Combined Betaseron R (recombinant human interferon beta) and radiation for inoperable non-small cell lung cancer

Management of Resectable Stage III-N2 Non-Small-Cell Lung Cancer (NSCLC) in the Age of Immunotherapy

Simple Summary

The treatment of resectable stage III non-small-cell lung cancer with N2 lymph node involvement is usually multimodal and is generally based on neoadjuvant chemotherapy +/− radiotherapy followed by surgery, but the cure rate is still low. Immunotherapy based on anti-PD1/PD-L1 immune checkpoint inhibitors has improved survival in advanced and stage III non-resectable NSCLC patients and is being studied in earlier stages to improve the cure rate of lung cancer. In this article, we review all therapeutic approaches to stage III-N2 NSCLC, analysing both completed and ongoing studies that evaluate the addition of immunotherapy with or without chemotherapy and/or radiotherapy.

Abstract

Stage III non-small-cell lung cancer (NSCLC) with N2 lymph node involvement is a heterogeneous group with different potential therapeutic approaches. Patients with potentially resectable III-N2 NSCLC are those who are considered to be able to receive a multimodality treatment that includes tumour resection after neoadjuvant therapy. Current treatment for these patients is based on neoadjuvant chemotherapy +/− radiotherapy followed by surgery and subsequent assessment for adjuvant chemotherapy and/or radiotherapy. In addition, some selected III-N2 patients could receive upfront surgery or pathologic N2 incidental involvement can be found a posteriori during analysis of the surgical specimen. The standard treatment for these patients is adjuvant chemotherapy and evaluation for complementary radiotherapy. Despite being a locally advanced stage, the cure rate for these patients continues to be low, with a broad improvement margin. The most immediate hope for improving survival data and curing these patients relies on integrating immunotherapy into perioperative treatment. Immunotherapy based on anti-PD1/PD-L1 immune checkpoint inhibitors is already a standard treatment in stage III unresectable and advanced NSCLC. Data from the first phase II studies in monotherapy neoadjuvant therapy and, in particular, in combination with chemotherapy, are highly promising, with impressive improved and complete pathological response rates. Despite the lack of confirmatory data from phase III trials and long-term survival data, and in spite of various unresolved questions, immunotherapy will soon be incorporated into the armamentarium for treating stage III-N2 NSCLC. In this article, we review all therapeutic approaches to stage III-N2 NSCLC, analysing both completed and ongoing studies that evaluate the addition of immunotherapy with or without chemotherapy and/or radiotherapy.

Combining Radiation Therapy With Interferons: Back to the Future

Radiation therapy has been linked to the induction of an intratumoral type I interferon (IFN) response, which positively affects the response to treatment. This has spiked the interest to combine radiation therapy with IFN-based treatment. Interestingly, this combination treatment has been considered previously, since preclinical studies demonstrated a radiosensitizing effect of interferons. As a result, multiple clinical trials have been performed combining radiation therapy with interferons in different tumor types. Although potential benefit has been suggested, the outcomes of the trials are diverse and challenging to interpret. In addition, increased grade ≥3 toxicity frequently resulted in a negative recommendation regarding the combination therapy. The latter appears premature because many studies were small and several aspects of the combination treatment have not yet been sufficiently explored to justify such a definite conclusion. This review summarizes the available literature on this combination therapy, with a focus on IFN-α and IFN-β. Based on preclinical studies and clinical trials, we evaluated the potential opportunities and describe the current challenges. In addition, we identify several issues that should be addressed to fully exploit the potential benefit of this combinatorial treatment approach.

Clinical trials exploring the benefit of immunotherapy and radiation in cancer treatment: A review of the past and a look into the future

Cancer immunotherapy is rapidly redefining the standard of cancer care. The role of radiation therapy in eliciting antitumoral immune response is also being actively investigated in combination with various immunotherapeutic agents to exploit potential synergy between the 2 modalities. In this review, we summarize the rationale and results of past and ongoing clinical trials that combined the use of radiation therapy and immunogenic agents such as vaccines, cytokines, immune checkpoint inhibitors, costimulatory agonists, and myeloid activators.

