Methotrexate

RE: Methotrexate

Stefano Zago — Sat, 03 Jun 2017 17:14:26 GMT

Like you said, v few certainties and lots of opinions in veterinary oncology!

Doxo cumulative cardiotoxicity is generally accepted to increase between 180-240mg/m2. Your JRT is presumably <10kg bw, are you dosing at 1mg/kg rather than 30mg/m2? In which case you should be able to do more than the six doxo injs before you reach the 180mg/m2.

I usually go up to 180mg/m2 than have a chat with the owners and decide whether to continue up to 240mg/m2 (never beyond) with echo before each additional treatment, especially in a breed at low-risk of DCM.

Troponin levels cannot be used as predictor of doxo-induced cardiotoxicity.

Once I've reached the limit I normally switch to mitoxantrone. Other possible choices include lomustine, dacarbazine or actinomycin D.

Stefano

RE: Methotrexate

Judith Archbold — Sat, 03 Jun 2017 13:44:47 GMT

"Charlie" is a 7 year old JRT. B-cell Lymphoma.

We did a 25 week ( extended time as had to skip odd weeks if he had diarrhoa etc. ) modified - Wisconsin CHOP protocol in the first half of last year.

in remission until about two months ago.

in himself he is great!....you really wouldn't now there was anything wrong with him. At the moment his bloods are all perfect too.

I took advice from an oncologist re second round of chemo. They suggested we run a CHOP protocol again ( he had LN biopsies and staging...lungs etc. all clear).

Cardiac troponin was high normal: we scanned his heart and systolic function / fractional shortening ok at the moment.

BUT... I want to be cautious so only prepared to give Doxorubicin once more in this session ... then over the year he will have reached his maximum recommended dose.

I know everyone has different opinions on total dosage of this drug but as we are fighting cancer there is no right or wrong. He is such a happy little chap that I don't want to lose this battle due to cardiotoxicity.

the oncologist I liased with suggested swapping onto another drug such a Methotrexate. I'm also debating whether to try him on metronomic chemotherapy with continued vincristine and chlorambucil?

Any thoughts on continuing treatment options in lymphoma cases that are doing OK will be welcomed !

RE: Methotrexate

Stefano Zago — Sat, 03 Jun 2017 13:19:30 GMT

Methorexate has little or no efficacy in canine LSA. It was included in the early protocols with a maintenance phase but dropped by all protocols later.

What breed dog, immunophenotype, protocol are you using?

Stefano

RE: Methotrexate

Emily Rainbow — Sat, 03 Jun 2017 12:40:59 GMT

Also try Chemopet - have been very helpful with some of my patients on the more unusual regimes!

RE: Methotrexate

Michael Woodhouse — Sat, 03 Jun 2017 10:20:33 GMT

[quote user="Judith Archbold"]'m using mitoxantrone for the TCC case.... need methotrexate for a lymphoma case that is having a second round of chemotherapy as he has reached his maximum dose of doxorubicin.[/quote]

See if Onkotrone gets you anywhere, that is the branded product.

RE: Methotrexate

Judith Archbold — Sat, 03 Jun 2017 06:56:06 GMT

You're absolutely right Stefano ! Moral of this is don't watch Britain's Got Talent while writing a post.

I'm using mitoxantrone for the TCC case.... need methotrexate for a lymphoma case that is having a second round of chemotherapy as he has reached his maximum dose of doxorubicin.

RE: Methotrexate

Judith Archbold — Sat, 03 Jun 2017 06:53:40 GMT

Thanks Michael

RE: Methotrexate

Stefano Zago — Fri, 02 Jun 2017 23:58:33 GMT

There is no data/protocols for methotrexate in canine TCC but it is used in multi-drug protocols in human bladder carcinomas. It has debatable efficacy and potential GI toxicity and I would not associate it with a NSAID.

Are you talking about mitoxantrone?

Stefano

RE: Methotrexate

Michael Woodhouse — Fri, 02 Jun 2017 23:03:29 GMT

Metoject seems to be the trade name for the injection in the UK

RE: Methotrexate

Michael Woodhouse — Fri, 02 Jun 2017 23:02:09 GMT

Munro have the tablets, but injection out of stock

http://munrovet.com/

Have you asked the local pharmacy if they can source with a script? Ours is helpful in such circumstances