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Purpose: To determine the maximum tolerated dose (MTD) of paclitaxel given as a 96-hour continuous infusion during Weeks 1 and 5 of an accelerated radiotherapy schedule for the definitive treatment of advanced (nonmetastatic) unresectable squamous cell carcinoma of the head and neck (SCCHN)., Methods and Materials: Thirteen patients with Stage IV SCCHN were enrolled. Radiotherapy consisted of 70-72 Gy over 6 weeks, with a fractionation scheme of 2 Gy q.d. for 4 weeks followed by 1.6 Gy b.i.d. for 2 weeks, with no planned interruptions. Paclitaxel was administered over a 96-hour continuous infusion during Weeks 1 and 5 of radiotherapy at the following dose levels: Dose Level 1: 40 mg/m(2)/96-hours (3 patients); Dose Level 2: 80 mg/m(2)/96-hrs (5 patients); Dose Level 3: 120 mg/m(2)/96-hours (2 patients); and Dose Level 2A: 100 mg/m(2)/96-hours (3 patients)., Results: The MTD of Paclitaxel was 100 mg/m(2)/96-hours. All but one patient (who experienced progressive disease after receiving 61 Gy and both cycles of paclitaxel) completed therapy as planned. Dose-limiting toxicity occurred in both patients enrolled at Dose Level 3, with one patient experiencing Grade 4 diffuse moist desquamation and the other patient experiencing Grade 4 mucositis and febrile neutropenia. Thus, Dose Level 2A was opened and no dose limiting toxicity was noted. Grade 3 non-dose limiting mucositis and dermatitis occurred at all paclitaxel dose levels. There were no treatment-related deaths. All Grade 3 and 4 toxicities were reversible. Complete responses were seen in 8 of 13 patients, 4 patients achieved partial responses, and 1 patient had no response/progressive disease., Conclusions: Infusional paclitaxel over 96 hours during Weeks 1 and 5 of this accelerated radiotherapy schedule is feasible. The MTD of paclitaxel in this protocol was 100 mg/m(2)/96-hours. Dose-limiting toxicities were primarily enhanced epithelial reactions, but febrile neutropenia also occurred. All patients develop non-dose limiting Grade 3 skin and mucosal reactions, reflecting the high treatment intensity. This regimen merits further investigation.

Clinical studies have been initiated in conformal radiotherapy using a computer controlled multi-leaf collimator. Quantitative dosimetry and treatment planning studies comparing field shaping by lead alloy blocks and the multi-leaf collimator demonstrate the clinical acceptability of the multi-leaf collimator. Sixteen patients with tumors in multiple sites have received some part of their treatments with both blocking systems. Studies of dosimetry and field shaping show that the multi-leaf collimator produces clinically acceptable blocking for most field shapes and disease sites. The 80-20% penumbra was characterized for a wide range of shaped beams. For straight edges perpendicular to the leaf travel, the penumbra of measured dose distributions from the multi-leaf collimator is equal to conventional divergent blocking. When the multi-leaf collimator leaves approach a contour at an angle, the penumbra increases. At forty-five degrees, the maximum angle of approach, the penumbra is approximately 4 mm wider than that for divergent blocks. Three-dimensional treatment planning demonstrates that equivalent dose distributions can be obtained from the two field shaping systems. The multi-leaf collimator can be used effectively and efficiently to treat a variety of disease sites. Its optimal utility may be in treating complex fields--five or more shaped coplanar or non-coplanar beams. It is well suited for conformal therapy applications.

The objectives of this randomized trial are to define the maximum tolerated dose of radiation therapy, at curative dose levels, that can be delivered following WR-2721, and to observe the anti-tumor effects and normal tissue responses. One hundred patients with inoperable, unresectable, or recurrent rectal cancer were stratified and randomized to radiation only, or WR-2721 and radiation. The entire pelvis is treated with 4 portals 4 times a week to a total of 4500 cGy (first level dose) in 5 weeks. WR-2721, 340 mg/m2 was given 15 minutes before radiation to the combination group. Subsequently, both groups received a conedown of 720 cGy in 4 days to 144(2) cm portals APPA, and if originally inoperable or unresectable 720 cGy in four days to second conedown of 64(2) cm. Patients were observed from 3 to 18 months (median = 12 months). No significant hypotension or hematologic toxicity occurred in the WR-2721 treated group. Mild to moderate emesis occurred in 80% of the courses. (No antiemetics were used.) Moderate or severe acute toxicities to normal tissues were observed less frequently in the WR-2721 arm. No moderate or severe late toxicities to the skin, mucous membrane, urinary bladder or intestine was observed in the WR-2721 group, however, 5 patients treated with radiation alone experienced moderate or severe late toxicity to these organs. No evidence of tumor protection was observed.