Lack of interferon beta-induced radiosensitization in four out of five human glioblastoma cell lines

PURPOSE

To investigate the potential of interferon beta to enhance the cytotoxic activity of ionizing irradiation against glioma cells, and to elucidate the possible mechanisms responsible for conflicting clinical results.

METHODS AND MATERIALS

Five glioblastoma cell lines (U87MG, U118MG, U373MG, MO59K, MO59J) with different radiosensitivity and genetic background were used. Experiments were performed in exponentially growing cultures, and cell survival was measured by a colony-forming assay. Cells were incubated with natural interferon beta (n-IFN-beta; 30-3000 IU/mL) for 24 h followed by single dose irradiation with 1 to 6 Gy of gamma-rays.

RESULTS

Significant differences in n-IFN-beta sensitivity were found. The cell lines also differed in their radiation sensitivity, and there was no correlation between the n-IFN-beta and the radiation sensitivity. In three of five cell lines, the interaction of n-IFN-beta and irradiation was infra-additive; in one cell line, it was additive. For MO59J cells only, which are NHEJ-deficient, supra-additivity was observed.

CONCLUSION

Our results confirm the remarkable heterogeneity that is characteristic of malignant glioma. The combined effect of n-IFN-beta and radiation was mostly infra-additive or additive; synergistic interaction might occur in tumor cells that already have acquired repair deficiencies because of their genetic instability, as shown for the MO59J cell line.

Concurrent interferon-alpha and radiation for head and neck melanoma

Melanoma cells are resistant to radiation in part due to their capacity to repair sublethal damage. A large fraction dose is therefore often utilized. However, if the tumour is located close to critical structures with modest tolerance, high fraction doses increase the risk for late complications compared with standard fractionation, but using the latter alone risks the desired outcome. Concurrent systemic biotherapy with standard radiation fractions may therefore represent an acceptable compromise. The outcome of concurrent systemic interferon-alpha (IFNalpha) and radiation in three patients with head and neck melanoma was evaluated. Standard radiation fractions were used because of the radiosensitizing properties of IFNalpha. Acute toxicity was significant and required treatment interruptions. However, all side effects subsided following treatment. All three patients achieved local control at follow-up periods of 24, 18 and 19 months, respectively. One patient developed widespread distant metastases. The combination of IFNalpha with radiation is considered feasible in terms of outcome and should be investigated with a larger cohort of patients. Toxicity is significant, and the addition of radioprotectors could be desirable.

A phase III comparison of radiation therapy with or without recombinant beta-interferon for poor-risk patients with locally advanced non-small-cell lung cancer (RTOG 93-04)

PURPOSE

The results of Phase I/II data testing beta-interferon with radiation therapy in a non-small-cell lung cancer population were promising. Based on these data, the Radiation Therapy Oncology Group (RTOG) initiated a Phase III trial to test the efficacy of beta-interferon in poor-risk patients with Stages IIIA and IIIB non-small-cell lung carcinoma.

METHODS

Between September 1994 and March 1998, 123 patients were accrued to this trial. Enrolled patients were not eligible for other chemoradiation studies within the RTOG. Eligibility criteria included histologically confirmed Stage IIIA or IIIB non-small-cell lung cancer (according to American Joint Committee on Cancer) considered clinically inoperable or unresectable at the time of surgery. Patients were required to have a Karnofsky performance status 50-70 or >70 and at least 5% weight loss over the preceding 3 months. Betaseron (recombinant human interferon beta(ser), rHuIFN-beta(ser),) was the chosen preparation of beta-interferon. The patients randomized to the investigational arm received 16 x 10(6) IU of Betaseron by i.v. bolus given 3 days a week (Monday-Wednesday) on Weeks 1, 3, and 5. The Betaseron was given 30 minutes before radiation therapy for a total of nine doses. Irradiation was delivered at 2 Gy per fraction, 5 days a week, for a total of 60 Gy over 6 weeks and was identical for both arms. The primary end point of the trial was overall survival with local control as a secondary end point. Toxicities occurring within 90 days of therapy completion were defined as acute.

