Results

Demographic distribution

This study evaluated 15 eligible patients. The median age at initial diagnosis was 65 years, with a distribution range between 40 and 76 years. Gender stratification showed eight male patients (53.3%) and seven female patients (46.7%). The precise sex distribution across age sub-brackets is outlined below (Table 1). In 40-49 years age group, four (26.7%) were male and 0 (0%) were female. In 50-59 years age group, one (6.7%) was male and two (13.3%) were female. In 60-69 years age group, four (26.7%) were male and two (13.3%) were female and in 70-79 years age group, 0 (0%) were male and two (13.3%) were female. Out of 15 patients, eight (53.3%) patients were smokers and seven (46.7%) were non-smokers. Twelve (80%) patients belonged to rural areas while three (20%) belonged to urban areas. Seven (46.7%) presented with ECOG performance status 0, six (40%) presented with performance status 1, and two (13.3%) presented with performance status 2. History of asbestos exposure was not present in any patient. Baseline characteristics are outlined in Table 2.

Age (Years) | Male n(%) | Female n(%) | Total n(%)
40-49 | 4 (26.7%) | 0 (0%) | 4 (26.7%)
50-59 | 1 (6.7%) | 2 (13.3%) | 3 (20%)
60-69 | 4 (26.7%) | 2 (13.3%) | 6 (40%)
70-79 | 0 (0%) | 2 (13.3%) | 2 (13.3%)

Baseline Characteristics | 
Median Age, years (range) | 65 (40-76)
Sex, n(%) | 
Male | 8 (53.3%)
Female | 7 (46.7%)
Smoking status, n(%) | 
Smoker | 8 (53.3%)
Non-smoker | 7 (46.7%)
Area,n(%) | 
Rural | 12 (80%)
Urban | 3 (20%)
ECOG PS, n(%) | 
0 | 7 (46.7%)
1 | 6 (40%)
2 | 2 (13.3%)

Treatment exposure

The analysis revealed a median of seven completed cycles of nivolumab (range: two to 26 cycles) and a median of three completed cycles of ipilimumab (range: one to 10 cycles).

Efficacy and survival outcomes

Radiological assessment at three months using FDG PET-CT revealed that nine patients (60%) achieved PR. This sub-cohort maintained clinical stability and persistent tumor control throughout the 12-month observation window. Conversely, six patients (40%) experienced early therapeutic failure or disease progression at or prior to the initial three-month scan. None of the patients achieved CR or SD. Thus ORR calculated was 60%. Figure 1 shows response on first reassessment at three months. All six progressing individuals exhibited rapid clinical decline, with survival failing to cross nine months despite subsequent salvage line chemotherapy.

Figure 1: Response at three months

During the follow-up, six events occurred, resulting in a cumulative event rate of 40%. The median overall survival time (95% CI) was not reached within the 12-month study period, as the survival probability remained above 50%. The estimated survival probabilities with 95% CIs at key time points were: 87% at three months, 80% at six months, and 60% at 12 months.

At the end of the 12 months, nine (60%) patients remained alive and actively maintained on immunotherapy maintenance. The one-year OS rate for the entire study population was 60%. Figure 2 shows the Kaplan-Meier curve of survival.

Figure 2: Kaplan-Meier curve of survival

Safety and adverse events profile

Immunotherapy-related toxicities of any grade manifested in 12 patients (80%). Severe Grade 3 or 4 TRAEs occurred in four individuals (26.7%). Gastrointestinal toxicities were the most frequent complication, with all-grade diarrhea recorded in four patients (26.7%), two of whom (13.3%) escalated to Grade 3/4 status requiring systemic corticosteroid intervention. Endocrine dysregulation was prominent, with three patients (20%) developing low-grade hypothyroidism/thyroiditis requiring regular levothyroxine supplementation. Cutaneous toxicity presenting as low-grade maculopapular rash occurred in two patients (13.3%). Grade 3/4 immune-mediated hepatitis occurred in one patient (6.7%), which responded to treatment suspension and steroid management. No treatment-related deaths were encountered. No new safety signals were observed. Treatment discontinuation was due to disease progression only; no toxicity-related discontinuation was seen. The profile of TRAEs is shown in Table 3.

Adverse Event Type | All-Grade Incidence, n (%) | Grade 3/4 Incidence, n (%)
Diarrhea | 4 (26%) | 2 (13%)
Hypothyroidism / Thyroiditis | 3 (20%) | 0 (0%)
Skin Rash | 2 (13%) | 0 (0%)
Immune-mediated Hepatitis | 1 (6%) | 1 (6%)
Any Adverse Event | 12 (80%) | 4 (26%)