A dose-finding study of raltitrexed (tomudex) with cisplatin and epirubicin in advanced gastro-oesophageal adenocarcinoma

Raltitrexed as a substitute for capecitabine in metastatic gastric cancer: a case report and literature review

Background

5-Fluorouracil and its oral prodrug, capecitabine, are frequently used in the treatment of gastrointestinal cancers-including gastric cancer-but carry a cardiotoxicity risk. Raltitrexed (brand name Tomudex), a direct inhibitor of thymidylate synthase, has been successfully used as an alternative to fluoropyrimidines in patients with 5-fluorouracil-induced cardiac events. We report the first case, to our knowledge, of raltitrexed used with trastuzumab and platinum-based chemotherapy as a substitute for fluoropyrimidines following cardiotoxicity in a 78-year-old male patient with metastatic gastric cancer.

Case Description

The patient experienced a myocardial infarction 3 days after beginning treatment with capecitabine, carboplatin, and trastuzumab for metastatic HER2⁺ gastric adenocarcinoma. Capecitabine was replaced with raltitrexed, and the patient ultimately received seven cycles of chemotherapy, five of which included raltitrexed. There were no cardiotoxic events attributable to raltitrexed, although the patient did experience hypotensive episodes, premature ventricular contractions, myelosuppression, and anemia. Progression-free survival was 4.5 months, within the expected range achieved with the ToGA regimen (trastuzumab, cisplatin, 5-fluorouracil chemotherapy). At time of writing, the patient has been alive for 48 weeks since diagnosis.

Conclusions

In summary, raltitrexed appears to be a safe alternative to fluoropyrimidines when combined with trastuzumab and platinum, although more data is needed to determine its relative effectiveness.

Phase I study of Tomudex and Doxorubicin in patients with locally advanced, inoperable or metastatic cancer (IND.98)

BACKGROUND

The primary objective of this Phase I study was to determine the maximum tolerated dose (MTD) and recommended phase II dose for Tomudex and Doxorubicin when given in combination to patients with advanced metastatic cancer. The secondary objective was to assess the toxicity profile.

PATIENTS AND METHODS

Starting doses were Tomudex 2.5 mg/m2 i.v. bolus day 1 and Doxorubicin 30 mg/m2 i.v. bolus day 1, repeated every 3 weeks. Doxorubicin was escalated in increments of 10 mg/m2 to 60 mg/m2, followed by escalation of Tomudex in increments of 0.5 mg/m2 to 3.5 mg/m2, on six dose levels. Twenty-five patients received 127 cycles of therapy, with at least 3 patients treated at each dose level.

RESULTS

There was no dose limiting toxicity (DLT) observed in the first five dose levels. Three of six patients on dose level six had DLT. Further dose escalation was not warranted and this was declared the MTD. Grade 3 or 4 granulocytopenia was observed in 16/25 patients, with associated fever in 3/25 patients. Responses were seen in this study with one complete response (duration 12.8 months) and 3 partial responses (median duration 8 months) in 21 evaluable patients. Fourteen patients had stable disease (median duration 2.5 months). All 4 responding patients and 10 patients with stable disease had gastric cancer.

CONCLUSIONS

The recommended phase-II dose for this combination in future studies is Tomudex 3 mg/m2 and Doxorubicin 60 mg/m2 given every 3 weeks.

Recent advances in the treatment of gastric cancer

Gastric cancer is one of the most common cancers in the world. The prognosis of the disease is poor, with only 40% of patients eligible to undergo potentially curative surgery. Even for those patients who undergo a complete resection, the rate of recurrence is very high. Extensive studies of multidisciplinary adjuvant treatment have been conducted seeking to improve the cure rates in the past two decades. The benefit of D2 dissection is still controversial and is undergoing prospective evaluation. Preliminary results from the United States Gastrointestinal Intergroup study, a well designed trial, have shown overall survival benefit of postoperative chemoradiation therapy. Neoadjuvant chemotherapy or chemoradiation is under active study in order to increase the number of patients to undergo potential curative surgery. Although many chemotherapy regimens have been developed recently, only modest clinical efficacy has been demonstrated for advanced metastatic disease. So far, there is no single regimen considered to be standard.

Raltitrexed/5-fluorouracil-based combination chemotherapy regimens in anticancer therapy

Preclinical evidence of a schedule-dependent synergism between raltitrexed and 5-fluorouracil (5-FU) has prompted clinical studies of this combination. We review the main preclinical and clinical results of raltitrexed/5-FU-based combination chemotherapy regimens in anticancer therapy. Promising results include: response rates of 25 and 23% with combinations of raltitrexed/5-FU/levofolinic acid (LFA) as first-line treatment and oxaliplatin/raltitrexed/5-FU/LFA as second-line treatment of metastatic colorectal cancer, respectively; and a 67% response rate in a phase I study of cisplatin/raltitrexed/5-FU/LFA as first-line treatment of advanced head and neck cancer, including a 100% response rate at the recommended dose. These combinations were well tolerated, with neutropenia as the main dose-limiting toxicity, allowing the drugs to be combined at the doses used in monotherapy. These results suggest a role for raltitrexed within combination regimens in colorectal cancer therapy, as well as other tumors such as head and neck cancer. A further potential application of raltitrexed in combination therapies is within multidisciplinary chemo-radiotherapy strategies, mainly in rectal cancer. Phase II studies are planned/ongoing to investigate these interesting possibilities.