Would you still offer durvalumab after chemoradiation in patients with stage III NSCLC whose treatment was delayed due to prolonged recovery from chemoradiation?

The PACIFIC study, which evaluated the use of durvalamab after completion of chemotherapy and radiation (both sequential and concurrent) is a landmark trial demonstrating improved survival for those receiving immunotherapy. The design of the study required that durvalamab commence within 42 days of completion of radiotherapy. I agree with @Dr. First Last that it is always most appropriate to follow the study design as closely as possible in practice, i.e. start within 42 days (6 weeks). I believe that an additional few weeks is unlikely to be detrimental.

I would like to make some other points relative to this question. An unplanned subgroup analyses indicated that patients who began durvalamab <14 days after completion of radiation had bett...

In general, I would follow the entry/eligibility criteria as described in the PACIFIC trial - i.e. up to 42 days/six weeks after completion of chemoradiation (last dose of radiation). In fact, in the supplementary data from the 2018 NEJM report, there was a trend towards improvement in OS with treatment that was started within 14 days compared to those being started within 42 days (this is probably a reflection of functional status and the patient's ability to withstand six weeks of chemoradiation. That being said, there is some "fuzziness" in the 42 day cutoff (acknowledging that the choice of 42 days was somewhat arbitrary - and changed from 14 days in an amendment in the protocol). If there were reasons/extenuating circumstances, I would...