Academic OB/GYN

This month’s Grey Journal feels a little light on substance, but one article I liked was an article looking at a new protocol for use of methotrexate for treatment of ectopics(1).  This protocol looked at giving a second dose of MTX if the day 7 HCG is not 50% lower than the Day 1 HCG, without checking a day 4.  This is opposed to a typical single dose protocol, checking a day 4 and repeating MTX if the day 7 is not 15% lower than the day 4.

This study was based on data abstraction from 187 patients who were treated with single dose MTX for ectopic pregnancies, with demographics and HCG levels recorded over time.   Based on these data, a comparison was made between a Day 1,4,7 strategy and a Day 1,7 strategy.  Here’s what they found.

A Day 1,7 strategy has a very high sensitivity for picking up women who need another dose of MTX to successfully end an ectopic pregnancy, but a much lower specificity.  This means that with a Day 1,7 strategy many more women will get treated with a second dose of MTX than with a Day 1,4,7 strategy.  However, in tradeoff they will not need to get a day 4 blood draw.  Depending on Beta HCG levels, anywhere from 2 to 10 additional women will get a second MTX dose per Day 4 blood draw avoided with this strategy.

So here’s a few thoughts on this:

1) This strategy leads to a lot more methotrexate use, in order to avoid a blood draw.  From a cost point of view this could be a problem. Dr Thurman points out that MTX is inexpensive, but in many hospitals it is delivered as a chemotherapy agent.  Even if it is  regular injection, it usually isn’t available in the MD office and hospital nursing charges are high.  Actual cost of drug is low, but delivery of drug can be expensive.

2) Some people think we should be doing 2 dose MTX for everybody anyway.  Failure rates for single dose MTX are around 10% in a mixed population (2), though a mandatory 2-dose regimen hasn’t done much better in trials(3).   This regimen would be a middle ground between a 1 dose and mandatory 2 dose regimen.

As this is just pilot data, it will be interesting to see this against a 1,4,7 regimen in a randomized trial.  I know several of the investigators, and suspect that they will be doing this in the future.  I look forward to those results.   For now I will still use a 1,4,7 regiment, as to me a day 4 lab draw is not as big a deal as a second dose of MTX.  But that being said, if a patient really hated getting blood drawn, this might be a better option for them.   Then again if they hate blood draws much, maybe a laparoscopy would be better!

Source:

Thurman AR, Cornelius M, Korte J, Fylstra D. An alternative monitoring protocol for single-dose methotrexate therapy in ectopic pregnancy. Am J Obset Gynecol 2010; 202:139.e-16

Lipscomb GH, Bran D, McCord ML, Portera C, Ling FW. An analysis of 315 ectopic pregnancies treated with single-dose methotrexate. Am J Obstet Gynecol 1998;178:1354-1358

Barnhart K, Hummel AC, Sammel MD, Menon S, Jain J, Chakhtoura N
Use of “2-dose” regimen of methotrexate to treat ectopic pregnancy.
Fertil Steril. 2007 Feb;87(2):250-6. Epub 2006 Nov 13.