WR-2721 is an organic thiophosphate compound which in the animal model selectively protects against the hematologic toxicity of cyclophosphamide by factors of 1.5 to 2.0. Controlled Phase I trials of WR-2721 and cyclophosphamide were initiated to determine if WR-2721 protected against cyclophosphamide's hematologic toxicity. Fifteen patients received WR-2721 (450-1100 mg/m2) prior to cyclophosphamide (1200-1800 mg/m2) and were subsequently retreated 4 weeks later with the same cyclophosphamide dose alone. With WR-2721 pretreatment, 11/15 (73%) patients had improved WBC counts. The mean WBC increased from 1800/mm3 on cyclophosphamide alone to 2700/mm3 with WR-2721 + cyclophosphamide (p = 0.008). In 11 patients who had nadir differential counts performed, 7 (64%) demonstrated improved nadir granulocyte counts with WR-2721. The mean granulocyte count increased from 765/mm3 on cyclophosphamide to 1274/mm3 with WR-2721 + cyclophosphamide (p = 0.05). In the second trial, 25 patients received the reverse sequence: an initial dose of cyclophosphamide (1200-1800 mg/m2) alone, followed 4 weeks later by WR-2721 (450-1100 mg/m2) prior to the same dose of cyclophosphamide. With WR-2721 pretreatment, 12/25 (48%) patients had improved nadir WBC counts. The mean WBC increased from 1550/mm3 on cyclophosphamide alone to 1850/mm3 with WR-2721 + cyclophosphamide (p = 0.02), while the nadir granulocyte count increased from 449/mm3 to 844/mm3 (p = 0.001). No patient developed microscopic or gross hematuria or inappropriate antidiuretic hormone secretion. One patient developed mild thrombocytopenia. These data suggest that WR-2721 provides significant protection against cyclophosphamide-induced granulocytopenia, but the dose modification factors and degree of clinical benefit remain to be established. The current recommended WR-2721 dose for Phase II trials is 740 mg/m2 administered over 15 minutes.

The pharmacokinetic properties of WR-2721 were investigated in 13 cancer patients given a 150 mg/M2 intravenous bolus dose of the drug. An average plasma clearance value of 2.17 L/min was obtained. Very little of the drug or the two metabolites, WR-1065 and WR-33278, were excreted in urine obtained after the blood collection schedule. Plasma concentrations of WR-2721 decreased by 94% within 6 minutes of drug administration. The mean value of 6.44 L obtained for the steady-state volume of distribution indicates that the extravascular space occupied by the drug is small. These observations suggest that in human cancer patients, WR-2721 is rapidly taken up by tissues and converted to metabolites.

Irradiation treatment portals of the upper abdomen must limit the dose to the kidneys. Sparing one-third of the parenchyma of each kidney will prevent late clinical sequelae. One hundred CT scans of the abdomen were studied to evaluate using the vertebrae as landmark for treatment planning. In lateral fields, using the anterior border of the vertebral column as a landmark for the posterior high isodose line will limit treatment to less than 60% (mean 22%) of a single kidney. Placing the edge of an anterior/posterior field 2 cm lateral to the vertebral column will limit the dose to less than 44% of a single kidney (mean 11%).

The radioprotector with clinical potential, S-2-(3 aminopropylamino)-ethylphosphorothioic acid (WR-2721) is undergoing two Phase I trials. The objectives of these trials are 1) to determine the maximum tolerated dose (MTD) of WR-2721 in a single dose and 2) to determine the highest dose of WR-2721 that can be tolerated daily in the greatest number of fractions per week. A total of 65 patients have been treated. The single maximum tolerated dose has not yet been reached, though 740 mg/m2 is well tolerated. A single dose of 910 mg/m2 has been successfully administered to one patient. The multiple dose MTD is at an early stage with patients currently receiving 170 mg/m2 four times a week. Among the toxicities noted in both trials are hypotension, hypertension, emesis and somnolence. In addition, in the multiple dose trial there have been three patients who have had allergic reactions including one which was life-threatening. Phase II studies are planned and will begin when the maximum tolerated dose is established from each Phase I trial.