RESULTS

The median follow-up was 4 years (range: 2.5-6 years) for surviving patients. Seventy-six percent of all patients completed beta-interferon. Toxicity was the primary reason for noncompliance. Radiotherapy (RT) compliance was excellent in the RT-alone arm, with 94% completing therapy, compared to 82% in the beta-interferon arm (p = 0.0475). Grade 3 and 4 acute toxicities were higher on the beta-interferon arm (p = 0.0249). Grade 3 and 4 acute toxicities were primarily related to lung (n = 8) and esophagus (n = 7). No Grade 4 or 5 late toxicities were seen for patients in the radiation-alone arm. However, three patients on the beta-interferon arm experienced Grade 4 toxicity, and one patient died. The 1-year survival rate for the RT-alone arm was 44% with a median survival time of 9.5 months. The 1-year survival on the beta-interferon arm was 42% with a median survival of 10.3 months. There was no statistical difference in survival times (p = 0.66).

CONCLUSIONS

This multicenter, controlled Phase III trial failed to confirm the efficacy of Betaseron in patients receiving definitive radiotherapy for locally advanced, nonmetastatic non-small-cell lung cancer. The use of beta-interferon led to greater rates of both acute and late treatment-related toxicity. The RTOG continues to investigate other biologic modifiers that may provide a nontoxic alternative for this poor-risk population.

Interferon-alpha combined with radiotherapy in the treatment of unresectable melanoma

A case of recurrent and twice resected sinonasal melanoma is presented. The large recurrent tumor was found to regress by a concurrent combination of 6660 cGy photon radiation and subcutaneous interferon-alpha injections given for a period of 8 weeks. Possible mechanisms of potentiation between interferon and radiation are discussed. The unexpected result in this case report raises interesting questions about this treatment combination.

Combined chemotherapy, radiotherapy, and immunotherapy for pancreatic carcinoma--a case report

Therapeutic modalities for incompletely resected pancreatic carcinoma are rare. Effective treatment must not only prolong the period of palliation but also limit the adverse sequelae of the Whipple procedure so as not to compromise the quality of the remaining life span. New treatments include the use of gemcitabine and type I interferons. We treated a patient with incomplete resection of a pancreatic tumor with two cycles of gemcitabine (1000 mg/m2) and cisplatinum (50 mg/m2) followed by radiotherapy (45 Gy/5 weeks) combined with interferon-beta (three times a week/5 x 10(6) IU). Two small liver metastases occurred subsequently. In all, four cycles of gemcitabine/cisplatinum were delivered. The patient lived at least 9 months with stable metastatic liver disease and local control. He had no acute toxic reactions except for a decrease in the leukocyte count, no long-term side effects, and a satisfactory quality of life. A regimen of sequential gemcitabine/cisplatinum and radiotherapy in combination with interferon-beta deserves further consideration as therapy for pancreatic carcinoma.

The combined effect of interferon beta and radiation on five human tumor cell lines and embryonal lung fibroblasts

PURPOSE

The combined effect of natural Interferon-beta (n-IFN-beta) and ionizing radiation was tested in vitro on 5 different tumor cell lines and 1 embryonal lung fibroblast cell line.

MATERIALS AND METHODS

The following cell lines were used: A549 (lung cancer), MCF-7 (breast cancer), CaSki (cervical cancer), WiDr (colon cancer), ZMK-1 (head and neck cancer), and MRC-5 (embryonal lung fibroblast line). Cells were incubated with n-IFN-beta (30 I.U./ml to 3000 I.U./ml) 24 h before irradiation. Irradiation was given as single dose between 1 and 6 Gy. Cell survival was evaluated using a standard colony-forming assay.

RESULTS

Incubation with n-IFN-beta enhanced the effect of radiation in all tumor cell lines tested. The maximum sensitizing enhancement ratios (SER) at the 37% survival level were: 1.66 for A549 cells, 1.47 for CaSki cells, 1.56 for MCF-7 cells, 1.40 for WiDr cells, and 1.57 for ZMK-1 cells. In the nonneoplastic MRC-5 cell line, no radiosensitizing effect of n-IFN-beta could be demonstrated. The linear quadratic fit of the survival curves showed an increase of the alpha-component for all tumor cell lines treated with n-IFN-beta.

