Unlike traditional chemotherapy dosed by body surface area, TKIs for GIST are dosed based on individual patient tolerance. Therapeutic drug monitoring of plasma levels has not proven effective. The standard approach is to start all patients at a recommended dose and then adjust based on side effects to find the highest tolerable dose that maintains efficacy.

The COMPEL study showed a near doubling of progression-free survival by continuing osimertinib with chemotherapy after first-line progression. This contradicts findings with first-generation TKIs (like gefitinib) and establishes "TKI continuation" as a new standard of care.

Data shows the next-generation KRAS G12C inhibitor deveracib achieves a median progression-free survival (PFS) of 13.8 months as a single agent. This represents a major leap forward, more than doubling the 5-6 month PFS seen with first-generation drugs like sotorasib and adagrasib, signaling a new efficacy benchmark.

With pirtobrutinib, time to next treatment often exceeds progression-free survival. This discrepancy exists because disease progression is frequently slow and asymptomatic, meaning clinicians do not need to switch therapies immediately upon seeing radiographic changes, allowing for longer treatment duration.

For patients intolerant to standard TKI starting doses, a "crescendo" approach can be highly effective. This involves starting at a very low dose (e.g., 200mg every other day) and slowly increasing it over several weeks. This gradual escalation allows the body to acclimate, enabling patients to eventually tolerate the full target dose without unacceptable toxicity.

Though ADCs like Sacituzumab Govitekan cause notable side effects like diarrhea and neutropenia, patient-reported outcome data shows they provide a meaningful and sustained improvement in quality of life compared to standard chemotherapy. This was observed even with longer treatment durations and lower discontinuation rates.

Despite a more challenging neurocognitive side effect profile, lorlatinib's median progression-free survival (PFS) of over seven years has shifted expert practice. This remarkable efficacy now positions it as the preferred first-line agent over better-tolerated second-generation TKIs for ALK-positive NSCLC.

The most significant, lasting effects of treatment toxicities on quality of life often become most apparent *after* therapy has concluded. Clinical trials that stop collecting data shortly after treatment completion miss this crucial long-term impact, underestimating the true burden of side effects.

Comparing control arms from the TOGA (11 months OS), KEYNOTE-811 (16 months), and HORIZON (19 months) trials reveals a steady improvement in patient outcomes. This trend, likely due to better second-line therapies and supportive care, makes it harder for new agents to show a relative benefit.