A phase I study of trimetrexate, an analog of methotrexate, administered monthly in the form of nine consecutive daily bolus injections

Radiation recall reactions: An oncologic enigma

Radiation recall reactions (RRR) are uncommon but are a well-known phenomenon to oncologists. Tissue damage in a prior irradiation portal is 'recalled' after the administration of a drug, historically cytotoxics, or more recently, targeted or immunotherapeutic agents. Even COVID-19 vaccines are a reported cause. RRR are enigmatic in that their cause is unknown, but they generally have the histopathological and clinical features of acute or chronic inflammation. They can occur in a variety of tissues, the commonest being skin, which accounts for two-thirds of reported cases. They are generally relatively mild and self-limiting once the trigger drug is stopped, although severe cases with tissue necrosis have occurred. Rechallenge with drug does not necessarily cause reactivation of the reaction. Symptomatic treatment with steroids and antihistamines are usually effective, but their impact on the clinical course is unclear. Various hypotheses have been proposed as to the mechanism of RRR; a non-immune fixed drug reaction-like condition, dysregulated release of reactive oxygen species, abnormalities of tissue vasculature and impaired DNA repair. All could lead to a characteristic inflammatory microenvironment, resulting in dysfunction of tissue stem cells, keratinocyte necrosis and dermal abnormalities. Alternatively or in addition, low levels of inflammatory tissue cytokines induced by previous irradiation might be further upregulated by drug exposure. Most information in this review refers to data derived from cutaneous RRR, since they are the most common form reported.

COVID-19 Vaccine-Induced Radiation Recall Phenomenon

Radiation recall phenomenon (RRP) is an uncommon, late occurring, acute inflammatory skin reaction that emerges in localized areas coincident with previously irradiated radiation therapy (RT) treatment fields. RRP has been known to be triggered by a number of chemotherapy agents. To the best of our knowledge, this report is the first description of RRP after administration of the Pfizer-BioNTech vaccine for COVID-19, or any other currently available vaccine against COVID-19. Acute skin reactions were observed in 2 RT patients with differing timelines of RT and vaccinations. In both cases however, the RRP presented within days of the patient receiving the second dose of vaccine. For each RT course, the treatment planning dosimetry of the radiation fields was compared with the area of the observable RRP. RRP developed within the borders of treatment fields where prescription dose constraints were prioritized over skin sparing. Our observation is currently limited to 2 patients. The actual incidence of RRP in conjunction with Pfizer-BioNTech vaccine or any other vaccine against COVID-19 is unknown. For patients with cancer being treated with radiation with significant dose to skin, consideration should be given to the probability of RRP side effects from vaccinations against COVID-19.

Radiation recall with anticancer agents

There is still much that needs to be understood about radiation recall, and it is not currently possible to predict which patients will be affected and to which drugs they will react. Furthermore, there are no clearly defined characteristics of drugs that cause radiation recall, and thus, it is a possibility that must be kept in mind with use of any drug after radiotherapy, including those from new drug classes. Although it is not yet possible to design treatment regimens to eliminate the risk of radiation recall, it seems likely that risks can be minimized by prolonging the interval between completion of radiotherapy and initiation of full-dose chemotherapy.

Radiation recall is an acute inflammatory reaction confined to previously irradiated areas that can be triggered when chemotherapy agents are administered after radiotherapy. It remains a poorly understood phenomenon, but increased awareness may aid early diagnosis and appropriate management. A diverse range of drugs used in the treatment of cancer has been associated with radiation recall. As most data come from case reports, it is not possible to determine the true incidence, but to date the antineoplastic drugs for which radiation recall reactions have been most commonly reported include the anthracycline doxorubicin, the taxanes docetaxel and paclitaxel, and the antimetabolites gemcitabine and capecitabine. Radiation recall is drug-specific for any individual patient; it is not possible to predict which patients will react to which drugs, and rechallenge does not uniformly induce a reaction. There are no identifiable characteristics of drugs that cause radiation recall, and thus, it is a possibility that must be kept in mind with use of any drug after radiotherapy, including those from new drug classes. Although it is not yet possible to design treatment regimens to eliminate the risk of radiation recall, it seems likely that risks can be minimized by prolonging the interval between completion of radiotherapy and initiation of chemotherapy.

