses (MTD), toxicities and PK interactions. Methods: Eligible pts had advanced cancer with no standard treatment option, Karnofsky performance status (KPS) > 70, and normal organ function. Pts with bone marrow or CNS involvement or who had more than 4 prior chemotherapy regimens were excluded. A dose escalation (dosesc) phase was conducted to determine the MTD followed by a dose expansion (dosexp) phase to assess PK interactions. PTK/ZK was given as a single oral daily doser without interruption and cape was given orally twice daily for 14 of 21 days. Results to Date: 43 pts (30 male, 13 female), median age 61 y (34–78 y) and median KPS 95 (70–100) were enrolled in the dosesc phase. 37 had prior chemotherapy; 5 had radiation only. Diagnoses included colorectal cancer (10), head/neck (7), sarcoma (5), renal (4), stomach/pancreas (3 each) and others (11). 29/43 pts were evaluable for MTD determination and received a total of 145 cycles. Doses of PTK/ZK-cape (mg-mg/m2) were: 750/2,500; 1,000/2,500; 750/2,000; 1,000/2,000; 1,250/2,000. DLT occurred in 1/6 pts (gr 3 fatigue) at 750/2,500; 2/2 pts (≥gr 3 fatigue, hypertension [HTN]) at 1,000/2,500; 0/3 pts at 750/2,000; 2/12 pts (≥ gr 3 dizziness, HTN and seizure) at 1,000/2,000 and in 1/6 (gr 3 proteinuria) pts at 1,250/2,000. 1,250 mg was the highest PTK/ZK dose planned. Other common toxicities in the dosesc phase were hand-foot syndrome (HFS, 93%) and HTN (28%). In the dosexp phase 26 pts (14 M, 12 F) have thus far received 73 cycles at the MTD (1,250/2,000). Median age is 65 y (26–79 y) and median KPS is 80 (70–100). 28/73 cycles were delayed or interrupted for toxicity with gr ≥3 toxicities (# cycles): HFS (7), fatigue (5), increased LFTs (5), HTN (3), DVT/PE (4). 23 pts (17 in dosesc and 6 in dosexp) had response or stable disease longer than 12 weeks. Final results and PK data will be presented. Conclusion: PTK/ZK and cape can be combined without unexpected toxicities.

No significant financial relationships to disclose.

Antitumor activity of DAB389IL-2 fusion toxin in mycosis fungoides

BACKGROUND

DAB389IL-2 is a novel fusion toxin that retargets the cytotoxic A-chain of diphtheria toxin to interleukin-2 (IL-2) receptor-expressing tumors.

OBJECTIVE

The purpose of this phase I trial was to study the toxicity, maximum tolerated dose, and clinical efficacy of DAB389IL-2 in IL-2 receptor expressing lymphoproliferative malignancies, including cutaneous T-cell lymphoma.

METHODS

DAB389IL-2 was administered intravenously daily for 5 days every 3 weeks. Dose escalation occurred between patient groups. Patients were monitored for laboratory and clinical toxicity, kinetics, immune response, and clinical efficacy.

RESULTS

Thirty-five patients with cutaneous T-cell lymphoma (including 30 patients with mycosis fungoides) were treated. Previously, conventional therapy had not worked for 34 of the patients. Thirteen patients (37%) achieved an objective response, including a complete response in five patients (14%). Complete response was achieved in patients with extensive erythroderma and tumor stage mycosis fungoides. Adverse events consisted of reversible fever/chills, hypotension, nausea/vomiting, and elevation of hepatic transaminase. Doses of less than 31 microg/kg per day were well tolerated. Clinical responses were observed at all dose levels.

CONCLUSION

DAB389IL-2 is well tolerated at doses of less than 31 microg/kg per day, and it induced clinical responses in previously treated mycosis fungoides, providing evidence for the antitumor activity of this molecule.