CONCLUSIONS

IFN-beta enhanced the effect of radiation in the tumor cell lines, but not in the nonmalignant lung fibroblasts. The increase of the alpha component in the survival curves indicates that impaired radiation repair or the accumulation of sublethal damage might play a role for the radiosensitizing effect of n-IFN-beta.

Tumour response and radiation-induced lung injury in patients with recurrent small cell lung cancer treated with radiotherapy and concomitant interferon-alpha

The aim of this study was to determine whether either natural or recombinant interferon (IFN)-alpha can improve the response to radiotherapy (RT) in patients with small cell lung cancer (SCLC), and to assess the role of IFN in radiation-induced lung injury. All patients had previously participated in a randomised trial of chemotherapy alone or in combination with IFN-alpha in three arms (arm O: no IFN, arm I: natural IFN-alpha, arm II: recombinant IFN-alpha). Patients with locally progressive disease in the lungs following chemotherapy were treated with RT and they continued with their concomitant IFN-alpha. The RT dose was 50 Gy. Radiation-induced lung injury was assessed by lung function tests, computed tomography and bronchoalveolar lavage fluid (BALF) analysis which included cell findings, Interleukin (IL)-1 alpha/-1 beta expression by alveolar macrophages and surfactant components. Seventeen patients were entered in the study, 16 of whom were evaluable. Response rates in Arms O, I and II were 50, 67 and 50%, respectively. Median survival was 18.5, 7 and 23 months respectively, and 1-year survival was 67, 29 and 75% respectively. Long-term survival as assessed by 2- and 3-year survival rates was 29% in patients receiving natural IFN-alpha as compared to 17% in patients not receiving IFN (not statistically significant findings). Every patient had abnormal results when assessed for radiation-induced lung injury. No statistically significant difference was found in toxicity between the treatment arms. A high surfactant protein (SP)-A/phospholipid ratio and a high level of SP-A in BALF before RT was associated with a high degree of radiation-induced lung injury measured by lung function tests and computed tomography in all arms of the study. Thus, we could not show that the combination of IFN-alpha and RT induced more lung toxicity than RT alone as we did in our previous study. The role of high SP-A/phospholipid ratios and high SP-A levels in BALF before RT as predictors of the development of lung injury after RT needs to be determined in the future.

Alternating radiotherapy and chemotherapy for inoperable Stage III non-small-cell lung cancer: long-term results of two Phase II GOTHA trials. Groupe d'Oncologie Thoracique Alpine

PURPOSE/OBJECTIVE

To report on two consecutive Phase II cooperative trials in which we evaluated the combination of alternating hyperfractionated accelerated radiotherapy and cisplatin-based chemotherapy in inoperable Stage III non-small cell lung cancer (NSCLC).

PATIENTS & METHODS

Between February 1986 and September 1989, 65 patients were entered in the first trial (GOTHA I), and between December 1989 and October 1992 67 were enrolled in the second trial (GOTHA II). In both protocols, radiotherapy (RT) was administered twice daily, at 6 h intervals, 5 days a week, to a total dose of 63 Gy in 42 fractions of 1.5 Gy. RT was given during weeks 2, 3, 6, and 7, over an elapsed time of 6 weeks. In GOTHA I, three cycles of cisplatin, 60 mg/m2 day 1, mitomycin, 8 mg/m2 day 1, and vindesin 3 mg/m2 day 1 and the first day of the following week, were given during weeks 1, 5, and 9; in GOTHA II, cisplatin 70 mg/m2 day 1 and vinblastin 5 mg/m2 day 1 and the first day of the following week were given during weeks 1, 5, 9, 13, 17, and 21.

