Regorafenib monotherapy as second-line treatment of patients with RAS-mutant advanced colorectal cancer (STREAM): an academic, multicenter, single-arm, two-stage, phase II study

BACKGROUND

Maintaining angiogenesis inhibition and switching the chemotherapy backbone represent the current second-line therapy in patients with RAS-mutant metastatic colorectal cancer (mCRC). Regorafenib, an oral multikinase inhibitor, prolonged overall survival (OS) in the chemorefractory setting.

MATERIALS AND METHODS

STREAM was an academic, multicenter, single-arm phase II trial, evaluating the activity of regorafenib in RAS-mutant mCRC, in terms of the rate of patients who were progression-free after 6 months from study entry (6mo-PF). Patients were pretreated with fluoropyrimidine, oxaliplatin, and bevacizumab. According to Simon's two-stage design, ≥18 patients 6mo-PF were needed in the overall population (N = 46). Secondary endpoints were safety, objective response rate (ORR), progression-free survival (PFS), and OS. Early metabolic response by [¹⁸F]2-fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography ([¹⁸F]-FDG PET/CT) scan was an exploratory endpoint. EudraCT Number: 2015-001105-13.

RESULTS

The number of patients 6mo-PF was 8/22 at the first stage and 14/46 in the overall population. The ORR was 10.9%, disease control rate was 54.6%, median (m)PFS was 3.6 months [95% confidence interval (CI) 1.9-6.7 months], mOS was 18.9 months (95% CI 10.3-35.3 months), and mPFS2 (from study entry to subsequent-line progression) was 13.3 months (95% CI 8.4-19.7 months). Long benefiter patients (>6mo-PF) significantly more often had a single metastatic site and lung-limited disease. No unexpected toxicity was reported. Grade ≥3 events occurred in 39.1% of patients, with hand-foot syndrome (13%), fatigue, and hyperbilirubinemia (6.5%) occurring mostly. Baseline metabolic assessment was associated with OS in the multivariate analysis, while early metabolic response was not associated with clinical outcomes.

CONCLUSIONS

The study did not meet its primary endpoint. However, regorafenib was well tolerated and did not preclude subsequent treatments. Patients with good prognostic features (single metastatic site and lung-limited disease) reported clinical benefit with regorafenib. The exploratory metabolic analysis suggests that baseline [¹⁸F]-FDG PET/CT might be useful to select patients with a favorable outcome. A chemotherapy-free interval with regorafenib was associated with durable disease control in a selected group of patients with favorable clinical characteristics.

Fluoropyrimidines in the Treatment of Advanced Neoplastic Diseases: Role and Advantages of UFT

The fluoropyrimidine antimetabolites were employed in a wide range of neoplastic diseases. In particular, 5-fluorouracil in association with other chemotherapeutic agents, or biochemical modulators was successfully used in the treatment of colorectal, gastric, breast, head and neck cancers. With this type of chemotherapy, a response rate ≤ 20% was obtained in gastrointestinal tumors, without a statistically significant impact on the overall survival.

UFT is a combination of tegafur an uracil, which has the important advantage of an improved oral bioavailability, if we compare it with 5-fluorouracil. Uracil, avoiding the fluoropyrimidine degradation inside the tumor cells, increases the permanence of the metabolically active fluropyrimidine into the target cell, so having an improvement in the therapeutic activity.

A very large spectrum of cancers were treated with this molecule. In particular, a response rate in the range of 20–40% was observed in the treatment of patients with metastatic colorectal cancer.

Phase III trials are ongoing to evaluate the advantage on 5-FU of this new fluoropyrimidine in terms of clinical efficacy, and quality of life, considering the possibility to administer it orally.

Preliminary Experience with High-Dose Cisplatin, Reduced Glutathione and Natural Interferon-α in Dacarbazine-Resistant Malignant Melanoma

Aims and background

The incidence of malignant melanoma is rapidly increasing in many countries, and when this disease has reached advanced stages, standard therapies have little impact. Dacarbazine (DTIC) is the most effective chemotherapeutic agent with an overall response rate of 20-25%, but durable responses are uncommon. Interesting results with the use of cisplatin (CDDP) have been reported in DTIC-resistant melanoma. Moreover, malignant melanoma is an immunogenic tumor and a potential target for biological response modifier (BRM) therapies. The aim of the present study was to evaluate the efficacy and tolerability of a chemo-immunotherapeutic regimen including high-dose CDDP combined with glutathione (GSH) to limit platinum-related toxicity, and natural interferon-α (IFN-α) in patients with DTIC-resistant metastatic melanoma.