Two hundred forty-three patients have received WR-2721 in Phase I-II studies. Separate studies were conducted in which patients with advanced malignancies received WR-2721 before single or multiple doses of radiotherapy or in single doses prior to cyclophosphamide, nitrogen mustard or cis-platinum. Single doses were escalated from 25 to 1330 mg/m2. An Acceptable Tolerated Dose (ATD) of 740 mg/m2 infused in 15 minutes has been established and is currently used in Phase II studies. Significant persistent hypotension (greater than 20 torr systolic) as a dose-limiting toxicity has occurred in 5% of patients in the single dose study. Fifty-five patients have been entered in the multiple dose trial. Dose levels of 340 mg/m2, four times a week for three weeks, and 250 mg/m2, four times a week for six weeks have been reached. There were five idiosynchratic reactions (fever, chills, rash, hypotension), one of which was severe. Some patients withdrew from the multiple dose study because of vomiting after each injection, or fear. No deaths nor any long-term untoward effects were observed. There is no suggestion of tumor protection.

Two hundred twenty-eight patients were treated at the Los Alamos Meson Physics Facility (LAMPF) with negative pi-mesons (pions) between 1974 and 1981. Of these, 19 patients with metastatic disease were treated in pilot studies. Following the clinical determination of relative biological effectiveness (RBE) of pions, 209 patients were treated in site and dose searching studies beginning in 1977. Advanced but regionally localized cancers that were considered poorly responsive to conventional therapy were selected for treatment. A wide range of treatment fractions (22 to 45) and of total dose (1800 to 4200 cGy at the 80% isodose level) to the prescribed target volumes was explored. A follow-up observation period of between 4.5 and 9 years has been completed. The analysis focuses on 129 patients receiving pion therapy alone. Thirty-six (28%) had persisting local tumor control of which 12 (9%) suffered complications of treatment. The results varied among treatment sites, for example: prostate cancer, 18/21 (86%) locally controlled, 6/21 (29%) complications; head and neck, 8/31 (26%) locally controlled, 1/31 (3%) complications; and pancreas, none controlled and no complications. Analysis of dose-fraction response suggests a steep rising curve of complications beyond the dose level of 3750 cGy minimum, 4700 cGy maximum, in 38 fractions. The tumor control response has a broader and ill-defined curve possibly due to the heterogeneity of tumor types. The RBE for late effects in normal tissues appeared to be higher than that for acute effects although the mixture of tumor types, sites, dose, and fractionation made this estimate highly uncertain. No late secondary neoplastic changes in pion irradiated tissues were seen. It is concluded that pions can locally ablate some advanced cancers, often without significant sequelae, but that the optimum therapeutic range is critical. The Los Alamos data may be of use to ongoing pion studies in Canada and Switzerland.

WR-2721 is a sulfhydryl compound which in the animal model improves renal tolerance to cis-platinum (DDP) by factors of 1.3 to 1.7. Phase I trials were initiated to establish the toxicity and dose modification factors when WR-2721 was given prior to escalating doses of DDP. Nineteen patients received 27 courses of WR-2721 (450-910 mg/m2) 20 minutes prior to DDP (50-120 mg/m2). Patients were prehydrated, but no mannitol or other diuretics were administered. Mild, transient nephrotoxicity was observed in only 2 of 15 courses of DDP 80-100 mg/m2 when WR-2721 was given prior to DDP. Although 5 of 9 patients treated with WR-2721 prior to 120 mg/m2 of DDP developed transient nephrotoxicity, their serum creatinines returned to normal baseline values within 1 to 2 weeks. Subsequently, the protocol was modified to include mannitol diuresis. Thirty-four courses of WR-2721 (740 mg/m2) prior to DDP 120-150 mg/m2 with mannitol diuresis were administered. Biweekly serum creatinine and monthly creatinine clearances have remained normal in all patients treated with 120 mg/m2 of platinum and WR-2721. Four of 10 patients treated with 150 mg/m2 of cis-platinum experienced transient nephrotoxicity 5-7 days after treatment. Mild ototoxicity was noted in 4 patients following 150 mg/m2 of DDP. WR-2721 does not appear to protect against the antitumor efficacy of DDP, as 57% of all patients achieved objective partial responses, lasting 1+ to 7+ months. Partial responses occurred in 3/4 (75%) of patients with melanoma and 7/10 (70%) patients with cancer of the head and neck. Compared to retrospective series, our data suggest that WR-2721 may provide some protection against platinum-induced nephrotoxicity, but the dose modification factors remain to be established.