RESULTS

With a minimum follow-up of 3 years, the 1-, 2-, 5-, and 8-year overall survival probability was 56% (95% CI 47-64%), 27% (20-35%), 12% (7-18%) and 9% (3-16%), respectively, with a median survival of 13.6 months (11.4-16.8). Median follow-up for survivors was 6 years (3.3-9.9). There were no survival differences between Stages IIIA and IIIB (p = 0.84), performance status 0, 1, 2 (p = 0.87), sex (p = 0.45) or between the two treatment protocols. At this time, 14 patients are alive, and 118 have died: 102 from NSCLC, 4 from acute toxicity, 2 from secondary surgery, 4 from other medical causes, and 6 from unknown causes. Correlation between response and long-term survival was poor, since of the 24 patients who survived 3 years or more, only 6 (25%) were classified as having a complete response; the remainder having either a partial response (11, 46%), no change (6, 25 %), or "progressive disease" (1, 4 %). First site of relapse was local in 31% of these cases, distant in 43%, local and distant in 15 %, and unknown in 11%. Main grade 3-4 acute toxicities were nausea-vomiting (17%), mucositis (15%), leukopenia (41%), and thrombocytopenia (11%). Eight patients presented with grade 3-4 symptomatic lung radiation pneumopathy.

CONCLUSION

Based on this experience with 132 patients, this combination of alternated RT and chemotherapy (CT) for inoperable Stage III NSCLC is feasible with acceptable toxicity, and long-term results suggest a gain in survival when compared to those obtained with conventional RT alone. However, the still high local and distant failure rates indicate that both local and systemic therapies need to be improved.

[Treatment of stage IIIB loco-regionally advanced non-small-cell bronchial carcinomas with radiation and interferon-beta. Preliminary results of a phase II study]

BACKGROUND

In-vitro and in-vivo studies demonstrated the radiosensitizing effect of interferon beta on malignant tumor tissue as well as simultaneously a radioprotective effect on normal lung tissue. In this phase II study the outcome of combining radiotherapy with interferon beta in patients with advanced non-small cell lung cancer was evaluated.

PATIENTS AND METHOD

From February 1994 until November 1996 14 patients with non-small cell lung cancer, stage IIIB were treated with locoregional radiation up to 59.4 Gy, with daily doses of 1.8 Gy and 5 fractions per week. Five million units of interferon beta (Fiblaferon) were given intravenously immediately preceding radiotherapy on the first 3 days of week 1, 3 and 5.

RESULTS

Four of 14 patients (28.6%) showed complete response and 7 patients (50%) partial response, resulting in an overall response rate of 78.6%. After a mean follow-up time of 23.3 months the 1-, 2- and 3-year survival rates were 56.3%, 37.5% and 37.5%, respectively. The median survival time was 13 months. Three of 14 patients (21.4%) suffered from 7 Grade-3 acute side effects and 2 patients (14.3%) from 1 Grade-3 late toxicity in each case. One further patient, whose right lung was resected 3 months after completion of radiotherapy, developed as a consequence of this operation 2 Grade-4 complications.

CONCLUSION

Considering the toxicity and the preliminary results of combining irradiation and interferon beta in the treatment of locally advanced non-small cell lung cancer it seems, that this procedure is worth to be tested in a phase III study.

Local low-dose interleukin-2 induces systemic immunity when combined with radiotherapy of cancer. A pre-clinical study

Tumor recurrence and outgrowth of metastases limit the therapeutical effect of radiotherapy. We have tested whether these problems can be overcome by supplementing radiotherapy with locoregional interleukin-2 (IL-2) treatment. The SL2 lymphoma and the M8013 mammary carcinoma were used. Mice bearing a 10-day-old s.c. tumor were locally irradiated and were treated daily with IL-2 peritumorally for 5 or 10 days. Low-dose IL-2 therapy improved local response (LR) and increased disease-free survival (DFS) in both tumor models following either single-dose irradiation or fractionated irradiation. For example, 93% of SL2-bearing mice treated with single-dose irradiation and 10 days of IL-2 experienced long-term DFS, compared with 17% for irradiation alone (p < 0.0001). Additionally, treatment of one tumor with irradiation +IL-2 led to anti-tumor effects in a second, untreated tumor in 80% of SL2-bearing mice. LR was increased to 100% and DFS to 70% when the second, non-irradiated tumor was also treated with peritumoral IL-2. We conclude that supplementing local radiotherapy with low doses of IL-2 results in increased local tumor control and regression of distant, non-irradiated tumors. This type of radioimmunotherapy is a promising new approach for the clinic.