Methods

The treatment schedule included GSH 1,500 mg/m2 i.v. and CDDP 40 mg/m2 i.v. for 4 consecutive days every 3 weeks, with a maximum of 6 courses, and IFN-α 3 MIU i.m. 3 times a week, continuative for a maximum of 12 months.

Results

Twelve patients were enrolled in this phase II trial. Accrual was stopped due to treatment-related toxicity. Ten patients were evaluable for response; there were 2 partial responses, lasting 5+ and 9+ months, respectively, and 2 cases of stable disease, lasting 3+ and 8+ months. None of these patients completed the therapeutic program due to treatment-related side effects.

Conclusions

This regimen seems to be only partially active in DTIC-resistant metastatic melanoma. Hematologic and non-hema-tologic (nausea and vomiting, peripheral neurotoxicity, and asthenia) side effects are significant and GSH is not effective in limiting CDDP-related neurotoxicity in pretreated patients. Therefore, there is no indication to employ this regimen as second-line treatment in metastatic melanoma and these disappointing results highlight the urgent need for new therapeutic approaches.

Capecitabine: Indications and Future Perspectives in the Treatment of Metastatic Colorectal and Breast Cancer

Fluoropyrimidines remain the most important drugs in the treatment of breast and colorectal carcinoma, but response rates and survival time have been disappointing. Optimal administration is by continuous intravenous infusion, which makes it cumbersome to use and compromises patient independence. Recently, a number of new agents, including fluorouracil prodrugs and selective dihydropyrimidine dehydrogenase inhibitors, have been studied, with promising results. Capecitabine is the first in a new class of fluoropyrimidines. It is an oral, tumor-activated anticancer drug whose activity mimics that of continuously infused 5-fluorouracil. Capecitabine circumvents dihydropyrimidine dehydrogenase catabolism and appears to be at least as active against metastatic colorectal and breast cancer as conventionally administered intravenous 5-fluorouracil, with significantly less toxicity, an improved quality of life, and lesser cost. Capecitabine may ultimately provide enhanced antitumor activity to fluorouracil-containing regimes for advanced colorectal and breast cancer.

Premenopausal breast cancer patients treated with a gonadotropin-releasing hormone analog alone or in combination with an aromatase inhibitor: a comparative endocrine study

BACKGROUND

The combination of a GnRH analogue and an aromatase inhibitor can induce a complete estrogen blockade in premenopausal breast cancer patients.

MATERIAL AND METHODS

Twenty-one premenopausal women with advanced breast cancer were randomised to receive the GnRH analog triptorelin (3.75 mg i.m. monthly; n = 10) alone or in combination with the aromatase inhibitor formestane (4-OHA, 500 mg i.m. fortnightly; n = 11) to compare the effect of both treatments on the patients' estrogenic milieu. Therefore, serum estrogen, gonadotropin and sex hormone-binding globulin (SHBG) levels were investigated before the start of treatment and subsequently over a three-month period.

RESULTS

There was a significant between-group difference in estrogen suppression during therapy. In comparison with baseline values, after four weeks of treatment the estradiol levels decreased by an average of 86.9% (95% CI, 70.5-94.2%) in the group treated with triptorelin alone and by 97.3% (95% CI, 94.1-98.8%; P = 0.0422) in the combination group; the respective figures for estrone were 48.5% (95% CI, 27.5-63.5%) and 70.4% (95% CI, 52.3-81.6%; P = 0.0007) and for estrone sulfate 56.7% (95% CI, 40-68.8%) and 80.5% (95% CI, 69.4-87.6%; P = 0.0055). No difference was observed between the groups in terms of gonadotropin suppression; both treatment modalities led to a slight but delayed decrease in SHBG levels. Three of the patients treated with triptorelin alone experienced tumor regression compared with four patients in the combination group. No appreciable side effects of the combination therapy were observed.

CONCLUSION

The treatment of premenopausal patients with triptorelin plus 4-OHA is feasible and leads to a much greater inhibition of main circulating estrogens than treatment with the analog alone. Since the combination of a GnRH analog and an aromatase inhibitor might potentially enhance the anti-tumor efficacy of the analog alone owing to more favorable endocrine effects, such a therapeutic approach deserves more extensive evaluation in the clinical setting.