This is the final report of the Phase I Protocol for the initial clinical study of Multiple Dose WR-2721 with radiotherapy (RTOG 80-02). The essential object of the study was to determine the highest dose of WR-2721 that could be given daily for the greatest number of weeks 15 to 30 minutes before conventional radiation treatment schedules. Eighty-four patients were entered into various dose levels. The major and dose-limiting toxicities were emesis, hypotension and malaise. The latter symptom was characterized by increasing weakness, fatigability, and ill-feeling. The maximum tolerated dose (MTD) established by this study is 340 mg/m2 given 4 days a week (excepting Wednesday) for 5 weeks. The drug is delivered intravenously in 7 minutes. There were no long-term blood chemistry changes. There were no deaths due to the administration of the radioprotector.

The volume, distribution, and mobility of opacified pelvic small bowel (PSB) were determined by fluoroscopy and orthogonal radiographs in 150 consecutive patients undergoing pelvic irradiation. Various techniques including uteropexy, omental transposition, bladder distention, inclining the patient, and anterior abdominal wall compression in the supine and prone treatment position were studied for their effect on the volume and location of small bowel within the pelvis. Abdominal wall compression in the prone position combined with bladder distention was selected for further investigation because of its simplicity, reproducibility, patient comfort, and ability to displace the small bowel. Factors correlating with the volume of pelvic small bowel (PSB) included prior pelvic surgery, pelvic irradiation (XRT), and body mass index. After pelvic surgery, especially following abdominoperineal resection (APR), there was a greater volume of PSB which was also less mobile. The severity of acute gastrointestinal effects positively correlated with the volume of irradiated small bowel. Overall, 67% of patients experienced little or no diarrhea, 30% developed mild diarrhea, and no patient required treatment interruption. Late gastrointestinal effects correlated with the prior pelvic surgery and with the volume of small bowel receiving greater than 45 Gy. Small bowel obstruction was not observed in 75 patients who had no previous pelvic surgery. However, following pelvic surgery excluding APR, 2/50 patients and following APR, 3/25 patients developed small bowel obstruction.

Renal dysfunction is a well-known dose-limiting toxicity of cis-platinum. Previous studies demonstrated a 32% incidence of nephrotoxicity following a 100 mg/M2 single dose of cis-platinum with mannitol diuresis. WR-2721 is an aminothiol which in the animal model improves renal tolerance to cis-platinum by factors of 1.3 to 1.7. Phase I trials were initiated to establish the toxicity when WR-2721 was given prior to escalating doses of cis-platinum. Fifty-two patients received 161 courses of WR-2721 prior to cis-platinum (60-150 mg/M2) with mannitol and hydration. Nephrotoxicity, measured by twice weekly serum creatinines and monthly creatinine clearances, occurred in only 10/97 (10%) courses with 120 mg/M2 of cis-platinum. No patient experienced a creatinine elevation after 135 mg/M2 of cis-platinum. With 150 mg/M2 of cis-platinum, 6/17 (35%) courses were associated with transient nephrotoxicity. Five patients who developed transient creatinine elevations following 150 gm/M2 of cis-platinum were subsequently retreated with WR-2721 and cis-platinum (100 mg/M2) without nephrotoxicity. Bone marrow suppression was mild and infrequent. Mild to moderate peripheral neuropathies were noted in seven patients following cumulative cis-platinum doses ranging from 460-1160 mg/M2. Objective partial responses were observed in 26/45 (58%) patients with measurable or evaluable disease. Thus, there is no evidence that WR-2721 protects against the antitumor efficacy of cis-platinum in man. Compared to retrospective series, our data suggest that WR-2721 may provide some protection against platinum-induced nephrotoxicity and neurotoxicity. Controlled trials will be required to define the potential clinical benefit of WR-2721 and cis-platinum.