Consolidative thoracic radiation therapy for extensive-stage small cell lung cancer in the era of first-line chemoimmunotherapy: preclinical data and a retrospective study in Southern Italy

Background

Consolidative thoracic radiotherapy (TRT) has been commonly used in the management of extensive-stage small cell lung cancer (ES-SCLC). Nevertheless, phase III trials exploring first-line chemoimmunotherapy have excluded this treatment approach. However, there is a strong biological rationale to support the use of radiotherapy (RT) as a boost to sustain anti-tumor immune responses. Currently, the benefit of TRT after chemoimmunotherapy remains unclear. The present report describes the real-world experiences of 120 patients with ES-SCLC treated with different chemoimmunotherapy combinations. Preclinical data supporting the hypothesis of anti-tumor immune responses induced by RT are also presented.

Methods

A total of 120 ES-SCLC patients treated with chemoimmunotherapy since 2019 in the South of Italy were retrospectively analyzed. None of the patients included in the analysis experienced disease progression after undergoing first-line chemoimmunotherapy. Of these, 59 patients underwent TRT after a multidisciplinary decision by the treatment team. Patient characteristics, chemoimmunotherapy schedule, and timing of TRT onset were assessed. Safety served as the primary endpoint, while efficacy measured in terms of overall survival (OS) and progression-free survival (PFS) was used as the secondary endpoint. Immune pathway activation induced by RT in SCLC cells was explored to investigate the biological rationale for combining RT and immunotherapy.

Results

Preclinical data supported the activation of innate immune pathways, including the STimulator of INterferon pathway (STING), gamma-interferon-inducible protein (IFI-16), and mitochondrial antiviral-signaling protein (MAVS) related to DNA and RNA release. Clinical data showed that TRT was associated with a good safety profile. Of the 59 patients treated with TRT, only 10% experienced radiation toxicity, while no ≥ G3 radiation-induced adverse events occurred. The median time for TRT onset after cycles of chemoimmunotherapy was 62 days. Total radiation dose and fraction dose of TRT include from 30 Gy in 10 fractions, up to definitive dose in selected patients. Consolidative TRT was associated with a significantly longer PFS than systemic therapy alone (one-year PFS of 61% vs. 31%, p<0.001), with a trend toward improved OS (one-year OS of 80% vs. 61%, p=0.027).

Conclusion

Multi-center data from establishments in the South of Italy provide a general confidence in using TRT as a consolidative strategy after chemoimmunotherapy. Considering the limits of a restrospective analysis, these preliminary results support the feasibility of the approach and encourage a prospective evaluation.

Injection of irradiated b16 melanoma genetically-modified to secrete IFN-alpha causes regression of an established tumor

Highly aggressive murine B16 melanoma was engineered to secrete IFN-alpha constitutively. Cells expressing IFN-alpha were injected into syngeneic C57BL/6 mice and the mice were monitored for tumor development. Secretion of IFN-alpha by B16 melanoma cells completely abrogated their tumorigenicity in syngeneic mice. LFN-alpha-secreting cells also abrogated the tumorigenicity of IFN-gamma-secreting and TNF-alpha-secreting cells when injected in combination whereas cells secreting either IFN-gamma or TNF-alpha grow progressively in mice when injected alone. Moreover, protected animals developed significant immunity against subsequent challenge with parental cells. Injection of parental cells and IFN-alpha-secreting cells together in a mixed tumor transplantation assay resulted in a significant reduction of tumorigenicity of the parental cells. Histopathological studies of the tissues from the injection site of the mice inoculated with a combination of parental and B16.IFN-alpha cells revealed the existence of a massive cellular infiltrate composed of lymphocytes and granulocytes at an early stage (7-11 days). In the later stages (22 days), no recognizable tumor tissue was detected. Injection of irradiated IFN-alpha-secreting cells in the mice carrying an established tumor completely prevented tumor development in 80% of the treated mice when injection was performed on the same side as the tumors. Injection of irradiated IFN-alpha-secreting cells in the contralateral site showed much less effect on the established tumor. Systemic antitumor effects on the established tumor can be enhanced by using a combination of irradiated IFN-alpha and IFN-gamma secreting cells as a vaccinating inoculum.