Phase I trial of a ligand fusion-protein (DAB389IL-2) in lymphomas expressing the receptor for interleukin-2

The purpose of this study was to evaluate the safety, tolerability, pharmacokinetics, and possible antitumor activity of a ligand fusion-protein, DAB389IL-2, in a phase I trial. This was a multicenter, open-label, dose-escalation trial. Patients with preserved organ function and histologically confirmed relapsed cutaneous T-cell lymphoma (CTCL), other non-Hodgkin's lymphomas (NHL), or Hodgkin's disease (HD) were eligible if their cancer was shown to express the interleukin (IL)-2 receptor by an immunohistochemical assay for the p55 or the p75 subunit. Patients received up to eight courses of DAB389IL-2 given as a short intravenous infusion daily for 5 days with subsequent courses every 21 days. The maximum tolerated dose (MTD) and tumor response was determined according to standard criteria. Seventy-three patients (44 men/29 women), aged 16 to 81 years (mean, 50.7) with CTCL (n = 35), NHL (n = 17), and HD (n = 21) were enrolled. The patients were extensively treated, failing 0 to 15 previous therapies (median, 4). Patients received one to six courses (mean, 3.3) of DAB389IL-2 over a range of 3 to 31 micrograms/kg/day. The dose-limiting toxicity was asthenia, establishing the maximum tolerated dose of 27 micrograms/kg/day. Approximately half of all patients had significant titers of antibody to diphtheria toxin or to DAB389IL-2 at the time of enrollment compared with 92% with titers at the end of treatment. The presence of antibody did not preclude clinical response. There were five complete (CR) and eight partial (PR) remissions in patients with CTCL with one CR and two PR occurring in NHL. The median time to response was 2 months and the duration of response was 2 to 39+ months. No responses were documented in patients with HD. DAB389IL-2 is well tolerated with an MTD of 27 micrograms/kg/day. This ligand fusion-protein showed antitumor effects in patients with IL-2 receptor expressing CTCL and NHL. Additional trials in these diseases are warranted.

Phase-I trial of Thiotepa, granulocyte-macrophage colony-stimulating factor and prednisone or pentoxifylline in patients with refractory solid tumors

In a phase I trial, 13 patients with refractory solid tumors received thiotepa, granulocyte-macrophage colony-stimulating factor (GM-CSF), and either prednisone or pentoxifylline (PTX) on alternate cycles. The prednisone and PTX were administered in an attempt to ameliorate toxicity related to GM-CSF. Of the first six patients treated at a thiotepa dose of 60 mg/m(2), five experienced grade 3 or 4 thrombocytopenia and four grade 2 or greater leukopenia. One of these patients died secondary to E. coli sepsis. Seven patients received a thiotepa dose of 50 mg/m(2), with one experiencing grade 3 thrombocytopenia and another grade 3 leukopenia. The latter patient died secondary to presumed sepsis. The five remaining patients at the 50 mg/m(2) dose did not experience greater than grade 1 hematologic toxicity. Serum tumor necrosis factor levels were not increased by GM-CSF. Patients in this trial were not evaluable for amelioration of GM-CSF toxicity as too few received a second cycle of treatment. We conclude that thiotepa doses greater than 50 mg/m(2) are not tolerated due to severe thrombocytopenia which is not diminished by the administration of GM-CSF.

Alpha-2 interferon therapy of hairy-cell leukemia: a multicenter study of 64 patients

Sixty-four patients with hairy-cell leukemia (HCL) (61 had undergone prior splenectomy) were treated with alpha-2 interferon (Intron A, Schering Corp, Kenilworth, NJ) subcutaneously three times per week at a dosage of 2 X 10(6) U/m2. Three patients (5%) demonstrated a complete response (CR) with apparent eradication of hairy cells from the bone marrow, 45 patients (70%) showed a partial response (PR) defined as normalization of all three blood counts associated with decreased involvement in the bone marrow, and nine patients (14%) showed a minor response that included improvement in at least one blood count. Three patients had no response, three patients died before completing 1 month of therapy, and one patient refused further therapy after 1 month of therapy. The median platelet count returned to normal by the second month of treatment. The median hemoglobin returned to greater than 12 mg/dL by the fourth month of treatment, and the median granulocyte count to greater than 1,500/mu by the fifth month of treatment. Bone marrow biopsy analysis during interferon therapy demonstrated a decrease in median hairy-cell index by more than half. Transfusion of both RBCs and platelets were decreased within 4 months of initiating treatment. Serious infections, which averaged four per month in 16 of the 64 patients before interferon therapy, were rarely observed after the first month of treatment. Treatment-induced toxicity was mild, consisting primarily of influenza-like symptoms, fatigue, and minor skin disorders. Alpha-2 interferon therapy is highly effective in reversing the course of progressive HCL and should be considered the treatment of choice for a minimum of 12 months in patients who have progressive disease post-splenectomy.