A phase I pilot study of pelvic radiation and alpha-2A interferon in patients with locally advanced or recurrent rectal cancer

PURPOSE

The purpose of this pilot study was to determine the maximum tolerated dose of alpha-2a interferon given by subcutaneous injection and combined with high dose pelvic radiation for locally advanced or recurrent rectal cancer.

METHODS AND MATERIALS

In this Phase I pilot study, patients with locally advanced, unresectable, or recurrent rectal cancer with or without distant metastases received external beam pelvic radiotherapy over 5 to 6 weeks combined with escalating doses of alpha-2a interferon. Interferon was escalated in increments of 3 million units for each patient cohort, starting at 3 million units subcutaneously 3 days weekly during pelvic radiation. Radiotherapy consisted of 44 Gy (2 Gy fractions) to the pelvis followed by a boost of 6 Gy or 16 Gy to gross pelvic tumor, depending on the presence or absence of small bowel in the boost field, respectively. Between 1991 and 1993, 10 patients were treated on this study, five with locally advanced and five with locally recurrent rectal cancer.

RESULTS

At 6 million units of interferon, Grade 3 (WHO criteria) toxicities were as follows: diarrhea (one), leukopenia (one), and neutropenia (one). One patient died of a massive GI bleed at this dose level. Death was not felt to be treatment related. The maximum tolerated dose of interferon was 3 million units three times weekly with radiation. Three patients had unusual complications at 4, 6, and 6 months possibly related to treatment. The first had a right distal ureteric stricture with a right urinoma. The second had a sudden left foot drop that has remained stable. The third had sudden onset of bilateral lower extremity paraplegia with spontaneous resolution.

CONCLUSIONS

The maximally tolerated dose of interferon alpha-2a given three times weekly during pelvic radiation was 3 million units based on acute side effects. Nevertheless, even at this dose level there were three unusual subacute complications possibly related to treatment. Caution is advised when combining interferon alpha-2a with high dose pelvic radiation, especially in patients with predisposing conditions (such as diabetes) for radiotherapy complications.

Recombinant human interferon-beta (rHuIFN-beta) and radiation therapy for inoperable non-small cell lung cancer

Fifteen patients with stage II, IIIA, and IIIB non-small cell lung cancer (NSCLC) received subcutaneous (s.c.) recombinant, glycosylated, human interferon-beta 1a (Rebif; rHuIFN-beta 1a) on each day of conventionally fractionated radiation therapy (RT) given in 2.0 Gy fractions to 60 Gy in 6 weeks. The rHuIFN-beta 1a was generated in CHO cells by recombinant DNA technology and is identical to natural IFN-beta produced by fibroblasts in primary sequence and glycosylation. Cohorts of three patients each were treated with escalating doses of rHuIFN-beta 1a: 1.5, 3, 6, 12, and 24 MIU/m2 per treatment day. Acute toxicity was assessed according to modified WHO criteria; late toxicity was graded using RTOG late toxicity criteria. The maximum tolerated dose (MTD) of rHuIFN-beta 1a was defined as the dose level immediately below that in which dose-limiting toxicity occurred in > or = two of six patients. Immunomodulatory effects and antigenicity of rHuIFN-beta 1a were assessed by 2-5A synthetase, beta 2-microglobulin, and neopterin levels and by measurement of anti-rHuIFN-beta antibodies, respectively. Fourteen of fifteen patients experienced grades 1-3 acute (early) toxicity (< or = 90 days), which was primarily gastrointestinal: dysphagia/esophagitis (14/15), nausea/vomiting (12/15), anorexia (7/15), and liver transaminasemia (6/15). One of three patients treated with 24 MIU/m2 per treatment day (total rHuIFN-beta 1a dose 672 MIU) died of complications secondary to pneumonia, sepsis, adult respiratory distress syndrome (ARDS), and radiation pneumonitis. Twelve patients were evaluable for late toxicity (> 90 days). Maximum toxicity was grade 0 in five patients, grade 1 in four patients, and grade 5 in one patient (radiation pneumonitis). Clinical responses from the combination were 1/15 CR, 6/15 PR, 6/15 stable disease, and 1/15 progressive disease. The MTD of rHuIFN-beta 1a has been estimated at 12 MIU/m2 per treatment day when given daily during conventional RT to 60 Gy in 6 weeks. Biologic response by rHuIFN-beta 1a alone was reflected by significant and dose-related increases in 2-5A synthetase, beta 2-microglobulin, and neopterin. Radiation therapy alone had no effect on these immune response parameters and did not diminish their augmentation by rHuIFN-beta 1a. There was no association of biologic modulation with clinical response or survival.

