Bernstein: SMMT Overvalued, Maintains Underperform Rating

Overview

Bernstein released a report reiterating its 'Underperform' rating on Summit Therapeutics (SMMT) and raised its target price from $7.70 to $9.80. Despite considering optimistic scenarios for the core drug ivonescimab in the HARMONi-3 clinical trial, the institution believes the current stock price is severely overvalued. The report points out that due to insufficient drug efficacy in older populations and increasing market competition, it's difficult to justify company valuation under the most favorable assumptions, advising investors to avoid risks before key clinical data releases.

Core views

Core views focus on the clinical prospects and commercial potential of ivonescimab. First, the institution takes a cautious stance towards the HARMONi-3 trial. While the Chinese HARMONi-6 trial showed advantages in progression-free survival (PFS) over overall survival (OS), this trial excluded patients over 75 years old, and in subgroups over 65 years old, OS hazard ratio (HR) increased to 0.93, showing a significant decrease in effectiveness. In contrast, among other global PD-1+VEGF combination therapies in non-small cell lung cancer (NSCLC) trials, there was generally an attenuation of PFS to OS conversion (mean HR difference of 0.31). Secondly, the competitive landscape is severe. The report notes that competing drugs like Sac-TMT (a TROP-2 inhibitor) show good efficacy and safety in treating first-line non-small cell lung cancer (1L NSCLC), exacerbating market fragmentation. Therefore, the institution limits the market penetration rate for PD-1+VEGF class drugs to approximately 40% of squamous cell carcinoma patients under 65, rather than the general population. Lastly, financial forecasts are substantially lower than consensus. Based on these assumptions, the institution predicts a global risk-adjusted peak revenue of just $250 million for ivonescimab (by 2040), far below market consensus. For colorectal cancer (mCRC) indications, since previous studies did not show significant benefits from adding PD-1 to standard therapy, the institution maintains a pessimistic success probability assumption.

Analysis framework

The institution uses a bottom-up discounted cash flow (DCF) model for valuation, primarily using a 'bullish scenario' stress test to validate the reasonableness of the current valuation. The analysis logic mainly includes three steps: first, cross-trial comparison, extrapolating China's HARMONi-6 data to the global HARMONi-3 by strictly deducting age-related efficacy decay factors; second, competitive analysis, incorporating data from competitors like Sac-TMT to reassess the upper limit of ivonescimab's market share in first-line treatment; third, risk adjustment, setting different success probabilities (PTS) for various indications (e.g., NSCLC vs mCRC), especially maintaining conservatism for mCRC without historical precedents.

Methodology notes

• Valuation methodsDCF Discounted Cash Flow

  DCF Valuation Model

  The institution uses a weighted average cost of capital (WACC) of 12% as the discount rate, discounting projected cash flows until 2040 back to present value, without assuming a terminal value, reflecting the high-risk and long-cycle nature of biotech companies.

• Industry/Industrial Analysis FrameworkVolume-price decomposition

  Patient Stratification & Market Penetration Modeling

  By segmenting patients based on histology (squamous/non-squamous), PD-L1 expression levels, and age (<65 years/>65 years), combined with clinical efficacy data from each subgroup, the method precisely estimates the actual addressable market share for the drug across different populations.

• Industry/Industrial Analysis FrameworkSubstitution Effect Analysis

  Competitive Threat Assessment

  Analyzing substitution threats from emerging therapies such as Sac-TMT to adjust downward the expected market concentration for targeted drugs in first-line treatments.

Asset mapping & comparison

Structured mapping from thesis to named assets (strengths, weaknesses, peers, risks).

• Summit Therapeutics (SMMT.US)

  Direct Coverage Target, Core Asset ivonescimab Faces Dual Clinical and Commercial Challenges

  Weaknesses

  High Single-Product Dependency; Poor Efficacy Data in Elderly Populations; Facing Intense Competition from Strong Rivals Like Sac-TMT

  Comparison

  Compared to Consensus Expectations, Bernstein’s Sales Predictions Are More Conservative, Success Rate Assumptions Lower

  Risks

  HARMONi-3 Trial Failure; Regulatory Approval Delays; Pricing Pressures

Key data

• Target Price9.80 USDUp from earlier $7.70, but still implies a 29% downside
• Current Stock Price13.75 USDAs of June 18, 2026
• Peak Sales Forecast$2.5 BillionRisk-adjusted peak sales forecast for ivonescimab globally (2040)
• OS HR in Patients >65 Years0.93Subgroup data from HARMONi-6 trial showing diminished efficacy
• Average PFS to OS Attenuation0.31Mean HR difference from seven prior PD-1+VEGF NSCLC trials

Impact & implications

The report suggests that Summit Therapeutics' current market capitalization already reflects excessive expectations of HARMONi-3 success. Even if trial outcomes are positive, constrained by poor efficacy in elderly patients and competitive pressure, its commercial value ceiling has been capped at a low level. For investors, continuing to hold presents substantial downside risk, particularly around late-year data readouts from HARMONi-3, where any negative signals could lead to significant stock corrections.

Risks

• HARMONi-3 Trial Fails to Meet Primary Endpoints for OS or PFS
• ivonescimab Continues to Show Subpar Efficacy in Elderly Patient Groups
• Sac-TMT and Other Competitors Capture a Larger Share of the First-Line NSCLC Market
• Unfavorable Changes in Regulatory Policies or Pricing Environment

What to watch

• Final Data Readout from HARMONi-3 Clinical Trial (Expected Late This Year)
• Further Clinical Progress and Market Feedback on Sac-TMT in First-Line NSCLC Treatment
• Approval Timeline for ivonescimab in Second-Line EGFR-mutated NSCLC Indication (PDUFA Date)