Radiation recall dermatitis: case report and review of the literature

"Radiation recall"-also called "radiation recall dermatitis"-has been defined as the "recalling" by skin of previous radiation exposure in response to the administration of certain response-inducing drugs. Although the phenomenon is relatively well known in the medical world, an exact cause has not been documented. Here, we report a rare occurrence of the radiation recall phenomenon in a breast cancer patient after palliative radiotherapy for bone, brain, and orbital metastases.

An ambiguous phenomenon of radiation and drugs: recall reactions

The term 'radiation recall' describes an acute inflammatory reaction in previously irradiated areas after the administration of certain inciting systemic agents. It was first described in 1959 by D'Angio that dermatitis is related to the application of actinomycin D on the skin. Though this reaction occurs frequently on the skin, it may also be seen in the oral mucosa, the larynx, esophagus, small intestine, lungs, muscle tissue, and brain. Most drugs associated with recall reactions are cytotoxics, however, several other drugs may also elicit the phenomenon. Although this phenomenon is well known, its etiology is not understood. Radiation recall reactions are generally associated with megavoltage radiotherapy. The time interval between the completion of radiotherapy and the recall reaction ranges from days to years. The recall reaction occurs on average 8 days (3 days to 2 months) after the application of the promoting agent. Although no standard treatment exists, some authors suggest discontinuation of the inciting drug and the use of corticosteroids or nonsteroidal anti-inflammatory agents.

Radiation recall: A well recognized but neglected phenomenon

INTRODUCTION

Radiation recall is an inflammatory skin reaction at a previously irradiated field subsequent to the administration of a variety of pharmacologic agents. Although skin has been the major site of radiation recall toxicity, instances involving other organ have been reported.

MATERIALS AND METHODS

Data for this review were identified by searches of Medline and Cancerlit. The search terms "radiation", "recall", and "toxicity" were used. References identified from within retrieved articles were also used. There was no limitation on year of publication and no abstract forms were included. Only articles published in English were taken into consideration.

RESULTS

Idiosyncratic drug hypersensitivity phenomenon is a recent hypothesis which correlates best with the available facts at this moment. The phenomenon may occur days to years after radiotherapy has been completed. The majority of the drugs commonly used in cancer therapy have been involved in the radiation recall phenomenon. A mixed non-specific inflammatory infiltrate seems to be the common histopathologic criteria in previous published reports. Universally, corticosteroids or the use of non-steroidal anti-inflammatory agents, in conjunction with withdrawal of the offending agent, produce prompt improvement.

CONCLUSION

We propose to collect all future radiation recall phenomenon in a Rare Cancer Network database in order to augment our understanding of this rare reaction.

Double modulation of 5-fluorouracil by trimetrexate and leucovorin in patients with advanced colorectal carcinoma

The purpose of this report is to evaluate the efficacy and toxicity (Tx) of a double modulation of 5-fluorouracil (5-FU) by trimetrexate (TMTX) and leucovorin (LV) in patients with advanced recurrent (inoperable) or metastatic colorectal cancer (ACC). Between December 1997 and August 2000, 36 patients were entered in this phase II study. Median age was 61 years, and 18 patients (50%) were female. Median performance status was 0 (range: 0-1), whereas primary tumor location was colon in 21 patients (58%) and rectum in 15 patients (42%). The number of metastatic sites was 1:29 patients (81%); 2:6 patients (17%) and 3:1 patient (3%). Hepatic involvement was observed in 33 patients (92%). Treatment consisted of TMTX 110 mg/m2 IV over 1 hour at hour (H) 0; LV 50 mg/m2 IV over 2 hours IV infusion starting at H 18; and 5-FU 900 mg/m2 IV bolus at H 20. LV (rescue) 15 mg/m2 orally was administered every 6 hours (total 6 doses) beginning at H 24. Cycles were repeated every 2 weeks until progressive disease (PD) or severe Tx. Thirty-four patients are assessable for response (R) (two patients refused further treatment after the first course of therapy), whereas all patients were assessable for Tx. Complete response: 1 patient (3%); partial response: 4 patients (12%), with an overall objective response rate of 15% (95% CI, 1%-25%); no change: 12 patients (35%); and progressive disease: 17 patients (50%). The median time to treatment failure was 4 months and median survival was 11 months. Tx was within acceptable limits. The dose-limiting side effect was mucositis. Eight episodes of grade II or III stomatitis were observed and were responsible for dosage modifications of TMTX and 5-FU. Leukopenia was observed in 16 patients (44%); neutropenia was registered in 19 patients (53%); anemia was seen in 18 patients (50%); emesis in 22 patients (61%); and dermatitis in 3 patients (8%). There were no therapy-related deaths. The double modulation of 5-FU by TMTX and LV showed modest antitumoral activity with mild to moderate Tx.

