Petosemtamab Receives FDA Breakthrough Therapy Designation: Head / Neck Cancers
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Re: Petosemtamab Receives FDA Breakthrough Therapy Designation: Head / Neck Cancers
#2I'm struggling to figure out what is being reported. They were mostly able to stop progression in 37% of their test cohort?
"At a data cutoff of February 1, 2023, efficacy-evaluable patients treated with petosemtamab (n = 43) experienced an overall response rate of 37.2%"
They discussed "progression free" survival, which seems to mean the condition didn't worsen.
Re: Petosemtamab Receives FDA Breakthrough Therapy Designation: Head / Neck Cancers
#3I'm struggling to figure out what is being reported. They were mostly able to stop progression in 37% of their test cohort? "At a data cutoff of February 1, 2023, efficacy-evaluable patients treated with petosemtamab (n = 43) experienced an overall response rate of 37.2%" They discussed "progression free" survival, which seems to mean the condition didn't worsen.
Yeah that’s all correct. It’s particularly notable because the study was a third line treatment. These patients had already progressed after taking a platinum based chemotherapy, which is a standard first treatment, and they also progressed after taking a PD-L1 immunotherapy. So these patients had very advanced and difficult to treat cancer. This represents a real improvement for them as they probably didn't have many options left outside very invasive surgeries or lots of radiation to the head and neck.
Also the treatment targets two cancer genes at the same time. The first is EGFR, which is a very well known therapeutic target. The second is LGR5, and I’m not as familiar with that one, but I think it might be a novel target for cancer. So that's important in that more drugs might target this gene or combinations of LGR5 and others and they might be more effective than this first effort.
Re: Petosemtamab Receives FDA Breakthrough Therapy Designation: Head / Neck Cancers
#4I'm struggling to figure out what is being reported. They were mostly able to stop progression in 37% of their test cohort? "At a data cutoff of February 1, 2023, efficacy-evaluable patients treated with petosemtamab (n = 43) experienced an overall response rate of 37.2%" They discussed "progression free" survival, which seems to mean the condition didn't worsen.
> which seems to mean the condition didn't worsen.
That is indeed what it means. The other metric you'll see is Overall Survival, which also is what it sounds like it is.
Re: Petosemtamab Receives FDA Breakthrough Therapy Designation: Head / Neck Cancers
#5"Breakthrough Therapy Designation" is a regulatory term. It's definitely good news, but it's also a pretty common occurrence that the FDA designates a breakthrough drug, and it does not guarantee that drug's ultimate approval.
It's also not really "news". It's a development that incrementally smoothes the path for what is still a highly uncertain outcome. And per the linked article it appears to be based on interim data in a phase 1/2 trial. Very early.
There are many drugs that look promising at this stage (that's why the breakthrough designation exists!) But this piece of news is unremarkable. Merus, the company behind Petosemtamab, alone has like seven cancer drugs in various stages of development.
And there are probably hundreds of cancer drugs in development at any given time.
So this is just a mechanical write-up of a regulatory checkpoint for a drug that's like 30% of the way to approval and is among many, many other cancer drugs all sitting at different points along the same continuum.
HN is really random sometimes.
Re: Petosemtamab Receives FDA Breakthrough Therapy Designation: Head / Neck Cancers
#6I'm struggling to figure out what is being reported. They were mostly able to stop progression in 37% of their test cohort? "At a data cutoff of February 1, 2023, efficacy-evaluable patients treated with petosemtamab (n = 43) experienced an overall response rate of 37.2%" They discussed "progression free" survival, which seems to mean the condition didn't worsen.
Which is good numbers in the cancer treatment arena.
>> “We look forward to continued constructive conversations with the FDA as we move forward in our plan to initiate a phase 3 trial in previously treated HNSCC mid-2024 and prepare for a potential phase 3 trial evaluating the combination of petosemtamab and pembrolizumab [Keytruda] in previously untreated patients."
I understand the caution, but I firmly believe oncologists need to get more aggressive with multi-line treatments.
Re: Petosemtamab Receives FDA Breakthrough Therapy Designation: Head / Neck Cancers
#7Petosemtamab (MCLA-158) is an investigational IgG1 antibody targeting EGFR.
Merus's other trials (EGFR X c-MET) in NSCLC had serious side effects, but effective.
https://www.fiercebiotech.com/biotech/merus-shares-dip-inter...
Merus's pipeline, looks interesting:
Re: Petosemtamab Receives FDA Breakthrough Therapy Designation: Head / Neck Cancers
#8I'm struggling to figure out what is being reported. They were mostly able to stop progression in 37% of their test cohort? "At a data cutoff of February 1, 2023, efficacy-evaluable patients treated with petosemtamab (n = 43) experienced an overall response rate of 37.2%" They discussed "progression free" survival, which seems to mean the condition didn't worsen.
Which is good numbers in the cancer treatment arena. >> “We look forward to continued constructive conversations with the FDA as we move forward in our plan to initiate a phase 3 trial in previously treated HNSCC mid-2024 and prepare for a potential phase 3 trial evaluating the combination of petosemtamab and pembrolizumab [Keytruda] in previously untreated patients." I understand the caution, but I firmly believe on…
I’m not sure I agree that conservatism treatment by oncologists is holding back cancer cure. Maybe in some cases but in others… eg multi-drug regimes like FOLFIRINOX, where cancer patients routinely choose hospice over treatment because of its toxicity and meager benefit. Or even more cutting edge drugs like ENHERTU, which has shown striking benefits for some, but something like 15% of patients have to be pulled off treatment due to intolerable toxicities, and twice that amount have serious adverse events and occasional patients die (“grade 5 to x”)
I agree there is much work to do in cancer, and oncologist behavior is included in that. Simply getting more aggressive may help some but isn’t necessarily a magic bullet and has risks. (please pardon my emotional reaction to this)
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Re: Petosemtamab Receives FDA Breakthrough Therapy Designation: Head / Neck Cancers
#9"Breakthrough Therapy Designation" is a regulatory term. It's definitely good news, but it's also a pretty common occurrence that the FDA designates a breakthrough drug, and it does not guarantee that drug's ultimate approval. It's also not really "news". It's a development that incrementally smoothes the path for what is still a highly uncertain outcome. And per the linked article it appears to be based on interim d…
HN is really random, but also the submitter is an author whose posts are regularly submitted to HN and is a participant (I believe) in a trial for the drug in the article. The regular updates (and the author’s participation in threads) have endeared him to the community.
Re: Petosemtamab Receives FDA Breakthrough Therapy Designation: Head / Neck Cancers
#10Petosemtamab (MCLA-158) is an investigational IgG1 antibody targeting EGFR. Merus's other trials (EGFR X c-MET) in NSCLC had serious side effects, but effective. https://www.fiercebiotech.com/biotech/merus-shares-dip-inter... Merus's pipeline, looks interesting: https://merus.nl/pipeline/
Yes: I was in the petosemtamab / MCLA-158 trial at UCSD from Sept. 27 2023 until March 2024, when the tumors in my neck grew by ~20%: http://jakeseliger.com/2024/03/18/in-which-the-squamous-cell... from January 2024.
Between September and January, however, the tumors in my neck shrank by about 20%, which is a startingly good response by R / M HNSCC standards.
Perhaps the most interesting question will ultimately be whether oncologists prescribe petosemtamab for patients who get early clean surgical margins, in an effort to prevent recurrence. Oncologists are reluctant to impose chemo-radiation because of chemo's deleterious side effects, but petosemtamab, though it causes rashes, paronychia, and other skin problems.