Clinical trial video from PANCAN- questions about first time treatment

Yesterday I watched a very informative video on clinical trials from the PANCAN network. Stageivsurvivor was a guest speaker and have an excellent presentation!
Here’s the link:
https://pancan.org/facing-pancreatic-cancer/patient-services/educational-events/event/webinar/spotlight-on-clinical-trials-a-pancan-conversation/

I knew very little about clinical trials so I found it very helpful. Personally, I’m in stage 4 following my diagnosis of stage 2 in September 2022. GAC chemo, after 5 months of treatment seems to be working very well for me. I’m 66 yrs old and have the ATM, KRAS12D, and TSP52 mutations. I check every box on the “list” of comorbidies . I have tested positive for the Cld18.2 protein and hope to enter a clinical trial through UCLA when appropriate to address my stable masses in the abdominal peritoneal area, but have no idea how the soft tissue area surround my hepatic/celiac artery will be addressed. My current CA 19-9 before yesterday’s chemo is at 17 (down from 3,840 measured in January 2024). My oncologist wants to keep me on this treatment until it’s no longer effective so I feel compelled to defer to his judgement and years of experience.
The presentation is obviously backed by several pharmaceutical companies. One point of the video mentions how some clinical trials prefer trials as a first line of treatment and I can see how advantageous this would be for the researcher (no background effects from previous types of treatment). I’m just wondering in what type of cases this would be beneficial for the patient. Maybe in situations for those that fear potential side effects of chemo?