Up-regulation of a tumor-associated antigen (tag-72) by interferon-alpha and interferon-gamma in patients with cutaneous breast-cancer recurrences

Up-regulation of a tumor-associated antigen (TAA) TAG-72 was investigated immunohistochemically in skin recurrences of 10 breast cancer patients treated with intralesional injections of natural interferons (nIFNs) alpha and gamma. Up-regulation was assessed by comparing the immunoreactivity of pre-IFN and post-IFN specimens stained with monoclonal antibodies (MoAbs) B72.3 and CC49 at near end-point dilutions. Varying degrees of enhanced immunoreactivity were detected in IFN-injected and non-IFN-injected lesions except in 1 patient with high constitutive expression of TAG-72 and another patient not expressing TAG-72. Thus, IFN-mediated up-regulation of TAG-72 can occur in patients whose breast cancer cells express this TAA, independently of the initial levels of antigenic expression.

Relationship between number of allergic sensitizations and immunity impairment: anything new in immunotherapy for allergies and vaccines planning?

To 106 14-56 year-old allergic people (30 monosensitized, 24 sensitized to 2 pollens, 52 polysensitized) we have evaluated the Global Immune Competence Status (GICS). That's a compound score, made of ten parameters, six regarding cell-mediated immunity (WBC/mmc, Gr/mmc, Ly/mmc, Ly CD3+/mmc, Ly CD4+/mmc, CD4/CD8 Ratio), four regarding nutritional status and humoral immunity (Tot. Protein mg/dl, Albumin mg/dl, Gammaglobulins mg/dl, IgG mg/dl). Each parameter is brought on a grid including 4 worth scores worsening from 4 to 1, related to different ranges of values; this way quickly leads to characterize type and grade of immune deficiency. So doing we found that in 30 monosensitized people 27 (90%) show a complete immune competence, while just 3 people (10%) have impaired GICS: in these 1 (3%) regards cell-mediated immunity, while 2 (7%) regard humoral immunity. In 24 patients sensitized to 2 allergenes, 18 (75%) showed complete immune competence, while 6 (25%) a GICS impairment regarding cell-mediated immunity. In leaving 52 polysensitized patients, 30 people showed complete immune competence (58%), while 20 (38%) showed a GICS impairment regarding cell-mediated immunity and 2 (4%) impaired humoral immunity. This work shows that the higher the number of sensitizations is, the stronger the cell-mediated immunity impairment in allergic people become.

Pregnancy in renal transplantation: immunologic evaluation of neonates from mothers with transplanted kidney

The occurrence of pregnancy in young female organ transplant recipients may sustain a high risk for prematurity and low rate of malformations in neonates. Therefore, it is necessary to counsel couples who want a child. In case of pregnancy, strict guidelines must be observed. Continuous exposure to CsA in utero seems to impair T-, B- and NK-cell development and function in neonates. This effect is prolonged throughout the first year of life. In addition, low levels of serum immunoglobulins occur at the same time. This leads to suggest a delayed administration of classical vaccinations (after the first 6 months of life) in view of the potential risks of both sub-optimal immunologic responses, and adverse events after the administration of live, attenuated vaccines in infants born from young female organ transplant recipients.

Immunologic evaluation during the first year of life of infants born to cyclosporine-treated female kidney transplant recipients: analysis of lymphocyte subpopulations and immunoglobulin serum levels

BACKGROUND

In rodents, CsA has been shown to affect T-cell development, giving rise to an abnormal production of mature T cells and the absence of many T-cell subsets as well as to autoimmunity. Surprisingly, only a few studies investigated the effect of the immunosuppressive drug on the immune system of the human fetus.

METHODS

We examined six infants born to female kidney transplant recipients who had received cyclosporine and methylprednisolone throughout their pregnancies. Peripheral blood was obtained 1 day and 2, 4, 6, and 12 months after birth, and two-color flow cytometric immunophenotyping of lymphocytes was performed.

