Hi Jenny, welcome to the forum.
You will have a break between the end of your induction therapy (D-VTd) and your stem cell transplant.
Exactly when that is and what happens will depend on your response to your current treatment.
Sometimes patients have an additional cycle or two if their myeloma levels are still present but are going down.
If you still have myeloma cells evident in tests (about half of us do), you will be given a one off dose of cyclophosphamide which is a chemotherapy drug. You will lose your head hair 2 weeks later, but should also lose remaining myeloma cells.
You will then be given a drug to stimulate stem cell production in your bone marrow. You will have to inject yourself daily with this for a week.
Then you will spend a day on an apheresis ward, whilst a machine like a dialysis machine removes your stem cells from your blood. This isn’t painful, but you have lines going in and out of both arms, so self care is next to impossible!
Stem cells sometimes only take a day to be collected, but can take a few days, or even a different drug to be used, in which case the process takes an extra few weeks. Once collected the cells are frozen in liquid nitrogen (?) until required.
The actual transplant happens a few weeks later, not necessarily in hospital. Some patients go backwards and forwards from home if they live close by, or stay in a hostel within the hospital site. Each hospital has their own arrangements.
The process starts with a high dose of a chemotherapy called melphalan. This destroys all the stem cells in the body (it’s a good idea to protect cells in the mouth and throat by sucking ice). Any remaining myeloma cells should be destroyed. The next day, or 2 days later if you have kidney problems, your stem cells will be delivered back to you by drip.
Patients react differently to the process. Some of us are quite sick after the melphalan, but others feel quite well for the first 5-7 days. During this time old stem cells will be dying off and not be being replaced. At this point all patients become neuropenic and vulnerable to infection. If patients are poorly they are always admitted to hospital. The new stem cells will establish themselves gradually, and our neurophils tend to start being evident on day 12. I definitely felt I was getting better on day 12.
I hope this answers your questions!