Gemcitabine-induced radiation recall

PURPOSE

To study and report 6 patients with radiation recall in unique sites, secondary to gemcitabine chemotherapy.

METHODS AND MATERIALS

The clinical presentations and outcomes of 6 patients with radiation recall secondary to gemcitabine chemotherapy were retrospectively analyzed over the course of a 1-year period.

RESULTS

Radiation recall reactions were seen in the central nervous system, skin, gastrointestinal tract, and in the lymphatic and musculoskeletal systems. The time between initiation of radiation and recall of the radiation phenomenon ranged from 3 weeks to 8 months from the time gemcitabine was initiated. The usual dosage of gemcitabine in these cases was 1000 mg/m(2) given on a weekly basis. No radiation therapy was given concomitantly with gemcitabine. Treatment of the recall reaction consisted of discontinuing gemcitabine and initiating steroid therapy, supportive therapy, and/or nonsteroidal anti-inflammatory agents. Minimal improvement was seen in 3 out of 6 patients, and resolution of the radiation recall was seen in 3 out of 6 patients. A comprehensive review of the literature revealed that radiation recall with gemcitabine has been related to skin reactions only; no previous cases of radiation recall occurring in the central nervous system have been reported with any chemotherapy agent.

CONCLUSION

Radiation recall from gemcitabine chemotherapy is rare, but can potentially arise in any site that has been previously irradiated. Treating physicians must be aware of this potential toxicity from gemcitabine and radiation and discontinue the gemcitabine if radiation recall is observed.

Characterizing the phenomenon of radiation recall dermatitis

Radiation recall represents the 'recalling' of an effect similar in appearance to that of an acute radiation reaction in a previously irradiated field. The recall is triggered by the administration of certain drugs days to years after the exposure to ionizing radiation. This review focuses almost exclusively on the skin manifestations of radiation recall to assemble the largest data base upon which to discuss this rare phenomenon. No absolute radiation dose threshold is apparent, but rather an interplay between dose and time before drug exposure seems to affect both the risk and speed of onset of recall. Recall usually occurs on first exposure to a particular recall-triggering drug. The skin reaction develops within minutes to days. The time to develop the reaction may be slightly longer for oral than intravenously administered drugs reflecting their bioavailability. Most drugs associated with recall are cytotoxics, but several other drugs may elicit the phenomenon. Individuals exposed to a number of potentially recall-triggering drugs reveal the marked drug specificity characteristic of the phenomenon. Skin reactions usually settle within a few days of stopping the triggering drug. The role of steroids or anti-histamines in affecting resolution is unclear. Drug rechallenge tends to produce either only a mild recurrence or no recurrence of recall. Steroids or dose reduction may favour uneventful rechallenge. A number of aetiological hypotheses on radiation recall exist. Using the available evidence these hypotheses are critically reviewed and a novel hypothesis based on radiation affecting local cutaneous immunological responses proposed.

