462P - Limited duration of treatment with checkpoint inhibitors in complete responders, yet prolonged survival: A real-world study from India

Background

Immune checkpoint inhibitors have revolutionised the treatment of malignancies particularly in metastatic setting with increased response rates and improved survival rates . Studies have shown that those with complete response tend to have a prolonged duration of response. However there is data lacking particularly in the Indian setting with regard to the duration of treatment in those who achieve a complete response (CR).

Methods

A retrospective study was carried out of all patients who received ICIs between April 2016- October 2021. They were followed up till May 2022. Response was assessed using RECIST criteria. Duration of treatment was noted for those who achieved complete response. Survival analysis was carried out for those who achieved a complete response.

Results

215 patients received checkpoint inhibitors during the study period. Metastatic renal cell carcinoma (mRCC: n=65,30.2 %), metastatic non small cell lung cancer (mNSCLC: n=62, 28.8%) were the most common indications.The rates of complete response (CR) were : RCC ( n=9,14%), Lung (n=7, 11.6%). The median duration of treatment received before stoppage by those in CR in mRCC was 14 months. All of them continue to be in remission with 5 out of the 9 patients in CR (55.5%) crossing 4 years of survival with a maximum ongoing survival of 72 months being noted. In mNSCLC, those with CR received a median duration of treatment of 12 months before stoppage. All of them continue to be in remission with 5 out of these 7 patients (71%) in CR having crossed 3 years of survival with a maximum ongoing survival of 60 months being noted.

Conclusions

Long lasting responses and survival can be seen with checkpoint inhibitors even after stopping treatment in those who achieve a complete response. Considering cost constraints in developing countries, prospective randomised studies need to be undertaken to evaluate the possibility of a shorter finite duration of treatment of 1 year with ICIs in patients with metastatic malignancies who achieve CR.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Dr. Nitin Yashas.

Funding

Has not received any funding.

Disclosure

A. Rauthan: Financial Interests, Personal, Advisory Role: BMS, Merck, Eli Lilly, Pfizer, Roche, MSD. All other authors have declared no conflicts of interest.