SPCEO1 wrote: I think we should drill down as best we canon the timelines for TH-1902's pahse I and possible phase II trial. The 3/21 endpoint for the phase I on Clinicaltrials.gov needs to be updated for the info the company gave at the webinar. The last slide if the presentation indicated we will get a safety and preliminary efficacy readout on the phase 1a in Q4, that the dose escalation and MTD determination will happen by the end of 2021 and that the phase 1b will start in early 2022.
Elsewhere in the presentation, we were told the phase 1a would be 28 weeks in length and the phase 1b would be 24 weeks in length.
If I recall correctly, the first patient in phase 1a was dosed in early March.
So, if phase 1a is really going to be 28 weeks in length and it started in the second week of March, we just are completing the 17th week and it should end the week of 9/13.
So, why would TH say the phase 1a not officially end until the end of 2021? Are they just giving themselves time to put the data together following the end of the trial in mid-Spetember and determine the MTD from it? Would they really need 3 and a half months to do that? Or has the tril been delayed in some way. Would the death of the first patient caused them to have to restart the trial and it has been delayed?
TH gave us a very optimistic view of TH-1902 in the webinar and brought up no concerns that they might be dealing with in the development of the drug. Did they tell us almost nothing about the trial, however, because there were some troubling details that they would have had to share if they said anything about it at all? Does this seemingly longer trial timeline tell us there have been some issues in the phase 1a? Or does it simply reflect the normal time a drug commpany takes to compile and analyze the data?
Scarlett suggested that the AACR meeting in early October might be a good time to have the preliminary phase 1a data presented, and that makes sense to me although it might be a bit optimistic depending on what they would choose to present.
As for a phase II start, that would depend in part on when the phase 1b ends. If the phase 1a data looks very good, I am going to guess they get it started in the middle of February 2022. 24 weeks after that is the third week of July for its completion. Do you think that leaves enough time to get the phase II started in September 2022?
How long should we expect the phase II to last?
Sorry for all the questions but it is good for us to have some sort of reasonable expectations about the likely timing of all this.
jfm1330 wrote: For a very effective cancer drug, the path to approval can be pretty quick. A phase I followed by a phase II on 100-200 patients. Look at Blenrep, an ADC approved in August 2020 in relapsed refractory multiple myelomas. They did a phase I on 73 patients with differents doses. Than, a phase II testing two doses on 218 patients. The primary endpoint goal was 15% overall reponse rate (ORR). They were finally approved for the lower of the two doses with a ORR of 31%. That was well over the primary endpoint goal, but still, only 31%, which shows that the bar in cancer is relatively low. It does not need to be close to 100% efficacy. ORR is defined as partial reponse rate or better. So it is based on tumor shrinkage, not on survival time. The phase II started in June 2018, and they got approval before the end of the trial in August 2020.
So on clinicaltrials.gov, TH1902 phase I is expected to end in March 2021. Let's say they would start a phase II in September 2022. It would mean a possible approval somewhere at the end of 2023. But if Thera goes in phase II with a single dose, less patients would be needed, so a shorter trial. Also, the level of efficacy, if any, they will see in phase I will be critical. The better it is, the faster the FDA will allow things to go forward. All that to say that cancer drugs showing early signs of very good efficacy can be approved very quickly.
https://aetion.com/evidence-hub/fda-decision-alerts/cder-approved-nda-for-blenrep-belantamab-mafodotin-blmf/