Pharmacokinetics and pharmacodynamics of recombinant human interferon-beta in healthy male volunteers

The pharmacokinetics and pharmacodynamics of recombinant human interferon-beta (rHuIFN-beta 1a) were assessed following administration to 12 healthy male volunteers. Each subject received, in a double-blind, balanced, random-order, crossover sequence, single doses of 6 MIU of rHuIFN-beta 1a (Rebif) i.v., i.m., and s.c. or matching placebo on four occasions separated by washout periods of 1 week. Blood samples were collected at preset times for the measurement of serum IFN-beta levels and of intracellular 2'-5'-oligoadenylate synthetase levels. Blood pressure, sitting heart rate, respiratory rate, oral body temperature, and tolerance were monitored regularly. All administrations of rHuIFN-beta 1a were well tolerated, although about half of the subjects had a flu-like syndrome, as expected. After i.v. bolus injection, the pharmacokinetics of rHuIFN-beta 1a were well described by a classic two-compartment model. Mean total clearance of rHuIFN-beta 1a was about 100 L.h-1. The distribution half-life was 5 min, and the terminal half-life was approximately 5 h. After i.m. or s.c. injection, serum IFN-beta profiles were rather flat, and about one sixth of the administered dose was available systemically. Extent and duration of clinical and biologic effects were independent of the route of administration and of the IFN-beta serum levels. Biologic pharmacodynamic effects persisted even when IFN-beta serum levels had returned to baseline and were still significantly elevated 3 days after a single dose. Because of the independence of the extent and duration of clinical and biologic pharmacodynamic effects from the route of administration and from the IFN-beta serum levels, the s.c route of administration is preferred in indications in which primarily an immunomodulatory action is sought. Predominantly antiviral and antiproliferative activity is enhanced by the i.v. route to provide adequate drug levels at the site of pathology, although its application is limited on practical grounds.

Interferons and the tumor cell

Optimal use of interferons (IFNs) for the treatment of tumor disease requires experimental work in order to precisely define IFN actions. We have pointed out three modes of such actions relevant for the antitumor efficacy exerted by IFNs: effects on apoptosis, effects on genes involved in malignant transformation and effects on angiogenesis. These are but three selected areas forming a basis for the development of optimal IFN therapy. Further experimental work, undertaken in these and additional IFN areas, is mandatory for the most effective clinical use of IFNs for the treatment of tumor disease.

Evolution and accomplishments of the Radiation Therapy Oncology Group

PURPOSE

The Radiation Therapy Oncology Group (RTOG) recently completed its first quarter century as a cooperative clinical cancer research organization. It is timely and appropriate to document its origins, evolution, and accomplishments.

METHODS AND MATERIALS

The historical review of the RTOG called upon written and oral documentation.

RESULTS

The RTOG is the most enduring product of the Committee for Radiation Therapy Studies (CRTS). Although not one of the original 17 clinical trials groups developed by the National Cancer Institute in 1956, the RTOG has pursued trials suggested by laboratory findings including the oxygen effect, intrinsic radiosensitivity, proliferation kinetics of normal and tumor cells, and interactions with other cytotoxic agents. Improvements in survival have been demonstrated for patients with carcinoma of the esophagus and cervix, and nonsmall cell carcinomas of the lung. The national and international radiation oncology communities have benefitted from standards and quality control/assurance guidelines for established and new modalities. A growing number of institutions in North America participate in RTOG trials.

CONCLUSION

The RTOG is an important clinical research resource, which has contributed to improved outcome for patients with many forms of cancer. It has become increasingly productive and widely adopted and endorsed by oncologists throughout North America.