Radiation recall dermatitis induced by methotrexate in a patient with Hodgkin's disease

Radiation recall dermatitis refers to an inflammatory skin reaction at a previously irradiated field subsequent to chemotherapy administration. A number of antineoplastic agents have been reported to cause this phenomenon. We observed radiation recall dermatitis in a patient with stage IV nodular sclerosing Hodgkin's disease after methotrexate therapy for acute graft-versus-host disease (GVHD) prophylaxis. The patient had previously undergone matched related bone marrow transplantation with busulfan and cyclophosphamide as a preparative regimen. Subsequently, she received cyclosporine and methotrexate for acute GVHD prophylaxis. Two areas of skin previously irradiated to 3,000 cGy developed radiation recall dermatitis after two doses of methotrexate given 2 days apart and exacerbated by the third and fourth doses. This reaction occurred 34 days after the last dose of radiation therapy (RT). We believe this is the first case of radiation recall dermatitis after methotrexate therapy. Given the increased use of methotrexate in several neoadjuvant and adjuvant protocols in association with RT, its potential to produce radiation recall reactions should be considered.

Radiation-recall skin disorders associated with the use of antineoplastic drugs. Pathogenesis, prevalence, and management

Radiation-recall dermatitis is the occurrence, with subsequent administration of cytotoxic chemotherapy, of an acute inflammatory toxicity in a previously quiescent radiation field. It may occur from days to weeks, and sometimes years, after the radiation therapy. The precise mechanism is unknown. One hypothesis suggests that the initial radiation therapy leads to a depletion of tissue stem cells within the irradiated field and that subsequent cytotoxic chemotherapy exposure causes a 'remembered' reaction among the remaining surviving cells. An alternative proposition suggests that radiation induces heritable mutations within surviving cells, which then produce a subgroup of defective stem cells that are unable to tolerate the second insult of chemotherapy. Recently, ataxia telangiectasia gene mutation and protein kinase deficiency have been associated with patients who have increased susceptibility to severe radiation-induced skin toxicity. Most of the lesions will heal with supportive treatment. Although some reports have noted that radiation-recall dermatitis recurred with subsequent continued administration of the same chemotherapeutic agent, such experience is not universal. At present, a decision as to whether the same chemotherapeutic agent can be continued will usually be determined by the severity of the initial reaction, the chemoresponsiveness of the tumor to this particular agent, the individual patient's wishes, and a clinical judgment that takes into account the availability of alternative therapy.

Radiation recall dermatitis induced by edatrexate in a patient with breast cancer

Enhancement of radiation injury to the skin and mucous membranes has been observed with a number of chemotherapeutic agents. A 32-year-old woman with metastatic breast cancer received local radiation therapy to the lumbosacral area. Six weeks later, systemic edatrexate therapy was initiated and a localized painful erythema with edema and a vesicular eruption occurred over the previous site of radiation therapy. Physicians should be aware that edatrexate can cause radiation recall, and that careful use of anti-inflammatory agents may allow continued chemotherapy treatment.

Radiation recall skin toxicity with bleomycin in a patient with Kaposi sarcoma related to acquired immune deficiency syndrome

BACKGROUND

Radiation recall is a recurrence of acute toxicity within a previously quiescent radiation field that occurs with subsequent administration of chemotherapy.

METHODS

A patient with acquired immune deficiency syndrome (AIDS)-related Kaposi sarcoma (KS) who had radiation recall is reported. The patient was participating in a randomized prospective trial of radiation treatment regimens for KS. Each lesion was randomized to one of three possible radiation fractionation schemes. All lesions were photographed and measured before treatment with radiation.

RESULTS

Two skin sites developed erythema and dry desquamation 18 days after completion of radiation therapy to a dose of 40 Gy in 20 fractions. These reactions took place after the second dose of bleomycin administered intravenously on a weekly basis. The reactions were exacerbated by oral etoposide therapy, which was started 4 days after the recall phenomenon was noted. Other cutaneous sites treated with 8 Gy in a single fraction and 20 Gy in ten fractions during the same time period showed no sign of recall skin toxicity.

CONCLUSIONS

The authors believe this to be the first report of radiation recall toxicity after bleomycin therapy and of a radiation dose response related to this phenomenon. The potential for radiation recall toxicity should be considered in treatment decisions pertaining to patients with AIDS-associated KS.

