To ensure my treatment with Folfirinox remained on schedule, A CBC was done after the infusion of 5-FU was completed on day 3. If WBC's were low, I would receive Neulasta. It brought the counts back up quickly so the schedule of infusions every 15th day over the course of 46 cycles in a 24 month period. I only required Neulasta twice. The taking of Claritin starting 36 hours before injection of the Neulasta prevented the bone pain which is caused by the release of histamine when the WBC precursors in the bone marrow begin to clonal expand.

Papaya and Papaya Leaf Extract have been found to increase platelets. I've heard from several patients that tried it and they reported it increased their platelet counts.
https://www.mskcc.org/cancer-care/integrative-medicine/herbs/papaya-leaf
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7219447/
https://www.medicalnewstoday.com/articles/322937#supplements-to-try