Treatment recommendations for cancer in dogs

I was just told by my dog’s vet that he probably has some form of bone cancer just above his elbow. He’s a Rhodesian Ridgeback and except for his llimp seems perfectly healthy. She’s sending the x-ray to a radiologist today. He’s a 10 year old Rhodesian Ridgeback.

Is anyone aware of any new promising treatment for this, perhaps including rapamycin. I actually had him on rapamycin for a couple years but discontinued it about 6 months ago (about when we noticed a limp…). Is there reason to put him back on now? If so, what dosage would you recommend? Any thoughts would be greatly appreciated!!!

Jim

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I’m not a Vet (or a medical professional in any way), but there seems to be some research showing benefits of sirolimus (rapamycin) in bone cancer in humans (if it works in humans, it probably works in dogs, most dog drugs are just human drugs). I did a quick search on PubMed on “sirolimus osteosarcomas” and here is what I found:

Conclusions: The potent antiproliferative activities of mTOR inhibitor rapamycin has been proven. Theses results strongly indicate that rapamycin may be a promising agent against osteosarcomas.

Sirolimus reduced tumor-related morbidity and resulted in biochemical and radiographic response in patients with progressive sarcoma

Conclusions: Sirolimus treatment was associated with improvement in tumor-related symptoms, performance status and biochemical markers of disease activity and inhibited tumor growth in pts with advanced sarcoma failing multiple prior therapies. Phase I studies of sirolimus in advanced cancer are underway at the University of Chicago. Formal study of sirolimus in advanced sarcoma is contemplated.

https://ascopubs.org/doi/abs/10.1200/jco.2006.24.18_suppl.9503

Full Pubmed Search on these topics: sirolimus osteosarcoma - Search Results - PubMed

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Yes, I wanted to write similar, that probably bone cancer is sarcoma and rapamycin has a potential net benefit in sarcomas. Me personally I would continue with rapamycin, I don’t think it will hurt your dog.

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Thanks! Much appreciated.
Jim

Look into new immunotherapy vaccines and treatments for dogs. Our dog had melanoma and we had consultation with oncologist and so much is happening in dog treatments as many human research start with dog treatments. Few years ago they had nothing to offer, but now there are really a lot of novel possibilities.

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To all who have responded, many thanks! I’m planning on putting Greco back on rapamycin. While none of us really knows, I’m wondering what dosage would you think sounds right? I’m tentatively thinking 4mg sirolimus 2x per week. Maybe more? Maybe less?

Do you think rapamycin could hurt immunotherapy treatment by perhaps reducing the immune response?

In all the cancer trials I’ve seen with rapamycin, the doses are very high, and the trade offs are side effects vs. efficacy at slowing the cancer.

In the dog aging study, Matt Kaeberlein has mentioned that he wished he had gotten a higher dose approved by the IRB, because with higher dosing there is more likelihood of benefits, but of course also risk of negative side effects and since this was the first dog aging study, with people’s pets, they went forward with very conservative dosing. The academic IRBs are (understandably) very sensitive to the potential issues around harming people’s favorite pets. I recommend you read this thread: How Do I Get Rapamycin for My Dog?

If I were you, I’d search up the studies on sirolimus and cancer and check out the dosing levels they are using in these cancer studies, then try to get as close as possible to an equivalent dose (in mg/kg) for your dog, and weigh that against the side effects you see.

You might start here on this thread, but it is focused on prevention, and I think you’ll find that for treating cancer they use much higher doses: Rapamycin - for Cancer Prevention

Ah - if you’re doing other therapeutic interventions for the cancer… yes - you want to work closely with the doctor / vet. There are definitely potential interactions here. Gather the data on rapamycin and bone cancer, and present it to your Vet and discussion to arrive at a potential plan of action. You don’t want to be interjecting new drug interventions that may counter, or not work well, with those your Vet is recommending.

I just gave him 4 mg’s but I’m not going to even see a doctor for a couple weeks.

My dog per above has osteosarcoma & will soon begin a chemo course of carboplatin. I’m finding a good number of journal articles showing that C combined w/ rapamycin has a strong synergy. While a recent trial found no benefit of R & C, the author notes at the end that the problem may well have been that R was applied after completion of C rather than starting R shortly after starting C. This fits well w/ Dr Blagosklony’s recent work on how to fight resistance.

I’m wondering if anyone here has any knowledge of the pros of cons of starting a R regime shortly after beginning w/ C. Likely effectiveness, risks, dose for both R & C, etc. I’m going to talk w/ the oncologist but I’m sure she’ll be reluctant. Are there any doctors out there who have experience? Any input would be appreciated!
Jim