A perpetual cascade of cytokines postirradiation leads to pulmonary fibrosis

PURPOSE

Radiation-induced pulmonary reactions have classically been viewed as distinct phases--acute pneumonitis and, later, fibrosis--occurring at different times after irradiation and attributed to different target cell populations. We prefer to view these events as a continuum, with no clear distinction between the temporal sequence of the different pulmonary reactions; the progression is the result of an early activation of an inflammatory reaction, leading to the expression and maintenance of a cytokine cascade. In the current study, we have examined the temporal and spatial expression of cytokine and extracellular matrix messenger ribonucleic acid (mRNA) abundance in fibrosis-sensitive mice after thoracic irradiation.

METHODS AND MATERIALS

Radiation fibrosis-prone (C57BL/6) mice received thoracic irradiation of 5 and 12.5 Gy. At Day 1, and 1, 2, 8, 16, and 24 weeks after treatment, animals were killed and lung tissue processed for light microscopy and isolation of RNA. Expression of cytokine and extracellular matrix mRNA abundance was evaluated by slot-blot analysis and cellular localization by in situ hybridization and immunochemistry.

RESULTS

One of the cytokines responsible for the inflammatory phase (IL-1 alpha) is elevated at 2 weeks, returns to normal baseline values, then increases at 8 weeks, remaining elevated until 26 weeks when lung fibrosis appears. Transforming growth factor-beta (TGF beta), a proliferative cytokine, is elevated at 2 weeks, persists until 8 weeks, and then returns to baseline values. In parallel with the cytokine cascade, the fibrogenic markers for CI/CIII/IV (collagen genes) correlate by showing a similar early and then later elevation of activity. For instance, the collagen gene expression of CI/CIII is a biphasic response with an initial increase at 1-2 weeks that remits at 8 weeks, remains inactive from 8 to 16 weeks, and then becomes elevated at 6 months when collagen deposition is recognized histopathologically.

CONCLUSION

These studies clearly demonstrate the early and persistent elevation of cytokine production following pulmonary irradiation. The temporal relationship between the elevation of specific cytokines and the histological and biochemical evidence of fibrosis serves to illustrate the continuum of response, which, we believe, underlies pulmonary radiation reactions and supports the concept of a perpetual cascade of cytokines produced immediately after irradiation, prompting collagen genes to turn on, and persisting until the expression of late effects becomes apparent pathologically and clinically.

The evolution of Radiation Therapy Oncology Group (RTOG) protocols for nonsmall cell lung cancer

Over the past 2 decades, the Radiation Therapy Oncology Group (RTOG) has played a significant role in clarifying the role of radiation therapy (RT) in the treatment of nonsmall cell lung cancer (NSCLC). RTOG lung cancer research has evolved over this time period through a systematic succession of investigations. For unresectable NSCLC, the dependence of local tumor control and survival on total dose of standard fractionation RT, as well as pretreatment performance characteristics, was demonstrated in initial RTOG trials. Subsequently, further radiation dose intensification was tested using altered fractionation RT to total doses up to 32% higher than standard RT to 60 Gy, given as either hyperfractionation or accelerated fractionation, while attempting to retain acceptable normal tissue toxicity. These higher doses required rethinking of established RT techniques and limitations, as well as careful surveillance of acute and late toxicity. A survival advantage was shown for hyperfractionation to 69.6 Gy, in favorable performance patients, compared to 60 Gy. Further testing of high dose standard RT will use three-dimensional, conformal techniques to minimize toxicity. RTOG further extended the theme of treatment intensification for unresectable NSCLC by evaluating combined chemotherapy (CT) and RT. Improved local control and survival was shown for induction CT followed by standard RT to 60 Gy, compared to standard RT (60 Gy) and altered fractionation RT (69.6 Gy). The intent of current studies is to optimize dose and scheduling of combined CT and standard RT, as well as combined CT and altered fractionation RT. Noncytotoxic RT adjuvants, such as hypoxic cell sensitizers, nonspecific immune stimulants, and biologic response modifiers have also been studied. Resectable NSCLC has also been an RTOG focus, with studies of preoperative and postoperative RT, CT, and CT/RT, including the prognostic value of serum and tissue factors. RTOG studies have yielded incremental improvements in treatment outcome for NSCLC, better understanding of the disease dynamics, and a strong foundation for future investigations.