For most of the last seven years on the previous regimen I was happy when the results at the end of a cycle were the same as the results of the previous cycle. "Still stable" was the byword. We only changed regimens because of a T5 spinal lesion found by a PET scan. I had hoped, though, that the results of this first cycle of the new regimen would show improvement, a reduction in IgG or M-spike, preferably both.
Results:
Nothing much yet. Today my IgG was 1230 mg/dL, actually up just slightly (within measurement tolerance) from recent months, and M-spike was 1.2 g/dL, about the same as recent months. No change there, but still stable. Dr L did not seem concerned, pointing out that this regimen isn't as likely as other regimens to produce quick, dramatic results.
Something strange did happen to light chains though. Both Lambda and Kappa went down, but Kappa went WAY down to a fifth of its value of five weeks ago, now below the bottom of the reference range at 0.3 mg/dL. Dr L was not too concerned about that, and in fact said it means that something is happening!
We'll just have to wait another month. Steady as she goes. I'll be a patient patient.
PET Scan Lesion in the T5 Vertebra:
We will wait at least six months to look at this lesion again, because it can only be seen as a sugar-sucking bright spot on a PET scan. PET scans are expensive and radiation intensive. This is a dime-sized lesion in a bone that is actually fairly large, so Dr L didn't think that it seriously weakens the vertebra yet.
I asked if it is likely to be a new and different clone (since it showed up while IgG and M-spike were stable). Dr L used the term "sub-clone," and said it is quite possible. If so, however, we may not know soon because we cannot biopsy it, hidden behind the spinal cord from the back, and the lungs and aorta from the front. We have to treat systemically. My hope is that the new sub-clone is more responsive to the new regimen than the original clone was after this first cycle. Hey, it could happen!
Neuropathy:
I have now heard from two friends who experienced painful neuropathy in their feet on my current regimen. In contrast, however, Dr L said that only about 10% of patients have that experience. So far I find myself in the 90% group - I feel some numbness in my feet and a slight tingling in my fingertips, but I'm not sure that either symptom is worse than it was before I started this regimen. There is no pain and no loss of function yet. I'm keeping my feet warm and busy, plus lots of Vitamin B. Next month I will have an appointment with a Complementary Medicine doctor at Mayo, to discuss other neuropathy treatments and practices.
Platelets:
Platelets were lower than usual for me today, 134 k/uL, slightly below the bottom of the reference range, even though two weeks have passed since the last dose of the new drug. On the previous regimen neutrophils were at risk, though mine never went below the study cutoff. This regimen is more likely to affect the platelets, so if that count goes too low I could be at risk for internal bleeds. Happily, this most-recent current platelet count is still well above the study cutoff of 25 k/uL.
Nevertheless I will be careful - as recommended by a knowledgeable Mayo pharmacist I have gone off aspirin and other supplements that could influence clotting. Again this month I will be getting a CBC done locally prior to each new dose of the medicine. If platelets (or anything!) are below the cutoff, we will stop the regimen at least until the numbers come back up again.
Plasma Cell Proliferation:
One of the results obtained from the bone marrow biopsy of five weeks ago is the Plasma Cell Proliferation Report. This stuff is well above my pay grade (I am most definitely not a doctor), but as I understand it, "flow cytometry" is used to examine biopsied plasma cells more or less one-by-one. Those cells which are determined to be monotypic (the myeloma cells) are examined by "quantitative DNA analysis" to see if they are in S-phase (in the process of dividing into two cells). Dividing is bad - that's how cells multiply!
My report says "Monotypic Plasma Cells S-phase: 0.3%. This means that about one third of one percent of the myeloma cells in that bone marrow biopsy on that day were dividing. According to Dr L, that is actually a good number - my plasma cells are not going hog-wild on me (I believe the doctor used a medical term).
Further, this result corresponds closely to a 2008 biopsy result called the Plasma Cell Labeling Index, then used at Mayo Clinic but now mostly replaced by this flow cytometry result. Still further, only one clone was detected - no new ones. Meaning? The plasma cells in that hip may not have changed much in 7 years on the prior therapy. It is quite possible, though, that the cells in the T5 vertebra are a new clone, and we can't know yet how fast those might be dividing. Fingers crossed.
Study Completion:
The Consent Form that the doctor and I signed does not mention a completion date for the study itself. According to ClinicalTrials.gov, however, this study will reach completion in July of this year. Dr L discounted that, thinking that's just the date at which the study will stop accruing patients, and the study itself will likely continue at least until the FDA approves the drug.
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