Spectrum Pharmaceutecals Inc (SPPI)

[antihama]

RE: Pozi EGFRex20 SoC competition.
At ASCO, we got data on efficacy in an undifferentiated Chinese population where they got

mPFS for patients who received 1st-line platinum-based chemotherapy (N = 105) (6.4m; 95% CI:5.7-7.1) vs. EGFR TKI (all generations, N = 23) (2.9m; 95%CI:1.5-4.3; P < 0.001) or vs. EGFR TKI (1G, N = 14) (2.6m; 95%CI:0.8-4.4; P < 0.001)...

...mPFS was numerically longer in patients who received 2nd-line paclitaxel-based chemotherapy (N = 34) (4.1m; 95%CI:3.3-4.9) versus patients who received 2nd-line EGFR TKIs (N = 18) (2.0m; 95%CI:0.8-3.2; P = 0.342)

Now we have data at IASLC 2019 from a undifferentiated Japanese population "OA07.03 - Clinical Outcome of Non-Small Cell Lung Cancer with EGFR/HER2 Exon 20 Insertions Identified in the LC-SCRUM-Japan"

Result
A total of 3441 advanced non-sq NSCLC patients were successfully analyzed from 2015 to 2018. EGFR Ex20ins were detected in 73 patients (2%; M766_A767insASV/A767_S768insSVD/H773_V774insH/D770_N771insNPH/N771_P772insPH/others=22/17/5/4/4/21) and HER2 Ex20ins were detected in 128 patients (4%; A775_G776insYVMA/G776delinsVC/P780_Y781insGSP/others=95/16/10/7). The median age of the patients was 62 (range, 33-90) years. Eighty-one patients (40%) were male and 114 (57%) were never smoker. Two-hundred patients (99%) were diagnosed as adenocarcinoma and 1 as adenosquamous-cell carcinoma. Based on our database, the median overall survivals in patients with EGFR Ex20ins were 22.4 (95%CI, 15.3-36.8) months, and those with HER2 Ex20ins were 18.8 (13.6-30.3) months. In the patients with EGFR/HER2 Ex20ins, the objective response rate (ORR) and median progression-free survivals (mPFS) of 1st-line platinum-containing chemotherapies were 32% and 6.0 (5.7-7.0) months, respectively. The ORR and mPFS of docetaxel with or without ramucirumab were 26% and 5.1 (3.8-5.9) months, respectively. The ORR and mPFS of PD-1 inhibitor were 0% and 2.0 (1.6-2.6) months, respectively. No significant difference in the therapeutic efficacy of these drugs was observed between the patients with EGFR Ex20ins and HER2 Ex20ins. In 19 patients with EGFR Ex20ins treated with 1st/2nd generation EGFR-TKIs, the ORR was 5% (a M766_A767insASV-positive tumor responded to afatinib) and the mPFS was 2.1 (1.3-4.2) months.

Conclusion
The patients with EGFR/HER2 Ex20ins-positive NSCLC showed poor responses to PD-1 inhibitors and 1st/2nd generation EGFR-TKIs. These historical data are highly informative in evaluating the efficacy of novel targeted therapies for EGFR/HER2 Ex20ins-positive NSCLC.

So, in sum, posi's competition is chemo (current Std of Care). 1st-line chemo is coming in at 6m PFS where pozi data presented to the FDA for BTD was 6.5m (though 12 of the 30 patients were censored). Comparing 1st-line much healthier patients vs heavily pretreated quasi palliative care pozi patients is like comparing apples to oranges. With the improvements in the Zenith trial PFS/ DOR results should be improved too.

Edit - I should note I'm citing Japanese 1st-line PFS data of 6m but if you look at the Chinese data it's around a third less.