Summit Therapeutics Inc. (SMMT) Earnings

Management highlights

### Lead Asset Clinical Progress and Data Updates * Ivonisibimab (Avenisumab) is the company's lead PD-1/VEGF bispecific investigational asset. To date, 4 Phase 3 trials have read out with positive results, leading to 2 approvals in China, one additional submission under review in China, and a pending BLA under review with the U.S. FDA. A total of 15 Phase 3 trials are ongoing or completed, 52 company-sponsored trials have been initiated, and 171 total trials (including investigator and collaborative studies) are registered on clinicaltrials.gov. Over 4,000 patients have been dosed in company/partner-sponsored trials globally, and over 70,000 patients have received the drug commercially in China. * Updated June 2026 overall survival (OS) analysis for the global Phase 3 HARMONY trial (evaluating Ivonisibimab + chemo vs chemo alone for EGFR-mutated non-small cell lung cancer (NSCLC) post-TKI therapy) showed a hazard ratio (HR) of 0.76 for OS in both the total study population and the Western patient subgroup. The HR for Western patients improved with longer follow-up, reaching a median follow-up of 23 months for Western patients and 33 months for Asian patients, with consistent magnitude of OS benefit across both regions. No new safety signals were observed, and the safety profile remains acceptable and manageable. This setting has no approved therapies that have demonstrated a statistically significant OS benefit over chemo alone, as multiple prior PD-1 inhibitor trials failed. * Four completed Phase 3 trials all achieved positive, statistically significant, clinically meaningful progression-free survival (PFS) results, with all OS hazard ratios below the 0.80 threshold for clinical meaningfulness: (1) The China-only Harmony A study in a similar EGFR-mutated NSCLC setting achieved statistically significant OS benefit; (2) Harmony 2 (China) head-to-head vs pembrolizumab monotherapy for frontline PD-L1 positive NSCLC achieved an OS HR of 0.78 at 39% data maturity; (3) Harmony 6 (China) head-to-head vs anti-PD-1 + chemo for frontline squamous NSCLC achieved an OS HR of 0.66, marking the first Phase 3 trial ever to show a statistically significant OS improvement over a PD-1 + chemo combination in a head-to-head setting. ### Pipeline and Trial Status * Summit's sponsored global Phase 3 pipeline includes: (1) Harmony 3: evaluating Ivonisibimab + chemo vs pembrolizumab + chemo for frontline NSCLC without genomic alterations, split into separate squamous and non-squamous cohorts. Enrollment is complete in both cohorts; (2) Harmony 7: evaluating Ivonisibimab monotherapy vs pembrolizumab monotherapy for frontline high PD-L1 expression NSCLC, with strong ongoing enrollment; (3) Harmony GI 3: evaluating Ivonisibimab + chemo vs bevacizumab + chemo for frontline unresectable colorectal cancer, an ongoing global trial initiated based on positive Phase 2 data. * An independent European cooperative group-sponsored Phase 3 Illumine trial for head and neck cancer is currently enrolling in Europe, plans to start in China later in 2026, and will evaluate U.S. site opening. The company supports over 65 investigator-sponsored trials (ISTs), 24 of which are currently enrolling, with data regularly presented at major oncology conferences. ### New Clinical Collaborations * A new collaboration with Arcus Biosciences was announced to evaluate Ivonisibimab in combination with Arcus' HIF-2-alpha inhibitor castatifan for first-line metastatic clear cell renal cell carcinoma, with initial data expected by mid-2027. * The existing collaboration with Revolution Medicines evaluating Ivonisibimab + three novel RAS inhibitors across multiple solid tumors began enrollment in Q1 2026. * The GSK collaboration evaluating Ivonisibimab + a B7H3 ADC across multiple solid tumors is expected to enroll its first patient in Q3 2026. ### Regulatory and Commercial Preparation * The BLA for Ivonisibimab + chemo for EGFR-mutated NSCLC post-TKI therapy is under review by the U.S. FDA with a PDUFA date of November 14, 2026. The company is actively building commercial capabilities in preparation for a potential U.S. launch, with all leadership, market access, marketing, and MSL teams already in place, and field force hiring planned closer to the PDUFA date. ### Market Opportunity * Management estimates the total addressable market for Ivonisibimab across approved anti-PD-1/anti-VEGF solid tumor settings exceeds $100 billion globally, with the NSCLC immunotherapy market alone expected to exceed $20 billion per year by 2028. Management believes Ivonisibimab has blockbuster platform potential across multiple solid tumor indications.

Guidance

• For the Harmony 3 squamous cohort: PFS analysis and accompanying interim OS analysis are expected in the middle to back half of H2 2026, with an independent interim OS analysis expected in H1 2027, which will have median follow-up consistent with the mature data seen in the Harmony 6 and Harmony Western patient datasets. • For the Harmony 3 non-squamous cohort: PFS analysis is expected in H1 2027. • Additional details from the updated HARMONY trial OS analysis will be presented at an upcoming future medical conference. • The Illumine head and neck cancer trial will start enrollment in China later in 2026, followed by potential evaluation of U.S. site opening. • Initial data from the new Arcus collaboration is expected by mid-2027. • The GSK collaboration is expected to enroll its first patient in Q3 2026. • The company will share details on additional new global studies, including new Phase 3 trials, throughout 2026 as they are ready for disclosure.

