Effectiveness of a shortened cycle of monoimmunotherapy in non-small cell lung cancer

Background. Monoimmunotherapy (mIT) in the 1st line of treatment for non-small cell lung cancer (NSCLC) is performed in patients with a high PD-L1 expression (>50%) or with severe concomitant pathology and contraindications to therapy with platinum drugs with an intermediate level of PD-L1 expression (1-49%). Therapy is carried out up to 2 years of disease progression or intolerable toxicity. An important issue is determining the optimal duration of treatment in order to find a balance between effectiveness, toxicity, cost and burden on the health care system. To date, there are no prospective studies with sufficient power devoted to this issue. Objective. Evaluation of long-term indicators of the effectiveness of the cycle of monotherapy with immune checkpoint inhibitors (ICPI) in the 1st-line therapy shortened for organizational or medical indication in patients with NSCLC. Methods. The analysis included patients with histologically verified inoperable NSCLC who received 1st-line therapy in 2019-2020. ICPI in the 1st line received 25/230 patients (16 men, 9 women; mean age - 65.4 years). PD-L1 level>/=50% was detected in 18 (72%) patients, 1-49% - in 3 (12%), 0% - in 1 (4%), not assessed - in 3 (12%); adenocarcinoma - in 13 (52%), squamous cell carcinoma - in 12 (48%) patients. All patients received therapy with pembrolizumab 200 mg once every 21 days. Results. The mean follow-up period was 13.1 (0.8-26) months. The mean number of injections of immunotherapy (IT, min-max) was 9.5 (1-28). The objective response rate (ORR) in the 1st line was 18 (72%): complete regression - 3 (12%), partial - 8 (32%), stabilization - 7 (28%), not assessed - 7 (28%), 2 (8%) patients died after the 1st injection of IT, 1 (4%) patient was lost for follow-up. Due to the registered progression of the tumor process, treatment was completed in 12 (48%) patients, the mean number of cycles performed was 4.1 (1-16). Before the progression of the disease or until the end of the planned duration, therapy was interrupted by 9 (36%) of 13 patients: six - due to the tightening of the requirements of the epidemiological situation, three - due to refusal to visit medical institutions. The mean follow-up period after the end of treatment was 8.5 (3.0-14.2) months; 6 (67%) patients whose treatment was interrupted not because of disease progression are observed without progression 9.3 (4.0-12,1) months (min-max). PD in 3 (33%) after the mean follow-up period was 9.3 (7.1-13.2) months (min-max). Conclusion. The data obtained indirectly indicate the absence of a tendency towards a decrease in mPFS and mOS in the group of patients with NSCLC who received mIT in the first line of treatment, for whom treatment was discontinued unscheduled, and not continued until 2 years or until the progression of the tumor process recorded.

non-small cell lung cancer, immunotherapy, shortened course, drug therapy