Hi Bills,
I have always thought that reducing the dose to reduce the side effect had meant the reducing the concentration rate of BCG. I recall that it was 80mg of BCG mixed with 50 ml of saline was administered to your dad, and that caused severe side effects, which led to the shortening of the 6 weeks induction course to 4 weeks. 40mg of BCG mixed with 20 ml of saline does not change much the concertation rate of BCG. We know that Dr. Lamm of University of Arizona, one of pioneer for BCG treatment had stated that It is also true that maintenance can cause side effects. That is why we always reduce the dose (1/3, 1/10, 1/100th even if needed) or hold treatment if increasing side effects are seen. In the US, TICE strain by MERCK with 50mg in 50ml saline is used. I could not find what volume of saline was used when Dr. Lamm mentioned about 1/100th dose. But, It does not make sense to use 0.5ml of saline for 1/100th dose BCG. It will not cover the whole bladder. So, we assume that Dr. Lamm had meant 1/100th of 50mg Tice BCG in 50 ml saline. I believe 50ml of saline is enough to fill the bladder lumen in emptied condition, thus cover the entire surface of the bladder wall. So, I think 40mg in 50ml makes more sense to reduce the concentration rate of BCG in the saline. 40mg in 20ml saline does not make sense to me.
Another case in point is that "Immunobladder" which is intravesical BCG manufactured by Japan BCG Lab is Tokyo-172 strain, Tokyo-172 strain BCG has been on clinical trail for 4-5 years now in the US. Immunobladder BCG come in two different vials, 40mg and 80mg. The administration instruction for 40mg or 80mg says to mix with 50ml saline. When I checked before Urologists in Japan some urologists use 40mg when their patients have side effects with 80 mg.
Consequently, I believe that 40mg BCG in 50ml saline is the correct administration if the new regimen is to reduce the side effect of the BCG, unless there is another reason why 40mg BCG in 20ml saline has been determined to be the right treatment for your dad.
Please note that 1/3 dose of BCG has shown equivalent efficacy compared to full dose BCG. That is why AUA has recommended 1/3 dose usage when the BCG is in shortage. So, it is assumed that 1/2 dose (40mg of 80mg) of SII-ONCO BCG should give similar efficacy
as the full dose 80mg, and 1/2 dose should give less side effects to your dad. That is the reason the reducing BCG dose was thought to be the suitable treatment. My understanding of 1/2 dose is the reduction of BCG concentration into a half.
I would definitely clarify with the urologist before the 2nd instilment.
best
Just for perspective, according to Merck product monograph. Merck Onco-Tice 50mg has approximately 1 to 8 x 10
8 colony forming units (CFU) or 1 to 8 x 10
8 bacteria in a 50mg via
l. SII ONCO-BCG 40mg has 1-19.2 x 10
8Colony Forming Units (CFU) according to their product description. Or it can be said that in average a 50mg Tice has 400 million BCG bacteria, and SII ONCO-BCG 40mg as 1 billion BCG bacteria. 40mg of SII ONCO-BCG contain the same or more number of BCG bacteria as 50mg Tice does.
One vial of BCG contain a mind blowing number of BCG bacteria. The product monograph of MERCK Tice and the product description of SII ONCO-BCG are described in the links below.
www.merck.ca/static/pdf/ONCOTICE-PM_E.pdf
www.seruminstitute.com/product_uro_uncology.php