Oral doxifluridine plus levoleucovorin in elderly patients with advanced breast cancer

BACKGROUND

There currently is no agreement regarding the appropriate treatment of elderly patients with advanced breast carcinoma (ABC). Doxifluridine (5-dFUR), a prodrug of 5-fluorouracil, has been found to be effective in this entity, but its use is limited by neurotoxicity and cardiotoxicity that are not observed when the oral formulation is used. The objective of this Phase II trial was to evaluate the effectiveness and tolerability of oral 5-dFUR, biomodulated with levoleucovorin (1-leucovorin), in elderly patients (age > 70 years) with ABC.

METHODS

5-dFUR was administered orally at 600 mg/m2 twice daily for 4 consecutive days every 12 days, and oral 1-leucovorin was administered as 25 mg 2 hours before each 5-dFUR administration. Response was assessed every five cycles according to the World Health Organization criteria. In the presence of response or stable disease, the patients were treated for a maximum of 15 cycles.

RESULTS

Seventy-three eligible patients were enrolled, 27 of whom had been pretreated with chemotherapy and/or hormonotherapy; all were assessable for response and toxicity after a median follow-up of 15 months. The objective response rate was 26% (95% confidence interval, 17.4-45.4). Regression predominantly occurred in the presence of soft tissue involvement (skin, lymph nodes, and breast). The median time to response was 2 months (range, 1-2 months) and the median response duration was 7 months (range, 2-17+ months). The median survival was 24 months (range, 2-42+ months). The treatment was very well tolerated, and the side effects were manageable and always reversible.

CONCLUSIONS

The results of the current study show that 5-dFUR plus 1-leucovorin, both given orally, are associated with excellent patient compliance. Although the results are suboptimal in terms of an objective response, this characteristic could allow 5-dFUR to be used in elderly patients considered unsuitable for "aggressive" chemotherapy.

5-Fluorouracil, dacarbazine, and epirubicin in the treatment of patients with neuroendocrine tumors

BACKGROUND

For patients with surgically untreatable neuroendocrine tumors (NETs), the optimal therapeutic approach remains undefined. Somatostatin analogs and interferons have failed to control neoplastic growth, and chemotherapy has been only moderately more effective. The authors' previous study of the combination of 5-fluorouracil (FU), dacarbazine (DTIC), and epirubicin (EPI) (the FDE regimen) documented good tolerability, but the results for tumor growth control were disappointing. In an attempt to improve these results, the authors conducted a preliminary trial of an intensified FDE regimen (FU 500 mg/m2 administered intravenously [i.v.], DTIC 200 mg/m2 i.v., and EPI 30 mg/m2 i.v. on Days 1, 2, and 3 every 3 weeks).

METHODS

Thirty NET patients (15 male, 15 female; median age, 55 years; age range, 19-72 years) were enrolled, none of whom had previously been given chemotherapy. The histologic types of disease were gastroenteropancreatic (GEP) tumors (n = 21, 6 carcinoid tumors and 15 pancreatic NETs), other carcinoid tumors (n = 3), other NETs (n = 4), medullary thyroid carcinoma (MTC) (n = 1), and Merkel cell carcinoma (n = 1). Six patients had a syndrome related to endocrine hypersecretion. One hundred fifty-four therapy cycles were delivered (median, six per patient), and all patients could be evaluated for response on the basis of intent-to-treat analysis.

RESULTS

There were 9 objective responses: 2 complete responses (in 1 patient with Merkel cell carcinoma and 1 with pancreatic NET) and 7 partial responses (in 3 patients with pancreatic NETs, 2 with other NETs, 1 with GEP carcinoid tumor, and 1 with MTC). The median duration of response was 10 months (range, 5+ to 24+ months). No reduction in symptoms was achieved among the six patients with endocrine hypersecretion syndrome. Levels of urinary 5-hydroxyindoleacetic acid and serum chromogranin A were decreased in 50% and 14% of patients, respectively, who presented with abnormal baseline values. Treatment toxicity was acceptable and included nausea and vomiting, alopecia, leukopenia, and mucositis.

CONCLUSIONS

This trial demonstrated that the FDE regimen may be at least as effective as other systemic regimens. Comparison of this experience with the authors' previous trial revealed a noteworthy increase in the activity of the intensified regimen, especially in GEP NETs (the most chemoresistant tumors). Continued clinical research to improve these results is highly justified.