Segment performance

Summit Therapeutics is a clinical-stage biotech focused exclusively on the development of its lead asset, Avenisumab (Ivonisibimab), a PD-1/VEGF bispecific for solid tumor treatment. No other commercial product segments are disclosed in this call. For Q2 2026, the company reported: cash and cash equivalents of $690.7 million, up from $598.7 million at the end of Q1 2026, with the $92 million increase driven by $231 million raised via the company's ATM facility, offset by $140 million in operating cash use. GAAP total operating expenses were $220.5 million, up from $195.2 million in Q1 2026. Non-GAAP total operating expenses (excluding stock-based compensation) were $151.8 million, up from $122.4 million in Q1 2026. The increase in operating expenses was primarily driven by higher R&D costs related to ongoing clinical trials for the company's lead asset. The company has no debt on its balance sheet and filed a new prospective supplement for an additional $380 million ATM facility to provide future financing flexibility.

Risks & headwinds

• Forward-looking statements regarding trial timelines, regulatory outcomes, efficacy, and launch plans are subject to inherent risks and uncertainties that could cause actual results to differ materially from expectations, as detailed in the company's SEC filings. • The FDA could choose to convene an ODAC advisory panel for the upcoming BLA review or extend the current November 14, 2026 PDUFA date following the submission of updated survival data, which is entirely at the agency's discretion. • Clinical trials may fail to meet their primary or secondary endpoints, even with positive earlier data, and benefit observed in Chinese patient populations may not translate to consistent benefit in Western patient populations, even with mature follow-up. • The company faces existing competition from already approved therapies in the EGFR-mutated NSCLC indication, and competition from emerging new agents including ADCs that may impact future market share if Ivonisibimab is approved. • Event accrual in clinical trials may be slower than expected, which could delay readout timelines for key trials.

Analyst Q&A

• Q: Can you speak to the translatability of the consistent cross-geography OS benefit seen in the updated Harmony trial to frontline NSCLC settings, and provide more granular timing for the Harmony 3 squamous PFS analysis and details on the interim OS disclosure? /

  A: The key learning from the updated Harmony data is that sufficient follow-up maturity is critical to showing the full clinical benefit of Ivonisibimab. With meaningful follow-up time across regions, consistent benefit seen in China translates globally, and the company expects this pattern to hold for frontline NSCLC trials. For Harmony 3 squamous, PFS analysis is expected mid-to-late H2 2026, rather than early in the half, due to slightly slower-than-expected event rates. Management expects to share a directional OS trend from the accompanying interim look, but no formal disclosure plan has been finalized.

• Q: For the independent interim OS analysis of Harmony 3 squamous in H1 2027, what level of median follow-up is expected, and how should investors interpret an interim result that does not reach statistical significance? /

  A: Median follow-up in H1 2027 is expected to be in the low 20s months, consistent with the mature follow-up that showed clear benefit in the Harmony 6 and updated Harmony Western datasets. The 2027 interim will be a powered, independent analysis separate from the PFS look, but the final OS analysis will occur much later. Management will look for early separation of survival curves at the 2026 interim analysis to support the PFS result, and the 2027 interim will provide a clearer, more mature view of the OS trend, with no preset specific thresholds for success given the need to evaluate the totality of the data.

• Q: Has the FDA requested the updated Harmony OS data, and has the company received feedback on it, and could the new data change the November 2026 PDUFA date or trigger an ODAC? /

  A: The analysis was only recently completed and submitted to the FDA, so no meaningful feedback has been received yet. Management does not currently expect the PDUFA date to change, but any change or decision to convene an ODAC is entirely at the FDA's discretion. In terms of competitive positioning, no currently approved agent in this indication has demonstrated a statistically significant OS benefit. Ivonisibimab has a well-established manageable safety profile across over 4,000 treated patients, and it adds a distinct mechanism option for physicians alongside already approved agents.

• Q: Is the addition of a second interim OS analysis for Harmony 3 a change to the original trial plan, and how is pre-commercial preparation for the November PDUFA progressing? /

  A: Management has previously disclosed multiple OS analyses for the trial, but the specific H1 2027 timing for the second independent interim was newly shared to improve transparency, aligned with learnings on the importance of follow-up maturity from prior trials. Pre-commercial preparation is on track: all commercial leadership, market access, marketing, and MSL teams have already been hired and are in place. Field force hiring will occur in the weeks immediately preceding the PDUFA decision, as planned.

• Q: What is the key takeaway from the updated Harmony OS data, and how has data maturity changed since the prior analysis? /

  A: The core takeaway is that after achieving meaningful follow-up maturity for both Asian and Western patient subgroups, the magnitude of OS benefit is consistent across both regions. The study enrolled first in China, then later in the West due to the timing of the company's in-license transaction, leading to earlier follow-up for Asian patients. With additional follow-up, Western patients now show the same 0.76 HR as the total population, confirming that the benefit is consistent across geographies, rather than the benefit being driven only by Asian patients.