A randomized phase II trial of trimetrexate or didemnin B for the treatment of metastatic or recurrent squamous carcinoma of the uterine cervix: a Southwest Oncology Group trial

Patients with measurable metastatic or recurrent squamous carcinoma of the uterine cervix who had failed prior surgery or radiation therapy were enrolled on this randomized phase II study. Twenty-seven eligible patients were assigned to receive didemnin B at either 2.6 mg/m2 iv every 28 days (sixteen patients) or at 5.6 mg/m2 (eleven patients). Sixteen patients were assigned to receive 12 mg/m2/day iv trimetrexate for 5 days, repeated every 21 days. Toxicity for didemnin B was characterized by nausea and vomiting (78% of patients), anemia (59%), mild diarrhea (11%), and episodic hypersensitivity (three patients). Toxicity for trimetrexate included nausea and vomiting (69%), leukopenia (51%), mild thrombocytopenia (38%), anemia (63%), and diarrhea (31%). No antitumor responses were observed for either agent. Neither trimetrexate nor didemnin B at these doses and schedules is recommended for the treatment of advanced squamous carcinoma of the uterine cervix.

Phase I studies of trimetrexate using single and weekly dose schedules

Trimetrexate (TMTX), a potent inhibitor of the enzyme dihydrofolate reductase, was shown to be more active than its analogue, Methotrexate, against murine and human tumor cell lines in vitro and in vivo. We conducted two sequential phase I studies using a single bolus injection of TMTX every 14 days (Schedule A) and a weekly x 3 schedule every 4-6 weeks (Schedule B). Twenty-seven patients were treated on Schedule A with a TMTX dose range of 5 mg/m2 to 450 mg/m2 and 23 patients were treated on Schedule B with a TMTX dose range of 50 mg/m2 to 200 mg/m2. The dose limiting toxicity was myelosuppression on both schedules. The development of hematological toxicity was highly variable at different dose levels and within the same patient at a particular dose level. The nadir of blood counts was reached by Day 8 to 10 on the single dose schedule with recovery by Day 14. On Schedule B, the nadir granulocyte count occurred on Day 14 while platelet count was generally lowest by Day 20; the blood counts usually recovered 7 to 10 days after the last dose. Other common side-effects includes skin toxicity and stomatitis which were worse on the weekly schedule. Less common toxicities included mild nausea and vomiting, diarrhea, and transient deterioration in renal and hepatic functions. The occurrence of toxicity was not related to the extent of prior treatment, liver metastases, or accumulation of third space fluids. Based on our results, we recommend a starting TMTX dose for Phase II studies of 200 mg/m2 every 2 weeks or 100 mg/m2 to 125 mg/m2 on the weekly schedule.

A phase I trial of trimetrexate glucuronate (NSC 352122) given every 3 weeks: clinical pharmacology and pharmacodynamics

Trimetrexate glucuronate (TMTX), a non-classic folate antagonist, has been evaluated clinically on several schedules. We studied TMTX given as an i.v. bolus over 5-30 min every 3 weeks in 44 patients with advanced solid tumors; it was given at doses ranging from 20 to 275 mg/m2. The maximal tolerated dose (MTD) on this schedule is 220 mg/m2, which we also recommend as a starting dose for phase II studies in patients without extensive prior therapy. Because of wide individual differences in drug tolerance, dose escalation in 25% increments is recommended for non-toxic patients. The principal dose-limiting toxicity was myelosuppression, although in some patients a flu-like syndrome precluded dose escalation. Significant rash and mucositis also frequently occurred in toxic patients. TMTX plasma concentrations were measured after the first dose and the data were fit by two- or three-compartment mammillary pharmacokinetic models. The TMTX clearance rate was 36.5 +/- 21 ml/min per m2 and did not change with dose; non-linearities with increasing dose were apparent in the steady-state volume of distribution (Vss) and in the terminal disposition half-life (t1/2). The difference between pre-treatment and nadir leucocyte counts was correlated with TMTX dose (r = 0.58; P = 0.0006) and with the area under the concentration vs time curve (AUC) (r = 0.41; P = 0.02). Pre-treatment plasma albumin concentrations correlated weakly with the nadir white blood count (r = -0.36; P = 0.047). Optimal schedules for the administration of TMTX have not been established and phase II trials using both bolus and daily X 5 schedules are under way.