RESULTS

Total T cells, as well as CD4+ and CD8+ T cells, were low at birth, but normalized thereafter. Among T-cell activation markers, the expression of CD25, the alpha chain of the interleukin-2 receptor, was below the normal range or low range throughout the study period, and HLA-DR expression was extremely low at birth and failed to increase up to 12 months. The number of total B cells was lower than normal at birth, but steeply increased over time. In contrast, B-cell subset bearing CD5 antigen was severely depleted throughout the first year of life. Total IgG concentration was significantly lower than in controls at 2 months, mainly because of subnormal levels of IgG1 and IgG3 subclasses, which remained in the low range up to 6 months. Finally, infants showed normal numbers of true natural killer (NK) cells (CD3-CD16+CD56+), whereas the expression of CD57 antigen, defining non-MHC-restricted cytotoxic lymphocytes, was barely detectable at birth and failed to increase over time, in both CD8+ and CD8- subsets. Of note, none of the infants had clinical evidence of an immunodeficient state.

CONCLUSIONS

continuous exposure to CsA in utero seemingly impairs T-, B-, and NK-cell development and/or maturation, and most of its effects are still apparent at 1 year, which might suggest that conventional vaccinations should be delayed in these infants.

Characterizing ventricular mechanics and energetics following repeated coronary microembolization

Myocardial mechanics and energetics were investigated in an animal model of moderate chronic heart failure (CHF) created by repeated coronary microembolizations in six dogs. The final fractional area change was 34 +/- 4%. Hearts of these animals were isolated and cross-perfused, and balloons were placed in the left ventricle (LV). Chamber contractile state was markedly depressed in embolized hearts as assessed by the slope (Ees 2.74 +/- 0.49 vs. 4.00 +/- 1.18 mmHg/ml, P < 0.01) and volume axis intercept (V: 8.7 +/- 5.9 vs. 1.0 +/- 3.2 ml, P < 0.01) of end-systolic pressure-volume relation compared with a group of six normal dogs. The end-diastolic pressure-volume relation of embolized hearts was shifted to the right, indicating a dilation of the LV. However, systolic and diastolic stress strain relationships were similar in the two groups, suggesting that the average myocardial properties of the embolized hearts are similar to those of normal hearts. The relationship between oxygen consumption and pressure-volume area in embolized hearts had smaller intercept (2.98 +/- 0.44 vs 3.92 +/- 0.39 x 10(-2) ml O2.beat-1.100 g LV-1, P < 0.01) compared with the control group, with no change in the slope. These results contrast with previous findings in pacing CHF and serve as an important characterization of ventricular properties in this model of CHF from different etiology.

IFN-gamma and b7 as costimulators of antitumor immune-responses

We transfected the mouse IFN-gamma and/or the mouse B7 (T cell costimulatory molecule) cDNAs into B16 melanoma cells to study the effects of local constitutive expression of these molecules on the tumorigenicity and immunogenicity of this aggressive tumor. Cells expressing IFN-gamma (B16.IFN-gamma), B7 (B16.B7), B7 and IFN-gamma (B16.IFN-gamma/B7), and parental cells were injected subcutaneously (s.c.) into syngeneic C57BL/6 mice to compare their in vivo growth. We report that IFN-gamma secretion significantly reduced the tumorigenicity of B16 cells. These effects were related to the direct action of secreted IFN-gamma since i) in vivo injection of antiserum to IFN-gamma accelerated tumor growth, ii) development of tumor correlated with loss of IFN-gamma production, and iii) B16.IFN-gamma cells were tumorigenic in IFN-II receptor (IFN-gamma R) knockout mice, but not in parental mice. We propose that immune mechanisms are being activated by IFN-gamma since i) immune effector cells were recruited to the injection site, ii) expression of MHC class I and class II antigens was increased on cells secreting IFN-gamma and, iii) B16.IFN-gamma tumors appeared earlier in athymic mice than in immunocompetent mice. Since the in vivo growth of B16.IFN-gamma cells was not completely abolished, we studied the effect of co-expression of IFN-gamma and the T cell costimulatory molecule B7 on the tumorigenicity of B16 cells. We report that B16.IFN-gamma/B7 cells, which also express increased levels of MHC class I and class II molecules as compared to parental cells, had a dramatically suppressed tumorigenicity, while B16 cells expressing the B7 molecule only (B16.B7) were as tumorigenic as the parental cells. B16.IFN-gamma/B7 cells induced specific immune responses since all of the protected mice were able to reject challenges with parental cells. Results indicate that co-expression of two molecules which are involved in the activation of immune responses and in antigen presentation can influence the ability of the immune system to recognize and eliminate both transfected as well as parental tumor cell inocula and suggest that vaccines consisting of such cells may be used for the immunotherapy of cancer.